27 lines
925 B
Plaintext
27 lines
925 B
Plaintext
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#version 100
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uniform sampler2D sampler0;
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uniform float fraction;
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uniform float height;
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const float c = -0.2;
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const float border_max_height = 60.0;
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mat4 contrast = mat4 (1.0 + c, 0.0, 0.0, 0.0,
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0.0, 1.0 + c, 0.0, 0.0,
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0.0, 0.0, 1.0 + c, 0.0,
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0.0, 0.0, 0.0, 1.0);
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vec4 off = vec4(0.633, 0.633, 0.633, 0);
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void main()
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{
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vec4 color = texture2D(sampler0, gl_TexCoord[0].st);
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float y = height * gl_TexCoord[0][1];
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// To reduce contrast, blend with a mid gray
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gl_FragColor = color * contrast - off * c;
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// We only fully dim at a distance of BORDER_MAX_HEIGHT from the edge and
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// when the fraction is 1.0. For other locations and fractions we linearly
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// interpolate back to the original undimmed color.
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gl_FragColor = color + (gl_FragColor - color) * min(y / border_max_height, 1.0);
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gl_FragColor = color + (gl_FragColor - color) * fraction;
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}
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