Pixel-Composer/shaders/sh_channel_A/sh_channel_A.fsh

//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;

void main() {
	vec4 col = texture2D( gm_BaseTexture, v_vTexcoord);
    gl_FragColor = vec4(col.a, col.a, col.a, 1.);
}