pico_gfx.h

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#ifndef PICO_GFX_H
#define PICO_GFX_H
 
// Backend conversion macros
#if defined (PICO_GFX_GL)
    #define SOKOL_GLCORE
#elif defined (PICO_GFX_GLES)
    #define SOKOL_GLES3
#elif defined (PICO_GFX_D3D)
    #define SOKOL_D3D11
#elif defined (PICO_GFX_METAL)
    #define SOKOL_METAL
#elif defined (PICO_GFX_WEBGPU)
    #define SOKOL_WGPU
#else
    #error "GFX backend must be specified"
#endif
 
#include "sokol_gfx.h"
 
#include <stdbool.h>
#include <stddef.h>
 
#define PG_MAX_VERTEX_ATTRIBUTES SG_MAX_VERTEX_ATTRIBUTES
#define PG_MAX_VERTEX_BUFFERS    SG_MAX_VERTEXBUFFER_BINDSLOTS
#define PG_MAX_TEXTURE_SLOTS     SG_MAX_IMAGE_BINDSLOTS
#define PG_MAX_SAMPLER_SLOTS     SG_MAX_SAMPLER_BINDSLOTS
 
typedef enum
{
    PG_BACKEND_GL,
    PG_BACKEND_GLES,
    PG_BACKEND_D3D,
    PG_BACKEND_METAL,
    PG_BACKEND_WGPU
} pg_backend_t;
 
typedef enum
{
    PG_DEFAULT_PRIMITIVE,
    PG_POINTS,         
    PG_LINES,          
    PG_LINE_STRIP,     
    PG_TRIANGLES,      
    PG_TRIANGLE_STRIP, 
} pg_primitive_t;
 
typedef enum
{
    PG_DEFAULT_BLEND_FACTOR,
    PG_ZERO,                
    PG_ONE,                 
    PG_SRC_COLOR,           
    PG_ONE_MINUS_SRC_COLOR, 
    PG_DST_COLOR,           
    PG_ONE_MINUS_DST_COLOR, 
    PG_SRC_ALPHA,           
    PG_ONE_MINUS_SRC_ALPHA, 
    PG_DST_ALPHA,           
    PG_ONE_MINUS_DST_ALPHA, 
} pg_blend_factor_t;
 
typedef enum
{
    PG_DEFAULT_BLEND_EQ,
    PG_ADD,              
    PG_SUBTRACT,         
    PG_REVERSE_SUBTRACT, 
} pg_blend_eq_t;
 
typedef struct
{
    pg_blend_factor_t color_src; 
    pg_blend_factor_t color_dst; 
    pg_blend_eq_t     color_eq;  
    pg_blend_factor_t alpha_src; 
    pg_blend_factor_t alpha_dst; 
    pg_blend_eq_t     alpha_eq;  
} pg_blend_mode_t;
 
typedef struct pg_ctx_t pg_ctx_t;
 
typedef struct pg_pipeline_t pg_pipeline_t;
 
typedef struct pg_shader_t pg_shader_t;
 
typedef struct pg_texture_t pg_texture_t;
 
typedef struct pg_sampler_t pg_sampler_t;
 
typedef struct pg_buffer_t pg_buffer_t;
 
void pg_init(void);
 
void pg_shutdown(void);
 
pg_ctx_t* pg_create_context(int window_width, int window_height, void* mem_ctx);
 
void pg_destroy_context(pg_ctx_t* ctx);
 
pg_backend_t pg_backend(void);
 
void pg_set_window_size(pg_ctx_t* ctx, int width, int height, bool reset);
 
void pg_get_window_size(pg_ctx_t* ctx, int* width, int* height);
 
void pg_begin_pass(pg_ctx_t* ctx, pg_texture_t* target, bool clear);
 
void pg_end_pass(pg_ctx_t* ctx);
 
void pg_flush(pg_ctx_t* ctx);
 
void pg_push_state(pg_ctx_t* ctx);
 
void pg_pop_state(pg_ctx_t* ctx);
 
void pg_set_clear_color(pg_ctx_t* ctx, float r, float g, float b, float a);
 
void pg_reset_clear_color(pg_ctx_t* ctx);
 
void pg_set_viewport(pg_ctx_t* ctx, int x, int y, int w, int h);
 
void pg_reset_viewport(pg_ctx_t* ctx);
 
void pg_set_scissor(pg_ctx_t* ctx, int x, int y, int w, int h);
 
void pg_reset_scissor(pg_ctx_t* ctx);
 
void pg_set_pipeline(pg_ctx_t* ctx, pg_pipeline_t* pipeline);
 
void pg_reset_pipeline(pg_ctx_t* ctx);
 
void pg_bind_buffer(pg_ctx_t* ctx, int slot, pg_buffer_t* buffer);
 
void pg_reset_buffers(pg_ctx_t* ctx);
 
void pg_set_index_buffer(pg_ctx_t* ctx, pg_buffer_t* buffer);
 
void pg_reset_index_buffer(pg_ctx_t* ctx);
 
void pg_bind_texture(pg_shader_t* shader, const char* name, pg_texture_t* texture);
 
void pg_reset_textures(pg_shader_t* shader);
 
void pg_bind_sampler(pg_shader_t* shader, const char* name, pg_sampler_t* sampler);
 
void pg_reset_samplers(pg_shader_t* shader);
 
void pg_reset_state(pg_ctx_t* ctx);
 
#define pg_create_shader(ctx, prefix)   \
    pg_create_shader_internal(          \
        ctx,                            \
        (pg_shader_internal_t)          \
        {                               \
            prefix##_shader_desc,       \
            prefix##_attr_slot,         \
            prefix##_image_slot,        \
            prefix##_sampler_slot,      \
            prefix##_uniformblock_slot, \
            prefix##_uniformblock_size, \
        }                               \
    )
 
void pg_destroy_shader(pg_shader_t* shader);
 
uint32_t pg_get_shader_id(const pg_shader_t* shader);
 
void pg_set_uniform_block(pg_shader_t* shader, const char* name, const void* data);
 
typedef enum
{
    PG_VERTEX_FORMAT_INVALID,
    PG_VERTEX_FORMAT_FLOAT,
    PG_VERTEX_FORMAT_FLOAT2,
    PG_VERTEX_FORMAT_FLOAT3,
    PG_VERTEX_FORMAT_FLOAT4,
    PG_VERTEX_FORMAT_BYTE4,
    PG_VERTEX_FORMAT_BYTE4N,
    PG_VERTEX_FORMAT_UBYTE4,
    PG_VERTEX_FORMAT_UBYTE4N,
    PG_VERTEX_FORMAT_SHORT2,
    PG_VERTEX_FORMAT_SHORT2N,
    PG_VERTEX_FORMAT_USHORT2N,
    PG_VERTEX_FORMAT_SHORT4,
    PG_VERTEX_FORMAT_SHORT4N,
    PG_VERTEX_FORMAT_USHORT4N,
    PG_VERTEX_FORMAT_UINT10_N2,
    PG_VERTEX_FORMAT_HALF2,
    PG_VERTEX_FORMAT_HALF4,
} pg_vertex_format_t;
 
typedef struct
{
    bool instanced; 
    int step;       
} pg_vertex_buf_t;
 
typedef struct
{
    int buffer_index;          
    pg_vertex_format_t format; 
    int offset;                
} pg_vertex_attr_t;
 
typedef struct
{
    pg_vertex_buf_t  bufs[PG_MAX_VERTEX_BUFFERS];     
    pg_vertex_attr_t attrs[PG_MAX_VERTEX_ATTRIBUTES]; 
} pg_pipeline_layout_t;
 
typedef struct pg_pipeline_opts_t
{
    pg_primitive_t primitive;    
    pg_pipeline_layout_t layout; 
    bool target;                 
    bool indexed;                
    bool blend_enabled;          
    pg_blend_mode_t blend;       
} pg_pipeline_opts_t;
 
pg_pipeline_t* pg_create_pipeline(pg_ctx_t* ctx,
                                  pg_shader_t* shader,
                                  const pg_pipeline_opts_t* opts);
 
void pg_destroy_pipeline(pg_pipeline_t* pipeline);
 
pg_shader_t* pg_get_shader(const pg_pipeline_t* pipeline);
 
const pg_blend_mode_t* pg_get_blend_mode(const pg_pipeline_t* pipeline);
 
