#version 330

uniform sampler2D tex0;
uniform sampler2D tex1;
uniform sampler2D tex2;
uniform sampler2D tex3;

in vec2 UV0;
in vec2 UV1;
in vec2 UV2;
in vec2 UV3;

out vec4 color;

void main()
{
    vec4 layer0 = texture2D(tex0, UV0);
    vec4 layer1 = texture2D(tex1, UV1);
    vec4 layer2 = texture2D(tex2, UV2);
    vec4 layer3 = texture2D(tex3, UV3);

    color = (vec4(layer0.rgb * layer0.a, layer0.a) * 1.0f) + (vec4(layer1.rgb * layer1.a, layer1.a) * 0.7f)
        + (vec4(layer2.rgb * layer2.a, layer2.a) * 0.7f)
        + (vec4(layer3.rgb * layer3.a, layer3.a) * 0.7f);
    // color = texture2D(tex0, UV0) * 0.8f;
}