oat text = texture2D(u_text_texture, vec2(vUv.x, 1. - vUv.y)).r;
        splat *= (.7 + .2 * text);

        vec3 base = texture2D(u_input_texture, vUv).xyz;
        gl_FragColor = vec4(base + splat, 1.);
    }
</script>

<script type="x-shader/x-fragment" id="fragShaderOutputShader">
    precision highp float;
    precision highp sampler2D;

    varying vec2 vUv;
    uniform sampler2D u_output_texture;
    uniform sampler2D u_text_texture;

    void main () {
        vec3 C = texture2D(u_o