21 lines
664 B
GLSL
21 lines
664 B
GLSL
#define PI 3.14
|
|
extern float yresolution;
|
|
vec4 effect(vec4 color,Image texture,vec2 texture_coords,vec2 screen_coords){
|
|
//Iterate through the occluder map's y-axis.
|
|
for(float y=0.;y<yresolution;y++){
|
|
//cartesian to polar
|
|
// y/yresolution=distance to light source(0~1)
|
|
vec2 norm=vec2(texture_coords.s,y/yresolution)*2.-1.;
|
|
float theta=PI*1.5+norm.x*PI;
|
|
float r=(1.+norm.y)*0.5;
|
|
|
|
//sample from solid
|
|
if(
|
|
Texel(texture,(
|
|
vec2(-r*sin(theta),-r*cos(theta))*0.5+0.5//coord of solid sampling
|
|
))
|
|
.a>0.1
|
|
)return vec4(vec3(y/yresolution),1.);//collision check, alpha>0.1 means transparent
|
|
}
|
|
return vec4(1.,1.,1.,1.);//return max distance 1
|
|
} |