Version: 2020.1
渲染纹理
电影纹理 (Movie Textures)

自定义渲染纹理

Custom Render Textures are a special type of texture that allows you to update a texture with a shader. They are an extension to Render Textures. You can use Custom Render Textures to create complex simulations like caustics, ripple simulation for rain effects and liquid splatters.

Custom Render Textures provides a scripting and Shader framework to help with more complicated configuration like partial or multi-pass updates or varying update frequency. To use this framework you need to assign a Material to the Custom Render Texture asset. To do this:

  1. Create a new Custom Render Texture asset
  2. Assign a Material to it in the inspector window in the Material property

This Material updates the content of the texture according to its parameters. You can assign any kind of Material to a Custom Render Texture, including a Material that is assigned to another Custom Render Texture.

Render Pipeline Compatibility

The table below describes the compatibility between the Custom Render Textures feature and each render pipeline:

功能 内置渲染管线 通用渲染管线 (URP) 高清渲染管线 (HDRP) Custom Scriptable Render Pipeline (SRP)
Custom Render Textures Yes (1) Yes (1) Yes (1) Yes (1)

注意:

  1. Currently, you can’t create Materials that update and initialize Custom Render Textures in Shader Graph. You can only create Unity shaders that operate on Custom Render Textures by writing ShaderLab code.

属性

The Custom Render Textures inspector window displays many of the same properties as the Render Texture inspector, and some properties specific to Custom Render Textures.

渲染纹理:

属性: 功能:
Dimension Dimension of the Render Texture.
     2D Makes the Render Texture two dimensional.
     Cube Makes the Render Texture a cube map.
     3D Makes the Render Texture three dimensional.
Size 渲染纹理的大小(以像素为单位)。
Color Format The Format of the Render Texture.
sRGB (Color Render Texture) Enable to allow the Render Texture to use sRGB read/write conversions (Read Only).
Enable Mip Maps Enable to allow the Render Texture to use Mip Maps.
Auto generate Mip Maps 启用此属性可自动生成 MipMap。
Wrap Mode Defines how the Texture behaves when tiled.
     Repeat The Texture repeats itself as a tile.
     Clamp 纹理的边缘被拉伸。
Filter Mode Defines how Unity filters the Texture when it is stretched by 3D transformations.
     Point The Texture becomes blocky up close.
     Bilinear The Texture becomes blurry up close.
     Trilinear Like Bilinear, but the Texture also blurs between different mip levels.
Aniso Level Increases Texture quality when viewing the texture at a steep angle. Good for floor and ground textures.

自定义纹理:

These properties are exclusive to Custom Render Textures. Custom Texture parameters are separated into three categories:

  • Material:定义用于更新纹理的着色器。

  • Initialization: Controls how the texture is initialized before the shader performs any updates.

  • Update: Controls how the shader updates the texture.

属性: 功能:
Material The Material used to update the Custom Render Texture
     Shader Pass The Shader Pass used to update the Custom Render Texture. The combo box shows all passes available in your Material.
Initialization Mode The rate at which Unity initializes the texture.
     OnLoad Unity initializes the texture once upon creation.
     Realtime Unity initializes the texture every frame.
     OnDemand Unity initializes the texture on demand from the script.
Source How Unity texture initializes the texture.
     Texture and Color A texture multiplied by a color initializes the texture.
         Initialization Color Defines the color that initializes the Custom Render Texture. If you also provide an Initialization Texture, the multiplication of the color and the texture initializes the the Custom Render Texture.
         Initialization Texture Defines the texture that initializes the Custom Render Texture. If you also provide an Initialization Color, the multiplication of the color and the texture initializes the the Custom Render Texture.
     Material A Material initialises the texture.
         Initialization Material Defines the Material that initializes the Custom Render Texture.
Update Mode The rate at which the shader updates the Custom Render Texture..
     OnLoad The shader updates the texture once upon creation.
     Realtime The shader updates the texture every frame.
     OnDemand The shader updates the texture on demand from script.
Period The period in seconds at which Unity updates a real-time texture. A value of 0.0 updates every frame. This property is only available in real time.
Double Buffered Double-buffers the texture. Each update swaps the two buffers. This allows you to read the result of the preceding update in the shader.
Wrap Update Zones 启用此属性允许部分更新区域包围纹理的边框。
Cubemap Faces (Cubemap only) Series of toggle allowing user to enable/disable update on each of the cube map faces.
Update Zone Space 在此坐标系统中定义更新区域。
     Normalized All coordinates and sizes are between 0 and 1 with the top-left corner starting at (0, 0).
     Pixel All coordinates and sizes are expressed in pixels limited by the width and height of the texture. Top-left corner starting at (0, 0).
Update Zone List List of update zones for the texture (see below for more details).

将自定义渲染纹理导出到文件:

You can export Custom Render Textures to a PNG or EXR file (depending on the texture format) via the contextual “Export” menu.

更新区域 (Update Zones):

When Unity updates the Custom Render Texture, the Material updates the whole texture at once by default. The Custom Texture allows you to define zones of partial update. You can use this to define as many zones as you want and the order in which the zones are processed.

This is useful for various purposes. For example, you could have multiple small zones to splat water drops on the texture and then do a full pass to simulate the ripples. This can also be used as an optimization when you know that you don’t need to update the full texture.

Update zones have their own set of properties. The Update Zone Space is visible in the display. Coordinates depend on the Dimension of the texture: 2D for 2D and Cube textures, or 3D for 3D textures.

属性: 功能:
Center 更新区域中心的坐标。
Size The size of the update zone.
Rotation The orientation of the update zone in degrees (unavailable for 3D textures).
Shader Pass Defines the Shader Pass to use for this update zone. If you set this property as default, this update zone uses the Shader Pass that you defined in the main part of the inspector. Otherwise it will use the Shader Pass you provide.
Swap (Double Buffer) (Only for Double Buffered textures) If Swap is enabled, Unity swaps the buffers before processing this update zone.