typedef struct pg_texture_opts_t
{
    int mipmaps; 
} pg_texture_opts_t;
 
pg_texture_t* pg_create_texture(pg_ctx_t* ctx,
                                int width, int height,
                                const uint8_t* data, size_t size,
                                const pg_texture_opts_t* opts);
 
pg_texture_t* pg_create_render_texture(pg_ctx_t* ctx,
                                       int width, int height,
                                       const pg_texture_opts_t* opts);
 
void pg_destroy_texture(pg_texture_t* texture);
 
uint32_t pg_get_texture_id(const pg_texture_t* texture);
 
void pg_get_texture_size(const pg_texture_t* texture, int* width, int* height);
 
void pg_update_texture(pg_texture_t* texture, char* data, int width, int height);
 
typedef struct
{
    bool smooth;   
    bool repeat_u; 
    bool repeat_v; 
} pg_sampler_opts_t;
 
pg_sampler_t* pg_create_sampler(pg_ctx_t* ctx, const pg_sampler_opts_t* opts);
 
void pg_destroy_sampler(pg_sampler_t* sampler);
 
typedef enum
{
    PG_USAGE_STATIC,  
    PG_USAGE_DYNAMIC, 
    PG_USAGE_STREAM   
} pg_buffer_usage_t;
 
pg_buffer_t* pg_create_vertex_buffer(pg_ctx_t* ctx,
                                     pg_buffer_usage_t usage,
                                     const void* data,
                                     size_t count,
                                     size_t max_elements,
                                     size_t element_size);
 
pg_buffer_t* pg_create_index_buffer(pg_ctx_t* ctx,
                                    pg_buffer_usage_t usage,
                                    const void* data,
                                    size_t count,
                                    size_t max_elements);
 
void pg_destroy_buffer(pg_buffer_t* buffer);
 
void pg_update_buffer(pg_buffer_t* buffer, void* data, size_t count);
 
int pg_append_buffer(pg_buffer_t* buffer, void* data, size_t count);
 
int pg_get_buffer_offset(pg_buffer_t* buffer);
 
void pg_set_buffer_offset(pg_buffer_t* buffer, int offset);
 
void pg_reset_buffer(pg_buffer_t* buffer);
 
void pg_draw(const pg_ctx_t* ctx, size_t start, size_t count, size_t instances);
 
/*=============================================================================
 * Internals
 *============================================================================*/
 
typedef struct
{
    const sg_shader_desc* (*get_shader_desc)(sg_backend backend);
    int (*get_attr_slot)(const char* attr_name);
    int (*get_img_slot)(const char* name);
    int (*get_smp_slot)(const char* name);
    int (*get_uniformblock_slot)(const char* ub_name);
    size_t (*get_uniformblock_size)(const char* ub_name);
} pg_shader_internal_t;
 
pg_shader_t* pg_create_shader_internal(pg_ctx_t* ctx, pg_shader_internal_t internal);
 
#endif // PICO_GFX_H
 
/*=============================================================================
 * Implementation
 *============================================================================*/
 
#ifdef PICO_GFX_IMPLEMENTATION
 
#include <string.h>
 
/*=============================================================================
 * Constants
 *============================================================================*/
 
#ifndef PICO_GFX_STACK_MAX_SIZE
#define PICO_GFX_STACK_MAX_SIZE 16
#endif
 
#ifndef PICO_GFX_HASHTABLE_KEY_SIZE
#define PICO_GFX_HASHTABLE_KEY_SIZE 16
#endif
 
/*=============================================================================
 * Macros
 *============================================================================*/
 
#ifdef NDEBUG
    #define PICO_GFX_ASSERT(expr) ((void)0)
#else
    #ifndef PICO_GFX_ASSERT
        #include <assert.h>
        #define PICO_GFX_ASSERT(expr) (assert(expr))
    #endif
#endif
 
#if !defined(PICO_GFX_MALLOC) || !defined(PICO_GFX_REALLOC) || !defined(PICO_GFX_FREE)
#include <stdlib.h>
#define PICO_GFX_MALLOC(size, ctx)       (malloc(size))
#define PICO_GFX_REALLOC(ptr, size, ctx) (realloc(ptr, size))
#define PICO_GFX_FREE(ptr, ctx)          (free(ptr))
#endif
 
#ifndef PICO_GFX_LOG
    #include <stdio.h>
    #define  PICO_GFX_LOG(...) (pg_log(__VA_ARGS__))
#endif
 
/*=============================================================================
 * GFX Static Funtions
 *============================================================================*/
 
static void pg_alloc_uniform_block(pg_shader_t* shader, const char* name);
 
typedef enum
{
    PG_BUFFER_TYPE_VERTEX,
    PG_BUFFER_TYPE_INDEX,
} pg_buffer_type_t;
 
static sg_primitive_type pg_map_primitive(pg_primitive_t primitive);
static sg_blend_factor pg_map_blend_factor(pg_blend_factor_t factor);
static sg_blend_op pg_map_blend_eq(pg_blend_eq_t eq);
static sg_vertex_format pg_map_vertex_format(pg_vertex_format_t format);
static sg_usage pg_map_usage(pg_buffer_usage_t format);
static sg_buffer_type pg_map_buffer_type(pg_buffer_type_t type);
 
static void pg_log_sg(const char* tag,              // e.g. 'sg'
                      uint32_t log_level,           // 0=panic, 1=error, 2=warn, 3=info
                      uint32_t log_item_id,         // SG_LOGITEM_*
                      const char* message_or_null,  // a message string, may be nullptr in release mode
                      uint32_t line_nr,             // line number in sokol_gfx.h
                      const char* filename_or_null, // source filename, may be nullptr in release mode
                      void* user_data);
 
static void pg_log(const char* fmt, ...);
 
/*=============================================================================
 * Hashtable Declarations
 *============================================================================*/
 
#ifdef PICO_GFX_32BIT
    typedef uint32_t pg_hash_t;
#else
    typedef uint64_t pg_hash_t;
#endif
 
typedef struct pg_hashtable_t pg_hashtable_t;
typedef struct pg_hashtable_iterator_t pg_hashtable_iterator_t;
 
typedef void (*pg_hashtable_iterator_fn)(pg_hashtable_iterator_t* iterator,
                                         char* key,
                                         void* value);
 
static pg_hashtable_t* pg_hashtable_new(size_t capacity, size_t key_size,
                                        size_t value_size, void* mem_ctx);
 
static void pg_hashtable_free(pg_hashtable_t* ht);
 
static void pg_hashtable_init_iterator(const pg_hashtable_t* ht,
                                       pg_hashtable_iterator_t* iterator);
 
static bool pg_hashtable_iterator_next(pg_hashtable_iterator_t* iterator,
                                       char** key, void** value);
 
static void pg_hashtable_put(pg_hashtable_t* ht,
                             const char* key,
                             const void* value);
 
static void* pg_hashtable_get(const pg_hashtable_t* ht, const char* key);
 
struct pg_hashtable_iterator_t
{
    const pg_hashtable_t* ht;
    size_t index;
    size_t count;
};
 
/*=============================================================================
 * Arena Allocator Declarations
 *============================================================================*/
 
typedef struct pg_arena_t pg_arena_t;
 
static pg_arena_t* pg_arena_new(size_t size, void* mem_ctx);
static void* pg_arena_alloc(pg_arena_t* arena, size_t size);
static void pg_arena_free(pg_arena_t* arena);
 
