Ray Tracing vs. Rasterization: What’s The Difference?
Last updated on September 19th, 2023 at 07:43 pm
Ray tracing and rasterization are two different ways to process shadows and lights to create better graphics and realistic 3D images.
Rasterization has been around for a long time and is the technique used to create graphics in most games.
However, ray tracing is a more advanced technique that is slowly becoming more popular as games and technology become more advanced.
What is Ray Tracing?
Ray tracing is used to simulate how light will interact with different objects in video games and films. Being able to simulate light in this will provide a more realistic environment creating stunning graphic visuals on your screen.
Using this technique will improve how shadows, reflections, and refractions work because it simulates how light works in real life.
Even though ray tracing is a newer technique when it comes to video games, it has actually been used for a long time being implemented in films that use CGI.
However, the use of ray tracing is very demanding on hardware and requires high-end graphics processing units in order to function properly.
What is Rasterization?
Rasterization is a process in which it turns vector graphics which is a combination of polygons, and lines used to create a 2D image, and turns it into pixels, which will create 3D-like images.
This is a technique used mostly in video games that allows you to experience 3D images and scenery in a 2D world.
Rasterization also works on other images used outside of video games such as printing or digital imaging.
In these situations it takes the vector data and converts it into pixels, creating a higher-quality image that can be transformed, stretched, and played with.
For a more in-depth explanation, I have written a detailed article on what rasterization is.
Ray Tracing vs. Rasterization Pros and Cons
Even though ray tracing and rasterization are both used for rendering images, these two rendering techniques both have their pros and cons when used to process images.
Rasterization Pros and Cons
Here are a few pros and cons of Rasterization.
Pros
- Speed: Rasterization is faster than ray tracing because it is a lot less demanding.
- Hardware Support: Every modern GPU supports and is optimized for rasterization. This makes it easier to run applications and games.
- Scalability: Easier to scale down for lower-end devices such as phones and tablets. This is important for mobile gaming.
- Efficient for Simple Scenes: When you have scenes that don’t use or need complex lighting, it is a lot more efficient to use rasterization instead of other techniques like ray tracing.
- Mature Technology: Rasterization has been around for a long time, which means it is constantly optimized, and there are many tools that make rasterization easier to use and run programs that use rasterization as a rendering technique.
Cons
- Less Realistic: Rasterization produces less realistic images, especially when it comes the lighting and shadows. The reason for this is because they have to be drawn out beforehand.
- Limited Global Illumination: It’s challenging to implement global illumination effects like reflections, refractions, and complex shadows.
- Overdraw: Rasterization uses pixels that can be drawn out multiple times. When this happens it makes rasterization inefficient.
- Z-Buffer Limitations: The use of a Z-buffer for depth can lead to artifacts like Z-fighting.
- Post-Processing Required: Many effects, like blur and anti-aliasing, often need to be added in post-processing stages, which can add complexity.
Ray Tracing Pros and Cons
Here are a few pros and cons of ray tracing.
Pros
- Realism: Ray tracing produces very realistic images because it can accurately simulate lighting, shadows, and reflections in real time.
- Global Illumination: Ray tracing can run complex lighting scenarios where light has to travel long distances and can simulate the light bouncing off multiple objects multiple times.
- Simplicity of Code: Coding algorithms for ray tracing can be very easy to understand to implement for certain effects, such as how shadows work, and how light reflects off of different objects.
- No Overdraw: Every pixel processed in this technique is processed once, which is a big problem with rasterization.
- Flexibility: It is a lot easier to implement certain effects such as depth of field, motion blur, and other complex interactions that rasterization can’t implement.
Cons
- Speed: Ray tracing is a lot slower than rasterization. This makes it unrealistic to be used in applications that aren’t highly optimized by ray tracing and that don’t have hardware support for this kind of technology.
- Hardware Requirements: You will need a high-end GPU to process ray tracing at a respectable speed because it requires a lot more computational power to run.
- Complexity: While some effects are simpler to implement, the overall algorithm can become complex and computationally intensive as more realism is added.
- Emerging Hardware Support: Even though ray tracing is rising in popularity, the technology and techniques used for ray tracing aren’t as optimized and as well understood as rasterization.
What to Takeaway?
Ray tracing and rasterization both have their own advantages and disadvantages when it comes to creating graphics. However, these two techniques are now often times used side-by-side to create something that is both well-optimized for everyone and an environment that is more immersive. (Especially when gaming.)
A game might use the rasterization technique for the majority of graphics but will implement ray tracing to create more realistic shadows, lighting, and reflections.
You should also check out: “Path Tracing vs. Ray Tracing”