双缓冲自定义纹理

Custom Render Textures can be double-buffered. This means that inside one Custom Render Texture there are two textures which Unity can swap after each update. This allows you to read the result of the last update while writing a new result in the Custom Render Texture. This is particularly useful if the shader needs to use the content already written in the texture but cannot mix the values with classic blend modes. This is also required if the shaders have to sample different pixels of the preceding result.

Performance warning: Double buffering currently involves a copy of the texture at each swap which can lead to a drop in performance depending on the frequency at which it is done and the resolution of the texture.

链接自定义渲染纹理

Custom Render Textures require a Material to be updated. This Material can have textures as an input. This means that you can use a Custom Render Texture as an input to generate another one. This way, you can chain up several Custom Textures to generate a more complex multi-step simulation. The system will correctly handle all the dependencies so that the different updates happen in the right order.

为自定义渲染纹理编写着色器

Updating a Custom Texture is like performing 2D post processing in a Render Texture. To help you write your custom texture shaders, here is a small framework with utility functions and built-in helper variables.

The following shader example fills the texture with a color multiplied by a color:

Shader "CustomRenderTexture/Simple"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _Tex("InputTex", 2D) = "white" {}
     }

     SubShader
     {
        Lighting Off
        Blend One Zero

        Pass
        {
            CGPROGRAM
            #include "UnityCustomRenderTexture.cginc"
            #pragma vertex CustomRenderTextureVertexShader
            #pragma fragment frag
            #pragma target 3.0

            float4      _Color;
            sampler2D   _Tex;

            float4 frag(v2f_customrendertexture IN) : COLOR
            {
                return _Color * tex2D(_Tex, IN.localTexcoord.xy);
            }
            ENDCG
            }
    }
}

为自定义纹理编写着色器时,唯一必需的步骤是:

  • #include "UnityCustomRenderTexture.cginc"

  • Use the provided Vertex Shader CustomRenderTextureVertexShader

  • Use the provided input structure v2f_customrendertexture for the pixel shader

Here is another example of a shader used in an initialization Material:

Shader "CustomRenderTexture/CustomTextureInit"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _Tex("InputTex", 2D) = "white" {}
    }

    SubShader
    {
        Lighting Off
        Blend One Zero

        Pass
        {
            CGPROGRAM
            #include "UnityCustomRenderTexture.cginc"

            #pragma vertex InitCustomRenderTextureVertexShader
            #pragma fragment frag
            #pragma target 3.0

            float4      _Color;
            sampler2D   _Tex;

            float4 frag(v2f_init_customrendertexture IN) : COLOR
            {
                return _Color * tex2D(_Tex, IN.texcoord.xy);
            }
            ENDCG
        }
    }
}

与更新着色器的情况下相同,唯一必需的步骤如下:

* #include “UnityCustomRenderTexture.cginc”

  • 使用提供的顶点着色器 InitCustomRenderTextureVertexShader

  • 为像素着色器使用提供的输入结构 v2f_init_customrendertexture

This example shader includes a set of built-in values. This includes Global values, values from the v2f_customrendertexture structure and values from the v2f_init_customrendertexture structure.

The input values from the v2f_customrendertexture structure:

名称 Type
localTexcoord float3 相对于当前正在处理的更新区域的纹理坐标。
globalTexcoord float3 相对于自定义渲染纹理本身的纹理坐标
primitiveID uint 当前正在处理的更新区域的索引。
direction float3 对于立方体自定义渲染纹理,立方体贴图内当前像素的方向。

The input values from the v2f_init_customrendertexture structure:

名称 Type
texcoord float3 相对于自定义渲染纹理本身的纹理坐标。

全局值:

名称 Type
_CustomRenderTextureWidth float 自定义纹理的宽度(以像素为单位)
_CustomRenderTextureHeight float 自定义纹理的高度(以像素为单位)
_CustomRenderTextureDepth float 自定义纹理的深度(以像素为单位,仅适用于 3D 纹理,否则将始终等于 1)。
_CustomRenderTextureCubeFace float 仅适用于立方体贴图:正在处理的当前立方体贴图面的索引 (-X, +X, -Y, +Y, -Z, +Z)。
_CustomRenderTexture3DSlice float 仅适用于 3D 纹理:正在处理的当前 3D 切片的索引。
_SelfTexture2D Sampler2D 仅适用于双缓冲纹理:该纹理包含上次交换之前的上次更新的结果。
_SelfTextureCube SamplerCUBE 仅适用于双缓冲纹理:该纹理包含上次交换之前的上次更新的结果。
_SelfTexture3D Sampler3D 仅适用于双缓冲纹理:该纹理包含上次交换之前的上次更新的结果。

通过脚本控制自定义渲染纹理

Most of the functionalities described here can be accessed via the Scripting API. Changing Material parameters, update frequency, update zones, requesting an update etc, can all be done with the script.

Any update requested for the Custom Texture will happen at a very specific time at the beginning of the frame with the current state of the Custom Texture. This guarantees that any Material using this texture will have the up-to-date result.

这意味着以下模式:

customRenderTexture.updateZones = updateZones1;
customRenderTexture.Update();
customRenderTexture.updateZones = updateZones2;
customRenderTexture.Update();

Will not yield the “expected” result of one update done with the first array of update zones and then a second update with the other array. This will perform two updates with the second array.

Essentially, any property modified will only be active in the next frame.


  • 2017–05–18 页面已发布

  • Unity 2017.1 中的新功能 NewIn20171

渲染纹理
电影纹理 (Movie Textures)