42 lines
881 B
GLSL
42 lines
881 B
GLSL
#version 300 es
|
|
|
|
precision highp float;
|
|
precision highp sampler2D;
|
|
|
|
in vec2 texCoord;
|
|
out vec4 fragColor;
|
|
|
|
uniform sampler2D src;
|
|
|
|
vec2 u(ivec2 coord)
|
|
{
|
|
return (texelFetch(src, coord, 0).xy);
|
|
}
|
|
|
|
void main()
|
|
{
|
|
ivec2 pixelCoord = ivec2(floor(gl_FragCoord.xy));
|
|
|
|
if(pixelCoord.x <= 0
|
|
|| pixelCoord.x >= textureSize(src, 0).x
|
|
|| pixelCoord.y <= 0
|
|
|| pixelCoord.y >= textureSize(src, 0).y)
|
|
{
|
|
fragColor = vec4(0, 0, 0, 1);
|
|
}
|
|
else
|
|
{
|
|
vec2 tl = u(pixelCoord + ivec2(-1, 0));
|
|
vec2 tr = u(pixelCoord);
|
|
vec2 bl = u(pixelCoord + ivec2(-1, -1));
|
|
vec2 br = u(pixelCoord + ivec2(0, -1));
|
|
|
|
float r = (tr.x + br.x) / 2.;
|
|
float l = (tl.x + bl.x) / 2.;
|
|
float t = (tl.y + tr.y) / 2.;
|
|
float b = (bl.y + br.y) / 2.;
|
|
|
|
fragColor = vec4(-2. * (r - l + t - b), 0, 0, 1);
|
|
}
|
|
}
|