/*=============================================================================
 * GFX Public API Implementation
 *============================================================================*/
 
static void* pg_malloc(size_t size, void* ctx)
{
    (void)ctx;
    return PICO_GFX_MALLOC(size, ctx);
}
 
static void pg_free(void* ptr, void* ctx)
{
    (void)ctx;
    PICO_GFX_FREE(ptr, ctx);
}
 
typedef struct pg_rect_t
{
    int x, y, width, height;
} pg_rect_t;
 
typedef struct pg_state_t
{
    sg_color       clear_color;
    pg_pipeline_t* pipeline;
    pg_rect_t      viewport;
    pg_rect_t      scissor;
    pg_shader_t*   shader;
    pg_buffer_t*   index_buffer;
    pg_buffer_t*   buffers[PG_MAX_VERTEX_BUFFERS];
} pg_state_t;
 
struct pg_ctx_t
{
    void* mem_ctx;
    sg_swapchain swapchain;
    int window_width;
    int window_height;
    bool indexed;
    bool pass_active;
    pg_texture_t* target;
    sg_pass default_pass;
    pg_state_t state;
    pg_state_t state_stack[PICO_GFX_STACK_MAX_SIZE];
    int stack_size;
};
 
struct pg_pipeline_t
{
    pg_ctx_t* ctx;
    sg_pipeline handle;
    size_t element_size;
    bool indexed;
    bool blend_enabled;
    pg_blend_mode_t blend_mode;
    pg_shader_t* shader;
};
 
struct pg_shader_t
{
    pg_ctx_t* ctx;
    const sg_shader_desc* desc;
    sg_shader handle;
    pg_shader_internal_t internal;
    pg_texture_t* textures[PG_MAX_TEXTURE_SLOTS];
    pg_sampler_t* samplers[PG_MAX_SAMPLER_SLOTS];
    pg_hashtable_t* uniform_blocks;
    pg_arena_t* arena;
};
 
typedef struct
{
    int    slot;
    void*  data;
    size_t size;
} pg_uniform_block_t;
 
struct pg_texture_t
{
    pg_ctx_t* ctx;
    int width, height;
    bool target;
    sg_image handle;
    sg_image depth_handle;
    sg_attachments attachments;
};
 
struct pg_sampler_t
{
    pg_ctx_t* ctx;
    sg_sampler handle;
};
 
struct pg_buffer_t
{
    pg_ctx_t* ctx;
    sg_buffer handle;
    pg_buffer_type_t type;
    pg_buffer_usage_t usage;
    size_t count;
    size_t element_size;
    size_t size;
    size_t offset;
};
 
void pg_init(void)
{
    sg_setup(&(sg_desc)
    {
        .logger.func = pg_log_sg,
        .allocator =
        {
            .alloc_fn = pg_malloc,
            .free_fn = pg_free,
            .user_data = NULL,
        },
        .environment.defaults.color_format = SG_PIXELFORMAT_RGBA8,
    });
}
 
void pg_shutdown(void)
{
    sg_shutdown();
}
 
pg_ctx_t* pg_create_context(int window_width, int window_height, void* mem_ctx)
{
    pg_ctx_t* ctx = PICO_GFX_MALLOC(sizeof(pg_ctx_t), mem_ctx);
 
    if (!ctx) return NULL;
 
    memset(ctx, 0, sizeof(pg_ctx_t));
 
    ctx->mem_ctx = mem_ctx;
    ctx->window_width  = window_width;
    ctx->window_height = window_height;
 
    pg_reset_state(ctx);
 
    ctx->swapchain = (sg_swapchain)
    {
        .width = window_width,
        .height = window_height,
    };
 
    return ctx;
}
 
void pg_destroy_context(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_FREE(ctx, ctx->mem_ctx);
}
 
pg_backend_t pg_backend(void)
{
    #if defined (PICO_GFX_GL)
        return PG_BACKEND_GL;
    #elif defined (PICO_GFX_GLES)
        return PG_BACKEND_GLES;
    #elif defined (PICO_GFX_D3D)
        return PG_BACKEND_D3D;
    #elif defined (PICO_GFX_METAL)
        return PG_BACKEND_METAL;
    #elif defined (PICO_GFX_WEBGPU)
        return PG_BACKEND_WGPU;
    #else
        #error "Unknown GFX backend"
    #endif
}
 
void pg_set_window_size(pg_ctx_t* ctx, int width, int height, bool reset)
{
    ctx->swapchain.width  = ctx->window_width  = width;
    ctx->swapchain.height = ctx->window_height = height;
 
    if (reset)
    {
        pg_reset_viewport(ctx);
        pg_reset_scissor(ctx);
    }
}
 
void pg_get_window_size(pg_ctx_t* ctx, int* width, int* height)
{
    if (width)
        *width = ctx->window_width;
 
    if (height)
        *height = ctx->window_height;
}
 
void pg_begin_pass(pg_ctx_t* ctx, pg_texture_t* target, bool clear)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(!ctx->pass_active);
 
    sg_pass_action action = { 0 };
 
    if (clear)
    {
        sg_color color = ctx->state.clear_color;
 
        action.colors[0] = (sg_color_attachment_action)
        {
            .load_action = SG_LOADACTION_CLEAR,
            .clear_value = color
        };
    }
 
    sg_pass pass = { .action = action };
 
    if (target)
    {
        pass.attachments = target->attachments;
        ctx->target = target;
    }
    else
    {
        //TODO: Do more research on swapchains
        pass.swapchain = ctx->swapchain;
    }
 
    sg_begin_pass(&pass);
 
    pg_reset_viewport(ctx);
    pg_reset_scissor(ctx);
 
    ctx->pass_active = true;
}
 
void pg_end_pass(pg_ctx_t* ctx)
{
    sg_end_pass();
    ctx->target = NULL;
    ctx->pass_active = false;
}
 
void pg_flush(pg_ctx_t* ctx)
{
    (void)ctx;
    sg_commit();
}
 
void pg_push_state(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(ctx->stack_size < PICO_GFX_STACK_MAX_SIZE);
 
    ctx->state_stack[ctx->stack_size] = ctx->state;
    ctx->stack_size++;
}
 
void pg_pop_state(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(ctx->stack_size > 0);
 
    ctx->state = ctx->state_stack[ctx->stack_size - 1];
    ctx->stack_size--;
}
 
void pg_set_clear_color(pg_ctx_t* ctx, float r, float g, float b, float a)
{
    PICO_GFX_ASSERT(ctx);
    ctx->state.clear_color = (sg_color){ r, g, b, a};
}
 
void pg_reset_clear_color(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    pg_set_clear_color(ctx, 0.f, 0.f, 0.f, 0.f);
}
 
void pg_set_viewport(pg_ctx_t* ctx, int x, int y, int w, int h)
{
    PICO_GFX_ASSERT(ctx);
    ctx->state.viewport = (pg_rect_t){ x, y, w, h};
}
 
void pg_reset_viewport(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
 
    if (ctx->target)
    {
        const pg_texture_t* texture = ctx->target;
        pg_set_viewport(ctx, 0, 0, texture->width, texture->height);
    }
    else
    {
        pg_set_viewport(ctx, 0, 0, ctx->window_width, ctx->window_height);
    }
}
 
void pg_set_scissor(pg_ctx_t* ctx, int x, int y, int w, int h)
{
    PICO_GFX_ASSERT(ctx);
    ctx->state.scissor = (pg_rect_t){ x, y, w, h};
}
 
void pg_reset_scissor(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
 
    if (ctx->target)
    {
        const pg_texture_t* texture = ctx->target;
        pg_set_scissor(ctx, 0, 0, texture->width, texture->height);
    }
    else
    {
        pg_set_scissor(ctx, 0, 0, ctx->window_width, ctx->window_height);
    }
}
 
void pg_set_pipeline(pg_ctx_t* ctx, pg_pipeline_t* pipeline)
{
    PICO_GFX_ASSERT(ctx);
    ctx->state.pipeline = pipeline;
}
 
void pg_reset_pipeline(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    pg_set_pipeline(ctx, NULL);
}
 
void pg_bind_buffer(pg_ctx_t* ctx, int slot, pg_buffer_t* buffer)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(!buffer || buffer->type == PG_BUFFER_TYPE_VERTEX);
 
    PICO_GFX_ASSERT(slot >= 0);
    PICO_GFX_ASSERT(slot < PG_MAX_VERTEX_BUFFERS);
 
    ctx->state.buffers[slot] = buffer;
}
 
void pg_reset_buffers(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    memset(&ctx->state.buffers, 0, sizeof(ctx->state.buffers));
}
 
void pg_set_index_buffer(pg_ctx_t* ctx, pg_buffer_t* buffer)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(!buffer || buffer->type == PG_BUFFER_TYPE_INDEX);
    ctx->state.index_buffer = buffer;
}
 
void pg_reset_index_buffer(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
    ctx->state.index_buffer = NULL;
}
 
void pg_bind_texture(pg_shader_t* shader, const char* name, pg_texture_t* texture)
{
    PICO_GFX_ASSERT(shader);
    PICO_GFX_ASSERT(name);
 
    int slot = shader->internal.get_img_slot(name);
 
