uniform sampler2D opacityMap;
uniform sampler2D source0;
uniform sampler2D source1;
uniform sampler2D source2;
uniform sampler2D source3;

void main()
{
	vec4 opacity	= texture2D(opacityMap,	gl_TexCoord[0].st);
	vec4 texel0		= texture2D(source0,	gl_TexCoord[0].st);
	vec4 texel1		= texture2D(source1,	gl_TexCoord[0].st);
	vec4 texel2		= texture2D(source2,	gl_TexCoord[0].st);
	vec4 texel3		= texture2D(source3,	gl_TexCoord[0].st);
	
	//Combine texel colours
	gl_FragColor = vec4(opacity.r * texel0.rgba +
						opacity.g * texel1.rgba +
						opacity.b * texel2.rgba +
						opacity.a * texel3.rgba);
}