sokol-gfx with C++20 designated init :/

imgui-emsc.cc

    // dynamic vertex- and index-buffers for imgui-generated geometry
    bind.vertex_buffers[0] = sg_make_buffer({
        .size = MaxVertices * sizeof(ImDrawVert),
        .usage = SG_USAGE_STREAM
    });
    bind.index_buffer = sg_make_buffer({
        .size = MaxIndices * sizeof(ImDrawIdx),
        .type = SG_BUFFERTYPE_INDEXBUFFER,
        .usage = SG_USAGE_STREAM
    });

    // font texture for imgui's default font
    unsigned char* font_pixels;
    int font_width, font_height;
    io.Fonts->GetTexDataAsRGBA32(&font_pixels, &font_width, &font_height);
    bind.fs_images[0] = sg_make_image({
        .width = font_width,
        .height = font_height,
        .pixel_format = SG_PIXELFORMAT_RGBA8,
        .wrap_u = SG_WRAP_CLAMP_TO_EDGE,
        .wrap_v = SG_WRAP_CLAMP_TO_EDGE,
        .content = {
            .subimage = {
                {
                    { .ptr = font_pixels, .size = font_width * font_height * 4 }
                }
            }
        }
    });

    // shader object for imgui rendering
    sg_shader shd = sg_make_shader({
        .attrs = {
            { .name = "position" },
            { .name = "texcoord0" },
            { .name = "color0" }
        },
        .vs = {
            .source =
                "uniform vec2 disp_size;\n"
                "attribute vec2 position;\n"
                "attribute vec2 texcoord0;\n"
                "attribute vec4 color0;\n"
                "varying vec2 uv;\n"
                "varying vec4 color;\n"
                "void main() {\n"
                "    gl_Position = vec4(((position/disp_size)-0.5)*vec2(2.0,-2.0), 0.5, 1.0);\n"
                "    uv = texcoord0;\n"
                "    color = color0;\n"
                "}\n",
            .uniform_blocks = {
                {
                    .size = sizeof(vs_params_t),
                    .uniforms = {
                        { .name="disp_size", .type=SG_UNIFORMTYPE_FLOAT2}
                    }
                }
            }
        },
        .fs = {
            .source =
                "precision mediump float;"
                "uniform sampler2D tex;\n"
                "varying vec2 uv;\n"
                "varying vec4 color;\n"
                "void main() {\n"
                "    gl_FragColor = texture2D(tex, uv) * color;\n"
                "}\n",
            .images = {

                { .name="tex", .type=SG_IMAGETYPE_2D }
            },
        }
    });

    // pipeline object for imgui rendering
    pip = sg_make_pipeline({
        .layout = {
            .buffers = {
                { .stride = sizeof(ImDrawVert) }
            },
            .attrs = {
                { .offset=offsetof(ImDrawVert,pos), .format=SG_VERTEXFORMAT_FLOAT2 },
                { .offset=offsetof(ImDrawVert,uv), .format=SG_VERTEXFORMAT_FLOAT2 },
                { .offset=offsetof(ImDrawVert,col), .format=SG_VERTEXFORMAT_UBYTE4N }
            }
        },
        .shader = shd,
        .index_type = SG_INDEXTYPE_UINT16,
        .blend = {
            .enabled = true,
            .src_factor_rgb = SG_BLENDFACTOR_SRC_ALPHA,
            .dst_factor_rgb = SG_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
            .color_write_mask = SG_COLORMASK_RGB
        }
    });

    // initial clear color
    pass_action = {
        .colors = {
            { .action = SG_ACTION_CLEAR, .val = { 0.0f, 0.5f, 0.7f, 1.0f } }
        }
    };