uniform sampler2D three_colors;
uniform sampler2D beton;
uniform sampler2D sand;
uniform sampler2D wall; 

void main(void)
{
 vec2 TexCoord = vec2(gl_TexCoord[0]);
 
 vec4 PixelColor = texture2D(three_colors, TexCoord);
 
gl_FragColor= PixelColor.x * texture2D(beton, TexCoord) + PixelColor.y * texture2D(sand, TexCoord) + PixelColor.z * texture2D(wall, TexCoord);
}