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Featured Unity Asset: Post Processing Stack

If you’re working on a scene in the Unity Game Engine and you’re content with its function, it might be time to begin thinking about fit and finish. There’s an easy shortcut to improved visuals in the Unity Asset Store called the Post Processing Stack. It’s a free asset made in-house by Unity Technologies.

The Post Processing Stack is a collection of common post processing effects used in rasterization pipelines. In other words, they are full screen camera filters that can dramatically improve the way your game looks. The appeal of this add-on is that it groups together some of the most used effects and combines them into one uber effect. This creates a single post-process pipeline with a simplified UI for easy organization of your settings.

According to Full Stack Developer at KTI, Chris Hodge, it’s “a must have inclusion for any Unity developer looking to make anything of AAA quality”. Hodge adds that the Post Processing Stack “adds a level of depth and realism to traditional rasterized images.”

Another great feature of the Post Processing Stack is that it ensures effects are always configured in the right order which can save you time fiddling with your cameras.

A number of vital filters and effects are included in the Post Processing Stack, including ambient occlusion, depth of field, motion blur, bloom, vignette and colour grading. Check below the quick tips for a rundown on each and every effect in the Post Processing Stack, courtesy of Hodge.

It’s a robust and simple toolset and the fact that it’s supported by Unity Technologies itself means that you can rest assured that it will receive continual quality of life updates and support in every new build of Unity.

Quick Tips

  • The Post Processing Stack is tied to your camera, as it’s a series of filters and effects, so ensure that it’s present on every camera in your scene to maintain continuity.
  • For a good rundown on getting set up with the Post Processing Stack in Unity, check out Unity wizard Brackeys’ video.

Post Processing Stack Rundown

There are many pieces to the Post Processing Stack and it’s easy to get overwhelmed. Here are some brief descriptions of each element of the Post Processing Stack.

Antialiasing

This cleans up jagged edges caused by the rendering process. In rasterization, geometry is projected at the screen, pixel-by-pixel. This process is very fast but doesn’t take into account contours and smooth edges that well. Antialiasing fixes this by sampling surrounding areas to smooth those edges off.

Ambient Occlusion

This effect adds some depth to the render by adding shadows to hard edges. The fake shadowing effect makes edges easier to see.

Screen Space Reflection

One of the more powerful features of the Post Processing Stack is the screen space reflections. This effect uses the information it can see on-screen to create real-time reflections from the camera’s viewpoint. Here is a good example of screen space reflections in action. On the left is the default rendered image. On the right is the same image but with screen space reflections enabled.

An image before screen space reflection is applied.

Screen Space Reflection effect is turned off in this image.

An image after screen space reflection is applied.

Screen Space Reflection effect is turned on in this image.

Bloom

Bloom is another powerful effect in the Post Processing Stack. In HDR (High Dynamic Range) render pipelines, this adds a glow effect around bright colours shown on-screen. This can be very useful in making light appear to have some volume. Here is an example of bloom turned off and on in a scene.

An image before bloom effect is applied.

Bloom effect is turned off in this image.

An image after bloom is applied.

Bloom effect is turned on in this image.

Depth of Field

The depth of field effect uses the camera depth buffer to apply a blurring to the image which has a focal point and aperture to dial in the focus. This simulates how camera lenses behave in the real world.

An image before depth of field is applied.

Depth of Field effect is turned off in this image.

An image's camera depth used in depth of field.

This is the Camera Depth used in Depth of Field for the first image.

An image after depth of field is applied.

Depth of Field is turned on in this image.

Motion Blur

The motion blur effect is a frame-over-frame effect which blurs the image wherever movement is present. This is added back into the image and then repeated every frame. This can work really well in cinematics but should be used sparingly in fast-paced situations as it can obscure detail.

Eye Adaptation

Eye adaptation is an effect which brightens or darkens an image based on available light on-screen. If the camera is shown a bright light it will darken the image to simulate how our eyes work.

Color Grading

Color grading takes an image and applies tone mapping properties to simulate a specific colour space.

User LUT

This is another form of color grading that allows you to use a custom look up table, or LUT.

Chromatic Aberration

Chromatic Aberration is an effect where the red/green/blue channels are pushed apart based on a vignette of the screen. The effect intensifies as it moves towards the edge of the frame.

Grain

The grain effect is used to add a small amount of noise to the image. Its most common use is in cinematics to simulate film grain.

Vignette

The vignette effect adds a border/edge effect which darkens the image slightly, drawing focus to the center of the screen.

Dithering

Dithering is a pattern effect used to try and prevent colour banding. In situations where colour depth is limited, artifacting can occur. This makes colours appear to have bands in them. Dithering is a process of patterning between the bands to dissolve them.

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