Note: Unity no longer develops or improves the rendering path that doesn’t use the render graph API. Use the render graph API instead when developing new graphics features. To use the instructions on this page, enable Compatibility Mode (Render Graph Disabled) in URP graphics settings (Project Settings > Graphics).
The following example is a ScriptableRenderPass
instance that performs the following steps:
RenderTextureDescriptor
API.RTHandle
and the Blit
API.After you write a Scriptable Render Pass, you can inject the render pass using one of the following methods:
This section demonstrates how to create a scriptable Render Pass.
Create a new C# script and name it RedTintRenderPass.cs
.
In the script, remove the code that Unity inserted in the RedTintRenderPass
class. Add the following using
directive:
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
Create the RedTintRenderPass
class that inherits from the ScriptableRenderPass class.
public class RedTintRenderPass : ScriptableRenderPass
Add the Execute
method to the class. Unity calls this method every frame, once for each camera. This method lets you implement the rendering logic of the scriptable Render Pass.
public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
{ }
Below is the complete code for the RedTintRenderPass.cs file from this section.
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
public class RedTintRenderPass : ScriptableRenderPass
{
public override void Execute(ScriptableRenderContext context,
ref RenderingData renderingData)
{
}
}
Add a field for the Material, and the constructor that uses the field.
private Material material;
public RedTintRenderPass(Material material)
{
this.material = material;
}
Add the RenderTextureDescriptor
field and initialize it in the constructor:
using UnityEngine;
private RenderTextureDescriptor textureDescriptor;
public RedTintRenderPass(Material material)
{
this.material = material;
textureDescriptor = new RenderTextureDescriptor(Screen.width,
Screen.height, RenderTextureFormat.Default, 0);
}
Declare the RTHandle
field to store the reference to the temporary red tint texture.
private RTHandle textureHandle;
Implement the Configure
method. Unity calls this method before executing the render pass.
public override void Configure(CommandBuffer cmd,
RenderTextureDescriptor cameraTextureDescriptor)
{
//Set the red tint texture size to be the same as the camera target size.
textureDescriptor.width = cameraTextureDescriptor.width;
textureDescriptor.height = cameraTextureDescriptor.height;
//Check if the descriptor has changed, and reallocate the RTHandle if necessary.
RenderingUtils.ReAllocateIfNeeded(ref textureHandle, textureDescriptor);
}
Use the BlitA shorthand term for “bit block transfer”. A blit operation is the process of transferring blocks of data from one place in memory to another.
See in Glossary method to apply the two render passes from the custom shaderA program that runs on the GPU. More info
See in Glossary to the camera output.
public override void Execute(ScriptableRenderContext context,
ref RenderingData renderingData)
{
//Get a CommandBuffer from pool.
CommandBuffer cmd = CommandBufferPool.Get();
RTHandle cameraTargetHandle =
renderingData.cameraData.renderer.cameraColorTargetHandle;
// Blit from the camera target to the temporary render texture,
// using the first shader pass.
Blit(cmd, cameraTargetHandle, textureHandle, material, 0);
// Blit from the temporary render texture to the camera target,
// using the second shader pass.
Blit(cmd, textureHandle, cameraTargetHandle, material, 1);
//Execute the command buffer and release it back to the pool.
context.ExecuteCommandBuffer(cmd);
CommandBufferPool.Release(cmd);
}
Implement the Dispose
method that destroys the Material and the temporary render texture after the render pass execution.
public void Dispose()
{
#if UNITY_EDITOR
if (EditorApplication.isPlaying)
{
Object.Destroy(material);
}
else
{
Object.DestroyImmediate(material);
}
#else
Object.Destroy(material);
#endif
if (textureHandle != null) textureHandle.Release();
}
Below is the complete code for the custom Render Pass script.
using UnityEditor;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
public class RedTintRenderPass : ScriptableRenderPass
{
private Material material;
private RenderTextureDescriptor textureDescriptor;
private RTHandle textureHandle;
public RedTintRenderPass(Material material)
{
this.material = material;
textureDescriptor = new RenderTextureDescriptor(Screen.width,
Screen.height, RenderTextureFormat.Default, 0);
}
public override void Configure(CommandBuffer cmd,
RenderTextureDescriptor cameraTextureDescriptor)
{
// Set the texture size to be the same as the camera target size.
textureDescriptor.width = cameraTextureDescriptor.width;
textureDescriptor.height = cameraTextureDescriptor.height;
// Check if the descriptor has changed, and reallocate the RTHandle if necessary
RenderingUtils.ReAllocateIfNeeded(ref textureHandle, textureDescriptor);
}
public override void Execute(ScriptableRenderContext context,
ref RenderingData renderingData)
{
//Get a CommandBuffer from pool.
CommandBuffer cmd = CommandBufferPool.Get();
RTHandle cameraTargetHandle =
renderingData.cameraData.renderer.cameraColorTargetHandle;
// Blit from the camera target to the temporary render texture,
// using the first shader pass.
Blit(cmd, cameraTargetHandle, textureHandle, material, 0);
// Blit from the temporary render texture to the camera target,
// using the second shader pass.
Blit(cmd, textureHandle, cameraTargetHandle, material, 1);
//Execute the command buffer and release it back to the pool.
context.ExecuteCommandBuffer(cmd);
CommandBufferPool.Release(cmd);
}
public void Dispose()
{
#if UNITY_EDITOR
if (EditorApplication.isPlaying)
{
Object.Destroy(material);
}
else
{
Object.DestroyImmediate(material);
}
#else
Object.Destroy(material);
#endif
if (textureHandle != null) textureHandle.Release();
}
}
This section contains the code for the custom shader that implements the red tint effect.
Shader "CustomEffects/RedTint"
{
HLSLINCLUDE
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
// The Blit.hlsl file provides the vertex shader (Vert),
// the input structure (Attributes), and the output structure (Varyings)
#include "Packages/com.unity.render-pipelines.core/Runtime/Utilities/Blit.hlsl"
float4 RedTint (Varyings input) : SV_Target
{
float3 color = SAMPLE_TEXTURE2D(_BlitTexture, sampler_LinearClamp, input.texcoord).rgb;
return float4(1, color.gb, 1);
}
float4 SimpleBlit (Varyings input) : SV_Target
{
float3 color = SAMPLE_TEXTURE2D(_BlitTexture, sampler_LinearClamp, input.texcoord).rgb;
return float4(color.rgb, 1);
}
ENDHLSL
SubShader
{
Tags { "RenderType"="Opaque" "RenderPipeline" = "UniversalPipeline"}
LOD 100
ZTest Always ZWrite Off Cull Off
Pass
{
Name "RedTint"
HLSLPROGRAM
#pragma vertex Vert
#pragma fragment RedTint
ENDHLSL
}
Pass
{
Name "SimpleBlit"
HLSLPROGRAM
#pragma vertex Vert
#pragma fragment SimpleBlit
ENDHLSL
}
}
}