Pixel-Composer/shaders/sh_blend_subtract/sh_blend_subtract.fsh

46 lines
940 B
Plaintext
Raw Normal View History

2022-01-13 05:24:03 +01:00
//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
uniform vec2 dimension;
uniform int tile_type;
uniform int useMask;
2023-02-14 05:32:32 +01:00
uniform int preserveAlpha;
2022-01-13 05:24:03 +01:00
uniform sampler2D mask;
uniform sampler2D fore;
uniform float opacity;
2023-01-01 02:06:02 +01:00
float sampleMask() {
if(useMask == 0) return 1.;
vec4 m = texture2D( mask, v_vTexcoord );
return (m.r + m.g + m.b) / 3. * m.a;
}
2022-01-13 05:24:03 +01:00
void main() {
vec4 _col0 = texture2D( gm_BaseTexture, v_vTexcoord );
_col0.rgb *= _col0.a;
vec2 fore_tex = v_vTexcoord;
if(tile_type == 0) {
fore_tex = v_vTexcoord;
} else if(tile_type == 1) {
fore_tex = fract(v_vTexcoord * dimension);
}
vec4 _col1 = texture2D( fore, fore_tex );
2023-01-01 02:06:02 +01:00
_col1.a *= opacity * sampleMask();
2022-01-13 05:24:03 +01:00
_col1.rgb *= _col1.a;
2023-05-16 21:28:16 +02:00
vec4 blend = _col0 - _col1;
float po = preserveAlpha == 1? _col1.a : opacity;
vec4 res = mix(_col0, blend, po);
2023-02-14 05:32:32 +01:00
if(preserveAlpha == 1) res.a = _col0.a;
2022-01-13 05:24:03 +01:00
gl_FragColor = res;
}