vec3 worldPosFromDepth(in vec2 texCoord, in sampler2D depthTex, in mat4 invView, in mat4 invProjection)
{
  float z = texture(depthTex, texCoord).r * 2.0 - 1.0;
  vec4 clipSpacePosition = vec4(texCoord * 2.0 - 1.0, z, 1.0);
  vec4 viewSpacePosition = invProjection * clipSpacePosition;
  viewSpacePosition /= viewSpacePosition.w;
  vec4 worldSpacePosition = invView * viewSpacePosition;
  return worldSpacePosition.xyz;
}