119 lines
3.6 KiB
GLSL
119 lines
3.6 KiB
GLSL
|
|
float quickDistance(vec4 a, vec4 b)
|
|
{
|
|
return abs(a.x - b.x) + abs(a.y - b.y) + abs(a.z - b.z);
|
|
}
|
|
|
|
vec4 omniScale(sampler2D image, vec2 texCoord)
|
|
{
|
|
vec2 pixel = texCoord * textureDimensions - vec2(0.5, 0.5);
|
|
|
|
vec4 q11 = texture2D(image, vec2(floor(pixel.x) / textureDimensions.x, floor(pixel.y) / textureDimensions.y));
|
|
vec4 q12 = texture2D(image, vec2(floor(pixel.x) / textureDimensions.x, ceil(pixel.y) / textureDimensions.y));
|
|
vec4 q21 = texture2D(image, vec2(ceil(pixel.x) / textureDimensions.x, floor(pixel.y) / textureDimensions.y));
|
|
vec4 q22 = texture2D(image, vec2(ceil(pixel.x) / textureDimensions.x, ceil(pixel.y) / textureDimensions.y));
|
|
|
|
vec2 pos = fract(pixel);
|
|
|
|
/* Special handling for diaonals */
|
|
bool hasDownDiagonal = false;
|
|
bool hasUpDiagonal = false;
|
|
if (q12 == q21 && q11 != q22) hasUpDiagonal = true;
|
|
else if (q12 != q21 && q11 == q22) hasDownDiagonal = true;
|
|
else if (q12 == q21 && q11 == q22) {
|
|
if (q11 == q12) return q11;
|
|
int diagonalBias = 0;
|
|
for (float y = -1.0; y < 3.0; y++) {
|
|
for (float x = -1.0; x < 3.0; x++) {
|
|
vec4 color = texture2D(image, (pixel + vec2(x, y)) / textureDimensions);
|
|
if (color == q11) diagonalBias++;
|
|
if (color == q12) diagonalBias--;
|
|
}
|
|
}
|
|
if (diagonalBias <= 0) {
|
|
hasDownDiagonal = true;
|
|
}
|
|
if (diagonalBias >= 0) {
|
|
hasUpDiagonal = true;
|
|
}
|
|
}
|
|
|
|
if (hasUpDiagonal || hasDownDiagonal) {
|
|
vec4 downDiagonalResult, upDiagonalResult;
|
|
|
|
if (hasUpDiagonal) {
|
|
float diagonalPos = pos.x + pos.y;
|
|
|
|
if (diagonalPos < 0.5) {
|
|
upDiagonalResult = q11;
|
|
}
|
|
else if (diagonalPos > 1.5) {
|
|
upDiagonalResult = q22;
|
|
}
|
|
else {
|
|
upDiagonalResult = q12;
|
|
}
|
|
}
|
|
|
|
if (hasDownDiagonal) {
|
|
float diagonalPos = 1.0 - pos.x + pos.y;
|
|
|
|
if (diagonalPos < 0.5) {
|
|
downDiagonalResult = q21;
|
|
}
|
|
else if (diagonalPos > 1.5) {
|
|
downDiagonalResult = q12;
|
|
}
|
|
else {
|
|
downDiagonalResult = q11;
|
|
}
|
|
}
|
|
|
|
if (!hasUpDiagonal) return downDiagonalResult;
|
|
if (!hasDownDiagonal) return upDiagonalResult;
|
|
return mix(downDiagonalResult, upDiagonalResult, 0.5);
|
|
}
|
|
|
|
vec4 r1 = mix(q11, q21, fract(pos.x));
|
|
vec4 r2 = mix(q12, q22, fract(pos.x));
|
|
|
|
vec4 unqunatized = mix(r1, r2, fract(pos.y));
|
|
|
|
float q11d = quickDistance(unqunatized, q11);
|
|
float q21d = quickDistance(unqunatized, q21);
|
|
float q12d = quickDistance(unqunatized, q12);
|
|
float q22d = quickDistance(unqunatized, q22);
|
|
|
|
float best = min(q11d,
|
|
min(q21d,
|
|
min(q12d,
|
|
q22d)));
|
|
|
|
if (q11d == best) {
|
|
return q11;
|
|
}
|
|
|
|
if (q21d == best) {
|
|
return q21;
|
|
}
|
|
|
|
if (q12d == best) {
|
|
return q12;
|
|
}
|
|
|
|
return q22;
|
|
}
|
|
|
|
vec4 filter(sampler2D image)
|
|
{
|
|
vec2 texCoord = vec2(gl_FragCoord.x, uResolution.y - gl_FragCoord.y) / uResolution;
|
|
vec2 pixel = vec2(1.0, 1.0) / uResolution;
|
|
// 4-pixel super sampling
|
|
|
|
vec4 q11 = omniScale(image, texCoord + pixel * vec2(-0.25, -0.25));
|
|
vec4 q21 = omniScale(image, texCoord + pixel * vec2(+0.25, -0.25));
|
|
vec4 q12 = omniScale(image, texCoord + pixel * vec2(-0.25, +0.25));
|
|
vec4 q22 = omniScale(image, texCoord + pixel * vec2(+0.25, +0.25));
|
|
|
|
return (q11 + q21 + q12 + q22) / 4.0;
|
|
} |