理解 Unity3D RenderWithShader Api

来源：互联网发布：广告清理软件编辑：程序博客网时间：2024/05/19 17:59

主要参考：

unity, 替换shader渲染（Rendering with Replaced Shaders）：http://www.cnblogs.com/wantnon/p/4528677.html

测试例子：

Test.cs挂到Camera上

using UnityEngine;using System.Collections;public class Test1 : MonoBehaviour {    private Camera shaderCamera;    private RenderTexture replaceRenderTexture;    public void Start()    {        shaderCamera = new GameObject("Test", typeof(Camera)).GetComponent<Camera>();        Camera origCamera = GetComponent<Camera>();        replaceRenderTexture = new RenderTexture((int)origCamera.pixelWidth, (int)origCamera.pixelHeight, 16, RenderTextureFormat.ARGB32);        replaceRenderTexture.wrapMode = TextureWrapMode.Clamp;        replaceRenderTexture.useMipMap = false;        replaceRenderTexture.filterMode = FilterMode.Bilinear;        replaceRenderTexture.Create();    }    public void OnPreRender()    {        Camera origCamera = GetComponent<Camera>();        shaderCamera.CopyFrom(origCamera);        //shaderCamera.backgroundColor = Color.clear;        shaderCamera.clearFlags = CameraClearFlags.SolidColor;        shaderCamera.renderingPath = RenderingPath.Forward;        shaderCamera.targetTexture = replaceRenderTexture;        shaderCamera.depth = 10;                shaderCamera.RenderWithShader(Shader.Find("Unlit/blueSphere"), "RenderType");    }}

redAndGreen.shader

Shader "Unlit/redAndGreenSphere"{Properties{_MainTex ("Texture", 2D) = "white" {}}SubShader{Tags { "RenderType"="Green" }LOD 100Pass{//Tags { "RenderType"="Green" }CGPROGRAM#pragma vertex vert#pragma fragment frag// make fog work#pragma multi_compile_fog#include "UnityCG.cginc"struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f{float2 uv : TEXCOORD0;UNITY_FOG_COORDS(1)float4 vertex : SV_POSITION;};sampler2D _MainTex;float4 _MainTex_ST;v2f vert (appdata v){v2f o;o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);o.uv = TRANSFORM_TEX(v.uv, _MainTex);UNITY_TRANSFER_FOG(o,o.vertex);return o;}fixed4 frag (v2f i) : SV_Target{// sample the texturefixed4 col = tex2D(_MainTex, i.uv);// apply fogUNITY_APPLY_FOG(i.fogCoord, col);return fixed4(0, 0.5, 0, 1);}ENDCG}}SubShader{Tags { "RenderType"="Red" }LOD 100Pass{//Tags { "RenderType"="Red" }CGPROGRAM#pragma vertex vert#pragma fragment frag// make fog work#pragma multi_compile_fog#include "UnityCG.cginc"struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f{float2 uv : TEXCOORD0;UNITY_FOG_COORDS(1)float4 vertex : SV_POSITION;};sampler2D _MainTex;float4 _MainTex_ST;v2f vert (appdata v){v2f o;o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);o.uv = TRANSFORM_TEX(v.uv, _MainTex);UNITY_TRANSFER_FOG(o,o.vertex);return o;}fixed4 frag (v2f i) : SV_Target{// sample the texturefixed4 col = tex2D(_MainTex, i.uv);// apply fogUNITY_APPLY_FOG(i.fogCoord, col);return fixed4(0.5, 0, 0, 1);}ENDCG}}}

blueSphere.shader

Shader "Unlit/blueSphere"{Properties{_MainTex ("Texture", 2D) = "white" {}}SubShader{Tags { "RenderType"="Green" }LOD 100Pass{CGPROGRAM#pragma vertex vert#pragma fragment frag// make fog work#pragma multi_compile_fog#include "UnityCG.cginc"struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f{float2 uv : TEXCOORD0;UNITY_FOG_COORDS(1)float4 vertex : SV_POSITION;};sampler2D _MainTex;float4 _MainTex_ST;v2f vert (appdata v){v2f o;o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);o.uv = TRANSFORM_TEX(v.uv, _MainTex);UNITY_TRANSFER_FOG(o,o.vertex);return o;}fixed4 frag (v2f i) : SV_Target{// sample the texturefixed4 col = tex2D(_MainTex, i.uv);// apply fogUNITY_APPLY_FOG(i.fogCoord, col);//return col;return fixed4(0, 0, 0.5, 1);}ENDCG}}}

结论：

在shaderCamera 中，因为调用了RenderWithShader(Shader.Find("Unlit/blueSphere"), "RenderType");，因为blueSphere的SubShader的 "RenderType"="Green"，所以，会在场景中进行寻找第一个SubShader的"RenderType"="Green" 的物体，用blueSphere的SubShader来代替这些物体就进行渲染。

所以，上面的挂上了redAndGreen材质的球，本来是绿色，会用blueSphere.shader来渲染，渲染为蓝色。

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