Unity3D 实现深度相机 Depth Camera
工作原因，又把Unity3D捡起来了，需要实现一个深度相机。网上查了查资料，整理如下。
参考：http://williamchyr.com/2013/11/unity-shaders-depth-and-normal-textures/
我的代码在：
https://github.com/NianLi71/Camera-Util-Unity3D/tree/master/DepthCamera
一、如下建立场景，做一排cube放入一个CubeRow中。放好MainCamera位置，然后复制出DepthCamera，这样两个相机的位置视角一致，方便后续调试。
新建一个shader，参考链接中的地址，输入代码：
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
Shader "Custom/DepthGrayscale" {
SubShader {
Tags { "RenderType"="Opaque" }
Pass{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _CameraDepthTexture;
struct v2f {
float4 pos : SV_POSITION;
float4 scrPos:TEXCOORD1;
};
//Vertex Shader
v2f vert (appdata_base v){
v2f o;
o.pos = UnityObjectToClipPos (v.vertex);
o.scrPos=ComputeScreenPos(o.pos);
//for some reason, the y position of the depth texture comes out inverted
//o.scrPos.y = 1 - o.scrPos.y;
return o;
}
//Fragment Shader
half4 frag (v2f i) : COLOR{
float depthValue = Linear01Depth (tex2Dproj(_CameraDepthTexture, UNITY_PROJ_COORD(i.scrPos)).r);
half4 depth;
depth.r = depthValue;
depth.g = depthValue;
depth.b = depthValue;
depth.a = 1;
return depth;
}
ENDCG
}
}
FallBack "Diffuse"
}新建一个Material，并选择刚刚建好的shader文件
给DepthCamera添加脚本文件，输入以下代码：
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[ExecuteInEditMode] // 可以在编辑界面看到深度绘制效果
public class MainCameraDepth : MonoBehaviour {
public Material mat;
public int width = 512;
public int height= 512;
private Camera cam;
private RenderTexture rt;
private int image_id = 0;
void Start () {
cam = GetComponent(); //获取当前绑定到脚本的相机
cam.depthTextureMode = DepthTextureMode.Depth;
// rt = new RenderTexture (width, height, 24); // 24 bit depth
// cam.targetTexture = rt;
}
void OnRenderImage (RenderTexture source, RenderTexture destination){
Graphics.Blit(source,destination,mat);
//mat is the material which contains the shader
//we are passing the destination RenderTexture to
}
// Update is called once per frame
void Update () {
}
}
二、回到Unity主界面，将material文件拖拽给DepthCamera相机脚本，并将Audio Listener取消勾选。
之后，如图将Main Camera的Camera方框取消勾选：
在编辑界面即可看到深度图输出：
看到全黑的cube原因是相机的远裁剪平面设置的太远了。将DepthCamera的Clipping Planes far调整近一些：
即可看到灰度深度图：
三、保存深度图到文件Duplicate复制DepthCamera，并重新命名SnapDepthCamera，再添加一个脚本文件SnapDepthCamera.cs，输入以下代码:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[ExecuteInEditMode] // 可以在编辑界面看到深度绘制效果
public class SnapDepthCamera : MonoBehaviour {
public Material mat;
public int width = 512;
public int height= 512;
private Camera cam;
private RenderTexture rt;
private int image_id = 0;
private bool SnapFlag = false;
void Start () {
cam = GetComponent(); //获取当前绑定到脚本的相机
cam.depthTextureMode = DepthTextureMode.Depth;
rt = new RenderTexture (width, height, 24); // 24 bit depth
cam.targetTexture = rt;
}
void OnRenderImage (RenderTexture source, RenderTexture destination){
Graphics.Blit(source,destination,mat);
//mat is the material which contains the shader
//we are passing the destination RenderTexture to
if(SnapFlag) {
RenderTexture currentRT = RenderTexture.active; // save current active rendertexture
RenderTexture.active = destination;
Texture2D image = new Texture2D(destination.width, destination.height,TextureFormat.RGB24, false);
image.ReadPixels(new Rect(0, 0, destination.width, destination.height), 0, 0);
image.Apply();
savePNG (image, "./depthImages/camera_image" + image_id + ".png");
image_id++;
RenderTexture.active = currentRT; // restore
}
}
private void savePNG(Texture2D image, string path_file) {
// store the texture into a .PNG file
byte[] bytes = image.EncodeToPNG ();
// save the encoded image to a file
System.IO.File.WriteAllBytes (path_file, bytes);
}
// Update is called once per frame
void Update () {
if (Input.GetKeyDown ("p")) {
SnapFlag = true;
} else
SnapFlag = false;
}
}
之后在项目首页新建文件夹：depthImages/，之后运行程序，按'p'键即可保存深度图。