mirror of
https://github.com/italicsjenga/slang-shaders.git
synced 2024-11-26 09:21:30 +11:00
304 lines
11 KiB
Plaintext
304 lines
11 KiB
Plaintext
#version 450
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// MMPX
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// by Morgan McGuire and Mara Gagiu
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// https://casual-effects.com/research/McGuire2021PixelArt/
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// License: MIT
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// adapted for slang by hunterk
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layout(push_constant) uniform Push
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{
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vec4 SourceSize;
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vec4 OriginalSize;
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vec4 OutputSize;
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uint FrameCount;
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} params;
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layout(std140, set = 0, binding = 0) uniform UBO
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{
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mat4 MVP;
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} global;
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#pragma stage vertex
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layout(location = 0) in vec4 Position;
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layout(location = 1) in vec2 TexCoord;
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layout(location = 0) out vec2 vTexCoord;
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void main()
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{
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gl_Position = global.MVP * Position;
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vTexCoord = TexCoord;
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}
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#pragma stage fragment
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layout(location = 0) in vec2 vTexCoord;
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layout(location = 0) out vec4 FragColor;
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layout(set = 0, binding = 2) uniform sampler2D Source;
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float luma(vec3 col){
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return dot(col, vec3(0.2126, 0.7152, 0.0722));
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}
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// I tried using a hash to speed these up but it didn't really help
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bool same(vec3 B, vec3 A0){
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return all(equal(B, A0));
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}
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bool notsame(vec3 B, vec3 A0){
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return any(notEqual(B, A0));
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}
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bool all_eq2(vec3 B, vec3 A0, vec3 A1) {
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return (same(B,A0) && same(B,A1));
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}
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bool all_eq3(vec3 B, vec3 A0, vec3 A1, vec3 A2) {
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return (same(B,A0) && same(B,A1) && same(B,A2));
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}
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bool all_eq4(vec3 B, vec3 A0, vec3 A1, vec3 A2, vec3 A3) {
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return (same(B,A0) && same(B,A1) && same(B,A2) && same(B,A3));
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}
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bool any_eq3(vec3 B, vec3 A0, vec3 A1, vec3 A2) {
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return (same(B,A0) || same(B,A1) || same(B,A2));
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}
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bool none_eq2(vec3 B, vec3 A0, vec3 A1) {
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return (notsame(B,A0) && notsame(B,A1));
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}
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bool none_eq4(vec3 B, vec3 A0, vec3 A1, vec3 A2, vec3 A3) {
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return (notsame(B,A0) && notsame(B,A1) && notsame(B,A2) && notsame(B,A3));
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}
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#define src(c,d) texture(Source, vTexCoord + vec2(c,d) * params.SourceSize.zw).rgb
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void main()
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{
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// these do nothing, but just for consistency with the original code...
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float srcX = 0.;
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float srcY = 0.;
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// Our current pixel
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vec3 E = src(srcX+0.,srcY+0.);
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// Input: A-I central 3x3 grid
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vec3 A = src(srcX-1.,srcY-1.);
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vec3 B = src(srcX+0.,srcY-1.);
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vec3 C = src(srcX+1.,srcY-1.);
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vec3 D = src(srcX-1.,srcY+0.);
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vec3 F = src(srcX+1.,srcY+0.);
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vec3 G = src(srcX-1.,srcY+1.);
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vec3 H = src(srcX+0.,srcY+1.);
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vec3 I = src(srcX+1.,srcY+1.);
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// Default to Nearest magnification
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vec3 J = E;
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vec3 K = E;
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vec3 L = E;
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vec3 M = E;
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// Go ahead and put this here so we can use an early return on the next
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// line to save some cycles
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FragColor = vec4(E, 1.0);
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// Skip constant 3x3 centers and just use nearest-neighbor
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// them. This gives a good speedup on spritesheets with
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// lots of padding and full screen images with large
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// constant regions such as skies.
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// EDIT: this is a wash for me, but we'll keep it around
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if(same(E,A) && same(E,B) && same(E,C) && same(E,D) && same(E,F) && same(E,G) && same(E,H) && same(E,I)) return;
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// Read additional values at the tips of the diamond pattern
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vec3 P = src(srcX+0.,srcY-2.);
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vec3 Q = src(srcX-2.,srcY+0.);
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vec3 R = src(srcX+2.,srcY+0.);
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vec3 S = src(srcX+0.,srcY+2.);
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// Precompute luminances
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float Bl = luma(B);
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float Dl = luma(D);
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float El = luma(E);
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float Fl = luma(F);
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float Hl = luma(H);
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// Round some corners and fill in 1:1 slopes, but preserve
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// sharp right angles.
