Ray core is a 3 stages pipeline design which allows different threads to be processed at the same time on different stage. The 3 stages are :
- Surface stage : This stage process the ray from camera and find the closest hit of the ray then pass the hit information to next stage.
- Shadow stage : This stage cast a ray from closest hit position to light source to find the first hit. If there is any hit then this thread is under shadow. It will pass the shadow information to next stage.
- Shade stage: This stage will use the closest hit information to decide if it's the final color or reflection/refraction will occur. If reflection/refraction occurs, it will cast a reflection/refraction ray and pass the data back to surface stage. Because the shade stage can recursively feed back to surface stage, the multiple bouncing is possible. The maximum bouncing level can be set in configration file, defult setting is 3.
Traverse BVH structure to find the possible leaves for hit test.
Find the closest hit between the current ray and all possible primitives.
Do intersection test between the current ray and one primitive. You can configure the number of hit units to increase the intersection test rate.
Traverse BVH structure to find the possible hit leaves.
Find the first hit between the light ray and all possible primitives.
Do intersection test between the current ray and one primitive. You can configure the number of hit units to increase the intersection test rate.
Compute reflection ray and feed back to Surface stage.
Compute refraction ray and feed back to Surface stage.
Combine the current color from reflection/refraction with previous color.
Output final color when there is no more reflection/refraction ray.