uniform raycasting in a selected sphere region of

Dear all
I want to impllement a uniform raycasting in a selected sphere region of a volume and want to calculate the intensity of each voxel that is traversed by a ray, I 'm a biginner in programing open gl,
can any one help me how I can do it?
any help from you appreciate alot.
Best

OpenGL is meant for rasterization, not raycasting.
You can, however, implement a raycaster in a fragment shader, but that would probably not the best ‘hello world’ to begin OpenGL programming…