    PICO_GFX_ASSERT(slot >= 0);
    PICO_GFX_ASSERT(slot < PG_MAX_TEXTURE_SLOTS);
 
    shader->textures[slot] = texture;
}
 
void pg_reset_textures(pg_shader_t* shader)
{
    PICO_GFX_ASSERT(shader);
    memset(shader->textures, 0, sizeof(shader->textures));
}
 
void pg_bind_sampler(pg_shader_t* shader, const char* name, pg_sampler_t* sampler)
{
    PICO_GFX_ASSERT(shader);
    PICO_GFX_ASSERT(name);
 
    int slot = shader->internal.get_smp_slot(name);
 
    PICO_GFX_ASSERT(slot >= 0);
    PICO_GFX_ASSERT(slot < PG_MAX_TEXTURE_SLOTS);
 
    shader->samplers[slot] = sampler;
}
 
void pg_reset_samplers(pg_shader_t* shader)
{
    PICO_GFX_ASSERT(shader);
    memset(shader->samplers, 0, sizeof(shader->samplers));
}
 
void pg_reset_state(pg_ctx_t* ctx)
{
    PICO_GFX_ASSERT(ctx);
 
    memset(&ctx->state, 0, sizeof(pg_state_t));
 
    pg_reset_clear_color(ctx);
    pg_reset_pipeline(ctx);
    pg_reset_viewport(ctx);
    pg_reset_scissor(ctx);
    pg_reset_buffers(ctx);
    pg_reset_index_buffer(ctx);
}
 
static void pg_set_attributes(const pg_pipeline_layout_t* layout, sg_pipeline_desc* desc)
{
    for (int slot = 0; slot < PG_MAX_VERTEX_ATTRIBUTES; slot++)
    {
        if (layout->attrs[slot].format != PG_VERTEX_FORMAT_INVALID)
        {
            desc->layout.attrs[slot] = (sg_vertex_attr_state)
            {
                .format = pg_map_vertex_format(layout->attrs[slot].format),
                .offset = layout->attrs[slot].offset,
                .buffer_index = layout->attrs[slot].buffer_index,
            };
        }
    }
}
 
static void pg_set_buffers(const pg_pipeline_layout_t* layout, sg_pipeline_desc* desc)
{
    for (int slot = 0; slot < PG_MAX_VERTEX_BUFFERS; slot++)
    {
        int step = layout->bufs[slot].step;
 
        if (layout->bufs[slot].instanced)
        {
            desc->layout.buffers[slot] = (sg_vertex_buffer_layout_state)
            {
                .step_func = SG_VERTEXSTEP_PER_INSTANCE,
            };
        }
 
        desc->layout.buffers[slot].step_rate = (step >= 1) ? step : 1;
    }
}
 
pg_pipeline_t* pg_create_pipeline(pg_ctx_t* ctx,
                                  pg_shader_t* shader,
                                  const pg_pipeline_opts_t* opts)
{
    PICO_GFX_ASSERT(shader);
    PICO_GFX_ASSERT(opts);
 
    pg_pipeline_t* pipeline = PICO_GFX_MALLOC(sizeof(pg_pipeline_t), ctx->mem_ctx);
 
    sg_pipeline_desc desc = { 0 };
 
    pg_set_attributes(&opts->layout, &desc);
    pg_set_buffers(&opts->layout, &desc);
 
    desc.primitive_type = pg_map_primitive(opts->primitive);
 
    pipeline->blend_enabled = false;
 
    if (opts->blend_enabled)
    {
        pipeline->blend_enabled = true;
        pipeline->blend_mode = opts->blend;
 
        const pg_blend_mode_t* blend_mode = &opts->blend;
        desc.colors[0].blend.enabled = true;
        desc.colors[0].blend.src_factor_rgb = pg_map_blend_factor(blend_mode->color_src);
        desc.colors[0].blend.dst_factor_rgb = pg_map_blend_factor(blend_mode->color_dst);
        desc.colors[0].blend.src_factor_alpha = pg_map_blend_factor(blend_mode->alpha_src);
        desc.colors[0].blend.dst_factor_alpha = pg_map_blend_factor(blend_mode->alpha_dst);
        desc.colors[0].blend.op_rgb = pg_map_blend_eq(blend_mode->color_eq);
        desc.colors[0].blend.op_alpha = pg_map_blend_eq(blend_mode->alpha_eq);
    }
 
    desc.colors[0].pixel_format = SG_PIXELFORMAT_RGBA8;
 
    if (opts->indexed)
        desc.index_type = SG_INDEXTYPE_UINT32;
    else
        desc.index_type = SG_INDEXTYPE_NONE;
 
    if (opts->target)
    {
        desc.depth.pixel_format = SG_PIXELFORMAT_DEPTH;
        desc.depth.write_enabled = true;
    }
 
    //TODO: Culling
 
    desc.face_winding = SG_FACEWINDING_CCW;
    desc.shader = shader->handle;
 
    pipeline->ctx = ctx;
    pipeline->handle = sg_make_pipeline(&desc);
    pipeline->indexed = opts->indexed;
    pipeline->shader = shader;
 
    PICO_GFX_ASSERT(sg_query_pipeline_state(pipeline->handle) == SG_RESOURCESTATE_VALID);
 
    return pipeline;
}
 
void pg_destroy_pipeline(pg_pipeline_t* pipeline)
{
    PICO_GFX_ASSERT(pipeline);
    sg_destroy_pipeline(pipeline->handle);
    PICO_GFX_FREE(pipeline, pipeline->ctx->mem_ctx);
}
 
pg_shader_t* pg_get_shader(const pg_pipeline_t* pipeline)
{
    PICO_GFX_ASSERT(pipeline);
    return pipeline->shader;
}
 
const pg_blend_mode_t* pg_get_blend_mode(const pg_pipeline_t* pipeline)
{
    PICO_GFX_ASSERT(pipeline);
 
    if (pipeline->blend_enabled)
        return &pipeline->blend_mode;
    else
        return NULL;
}
 
pg_shader_t* pg_create_shader_internal(pg_ctx_t* ctx, pg_shader_internal_t internal)
{
    pg_shader_t* shader = PICO_GFX_MALLOC(sizeof(pg_shader_t), ctx->mem_ctx);
 
    pg_reset_textures(shader);
    pg_reset_samplers(shader);
 
    shader->ctx = ctx;
    shader->internal = internal;
    shader->desc = internal.get_shader_desc(sg_query_backend());
 
    PICO_GFX_ASSERT(shader->desc);
 
    shader->handle = sg_make_shader(shader->desc);
 
    shader->uniform_blocks = pg_hashtable_new(16, PICO_GFX_HASHTABLE_KEY_SIZE,
                                              sizeof(pg_uniform_block_t),
                                              ctx->mem_ctx);
 
    shader->arena = pg_arena_new(512, ctx->mem_ctx);
 
    return shader;
}
 
void pg_destroy_shader(pg_shader_t* shader)
{
    PICO_GFX_ASSERT(shader);
    sg_destroy_shader(shader->handle);
    pg_hashtable_free(shader->uniform_blocks);
    pg_arena_free(shader->arena);
    PICO_GFX_FREE(shader, shader->ctx->mem_ctx);
}
 
uint32_t pg_get_shader_id(const pg_shader_t* shader)
{
    PICO_GFX_ASSERT(shader);
    return shader->handle.id;
}
 
void pg_set_uniform_block(pg_shader_t* shader,
                          const char* name,
                          const void* data)
{
    PICO_GFX_ASSERT(shader);
    PICO_GFX_ASSERT(name);
    PICO_GFX_ASSERT(data);
 
    pg_uniform_block_t* block = pg_hashtable_get(shader->uniform_blocks, name);
 
    if (!block)
    {
        pg_alloc_uniform_block(shader, name);
        block = pg_hashtable_get(shader->uniform_blocks, name);
    }
 
    PICO_GFX_ASSERT(block);
 
    memcpy(block->data, data, block->size);
}
 
pg_texture_t* pg_create_texture(pg_ctx_t* ctx,
                                int width, int height,
                                const uint8_t* data, size_t size,
                                const pg_texture_opts_t* opts)
{
    PICO_GFX_ASSERT(width > 0);
    PICO_GFX_ASSERT(height > 0);
    PICO_GFX_ASSERT(data);
    PICO_GFX_ASSERT(size > 0);
 
    if (opts == NULL)
        opts = &(pg_texture_opts_t){ 0 };
 
