SameBoy/Shaders/Scale4x.fsh

80 lines
3.2 KiB
GLSL

STATIC vec4 scale2x(sampler2D image, vec2 position, vec2 input_resolution, vec2 output_resolution)
{
// o = offset, the width of a pixel
vec2 o = 1.0 / input_resolution;
// texel arrangement
// A B C
// D E F
// G H I
// vec4 A = texture(image, position + vec2( -o.x, o.y));
vec4 B = texture(image, position + vec2( 0, o.y));
// vec4 C = texture(image, position + vec2( o.x, o.y));
vec4 D = texture(image, position + vec2( -o.x, 0));
vec4 E = texture(image, position + vec2( 0, 0));
vec4 F = texture(image, position + vec2( o.x, 0));
// vec4 G = texture(image, position + vec2( -o.x, -o.y));
vec4 H = texture(image, position + vec2( 0, -o.y));
// vec4 I = texture(image, position + vec2( o.x, -o.y));
vec2 p = position * input_resolution;
// p = the position within a pixel [0...1]
vec4 R;
p = fract(p);
if (p.x > .5) {
if (p.y > .5) {
// Top Right
return equal(B, F) && inequal(B, D) && inequal(F, H) ? F : E;
} else {
// Bottom Right
return equal(H, F) && inequal(D, H) && inequal(B, F) ? F : E;
}
} else {
if (p.y > .5) {
// Top Left
return equal(D, B) && inequal(B, F) && inequal(D, H) ? D : E;
} else {
// Bottom Left
return equal(D, H) && inequal(D, B) && inequal(H, F) ? D : E;
}
}
}
STATIC vec4 scale(sampler2D image, vec2 position, vec2 input_resolution, vec2 output_resolution)
{
// o = offset, the width of a pixel
vec2 o = 1.0 / (input_resolution * 2.);
// texel arrangement
// A B C
// D E F
// G H I
// vec4 A = scale2x(image, position + vec2( -o.x, o.y), input_resolution, output_resolution);
vec4 B = scale2x(image, position + vec2( 0, o.y), input_resolution, output_resolution);
// vec4 C = scale2x(image, position + vec2( o.x, o.y), input_resolution, output_resolution);
vec4 D = scale2x(image, position + vec2( -o.x, 0), input_resolution, output_resolution);
vec4 E = scale2x(image, position + vec2( 0, 0), input_resolution, output_resolution);
vec4 F = scale2x(image, position + vec2( o.x, 0), input_resolution, output_resolution);
// vec4 G = scale2x(image, position + vec2( -o.x, -o.y), input_resolution, output_resolution);
vec4 H = scale2x(image, position + vec2( 0, -o.y), input_resolution, output_resolution);
// vec4 I = scale2x(image, position + vec2( o.x, -o.y), input_resolution, output_resolution);
vec2 p = position * input_resolution * 2.;
// p = the position within a pixel [0...1]
p = fract(p);
if (p.x > .5) {
if (p.y > .5) {
// Top Right
return equal(B, F) && inequal(B, D) && inequal(F, H) ? F : E;
} else {
// Bottom Right
return equal(H, F) && inequal(D, H) && inequal(B, F) ? F : E;
}
} else {
if (p.y > .5) {
// Top Left
return equal(D, B) && inequal(B, F) && inequal(D, H) ? D : E;
} else {
// Bottom Left
return equal(D, H) && inequal(D, B) && inequal(H, F) ? D : E;
}
}
}