Ray tracing vs Rasterization

Hello there !

Today, we are talking about a choice to use ray tracing, or rasterization.
We are going to begin to speak about rasterization.

Rasteri What?

It’s a barbarian word, I know. But you use that every time, Indeed, current video games used this technique to « draw » at the screen the scene. It’s a good technique because it is very fast (several millions of triangles can be rendered at 60 FPS), but, it’s difficult to implement reflections, refractions and others.

Ray tracing is one other technique to draw in the screen. The principle is to trace a ray in opposite direction of reality. Indeed, in the real world, photons started from the light, and arrive on the object. Ray tracing do other. Ray start from eyes (camera) and the finish way is the light.

Sheme of ray tracing
Sheme of ray tracing

To implement global illumination, Raytracing is easier than Rasterization but need so much compute to compare with rasterization. That’s why ray tracing is not used yet in video games, or begin to arrive in video games (Unreal Engine used : Ray traced distance field soft shadows)

What is my choice ?

I’m going to create one hybrid rendering. Indeed, my first ray will be create by rasterization, and shadows, reflections, refractions are ray traced. With that, we can obtain a render very quickly, after, we « just » have to optimise our algorithm to improve computes :-).

We hope obtain this scene at 5-10 FPS (or much).


Bye :).


What is this blog?

Hello there.

This first article is meant to give you a bird’s view about the subjects we’ll deal with in this blog.
You thought I’m going to talk about Global Illumination.

Wait !! What is « Global Illumination »?
Global illumination is one « idea ». Indeed, in cartoon, or in video games (they are more interesting to make global illumination in real time), you have reflections, refractions, and … soft shadows (they need too much computes, so, generally, you love disable this option).

One exemple ?

Global Illumination

This scene is a good example of Global Illumination. You can see refraction, reflection and soft shadows.

More About me :

My name is Antoine MORRIER, I’m 20 years old and I’m student at Télécom SudParis, and I try to create a real time 3D engine with global illumination. I use for that, OpenGL 4.4 with GLSL.



Bye :).