    PICO_GFX_ASSERT(opts->mipmaps >= 0);
 
    pg_texture_t* texture = PICO_GFX_MALLOC(sizeof(pg_texture_t), ctx->mem_ctx);
 
    sg_image_desc desc = { 0 };
 
    desc.pixel_format = SG_PIXELFORMAT_RGBA8;
 
    desc.width  = texture->width  = width;
    desc.height = texture->height = height;
 
    desc.num_mipmaps = opts->mipmaps;
    desc.data.subimage[0][0] = (sg_range){ .ptr = data, .size = size };
 
    texture->ctx = ctx;
    texture->target = false;
    texture->handle = sg_make_image(&desc);
 
    PICO_GFX_ASSERT(sg_query_image_state(texture->handle) == SG_RESOURCESTATE_VALID);
 
    return texture;
}
 
pg_texture_t* pg_create_render_texture(pg_ctx_t* ctx,
                                       int width, int height,
                                       const pg_texture_opts_t* opts)
{
    PICO_GFX_ASSERT(width > 0);
    PICO_GFX_ASSERT(height > 0);
 
    if (opts == NULL)
        opts = &(pg_texture_opts_t){ 0 };
 
    PICO_GFX_ASSERT(opts->mipmaps >= 0);
 
    pg_texture_t* texture = PICO_GFX_MALLOC(sizeof(pg_texture_t), ctx->mem_ctx);
 
    sg_image_desc desc = { 0 };
 
    desc.render_target = true;
    desc.pixel_format = SG_PIXELFORMAT_RGBA8;
 
    desc.width  = texture->width  = width;
    desc.height = texture->height = height;
 
    desc.num_mipmaps = opts->mipmaps;
 
    texture->ctx = ctx;
    texture->handle = sg_make_image(&desc);
    texture->target = true;
 
    PICO_GFX_ASSERT(sg_query_image_state(texture->handle) == SG_RESOURCESTATE_VALID);
 
    desc.pixel_format = SG_PIXELFORMAT_DEPTH;
    texture->depth_handle = sg_make_image(&desc);
 
    PICO_GFX_ASSERT(sg_query_image_state(texture->depth_handle) == SG_RESOURCESTATE_VALID);
 
    //TODO: Research multiple color attachments
    texture->attachments = sg_make_attachments(&(sg_attachments_desc)
    {
        .colors[0].image = texture->handle,
        .depth_stencil.image = texture->depth_handle,
    });
 
    return texture;
}
 
void pg_destroy_texture(pg_texture_t* texture)
{
    if (texture->target)
    {
        sg_destroy_image(texture->depth_handle);
    }
 
    sg_destroy_image(texture->handle);
    PICO_GFX_FREE(texture, texture->ctx->mem_ctx);
}
 
void pg_update_texture(pg_texture_t* texture, char* data, int width, int height)
{
    // NOTE: Replaces all existing data
    sg_image_data img_data = { 0 };
    img_data.subimage[0][0].ptr = data;
    img_data.subimage[0][0].size = (size_t)(width * height);
    sg_update_image(texture->handle, &img_data);
}
 
uint32_t pg_get_texture_id(const pg_texture_t* texture)
{
    PICO_GFX_ASSERT(texture);
    return texture->handle.id;
}
 
void pg_get_texture_size(const pg_texture_t* texture, int* width, int* height)
{
    PICO_GFX_ASSERT(texture);
 
    if (width)
        *width = texture->width;
 
    if (height)
        *height = texture->height;
}
 
pg_sampler_t* pg_create_sampler(pg_ctx_t* ctx, const pg_sampler_opts_t* opts)
{
    if (opts == NULL)
        opts = &(pg_sampler_opts_t){ 0 };
 
    pg_sampler_t* sampler = PICO_GFX_MALLOC(sizeof(pg_sampler_t), ctx->mem_ctx);
 
    sg_sampler_desc desc = { 0 };
 
    desc.min_filter = (opts->smooth) ? SG_FILTER_LINEAR : SG_FILTER_NEAREST;
    desc.mag_filter = (opts->smooth) ? SG_FILTER_LINEAR : SG_FILTER_NEAREST;
 
    desc.wrap_u = (opts->repeat_u) ? SG_WRAP_REPEAT : SG_WRAP_CLAMP_TO_EDGE;
    desc.wrap_v = (opts->repeat_v) ? SG_WRAP_REPEAT : SG_WRAP_CLAMP_TO_EDGE;
 
    sampler->ctx = ctx;
    sampler->handle = sg_make_sampler(&desc);
 
    return sampler;
}
 
void pg_destroy_sampler(pg_sampler_t* sampler)
{
    sg_destroy_sampler(sampler->handle);
    PICO_GFX_FREE(sampler, sampler->ctx->mem_ctx);
}
 
static void pg_apply_uniforms(pg_shader_t* shader)
{
    PICO_GFX_ASSERT(shader);
 
    pg_hashtable_iterator_t iterator;
    pg_hashtable_init_iterator(shader->uniform_blocks, &iterator);
 
    char* key = NULL;
    void* value = NULL;
 
    while (pg_hashtable_iterator_next(&iterator, &key, &value))
    {
        pg_uniform_block_t* block = (pg_uniform_block_t*)value;
 
        sg_range range = { .ptr = block->data, .size = block->size };
 
        sg_apply_uniforms(block->slot, &range);
    }
}
 
pg_buffer_t* pg_create_vertex_buffer(pg_ctx_t* ctx,
                                     pg_buffer_usage_t usage,
                                     const void* data,
                                     size_t count,
                                     size_t max_elements,
                                     size_t element_size)
{
    PICO_GFX_ASSERT(ctx);
 
    pg_buffer_t* buffer = PICO_GFX_MALLOC(sizeof(pg_buffer_t), ctx->mem_ctx);
 
    buffer->ctx = ctx;
    buffer->type = PG_BUFFER_TYPE_VERTEX;
    buffer->usage = usage;
    buffer->count = count;
    buffer->element_size = element_size;
    buffer->size = max_elements * element_size;
    buffer->offset = 0;
 
    buffer->handle = sg_make_buffer(&(sg_buffer_desc)
    {
        .type  = SG_BUFFERTYPE_VERTEXBUFFER,
        .usage = pg_map_usage(usage),
        .data  = { .ptr = data, .size = count * element_size },
        .size  = buffer->size
    });
 
    PICO_GFX_ASSERT(sg_query_buffer_state(buffer->handle) == SG_RESOURCESTATE_VALID);
 
    return buffer;
}
 
pg_buffer_t* pg_create_index_buffer(pg_ctx_t* ctx,
                                    pg_buffer_usage_t usage,
                                    const void* data,
                                    size_t count,
                                    size_t max_elements)
{
    PICO_GFX_ASSERT(ctx);
 
    pg_buffer_t* buffer = PICO_GFX_MALLOC(sizeof(pg_buffer_t), ctx->mem_ctx);
 
    buffer->ctx = ctx;
    buffer->type = PG_BUFFER_TYPE_INDEX;
    buffer->usage = usage;
    buffer->count = count;
    buffer->size = max_elements * sizeof(uint32_t);
    buffer->offset = 0;
 
    buffer->handle = sg_make_buffer(&(sg_buffer_desc)
    {
        .type  = SG_BUFFERTYPE_INDEXBUFFER,
        .usage = pg_map_usage(usage),
        .data  = { .ptr = data, .size = count * sizeof(uint32_t) },
        .size  = buffer->size
    });
 
