33 lines
933 B
Plaintext
33 lines
933 B
Plaintext
shader_type canvas_item;
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uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_nearest;
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uniform float pixel_scale : hint_range(1.0, 8.0, 1.0) = 4.0;
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uniform float color_depth : hint_range(2.0, 8.0, 1.0) = 5.0;
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uniform float dither_strength : hint_range(0.0, 2.0, 0.05) = 0.8;
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float bayer4(ivec2 p) {
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int x = p.x & 3;
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int y = p.y & 3;
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float m[16] = float[16](
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0.0, 8.0, 2.0, 10.0,
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12.0, 4.0, 14.0, 6.0,
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3.0, 11.0, 1.0, 9.0,
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15.0, 7.0, 13.0, 5.0
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);
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return m[y * 4 + x] / 16.0 - 0.5;
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}
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void fragment() {
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vec2 pixel_size = SCREEN_PIXEL_SIZE * pixel_scale;
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vec2 snapped = (floor(SCREEN_UV / pixel_size) + 0.5) * pixel_size;
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vec3 col = texture(SCREEN_TEXTURE, snapped).rgb;
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ivec2 dpos = ivec2(FRAGCOORD.xy / pixel_scale);
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float t = bayer4(dpos) * dither_strength;
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float levels = exp2(color_depth) - 1.0;
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col = clamp(floor(col * levels + t + 0.5) / levels, 0.0, 1.0);
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COLOR = vec4(col, 1.0);
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}
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