发表于 | 分类于

创建正交相机，从光源视角渲染场景到全局纹理

1.新建场景，放置plane与若干物体，添加方向光，关闭其阴影。

upload successful

upload successful

2.新建脚本DepthTextureCamera.cs，附加到光源节点。

upload successful
脚本大致作用，动态创建正交相机，与光源节点transform完全一致，调用其Render，渲染至RenderTexture，仅保留深度信息。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class DepthTextureCamera : MonoBehaviour
{
    //正交相机对象
    Camera depthCamera;
    //shader,正交相机渲染时使用，仅保留深度信息
    Shader depthTextureShader;
    //全局纹理
    RenderTexture depthTexture;

    // Start is called before the first frame update
    private void Start()
    {
        depthCamera = new GameObject().AddComponent<Camera>();
        depthCamera.name = "DepthCamera";
        depthCamera.depth = 2;
        depthCamera.clearFlags = CameraClearFlags.SolidColor;
        depthCamera.backgroundColor = new Color(0, 0, 0, 0);
        depthCamera.aspect = 1;
        depthCamera.transform.position = this.transform.position;
        depthCamera.transform.rotation = this.transform.rotation;
        depthCamera.transform.parent = this.transform;
        depthCamera.orthographic = true;
        depthCamera.orthographicSize = 20;
		//阴影贴图分辨率
        depthTexture = new RenderTexture(512, 512, 0);
        depthTexture.wrapMode = TextureWrapMode.Clamp;
        depthCamera.targetTexture = depthTexture;
        depthCamera.enabled = false;
        depthTextureShader = Shader.Find("ShadowMap/DepthTextureShader");
    }

    // Update is called once per frame
    void Update()
    {
    	//每帧刷新纹理
        depthCamera.RenderWithShader(depthTextureShader, "RenderType");
        Shader.SetGlobalTexture("_DepthTexture", depthTexture);
    }
}

DepthTextureShader内容也很简单，只保留z坐标信息，保存成像素点数据。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
Shader "ShadowMap/DepthTextureShader"
{
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
                float2 depth : TEXCOORD1;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                o.depth = o.vertex.zw;
                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
            	//这里的xy对应顶点函数的zw，z/w齐次坐标坐标转为正交坐标
                float depth = i.depth.x/i.depth.y;
                fixed4 col = EncodeFloatRGBA(depth);//浮点数保存为RGBA值
                return col;
            }
            ENDCG
        }
    }
}

运行，打开Window->Analysis->Frame Debugger.

upload successful

能看到这个图，就是成功了。