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//
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// In each expression, the left clause is from
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// EPX and the others are new. EPX
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// recognizes 1:1 single-pixel lines because it
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// applies the rounding only to the LINE, and not
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// to the background (it looks at the mirrored
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// side). It thus fails on thick 1:1 edges
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// because it rounds *both* sides and produces an
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// aliased edge shifted by 1 dst pixel. (This
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// also yields the mushroom-shaped arrow heads,
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// where that 1-pixel offset runs up against the
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// 2-pixel aligned end; this is an inherent
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// problem with 2X in-palette scaling.)
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//
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// The 2nd clause clauses avoid *double* diagonal
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// filling on 1:1 slopes to prevent them becoming
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// aliased again. It does this by breaking
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// symmetry ties using luminance when working with
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// thick features (it allows thin and transparent
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// features to pass always).
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//
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// The 3rd clause seeks to preserve square corners
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// by considering the center value before
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// rounding.
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//
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// The 4th clause identifies 1-pixel bumps on
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// straight lines that are darker than their
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// background, such as the tail on a pixel art
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// "4", and prevents them from being rounded. This
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// corrects for asymmetry in this case that the
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// luminance tie breaker introduced.
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// .------------ 1st ------------. .----- 2nd ---------. .------ 3rd -----. .--------------- 4th -----------------------.
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if (((same(D,B) && notsame(D,H) && notsame(D,F))) && ((El>=Dl) || same(E,A)) && any_eq3(E,A,C,G) && ((El<Dl) || notsame(A,D) || notsame(E,P) || notsame(E,Q))) J=D;
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if (((same(B,F) && notsame(B,D) && notsame(B,H))) && ((El>=Bl) || same(E,C)) && any_eq3(E,A,C,I) && ((El<Bl) || notsame(C,B) || notsame(E,P) || notsame(E,R))) K=B;
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if (((same(H,D) && notsame(H,F) && notsame(H,B))) && ((El>=Hl) || same(E,G)) && any_eq3(E,A,G,I) && ((El<Hl) || notsame(G,H) || notsame(E,S) || notsame(E,Q))) L=H;
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if (((same(F,H) && notsame(F,B) && notsame(F,D))) && ((El>=Fl) || same(E,I)) && any_eq3(E,C,G,I) && ((El<Fl) || notsame(I,H) || notsame(E,R) || notsame(E,S))) M=F;
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// Clean up disconnected line intersections.
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//
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// The first clause recognizes being on the inside
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// of a diagonal corner and ensures that the "foreground"
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// has been correctly identified to avoid
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// ambiguous cases such as this:
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//
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// o#o#
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// oo##
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// o#o#
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//
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// where trying to fix the center intersection of
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// either the "o" or the "#" will leave the other
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// one disconnected. This occurs, for example,
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// when a pixel-art letter "B" or "R" is next to
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// another letter on the right.
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//
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// The second clause ensures that the pattern is
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// not a notch at the edge of a checkerboard
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// dithering pattern.
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//
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// >
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// .--------------------- 1st ------------------------. .--------- 2nd -----------.
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if ((notsame(E,F) && all_eq4(E,C,I,D,Q) && all_eq2(F,B,H)) && notsame(F,src(srcX+3.,srcY))) K=M=F;
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if ((notsame(E,D) && all_eq4(E,A,G,F,R) && all_eq2(D,B,H)) && notsame(D,src(srcX-3.,srcY))) J=L=D;
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if ((notsame(E,H) && all_eq4(E,G,I,B,P) && all_eq2(H,D,F)) && notsame(H,src(srcX,srcY+3.))) L=M=H;
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if ((notsame(E,B) && all_eq4(E,A,C,H,S) && all_eq2(B,D,F)) && notsame(B,src(srcX,srcY-3.))) J=K=B;
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// Remove tips of bright triangles on dark
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// backgrounds. The luminance tie breaker for 1:1
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// pixel lines leaves these as sticking up squared
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// off, which makes bright triangles and diamonds
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// look bad.
