rtengine/src/gfx/gfx.h

#ifndef RT_GFX_H
#define RT_GFX_H

/* graphics system. this is the interface of the rendering code.
 *
 * we need (at least) three different renderers:
 * - world cell renderer (for world & dungeon environments)
 * - character renderer (for animated models)
 * - object renderer (for static models)
 */

#include <stdint.h>

#include "runtime/runtime.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef union {
    float v[4];
    struct {
        float r;
        float g;
        float b;
        float a;
    };
} rt_color;

/* NOTE(kevin): When you add a value here, you need to handle them in
 * framegraph_processor.c : ParseFramegraph
 * and in the render target and texture functions of all renderers. */

typedef enum {
    RT_PIXEL_FORMAT_INVALID,

    RT_PIXEL_FORMAT_R8G8B8A8_UNORM,
    RT_PIXEL_FORMAT_B8G8R8A8_UNORM,
    RT_PIXEL_FORMAT_R8G8B8A8_SRGB,
    RT_PIXEL_FORMAT_B8G8R8A8_SRGB,
    RT_PIXEL_FORMAT_R8G8B8_UNORM,
    RT_PIXEL_FORMAT_B8G8R8_UNORM,
    RT_PIXEL_FORMAT_R8G8B8_SRGB,
    RT_PIXEL_FORMAT_B8G8R8_SRGB,

    RT_PIXEL_FORMAT_DEPTH24_STENCIL8,
    RT_PIXEL_FORMAT_DEPTH32,

    /* Special value indicating whichever format the swapchain uses */
    RT_PIXEL_FORMAT_SWAPCHAIN,

    RT_PIXEL_FORMAT_count,
} rt_pixel_format;

/* In renderer_api.h -> Not necessary for almost all gfx usage */
typedef struct rt_renderer_init_info_s rt_renderer_init_info;

RT_DLLEXPORT void rtRegisterRendererCVars(void);

RT_DLLEXPORT rt_result rtInitGFX(rt_renderer_init_info *renderer_info);

RT_DLLEXPORT void rtShutdownGFX(void);

RT_DLLEXPORT void rtBeginGFXFrame(unsigned int frame_id);

RT_DLLEXPORT void rtEndGFXFrame(unsigned int frame_id);

/* *********************************************************************
 * Framegraph API
 *
 * The framegraph is used to organize and schedule the work for a frame.
 * *********************************************************************/

/* Special value for the .width and .height fields of rt_render_target_info
 * to indicate that these should be set to the width or height of the swapchain, respectively. */
#define RT_RENDER_TARGET_SIZE_SWAPCHAIN 0
/* 32 bit string hashes */
typedef uint32_t rt_render_target_id;
typedef uint32_t rt_render_pass_id;

typedef struct {
    rt_render_target_id id;
    rt_pixel_format format;
    uint32_t width;
    uint32_t height;
    uint32_t sample_count;

    /* For debug purposes, can be 0 */
    rt_relptr name;
    uint32_t name_len;
} rt_render_target_info;

typedef enum {
    RT_RENDER_TARGET_READ_SAMPLED,
    RT_RENDER_TARGET_READ_DIRECT,

    RT_RENDER_TARGET_READ_count,
} rt_render_target_read_mode;

typedef struct {
    rt_render_target_id render_target;
    rt_render_target_read_mode mode;
} rt_render_target_read;

typedef enum {
    /* Clears the render target with the clear value before executing the pass */
    RT_RENDER_TARGET_WRITE_CLEAR = 0x01,

    /* Discards the written values after the pass has finished executing */
    RT_RENDER_TARGET_WRITE_DISCARD = 0x02,
} rt_render_target_write_flags;

typedef struct {
    rt_render_target_id render_target;
    union {
        rt_color color;
        struct {
            float depth;
            int32_t stencil;
        } depth_stencil;
    } clear;
    rt_render_target_write_flags flags;
} rt_render_target_write;

typedef enum {
    RT_RENDER_PASS_TYPE_GRAPHICS,
    RT_RENDER_PASS_TYPE_COMPUTE,
} rt_render_pass_type;

typedef struct {
    rt_render_pass_id id;

    /* For debug purposes, can be 0 */
    rt_relptr name;
    uint32_t name_len;

    rt_render_pass_type type;
    /* list of rt_render_target_reads  */
    rt_relptr read_render_targets;
    /* list of rt_render_target_writes */
    rt_relptr write_render_targets;
    uint32_t read_render_target_count;
    uint32_t write_render_target_count;
} rt_render_pass_info;

typedef struct {
    rt_relptr render_targets;
    rt_relptr render_passes;
    uint32_t render_target_count;
    uint32_t render_pass_count;
    rt_relptr names;
    uint32_t names_size;
} rt_framegraph_info;

typedef void rt_render_pass_prepare_fn(rt_render_pass_id id,
                                       const rt_render_target_write *writes,
                                       uint32_t write_count,
                                       const rt_render_target_read *reads,
                                       uint32_t read_count);
typedef void rt_render_pass_execute_fn(rt_render_pass_id id,
                                       const rt_render_target_write *writes,
                                       uint32_t write_count,
                                       const rt_render_target_read *reads,
                                       uint32_t read_count);
typedef void rt_render_pass_finalize_fn(rt_render_pass_id id,
                                        const rt_render_target_write *writes,
                                        uint32_t write_count,
                                        const rt_render_target_read *reads,
                                        uint32_t read_count);

typedef struct {
    rt_render_pass_prepare_fn *Prepare;
    rt_render_pass_execute_fn *Execute;
    rt_render_pass_finalize_fn *Finalize;
} rt_render_pass_bind_fns;

typedef struct rt_framegraph_s rt_framegraph;

RT_DLLEXPORT rt_framegraph *rtCreateFramegraph(const rt_framegraph_info *info);

RT_DLLEXPORT void rtDestroyFramegraph(rt_framegraph *framegraph);

RT_DLLEXPORT void rtBindRenderPass(rt_framegraph *framegraph,
                                   rt_render_pass_id pass,
                                   const rt_render_pass_bind_fns *bind_fns);

RT_DLLEXPORT void rtExecuteFramegraph(rt_framegraph *framegraph, unsigned int frame_id);

/* Utility to turn a string into a usable render target id. */
RT_DLLEXPORT rt_render_target_id rtCalculateRenderTargetID(const char *name, size_t len);

/* Utility to turn a string into a usable render pass id. */
RT_DLLEXPORT rt_render_pass_id rtCalculateRenderPassID(const char *name, size_t len);

#ifdef __cplusplus
}
#endif

#endif