48 lines
1.7 KiB
Plaintext
48 lines
1.7 KiB
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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uniform float scanline_strength : hint_range(0.0, 1.0, 0.05) = 0.2;
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uniform float roll_speed : hint_range(0.0, 10.0, 0.1) = 3.0;
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uniform float roll_strength : hint_range(0.0, 1.0, 0.05) = 1.0;
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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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if (scanline_strength > 0.0) {
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// Rolling gradient mask scrolling top-to-bottom
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float screen_y = FRAGCOORD.y * SCREEN_PIXEL_SIZE.y;
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float roll_mask = sin(screen_y * TAU - TIME * roll_speed) * 0.5 + 0.5;
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// Scanlines modulated by the roll: strong at peak, faint at trough
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float effective_strength = scanline_strength * mix(1.0 - roll_strength, 1.0, roll_mask);
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float row_frac = fract(FRAGCOORD.y / pixel_scale);
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float scan = smoothstep(0.0, 0.3, row_frac) * (1.0 - smoothstep(0.7, 1.0, row_frac));
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col *= 1.0 - effective_strength * (1.0 - scan);
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}
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COLOR = vec4(col, 1.0);
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}
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