c++raytracingphong

Ray Tracing - Reflection


I'm now working on the ray tracer, reflection part. I have everything working correctly, including creating a sphere with shadow. Now, I'm implementing the reflection part. However, I couldn't get it. My algorithm is below:

traceRay(Ray ray, int counter){
// look through the intersection between ray and list of objects
// find the final index aka the winning index, (if final index == -1, return background color)
// then calculate the intersection point

// perform reflection calculation here
if(counter > 1  && winning object's reflectivity > 1 ){
  //get the intersection normal, vector N
  //Calculate the reflection ray, R
  // let I is the inverse of direction of incoming ray
  //Calculate R = 2aN - I (a = N dotProduct I)

  // the reflection ray is origin at the point of intersection between incoming ray and sphere with the R direction
  Ray reflecRay (intersection_poisition, R);

  Color reflection = traceRay(reflecRay, counter + 1);
  // multiply by fraction ks
  reflection = reflection * ks;
}


// the color of the sphere calculated using phong formula in shadeRay function
Color prefinal = shadeRay();


// return the total color of prefinal + reflection

}

I trying to get the reflection but couldn't get it, can anyone please let me know if my algorithm for traceRay function is correct?


Solution

  • When reflecting a ray, you need to move it along the reflector's normal to avoid intersection with the reflector itself. For example:

     const double ERR = 1e-12;
     Ray reflecRay (intersection_poisition + normal*ERR, R);