slang-shaders/eagle/shaders/2xsai.slang

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2022-07-10 09:42:04 +10:00
#version 450
layout(push_constant) uniform Push
{
vec4 OutputSize;
vec4 OriginalSize;
vec4 SourceSize;
} params;
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
} global;
const vec3 dt = vec3(65536.0,256.0,1.0);
float GET_RESULT(float A, float B, float C, float D)
{
return (sign(abs(A-C)+abs(A-D)) - sign(abs(B-C)+abs(B-D)));
}
float reduce(vec3 color)
{
return dot(color,dt);
}
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
/* Default Vertex shader */
void main()
{
gl_Position = global.MVP * Position;
vTexCoord = TexCoord * 1.0001;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 1) in vec2 FragCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
void main()
{
vec2 OGL2Size = params.SourceSize.xy;
vec2 OGL2InvSize = params.SourceSize.zw;
// Calculating texel coordinates
vec2 OGL2Pos = vTexCoord.xy*OGL2Size.xy;
vec2 fp = fract(OGL2Pos);
vec2 g1 = vec2( OGL2InvSize.x,OGL2InvSize.y);
vec2 g2 = vec2(-OGL2InvSize.x,OGL2InvSize.y);
if ((fp.x >= 0.50) && (fp.y < 0.50)) g2*=-1.0;
vec2 pC4 = floor(OGL2Pos)/OGL2Size.xy + 0.5*OGL2InvSize;
vec2 pC8 = pC4 + g1;
vec2 pC0 = pC4 - g1;
vec2 p04 = pC4 - 0.5*g1;
vec2 pC3 = p04 + 0.5*g2;
vec2 pC1 = pC3 - g2;
vec2 pC5 = pC1 + g1;
vec2 pC7 = pC3 + g1;
// Reading the texels
vec3 C0 = texture(Source,pC0 ).xyz;
vec3 C1 = texture(Source,pC1 ).xyz;
vec3 C2 = texture(Source,pC4-g2).xyz;
vec3 C3 = texture(Source,pC3 ).xyz;
vec3 C4 = texture(Source,pC4 ).xyz;
vec3 C5 = texture(Source,pC5 ).xyz;
vec3 D4 = texture(Source,pC8-g2).xyz;
vec3 C6 = texture(Source,pC4+g2).xyz;
vec3 C7 = texture(Source,pC7 ).xyz;
vec3 C8 = texture(Source,pC8 ).xyz;
vec3 D5 = texture(Source,pC5+g1).xyz;
vec3 D0 = texture(Source,pC7+g2).xyz;
vec3 D1 = texture(Source,pC8+g2).xyz;
vec3 D2 = texture(Source,pC7+g1).xyz;
vec3 p10,p11;
float c0 = reduce(C0);float c1 = reduce(C1);
float c2 = reduce(C2);float c3 = reduce(C3);
float c4 = reduce(C4);float c5 = reduce(C5);
float c6 = reduce(C6);float c7 = reduce(C7);
float c8 = reduce(C8);float d0 = reduce(D0);
float d1 = reduce(D1);float d2 = reduce(D2);
float d4 = reduce(D4);float d5 = reduce(D5);
/* 2xSaI code */
/* Copied from the Dosbox source code */
/* Copyright (C) 2002-2007 The DOSBox Team */
/* License: GNU-GPL */
/* Adapted by guest(r) on 20.4 and 9.5. 2007 */
if (c4 == c8) {
if (c5 != c7) {
if (((c4 == c3)&&(c7 == d2))||((c4 == c5)&&(c4 == c6)&&(c3 != c7)&&(c7 == d0))) {
p10 = C4;
} else {
p10 = 0.5*(C4+C7);
}
p11 = C4;
} else {
if (c4 == c5) {
p10 = C4;
p11 = C4;
} else {
float r;
r = GET_RESULT(c4,c5,c3,c1);
r -= GET_RESULT(c5,c4,d4,c2);
r -= GET_RESULT(c5,c4,c6,d1);
r += GET_RESULT(c4,c5,d5,d2);
if (r > 0.0) p11 = C4;
else if (r < 0.0) p11 = C5;
else p11 = 0.25*(C4+C5+C7+C8);
p10 = 0.5*(C4+C7);
}
}
} else
if (c5 == c7) {
if (((c7 == c6)&&(c4 == c2))||((c7 == c3)&&(c7 == c8)&&(c4 != c6)&&(c4 == c0))) {
p10 = C7;
} else {
p10 = 0.5*(C4+C7);
}
p11 = C5;
} else {
p11 = 0.25*(C4+C5+C7+C8);
if ((c4 == c5)&&(c4 == c6)&&(c3 != c7)&&(c7 == d0)) {
p10 = C4;
} else if ((c7 == c3)&&(c7 == c8)&&(c4 != c6)&&(c4 == c0)) {
p10 = C7;
} else {
p10 = 0.5*(C4+C7);
}
}
// Distributing the final products
vec3 color;
if (fp.x >= 0.5 && fp.y >= 0.5) color = p11; else
if (fp.x < 0.5 && fp.y < 0.5) color = C4; else color = p10;
FragColor = vec4(color, 1.0);
}