I'm writing a shader, and I was wondering if there is anyway to only check a specific layer when sampling the background.
For example when I use:
lowp vec4 back = texture2D(samplerBack, mix(destStart, destEnd, vTex));
if (back.a > 0.5)
is there anyway to exclude or specify a layer, or is it always the sum of every layer other than the current layer ? So in this instance back.a would only refer to the alpha of the layer under the current layer.