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if ((Bl<El) && all_eq4(E,G,H,I,S) && none_eq4(E,A,D,C,F)) J=K=B;
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if ((Hl<El) && all_eq4(E,A,B,C,P) && none_eq4(E,D,G,I,F)) L=M=H;
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if ((Fl<El) && all_eq4(E,A,D,G,Q) && none_eq4(E,B,C,I,H)) K=M=F;
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if ((Dl<El) && all_eq4(E,C,F,I,R) && none_eq4(E,B,A,G,H)) J=L=D;
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//////////////////////////////////////////////////////////////////////////////////
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// Do further neighborhood peeking to identify
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// 2:1 and 1:2 slopes of constant color.
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// The first clause of each rule identifies a 2:1 slope line
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// of consistent color.
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//
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// The second clause verifies that the line is separated from
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// every adjacent pixel on one side and not part of a more
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// complex pattern. Common subexpressions from the second clause
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// are lifted to an outer test on pairs of rules.
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//
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// The actions taken by rules are unusual in that they extend
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// a color assigned by previous rules rather than drawing from
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// the original source image.
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//
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// The comments show a diagram of the local
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// neighborhood in which letters shown with the
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// same shape and color must match each other and
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// everything else without annotation must be
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// different from the solid colored, square
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// letters.
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if (notsame(H,B)) { // Common subexpression
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// Above a 2:1 slope or -2:1 slope ◢ ◣
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// First:
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if (notsame(H,A) && notsame(H,E) && notsame(H,C)) {
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// Second:
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// P
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// Ⓐ B C .
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// Q D 🄴 🅵 🆁
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// 🅶 🅷 I
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// S
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if (all_eq3(H,G,F,R) && none_eq2(H,D,src(srcX+2.,srcY-1.))) L=M;
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// Third:
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// P
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// . A B Ⓒ
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// 🆀 🅳 🄴 F R
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// G 🅷 🅸
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// S
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if (all_eq3(H,I,D,Q) && none_eq2(H,F,src(srcX-2.,srcY-1.))) M=L;
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}
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// Below a 2:1 (◤) or -2:1 (◥) slope (reflect the above 2:1 patterns vertically)
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if (notsame(B,I) && notsame(B,G) && notsame(B,E)) {
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// P
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// 🅰 🅱 C
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// Q D 🄴 🅵 🆁
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// Ⓖ H I .
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// S
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if (all_eq3(B,A,F,R) && none_eq2(B,D,src(srcX+2.,srcY+1.))) J=K;
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// P
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// A 🅱 🅲
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// 🆀 🅳 🄴 F R
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// . G H Ⓘ
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// S
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if (all_eq3(B,C,D,Q) && none_eq2(B,F,src(srcX-2.,srcY+1.))) K=J;
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}
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}
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if (notsame(F,D)) { // Common subexpression
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// Right of a -1:2 (\) or -1:2 (/) slope (reflect the left 1:2 patterns horizontally)
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if (notsame(D,I) && notsame(D,E) && notsame(D,C)) {
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// P
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// 🅰 B Ⓒ
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// Q 🅳 🄴 F R
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// G 🅷 I
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// 🆂 .
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if (all_eq3(D,A,H,S) && none_eq2(D,B,src(srcX+1.,srcY+2.))) J=L;
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// 🅿 .
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// A 🅱 C
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// Q 🅳 🄴 F R
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// 🅶 H Ⓘ
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// S
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if (all_eq3(D,G,B,P) && none_eq2(D,H,src(srcX+1.,srcY-2.))) L=J;
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}
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// Left of a 1:2 (/) slope or -1:2 (\) slope (transpose the above 2:1 patterns)
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// Pull common none_eq subexpressions out
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if (notsame(F,E) && notsame(F,A) && notsame(F,G)) {
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// P
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// Ⓐ B 🅲
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// Q D 🄴 🅵 R
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// G 🅷 I
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// . 🆂
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if (all_eq3(F,C,H,S) && none_eq2(F,B,src(srcX-1.,srcY+2.))) K=M;
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// . 🅿
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// A 🅱 C
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// Q D 🄴 🅵 R
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// Ⓖ H 🅸
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// S
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if (all_eq3(F,I,B,P) && none_eq2(F,H,src(srcX-1.,srcY-2.))) M=K;
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}
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}
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// Determine which of our 4 output pixels we need to use
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vec2 a = fract(vTexCoord * params.SourceSize.xy);
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FragColor.rgb = (a.x < 0.5) ? (a.y < 0.5 ? J : L) : (a.y < 0.5 ? K : M);
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}
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