Post-processing effects in Unity - Step-by-Step Execution

Concept Flow - Post-processing effects

Render Scene

↓

Apply Post-processing Stack

↓

Effects: Bloom, Color Grading, Vignette, etc.

↓

Combine Effects

↓

Output Final Image to Screen

The game scene is rendered first, then post-processing effects like bloom and color grading are applied in order, combined, and finally shown on screen.

Execution Sample

Unity

using UnityEngine;
using UnityEngine.Rendering.PostProcessing;

public class PostProcessSetup : MonoBehaviour {
  public PostProcessVolume volume;
  void Start() {
    var bloom = ScriptableObject.CreateInstance<Bloom>();
    bloom.intensity.value = 5f;
    volume = PostProcessManager.instance.QuickVolume(gameObject.layer, 100f, bloom);
  }
}

This code creates a bloom effect with intensity 5 and applies it to the camera's post-processing volume.

Execution Table

Step	Action	Effect Created/Modified	Value Set	Result
1	Create Bloom instance	Bloom	default values	Bloom effect object created
2	Set bloom intensity	Bloom	intensity = 5f	Bloom intensity updated
3	Create PostProcessVolume	Volume	priority = 100f	Volume created with bloom effect
4	Assign volume to camera layer	Volume	layer = gameObject.layer	Volume active on camera
5	Render frame	Scene + Bloom	N/A	Scene rendered with bloom effect applied
6	End	N/A	N/A	Post-processing applied successfully

💡 All post-processing effects applied and frame rendered to screen

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
bloom	null	Bloom instance created	Intensity set to 5f	Same	Same	Same
volume	null	null	null	Volume created with bloom	Assigned to layer	Same

Key Moments - 2 Insights

Why do we create a Bloom instance before setting its intensity?

Because the bloom variable must reference a valid Bloom object before we can change its properties, as shown in execution_table step 1 and 2.

What happens if the PostProcessVolume is not assigned to the camera's layer?

The effects won't apply to the camera's view, so no post-processing will be visible, as seen in step 4 where assignment activates the volume.

Visual Quiz - 3 Questions

Look at the execution table, what is the bloom intensity value after step 2?

A 0f

B 5f

C 10f

D Not set yet

💡 Hint

Check the 'Value Set' column in step 2 of the execution_table.

At which step is the PostProcessVolume created?

A Step 3

B Step 1

C Step 4

D Step 5

💡 Hint

Look at the 'Action' column in the execution_table for volume creation.

If we skip assigning the volume to the camera's layer, what will happen?

A Post-processing effects will still apply

B The bloom intensity will reset

C No post-processing effects will be visible

D The game will crash

💡 Hint

Refer to key_moments question 2 and execution_table step 4.

Concept Snapshot

Post-processing effects modify the final rendered image.
Create effect instances (e.g., Bloom), set their properties.
Add effects to a PostProcessVolume.
Assign volume to camera layer to activate.
Effects combine and render on screen each frame.

Full Transcript

Post-processing effects in Unity are applied after the scene is rendered. First, you create effect instances like Bloom and set their properties such as intensity. Then, you create a PostProcessVolume and add these effects to it. Assigning this volume to the camera's layer activates the effects. When the frame renders, the scene image passes through these effects and the final image with visual enhancements is shown on screen. This process repeats every frame to keep effects active.