    PICO_GFX_ASSERT(sg_query_buffer_state(buffer->handle) == SG_RESOURCESTATE_VALID);
 
    return buffer;
}
 
void pg_update_buffer(pg_buffer_t* buffer, void* data, size_t count)
{
    PICO_GFX_ASSERT(buffer);
    PICO_GFX_ASSERT(data);
    PICO_GFX_ASSERT(count > 0);
 
    sg_update_buffer(buffer->handle, &(sg_range)
    {
        .ptr = data,
        .size = count * buffer->element_size
    });
 
    buffer->count = count;
    buffer->offset = 0;
}
 
int pg_append_buffer(pg_buffer_t* buffer, void* data, size_t count)
{
    PICO_GFX_ASSERT(buffer);
    PICO_GFX_ASSERT(data);
    PICO_GFX_ASSERT(count > 0);
 
    int offset = sg_append_buffer(buffer->handle, &(sg_range)
    {
        .ptr = data,
        .size = count * buffer->element_size
    });
 
    buffer->count = count;
    buffer->offset = offset;
 
    return offset;
}
 
int pg_get_buffer_offset(pg_buffer_t* buffer)
{
    PICO_GFX_ASSERT(buffer);
    return buffer->offset;
}
 
void pg_set_buffer_offset(pg_buffer_t* buffer, int offset)
{
    PICO_GFX_ASSERT(buffer);
    buffer->offset = offset;
}
 
void pg_reset_buffer(pg_buffer_t* buffer)
{
    PICO_GFX_ASSERT(buffer);
 
    sg_destroy_buffer(buffer->handle);
 
    buffer->handle = sg_make_buffer(&(sg_buffer_desc)
    {
        .type  = pg_map_buffer_type(buffer->type),
        .usage = pg_map_usage(buffer->usage),
        .data  = { .ptr = NULL, .size = 0 },
        .size  = buffer->size
    });
 
    PICO_GFX_ASSERT(sg_query_buffer_state(buffer->handle) == SG_RESOURCESTATE_VALID);
}
 
void pg_destroy_buffer(pg_buffer_t* buffer)
{
    PICO_GFX_ASSERT(buffer);
    sg_destroy_buffer(buffer->handle);
    PICO_GFX_FREE(buffer, buffer->ctx->mem_ctx);
}
 
static void pg_apply_view_state(const pg_ctx_t* ctx)
{
    const pg_rect_t* vp_rect = &ctx->state.viewport;
    sg_apply_viewport(vp_rect->x, vp_rect->y, vp_rect->width, vp_rect->height, true);
 
    const pg_rect_t* s_rect = &ctx->state.scissor;
    sg_apply_scissor_rect(s_rect->x, s_rect->y, s_rect->width, s_rect->height, true);
}
 
static void pg_apply_textures(const pg_shader_t* shader, sg_bindings* bindings)
{
    for (int i = 0; i < PG_MAX_TEXTURE_SLOTS; i++)
    {
        if (!shader->textures[i])
            continue;
 
        bindings->images[i] = shader->textures[i]->handle;
    }
}
 
static void pg_apply_samplers(const pg_shader_t* shader, sg_bindings* bindings)
{
    for (int i = 0; i < PG_MAX_SAMPLER_SLOTS; i++)
    {
        if (!shader->samplers[i])
            continue;
 
        bindings->samplers[i] = shader->samplers[i]->handle;
    }
}
 
static void pg_apply_buffers(const pg_ctx_t* ctx, sg_bindings* bindings)
{
    pg_buffer_t* const* buffers = ctx->state.buffers;
 
    for (int slot = 0; buffers[slot] != NULL; slot++)
    {
        bindings->vertex_buffer_offsets[slot] = buffers[slot]->offset;
        bindings->vertex_buffers[slot] = buffers[slot]->handle;
    }
}
 
void pg_draw(const pg_ctx_t* ctx, size_t start, size_t count, size_t instances)
{
    PICO_GFX_ASSERT(ctx);
    PICO_GFX_ASSERT(ctx->pass_active);
 
    sg_bindings bindings = { 0 };
 
    pg_pipeline_t* pipeline = ctx->state.pipeline;
 
    pg_apply_textures(pipeline->shader, &bindings);
    pg_apply_samplers(pipeline->shader, &bindings);
 
    pg_apply_buffers(ctx, &bindings);
    pg_apply_view_state(ctx);
 
    if (ctx->state.index_buffer)
    {
        bindings.index_buffer_offset = ctx->state.index_buffer->offset;
        bindings.index_buffer = ctx->state.index_buffer->handle;
    }
 
    sg_apply_pipeline(pipeline->handle);
    sg_apply_bindings(&bindings);
    pg_apply_uniforms(pipeline->shader);
 
    sg_draw(start, count, instances);
}
 
/*==============================================================================
 * GFX Static Functions
 *============================================================================*/
 
static void pg_alloc_uniform_block(pg_shader_t* shader, const char* name)
{
    PICO_GFX_ASSERT(shader);
    PICO_GFX_ASSERT(name);
 
    size_t size = shader->internal.get_uniformblock_size(name);
 
    pg_uniform_block_t block =
    {
        .slot  = shader->internal.get_uniformblock_slot(name),
        .data  = pg_arena_alloc(shader->arena, size),
        .size  = size,
    };
 
    pg_hashtable_put(shader->uniform_blocks, name, &block);
}
 
static sg_primitive_type pg_map_primitive(pg_primitive_t primitive)
{
    if (primitive == PG_DEFAULT_PRIMITIVE)
        primitive = PG_TRIANGLES;
 
    switch (primitive)
    {
        case PG_POINTS:         return SG_PRIMITIVETYPE_POINTS;
        case PG_LINES:          return SG_PRIMITIVETYPE_LINES;
        case PG_LINE_STRIP:     return SG_PRIMITIVETYPE_LINE_STRIP;
        case PG_TRIANGLES:      return SG_PRIMITIVETYPE_TRIANGLES;
        case PG_TRIANGLE_STRIP: return SG_PRIMITIVETYPE_TRIANGLE_STRIP;
        default: PICO_GFX_ASSERT(false); return SG_PRIMITIVETYPE_TRIANGLES;
    }
}
 
static sg_blend_factor pg_map_blend_factor(pg_blend_factor_t factor)
{
    if (factor == PG_DEFAULT_BLEND_FACTOR)
        factor = PG_ONE;
 
    switch (factor)
    {
        case PG_ZERO:                return SG_BLENDFACTOR_ZERO;
        case PG_ONE:                 return SG_BLENDFACTOR_ONE;
        case PG_SRC_COLOR:           return SG_BLENDFACTOR_SRC_COLOR;
        case PG_ONE_MINUS_SRC_COLOR: return SG_BLENDFACTOR_ONE_MINUS_SRC_COLOR;
        case PG_DST_COLOR:           return SG_BLENDFACTOR_DST_COLOR;
        case PG_ONE_MINUS_DST_COLOR: return SG_BLENDFACTOR_ONE_MINUS_DST_COLOR;
        case PG_SRC_ALPHA:           return SG_BLENDFACTOR_SRC_ALPHA;
        case PG_ONE_MINUS_SRC_ALPHA: return SG_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
        case PG_DST_ALPHA:           return SG_BLENDFACTOR_DST_ALPHA;
        case PG_ONE_MINUS_DST_ALPHA: return SG_BLENDFACTOR_ONE_MINUS_DST_ALPHA;
        default: PICO_GFX_ASSERT(false); return SG_BLENDFACTOR_ONE;
    }
}
 
static sg_blend_op pg_map_blend_eq(pg_blend_eq_t eq)
{
    if (eq == PG_DEFAULT_BLEND_EQ)
        eq = PG_ADD;
 
    switch (eq)
    {
        case PG_ADD:              return SG_BLENDOP_ADD;
        case PG_SUBTRACT:         return SG_BLENDOP_SUBTRACT;
        case PG_REVERSE_SUBTRACT: return SG_BLENDOP_REVERSE_SUBTRACT;
        default: PICO_GFX_ASSERT(false); return SG_BLENDOP_ADD;
    }
}
 
static sg_vertex_format pg_map_vertex_format(pg_vertex_format_t format)
{
    switch (format)
    {
        case PG_VERTEX_FORMAT_INVALID:   return SG_VERTEXFORMAT_INVALID;
        case PG_VERTEX_FORMAT_FLOAT:     return SG_VERTEXFORMAT_FLOAT;
        case PG_VERTEX_FORMAT_FLOAT2:    return SG_VERTEXFORMAT_FLOAT2;
        case PG_VERTEX_FORMAT_FLOAT3:    return SG_VERTEXFORMAT_FLOAT3;
        case PG_VERTEX_FORMAT_FLOAT4:    return SG_VERTEXFORMAT_FLOAT4;
        case PG_VERTEX_FORMAT_BYTE4:     return SG_VERTEXFORMAT_BYTE4;
        case PG_VERTEX_FORMAT_BYTE4N:    return SG_VERTEXFORMAT_BYTE4N;
        case PG_VERTEX_FORMAT_UBYTE4:    return SG_VERTEXFORMAT_UBYTE4;
        case PG_VERTEX_FORMAT_UBYTE4N:   return SG_VERTEXFORMAT_UBYTE4N;
        case PG_VERTEX_FORMAT_SHORT2:    return SG_VERTEXFORMAT_SHORT2;
        case PG_VERTEX_FORMAT_SHORT2N:   return SG_VERTEXFORMAT_SHORT2N;
        case PG_VERTEX_FORMAT_USHORT2N:  return SG_VERTEXFORMAT_USHORT2N;
        case PG_VERTEX_FORMAT_SHORT4:    return SG_VERTEXFORMAT_USHORT2N;
        case PG_VERTEX_FORMAT_SHORT4N:   return SG_VERTEXFORMAT_SHORT4;
        case PG_VERTEX_FORMAT_USHORT4N:  return SG_VERTEXFORMAT_SHORT4N;
        case PG_VERTEX_FORMAT_UINT10_N2: return SG_VERTEXFORMAT_USHORT4N;
        case PG_VERTEX_FORMAT_HALF2:     return SG_VERTEXFORMAT_HALF2;
        case PG_VERTEX_FORMAT_HALF4:     return SG_VERTEXFORMAT_HALF4;
        default: PICO_GFX_ASSERT(false); return SG_VERTEXFORMAT_INVALID;
    }
}
 
