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#version 450
layout(set = 2, binding = 0) uniform sampler2D u_image;
layout(location = 0) in vec2 v_uv;
layout(location = 1) in vec2 v_panel_uv;
layout(location = 2) flat in uvec4 v_effect;
layout(location = 0) out vec4 o_col;
float cellNoise(uint serial, uint col, uint row) {
uint x = serial ^ (col * 0x9e3779b9u) ^ (row * 0x85ebca6bu);
x ^= x >> 16;
x *= 0x7feb352du;
x ^= x >> 15;
x *= 0x846ca68bu;
x ^= x >> 16;
return float(x & 0xffffu) / 65535.0;
}
// The same seven procedural ASCII marks as ui.frag.glsl and the macOS Metal
// panel kernel. Native attachments are content in the panel, so they should
// not switch to a smaller two-symbol animation when the glyph grid over them
// is using `. : + * # % @`.
float asciiGlyph(vec2 uv, int glyph) {
vec2 p = uv * 2.0 - 1.0;
float thin = 0.12;
float dotShape = 1.0 - smoothstep(0.10, 0.20, length(p - vec2(0.0, 0.45)));
float barH = 1.0 - smoothstep(thin, thin + 0.08, abs(p.y));
float barV = 1.0 - smoothstep(thin, thin + 0.08, abs(p.x));
if (glyph == 0) return dotShape;
if (glyph == 1) return max(dotShape, 1.0 - smoothstep(0.10, 0.20, length(p + vec2(0.0, 0.45))));
if (glyph == 2) return max(barH, barV);
if (glyph == 3) {
float d0 = 1.0 - smoothstep(thin, thin + 0.08, abs(p.x - p.y));
float d1 = 1.0 - smoothstep(thin, thin + 0.08, abs(p.x + p.y));
return max(max(d0, d1), max(barH, barV));
}
if (glyph == 4) {
float rails = max(
1.0 - smoothstep(thin, thin + 0.08, abs(abs(p.x) - 0.34)),
1.0 - smoothstep(thin, thin + 0.08, abs(abs(p.y) - 0.34))
);
return rails;
}
float ring = 1.0 - smoothstep(thin, thin + 0.08, abs(length(p * vec2(0.8, 1.0)) - 0.48));
return max(ring, glyph == 6 ? dotShape : 0.0);
}
void main() {
vec4 source = texture(u_image, v_uv);
uint effect = v_effect.x & 0x7fffffffu;
bool oldLayer = (v_effect.x & 0x80000000u) != 0u;
float progress = clamp(uintBitsToFloat(v_effect.y), 0.0, 1.0);
uvec2 dimensions = max(
uvec2(v_effect.w & 0xffffu, v_effect.w >> 16),
uvec2(1u));
uvec2 cellCoord = min(
uvec2(floor(max(v_panel_uv, vec2(0.0)) * vec2(dimensions))),
dimensions - 1u);
float noise = cellNoise(v_effect.z, cellCoord.x, cellCoord.y);
if (effect == 3u) {
bool reveal = progress >= 1.0 || (progress > 0.0 && noise < progress);
if (oldLayer == reveal) discard;
o_col = source;
return;
}
if (effect == 4u) {
float diagonal = float((cellCoord.x + cellCoord.y * 2u) % 17u) / 17.0;
float threshold = noise * 0.72 + diagonal * 0.28;
bool reveal = progress >= 1.0 || (progress > 0.0 && progress >= threshold);
bool wave = !reveal && progress > 0.0 && progress + 0.22 >= threshold;
if (oldLayer) {
if (wave || reveal) discard;
o_col = source;
return;
}
if (reveal) {
o_col = source;
return;
}
if (!wave) discard;
vec2 cellUV = fract(v_panel_uv * vec2(dimensions));
int glyph = min(int(floor(noise * 7.0)), 6);
float mark = asciiGlyph(cellUV, glyph);
float luma = dot(source.rgb, vec3(0.2126, 0.7152, 0.0722));
vec3 paper = source.rgb * 0.10;
// Preserve source colour when it already separates from the dimmed
// paper. Solid black pixels have no such separation, so derive a
// readable mark from their own luminance instead of letting the ASCII
// phase disappear on dark images/PDF regions.
vec3 contrastInk = luma > 0.5 ? vec3(0.0) : vec3(1.0);
float sourceContrast = smoothstep(0.025, 0.14, length(source.rgb - paper));
vec3 ink = mix(contrastInk, source.rgb, sourceContrast);
vec3 dimInk = mix(paper, ink, 0.62);
o_col = vec4(mix(paper, dimInk, mark), source.a);
return;
}
o_col = source;
}
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