gear/src/main.c

#include <sokol/sokol_app.h>
#include <sokol/sokol_gfx.h>
#include <sokol/sokol_log.h>
#include <sokol/sokol_glue.h>
#include <slibs/slibs.h>
#include <HandmadeMath/HandmadeMath.h>

#define STB_IMAGE_IMPLEMENTATION
#include <stb/stb_image.h>

#include <stdio.h>

#include <shaders/transform.glsl.h>

static struct {
    sg_pipeline pip;
    sl_vec(sg_bindings*) bindings;
    sg_pass_action pass_action;
} state;

typedef struct {
    float x, y, z;
    uint32_t color;
    int16_t u, v;
} vertex_t;

static void init(void) {
    sg_setup(&(sg_desc){
        .environment = sglue_environment(),
        .logger.func = slog_func,
    });

    vertex_t vertices[] = {
        {  1.0f,  1.0f, 0.0f, 0xFFFFFFFF, 1.0f * 32767, 1.0f * 32767 },   // top right
        {  1.0f, -1.0f, 0.0f, 0xFFFFFFFF, 1.0f * 32767, 0.0f * 32767 },  // bottom right
        { -1.0f, -1.0f, 0.0f, 0xFFFFFFFF, 0.0f * 32767, 0.0f * 32767 },  // bottom left
        { -1.0f,  1.0f, 0.0f, 0xFFFFFFFF, 0.0f * 32767, 1.0f * 32767 }  // top left 
    };

    uint16_t indices[] = {  // note that we start from 0!
        0, 1, 3,   // first triangle
        1, 2, 3    // second triangle
    };

    sg_bindings* bind = calloc(1, sizeof(sg_bindings));
    sl_vec_push(state.bindings, bind);
    bind->vertex_buffers[0] = sg_make_buffer(&(sg_buffer_desc){
        .data = SG_RANGE(vertices),
        .label = "triangle-vertices"
    });

    bind->index_buffer = sg_make_buffer(&(sg_buffer_desc){
        .type = SG_BUFFERTYPE_INDEXBUFFER,
        .data = SG_RANGE(indices),
        .label = "triangle-indices"
    });

    int desired_channels = 4;
    int width, height, channels;
    stbi_set_flip_vertically_on_load(true);
    uint8_t* pixels = stbi_load("happi.jpg", &width, &height, &channels, desired_channels);

    bind->fs.images[SLOT_tex] = sg_make_image(&(sg_image_desc){
        .width = width,
        .height = height,
        .data.subimage[0][0] = {.ptr = pixels, .size = width * height * desired_channels},
        .label = "triangle-texture",
        .pixel_format = SG_PIXELFORMAT_RGBA8,
    });

    stbi_image_free(pixels);

    bind->fs.samplers[SLOT_smp] = sg_make_sampler(&(sg_sampler_desc){
        .label = "triangle-sampler",
    });

    sg_shader shd = sg_make_shader(transform_shader_desc(sg_query_backend()));

    state.pip = sg_make_pipeline(&(sg_pipeline_desc){
        .shader = shd,
        .layout = {
            .attrs = {
                [ATTR_vs_pos].format = SG_VERTEXFORMAT_FLOAT3,
                [ATTR_vs_color0].format = SG_VERTEXFORMAT_UBYTE4N,
                [ATTR_vs_texcoord0].format = SG_VERTEXFORMAT_SHORT2N,
            }
        },
        .index_type = SG_INDEXTYPE_UINT16,
        .cull_mode = SG_CULLMODE_BACK,
        .depth = {
            .compare = SG_COMPAREFUNC_LESS_EQUAL,
            .write_enabled = true,
        },
        .label = "triangle-pipeline",
    });

    state.pass_action = (sg_pass_action) {
        .colors[0] = { .load_action=SG_LOADACTION_CLEAR, .clear_value={0.2f, 0.4f, 0.3f, 1.0f } }
    };
}

float t = 0.0f;

void frame(void) {
    t += sapp_frame_duration();

    printf("%f\n", 1.0f/sapp_frame_duration());

    sg_begin_pass(&(sg_pass){ .action = state.pass_action, .swapchain = sglue_swapchain() });
    sg_apply_pipeline(state.pip);

    HMM_Mat4 view = HMM_Translate(HMM_V3(0.0f, 0.0f, -3.0f));
    HMM_Mat4 projection = HMM_Perspective_RH_NO(HMM_AngleDeg(45.0f), sapp_widthf() / sapp_heightf(), 0.1f, 100.0f);
    HMM_Mat4 view_proj = HMM_MulM4(projection, view);

    for(size_t i = 0; i < state.bindings.size; i++) {
        HMM_Mat4 model = HMM_Rotate_RH(HMM_AngleDeg(-55.0f), HMM_V3(1.0f, 0.0f, 0.0f));
        model = HMM_MulM4(model, HMM_Rotate_RH(HMM_AngleDeg(sin(t * 2) * 10), HMM_V3(0.0f, 0.2f, 0.0f)));
        HMM_Mat4 mvp = HMM_MulM4(view_proj, model);

        vs_params_t params = {
            .mvp = mvp,
            .texture_scale = HMM_V2(1.0f, 1.0f),
        };

        sg_apply_bindings(state.bindings.data[i]);
        sg_apply_uniforms(SG_SHADERSTAGE_VS, SLOT_vs_params, SG_RANGE_REF(params));
        sg_draw(0, 6, 1);
    }
    sg_end_pass();
    sg_commit();
}

void cleanup(void) {
    sg_shutdown();
}

sapp_desc sokol_main(int argc, char* argv[]) {
    (void)argc; (void)argv;
    return (sapp_desc){
        .init_cb = init,
        .frame_cb = frame,
        .cleanup_cb = cleanup,
        .width = 640,
        .height = 480,
        .window_title = "Gear",
        .icon.sokol_default = true,
        .logger.func = slog_func,
        .swap_interval = 0
    };
}