Pixel-Composer/shaders/sh_blend_multiply/sh_blend_multiply.fsh
2023-09-19 12:53:24 +02:00

45 lines
1000 B
GLSL

//
// Simple passthrough fragment shader
//
varying vec2 v_vTexcoord;
varying vec4 v_vColour;
uniform vec2 dimension;
uniform int tile_type;
uniform int useMask;
uniform int preserveAlpha;
uniform sampler2D mask;
uniform sampler2D fore;
uniform float opacity;
float sampleMask() {
if(useMask == 0) return 1.;
vec4 m = texture2D( mask, v_vTexcoord );
return (m.r + m.g + m.b) / 3. * m.a;
}
void main() {
vec4 _col0 = texture2D( gm_BaseTexture, v_vTexcoord );
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 );
_col1.a *= opacity * sampleMask();
vec4 blend = (_col0 * (1. - opacity)) + (_col0 * _col1 * opacity);
float po = preserveAlpha == 1? _col1.a : opacity;
float al = _col1.a + _col0.a * (1. - _col1.a);
vec4 res = mix(_col0, blend, po);
res.rgb /= al;
res.a = preserveAlpha == 1? _col0.a : res.a;
gl_FragColor = res;
}