generated from krampus/template-godot4
36 lines
917 B
Plaintext
36 lines
917 B
Plaintext
/* Binary threshold shader
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* See https://stackoverflow.com/a/56678483
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*/
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shader_type canvas_item;
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uniform vec4 color_low: source_color = vec4(0.0, 0.0, 0.0, 1.0);
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uniform vec4 color_hi: source_color = vec4(1.0, 1.0, 1.0, 1.0);
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uniform float threshold: hint_range(0.0, 1.0) = 0.455;
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uniform float contrast: hint_range(0.0, 1.0) = 1.0;
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uniform float offset: hint_range(-1.0, 1.0) = 0.0;
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float linearSRGB(float channel) {
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if (channel <= 0.04045) {
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return channel / 12.92;
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} else {
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return pow(((channel + 0.055) / 1.055), 2.4);
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}
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}
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float luminance(vec3 color) {
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return 0.2126 * linearSRGB(color.r) + 0.7152 * linearSRGB(color.g) + 0.0722 * linearSRGB(color.b);
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}
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void fragment() {
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vec3 screen_col = texture(TEXTURE, UV).rgb;
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float Y = luminance(screen_col);
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// adjust contrast & offset
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Y = clamp((Y - 0.5 + offset) * contrast + 0.5, 0.0, 1.0);
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COLOR.rgba = Y > threshold ? color_hi : color_low;
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}
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