33 lines
935 B
GLSL
33 lines
935 B
GLSL
uniform sampler2D colorMapG;
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const float threshold = 0.1;
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out vec4 FragColor;
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void main() {
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vec3 weights = vec3(0.2126,0.7152, 0.0722); // ITU-R BT. 709
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vec2 uv = gl_FragCoord.xy / u_screen;
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vec2 uv_left = uv + vec2(-1., 0.) / u_screen;
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vec2 uv_top = uv + vec2(0., 1.) / u_screen;
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vec2 uv_right = uv + vec2(1., 0.) / u_screen;
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vec2 uv_bottom = uv + vec2(0., -1.) / u_screen;
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/**
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* Luma calculation requires gamma-corrected colors:
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*/
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float L = dot(texture(colorMapG, uv).rgb, weights);
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float Lleft = dot(texture(colorMapG, uv_left).rgb, weights);
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float Ltop = dot(texture(colorMapG, uv_top).rgb, weights);
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float Lright = dot(texture(colorMapG, uv_right).rgb, weights);
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float Lbottom = dot(texture(colorMapG, uv_bottom).rgb, weights);
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vec4 delta = abs(vec4(L) - vec4(Lleft, Ltop, Lright, Lbottom));
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vec4 edges = step(vec4(threshold), delta);
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if (dot(edges, vec4(1.0)) == 0.0)
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discard;
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FragColor = edges;
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}
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