FragmentShaderESSL300]);

    const readStencilShader = `#version 300 es
        precision highp float;
        uniform highp usampler2D tex;
        in vec2 texCoord;
        out vec4 out_color;
        void main() {
            out_color = vec4(texture(tex, texCoord)) / 255.0;
        }`;
    const readStencilProgram = wtu.setupProgram(gl, [wtu.simpleTextureVertexShaderESSL300,
                                                     readStencilShader]);

    for (const format of formats) {
        debug("");