#version 450 core
layout(location=0)uniform vec3 lightPos;
layout(location=1)uniform vec4 lumRad;
layout (binding = 0) uniform sampler2D screenTexture;
layout (binding = 1) uniform sampler2D normals;
in vec2 vTexPos;
out vec4 fColor;
float rad = lumRad.a;
void main() {
  vec3 pos = texture(screenTexture, vTexPos).xyz;
  vec3 distVec = pos - lightPos;
  float dist = dot(distVec, distVec);
  if (dist > rad) {
    discard;
  }
  vec4 normbit = texture(normals, vTexPos);
  vec3 norm = normbit.xyz;
  float y1 = dot(normalize(norm), normalize(distVec));
  float y2 = float(y1 > 0 ? 1 : 0);
  //float y3 = clamp(0.5 * (y1 + 1),0,1) ;
  float y3 = clamp(2*y1 + 1,0,1) ;
  //float y3 = clamp(0.5 * (y1 + 2),0,1) ;
  //float y = float(normbit.w == 0 ? y3 : y2);
  float y = y2;
  float x = 1 - dist / rad;
  vec3 c = y* (x * x * x) * lumRad.rgb;
  fColor = vec4(c, 0);
}