Function upload_texture

examples/main_image.cpp:160–169

};

static GLuint upload_texture(const uint8_t* data, int w, int h, int ch, GLuint existing = 0) {
    GLuint tex = existing;
    if (!tex) glGenTextures(1, &tex);
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    GLenum fmt = (ch == 4) ? GL_RGBA : GL_RGB;
    glTexImage2D(GL_TEXTURE_2D, 0, fmt, w, h, 0, fmt, GL_UNSIGNED_BYTE, data);
    return tex;
}

static void build_overlay(app_state& app) {
    if (app.image.data.empty()) return;