Method texture_for

src/host/ui/svg_icon_cache.cpp:93–134

The GL calls below are used raw (not via GlfwCanvas's dispatch table): glGenTextures/glBindTexture/glTexParameteri/glTexImage2D/glDeleteTextures are OpenGL 1.0/1.1 entry points, exported directly by every desktop GL library the app links (OpenGL.framework, libGL, opengl32) -- no glfwGetProcAddress loading is required for them, unlike the post-1.1 functions GlfwCanvas has to load. Do not extrapolat

// functions GlfwCanvas has to load. Do not extrapolate this to newer GL
// functions.
GLuint SvgIconCache::texture_for(IconId id, int logical_w, int logical_h) {
    Entry& entry = entries_[static_cast<std::size_t>(id)];
    if (entry.cached) {
        return entry.failed ? 0 : entry.tex;
    }

    const auto out_w =
        static_cast<int>(static_cast<float>(logical_w) * content_scale_);
    const auto out_h =
        static_cast<int>(static_cast<float>(logical_h) * content_scale_);

    const auto [svg_data, svg_size] = svg_source_for(id);
    const std::vector<unsigned char> rgba =
        rasterize_svg(svg_data, svg_size, out_w, out_h);
    if (rgba.empty()) {
        entry = Entry{/*tex=*/0, /*failed=*/true, /*cached=*/true};
        return 0;
    }

    // Mirror ThumbnailCache's texture parameterization (thumbnail_cache.cpp)
    // -- linear filtering, clamp to edge -- so these icons scale/sample the
    // same way the buffer-list thumbnails do.
    GLuint tex = 0;
    glGenTextures(1, &tex);
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D,
                 0,
                 GL_RGBA8,
                 out_w,
                 out_h,
                 0,
                 GL_RGBA,
                 GL_UNSIGNED_BYTE,
                 rgba.data());

    entry = Entry{tex, /*failed=*/false, /*cached=*/true};
    return tex;
}

} // namespace oid::host