static sg_usage pg_map_usage(pg_buffer_usage_t format)
{
    switch (format)
    {
        case PG_USAGE_STATIC:  return SG_USAGE_IMMUTABLE;
        case PG_USAGE_DYNAMIC: return SG_USAGE_DYNAMIC;
        case PG_USAGE_STREAM:  return SG_USAGE_STREAM;
        default: PICO_GFX_ASSERT(false); return SG_USAGE_IMMUTABLE;
    }
}
 
static sg_buffer_type pg_map_buffer_type(pg_buffer_type_t type)
{
    switch (type)
    {
        case PG_BUFFER_TYPE_VERTEX: return SG_BUFFERTYPE_VERTEXBUFFER;
        case PG_BUFFER_TYPE_INDEX:  return SG_BUFFERTYPE_INDEXBUFFER;
        default: PICO_GFX_ASSERT(false); return SG_BUFFERTYPE_VERTEXBUFFER;
    }
}
 
static void pg_log(const char* fmt, ...)
{
    PICO_GFX_ASSERT(fmt);
 
    va_list args;
    va_start(args, fmt);
    vprintf(fmt, args);
    va_end(args);
    printf("\n");
    fflush(stdout);
}
 
static void pg_log_sg(const char* tag,                // e.g. 'sg'
                      uint32_t log_level,             // 0=panic, 1=error, 2=warn, 3=info
                      uint32_t log_item_id,           // SG_LOGITEM_*
                      const char* message_or_null,    // a message string, may be nullptr in release mode
                      uint32_t line_nr,               // line number in sokol_gfx.h
                      const char* filename_or_null,   // source filename, may be nullptr in release mode
                      void* user_data)
{
    (void)log_item_id;
    (void)user_data;
 
    static const char* level[] =
    {
        "Panic",
        "Error",
        "Warn",
        "Info",
    };
 
    // FIXME: Handle non-debug case
 
    if (message_or_null && !filename_or_null)
    {
        PICO_GFX_LOG("Tag: %s, Level: %s, Message: %s",
                      tag, level[log_level], message_or_null);
    }
 
    if (!message_or_null && filename_or_null)
    {
        PICO_GFX_LOG("Tag: %s, Level: %s, File: %s, Line: %d",
                      tag, level[log_level], filename_or_null, line_nr);
    }
 
    if (message_or_null && filename_or_null)
    {
        PICO_GFX_LOG("Tag: %s, Level: %s, File: %s, Line: %d, Message: %s",
                      tag, level[log_level], filename_or_null, line_nr, message_or_null);
    }
}
 
/*==============================================================================
 * Hashtable Data Structures
 *============================================================================*/
 
typedef struct
{
    pg_hash_t hash;
    char* key;
    void* value;
} pg_hashtable_entry_t;
 
struct pg_hashtable_t
{
    void* mem_ctx;
    size_t capacity;
    size_t size;
 
    pg_hashtable_entry_t* entries;
 
    size_t key_size;
    char* keys;
 
    size_t value_size;
    void* values;
};
 
/*==============================================================================
 * Hashtable Internal Declarations
 *============================================================================*/
 
static size_t pg_hashtable_compute_hash(const pg_hashtable_t* ht,
                                        const char* key);
 
static bool pg_hashtable_key_equal(const pg_hashtable_t* ht,
                                   const char* key1,
                                   const char* key2);
 
static void pg_hashtable_copy_value(pg_hashtable_t* ht,
                                    pg_hashtable_entry_t* entry,
                                    const void* value);
 
static void pg_hashtable_swap_size(size_t* a, size_t* b);
static void pg_hashtable_swap_ptr(void** a, void** b);
static void pg_hashtable_swap(pg_hashtable_t* ht1, pg_hashtable_t* ht2);
static void pg_hashtable_rehash(pg_hashtable_t* ht);
 
/*==============================================================================
 * Hashtable Public Implementation
 *============================================================================*/
 
static pg_hashtable_t* pg_hashtable_new(size_t capacity,
                                        size_t key_size,
                                        size_t value_size,
                                        void* mem_ctx)
{
    bool power_of_two = (0 == (capacity & (capacity - 1)));
 
    PICO_GFX_ASSERT(capacity > 2 && power_of_two);
    PICO_GFX_ASSERT(key_size > 0);
    PICO_GFX_ASSERT(value_size > 0);
 
    if (capacity <= 2 || !power_of_two)
        return NULL;
 
    if (0 == key_size || 0 == value_size)
        return NULL;
 
    pg_hashtable_t* ht = PICO_GFX_MALLOC(sizeof(pg_hashtable_t), mem_ctx);
 
    if (!ht)
        return NULL;
 
    ht->mem_ctx = mem_ctx;
    ht->capacity = capacity;
    ht->size = 0;
    ht->key_size = key_size;
    ht->value_size = value_size;
 
    ht->entries = PICO_GFX_MALLOC(capacity * sizeof(pg_hashtable_entry_t), mem_ctx);
 
    if (!ht->entries)
    {
        PICO_GFX_FREE(ht, mem_ctx);
        return NULL;
    }
 
    ht->keys = PICO_GFX_MALLOC(capacity * key_size, mem_ctx);
 
    if (!ht->keys)
    {
        PICO_GFX_FREE(ht->entries, mem_ctx);
        PICO_GFX_FREE(ht, mem_ctx);
 
        return NULL;
    }
 
    ht->values = PICO_GFX_MALLOC(capacity * value_size, mem_ctx);
 
    if (!ht->values)
    {
        PICO_GFX_FREE(ht->entries, mem_ctx);
        PICO_GFX_FREE(ht->keys, mem_ctx);
        PICO_GFX_FREE(ht, mem_ctx);
        return NULL;
    }
 
    for (size_t i = 0; i < capacity; i++)
    {
        pg_hashtable_entry_t* entry = &ht->entries[i];
        entry->hash = 0;
        entry->key = (char*)ht->keys + i * key_size;
        entry->value = (char*)ht->values + i * value_size;
    }
 
    return ht;
}
 
static void pg_hashtable_free(pg_hashtable_t* ht)
{
    PICO_GFX_ASSERT(NULL != ht);
 
    PICO_GFX_FREE(ht->entries, ht->mem_ctx);
    PICO_GFX_FREE(ht->keys, ht->mem_ctx);
    PICO_GFX_FREE(ht->values, ht->mem_ctx);
    PICO_GFX_FREE(ht, ht->mem_ctx);
}
 
static void pg_hashtable_init_iterator(const pg_hashtable_t* ht,
                                       pg_hashtable_iterator_t* iterator)
{
    PICO_GFX_ASSERT(NULL != ht);
    iterator->ht = ht;
    iterator->index = 0;
    iterator->count = 0;
}
 
static bool pg_hashtable_iterator_next(pg_hashtable_iterator_t* iterator,
                                       char** key, void** value)
{
    PICO_GFX_ASSERT(NULL != iterator);
 
    const pg_hashtable_t* ht = iterator->ht;
 
    if (iterator->count >= ht->capacity)
        return false;
 
    while (iterator->index < ht->capacity)
    {
        pg_hashtable_entry_t* entry = &ht->entries[iterator->index];
 
        if (entry->hash != 0)
        {
            if (key)
                *key = entry->key;
 
            if (value)
                *value = entry->value;
 
            iterator->count++;
            iterator->index++;
 
            return true;
        }
 
        iterator->index++;
    }
 
    return false;
}
 
static void pg_hashtable_put(pg_hashtable_t* ht,
                             const char* key,
                             const void* value)
{
    PICO_GFX_ASSERT(NULL != ht);
 
    if (ht->size == ht->capacity)
    {
        pg_hashtable_rehash(ht);
        PICO_GFX_ASSERT(ht->capacity > 0);
    }
 
    pg_hash_t hash = pg_hashtable_compute_hash(ht, key);
 
