slang-shaders/crt/sinc.slang
Hans-Kristian Arntzen a37cff4905 Fix lanczos.
2016-08-02 16:11:44 +02:00

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#version 450
#include "common.inc"
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
void main()
{
gl_Position = MVP * Position;
vTexCoord = TexCoord;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 1) uniform sampler2D Source;
#define PI 3.1415926535
float sinc(float x)
{
return sin(x) / x;
}
float kernel(float x)
{
x = max(abs(x) * PI, 0.0001);
return sinc(x) * sinc(0.5 * x);
}
void main()
{
float u = vTexCoord.x * global.SourceSize.x - 0.5;
float a = fract(u);
vec2 tex = vec2((floor(u) + 0.5) * global.SourceSize.z, vTexCoord.y);
#define TEX(x, y) textureLodOffset(Source, tex, 0.0, ivec2(x, y)).rgb
vec3 color =
kernel(a + 1.0) * TEX(-1, 0) +
kernel(a ) * TEX( 0, 0) +
kernel(a - 1.0) * TEX( 1, 0) +
kernel(a - 2.0) * TEX( 2, 0);
FragColor = vec4(color, 1.0);
}