    PICO_GFX_ASSERT(hash > 0);
 
    size_t start_index = hash % ht->capacity;
    size_t index = start_index;
 
    do
    {
        pg_hashtable_entry_t* entry = &ht->entries[index];
 
        if (entry->hash == hash && pg_hashtable_key_equal(ht, key, entry->key))
        {
            pg_hashtable_copy_value(ht, entry, value);
            break;
        }
 
        if (entry->hash == 0)
        {
            entry->hash = hash;
 
            strncpy(entry->key, key, ht->key_size);
            pg_hashtable_copy_value(ht, entry, value);
 
            ht->size++;
 
            break;
        }
 
        index = (index + 1) % ht->capacity;
 
    } while (index != start_index);
 
    start_index = index;
    index = (index + 1) % ht->capacity;
 
    while (index != start_index)
    {
        pg_hashtable_entry_t* entry = &ht->entries[index];
 
        if (entry->hash == hash && pg_hashtable_key_equal(ht, key, entry->key))
        {
            entry->hash = 0;
            ht->size--;
            return;
        }
 
        index = (index + 1) % ht->capacity;
    }
}
 
static void* pg_hashtable_get(const pg_hashtable_t* ht, const char* key)
{
    PICO_GFX_ASSERT(NULL != ht);
 
    pg_hash_t hash = pg_hashtable_compute_hash(ht, key);
 
    PICO_GFX_ASSERT(hash > 0);
 
    size_t start_index = hash % ht->capacity;
    size_t index = start_index;
 
    do
    {
        pg_hashtable_entry_t* entry = &ht->entries[index];
 
        if (entry->hash == hash && pg_hashtable_key_equal(ht, key, entry->key))
        {
            return entry->value;
        }
 
        index = (index + 1) % ht->capacity;
 
    } while (index != start_index);
 
    return NULL;
}
 
/*==============================================================================
 * Hashtable Internal API
 *============================================================================*/
 
static bool pg_hashtable_key_equal(const pg_hashtable_t* ht,
                                   const char* key1,
                                   const char* key2)
{
    return 0 == strncmp(key1, key2, ht->key_size);
}
 
static void pg_hashtable_copy_value(pg_hashtable_t* ht,
                                    pg_hashtable_entry_t* entry,
                                    const void* value)
{
    memcpy(entry->value, value, ht->value_size);
}
 
static void pg_hashtable_swap_size(size_t* a, size_t* b)
{
    size_t tmp = *a;
    *a = *b;
    *b = tmp;
}
 
static void pg_hashtable_swap_ptr(void** a, void** b)
{
    void* tmp = *a;
    *a = *b;
    *b = tmp;
}
 
static void pg_hashtable_swap(pg_hashtable_t* ht1, pg_hashtable_t* ht2)
{
    pg_hashtable_swap_size(&ht1->capacity, &ht2->capacity);
    pg_hashtable_swap_size(&ht1->size, &ht2->size);
 
    pg_hashtable_swap_ptr((void**)&ht1->entries, (void**)&ht2->entries);
 
    pg_hashtable_swap_size(&ht1->key_size, &ht2->key_size);
    pg_hashtable_swap_ptr((void**)&ht1->keys, (void**)&ht2->keys);
 
    pg_hashtable_swap_size(&ht1->value_size, &ht2->value_size);
    pg_hashtable_swap_ptr(&ht1->values, &ht2->values);
}
 
static void pg_hashtable_rehash(pg_hashtable_t* ht)
{
    pg_hashtable_t* new_ht = pg_hashtable_new(ht->capacity * 2,
                                              ht->key_size,
                                              ht->size,
                                              ht->mem_ctx);
 
    pg_hashtable_iterator_t iterator;
    pg_hashtable_init_iterator(ht, &iterator);
 
    char* key;
    void* value;
 
    while (pg_hashtable_iterator_next(&iterator, &key, &value))
    {
        pg_hashtable_put(new_ht, key, value);
    }
 
    pg_hashtable_swap(ht, new_ht);
 
    pg_hashtable_free(new_ht);
}
 
/*==============================================================================
 * Hash Functions
 *============================================================================*/
 
static size_t pg_hashtable_compute_hash(const pg_hashtable_t* ht, const char* key)
{
 
#ifdef PICO_GFX_32BIT
    static const uint32_t offset_basis = 0x811C9DC5;
    static const uint32_t prime = 0x1000193;
#else
    static const uint64_t offset_basis = 0xCBF29CE484222325;
    static const uint64_t prime = 0x100000001B3;
#endif
 
    const char* data = key;
 
    pg_hash_t hash = offset_basis;
 
    for (size_t i = 0; i < ht->key_size; i++) {
        hash ^= (pg_hash_t)data[i];
        hash *= prime;
    }
 
    // Ensure hash is never zero
    if (hash == 0)
        hash++;
 
    return hash;
}
 
/*==============================================================================
 * Arena Allocator
 *============================================================================*/
 
struct pg_arena_t
{
    void*  mem_ctx;
    size_t capacity;
    size_t size;
    void*  block;
};
 
static pg_arena_t* pg_arena_new(size_t size, void* mem_ctx)
{
    PICO_GFX_ASSERT(size > 0);
 
    pg_arena_t* arena = PICO_GFX_MALLOC(sizeof(pg_arena_t), mem_ctx);
 
    memset(arena, 0, sizeof(pg_arena_t));
 
    arena->mem_ctx = mem_ctx;
    arena->capacity = size * 2;
    arena->block = PICO_GFX_MALLOC(arena->capacity, mem_ctx);
    arena->size = size;
 
    return arena;
}
 
static void* pg_arena_alloc(pg_arena_t* arena, size_t size)
{
    if (arena->size + size > arena->capacity)
    {
        while (arena->size + size >= arena->capacity)
        {
            arena->capacity *= 2;
        }
 
        arena->block = PICO_GFX_REALLOC(arena->block, arena->capacity, arena->mem_ctx);
    }
 
    void* mem = (char*)arena->block + arena->size;
 
    arena->size += size;
 
    return mem;
}
 
static void pg_arena_free(pg_arena_t* arena)
{
    PICO_GFX_FREE(arena->block, arena->mem_ctx);
    PICO_GFX_FREE(arena, arena->mem_ctx);
}
 
#define SOKOL_GFX_IMPL
#include "sokol_gfx.h"
 
#endif //PICO_GFX_IMPLEMENTATION
 
/*
    ----------------------------------------------------------------------------
    This software is available under two licenses (A) or (B). You may choose
    either one as you wish:
    ----------------------------------------------------------------------------
 
    (A) The zlib License
 
    Copyright (c) 2023 James McLean
 
    This software is provided 'as-is', without any express or implied warranty.
    In no event will the authors be held liable for any damages arising from the
    use of this software.
 
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
 
    1. The origin of this software must not be misrepresented; you must not
    claim that you wrote the original software. If you use this software in a
    product, an acknowledgment in the product documentation would be appreciated
    but is not required.
 
    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original software.
 
    3. This notice may not be removed or altered from any source distribution.
 
    ----------------------------------------------------------------------------
 
    (B) Public Domain (www.unlicense.org)
 
    This is free and unencumbered software released into the public domain.
 
    Anyone is free to copy, modify, publish, use, compile, sell, or distribute
    this software, either in source code form or as a compiled binary, for any
    purpose, commercial or non-commercial, and by any means.
 
    In jurisdictions that recognize copyright laws, the author or authors of
    this software dedicate any and all copyright interest in the software to the
    public domain. We make this dedication for the benefit of the public at
    large and to the detriment of our heirs and successors. We intend this
    dedication to be an overt act of relinquishment in perpetuity of all present
    and future rights to this software under copyright law.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
    ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
 
// EoF