[游戏开发]商业Shader渲染-深度图

万物皆可深度图

这个图如何得到的呢？和一般网上说的Unity方法，cg方法都有点不同

        //VP矩阵（projectionMatrix），是将相机空间中的点从视锥体(frustum)变换到规则观察体(Canonical View Volume)中
        //实际上也就是3d->2d，世界坐标，转视线贴图
        Matrix4x4 projectionMatrix = GL.GetGPUProjectionMatrix(m_LightCamera.projectionMatrix, false) * m_LightCamera.worldToCameraMatrix;
        Shader.SetGlobalMatrix("_gWorldToShadow", projectionMatrix);

有了这个矩阵之后，在Shader这么写

v2f vert(appdata v)
{
    v2f o;
    o.shadowCoord = mul(_gWorldToShadow, o.vertex);
}

传统的深度图方法

以下方法，和上面是分开滴

以下非完整代码，无法商用，只是侃侃

			#include "UnityCG.cginc"
			sampler2D _CameraDepthTexture;
     /*       struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };*/

            struct v2f
            {
                float4 srcPos : TEXCOORD0;
				//float2 uv :TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            v2f vert (appdata_base v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                //o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				o.srcPos = ComputeScreenPos(o.vertex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                //fixed4 col = tex2D(_MainTex, i.uv);   
                //return col;
				float depth = 1 - Linear01Depth(tex2Dproj(_CameraDepthTexture,UNITY_PROJ_COORD(i.srcPos)).r);
				return float4(depth, depth, depth, 1.0f);
            }

用了一减去（反转), 所以深度图也是翻转的

文字深度图

?关键在于Text UI的材质和shader

深度图和原图同屏对比

Shader "UnLit/RGBDepth" {
    Properties{
        _MainTex("Base (RGB)", 2D) = "white" {}
    }
    SubShader{
    Tags{ "RenderType" = "Opaque" }

    Pass{
    Cull off

    ZTest Always Cull Off ZWrite Off

    CGPROGRAM
    //Physically based Standard lighting model, and enable shadows on all light types
    //#pragma surface surf Standard fullforwardshadows

    // Use shader model 3.0 target, to get nicer looking lighting
    #pragma glsl
    #pragma fragmentoption ARB_precision_hint_fastest
    #pragma target 3.0
    #pragma vertex vert
    #pragma fragment frag
    #include "unityCG.cginc"



    sampler2D _CameraDepthTexture;
    uniform sampler2D _MainTex;

    struct v2f {
        float4 pos : SV_POSITION;
        float4 scrPos:TEXCOORD0;
        float2 uv : TEXCOORD1;
    };
    //Vertex Shader
    v2f vert(appdata_base v) {
        v2f o;
        o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
        o.scrPos = ComputeScreenPos(o.pos);
        o.uv = v.texcoord.xy;
        return o;
    }

    //Fragment Shader
    float4 frag(v2f i) :COLOR{
        int width = 2560;//画面宽度放大比率
        int height = 1440;//画面高度放大比率
        int frame = 128;//边框宽度
        int RGBWidht = 1536;//RGB图宽度放大比率
        int depthWidth = 768;//深度图宽度放大比率
        int targetHeight = 1184;//输出图像部分高度

        float x = i.uv.x*width;
        float y = i.uv.y*height;
        //生成四边框
        if (x<frame)
            return float4(1.0f, 1.0f, 1.0f, 1.0f);
        if (x>width - frame)
            return float4(1.0f, 1.0f, 1.0f, 1.0f);
        if (y<frame)
            return float4(1.0f, 1.0f, 1.0f, 1.0f);
        if (y>height - frame)
            return float4(1.0f, 1.0f, 1.0f, 1.0f);

        y = (y-frame);
        //分割画面
        if (x < frame + RGBWidht) {
            x = (x - frame) / RGBWidht;
            y= y / targetHeight;
            return tex2D(_MainTex, float2(x , y ));
        }
        else {
            x= (x - frame - RGBWidht) ;
            i.scrPos.x= x / depthWidth;
            i.scrPos.y = y / targetHeight;
            float4 uv = UNITY_PROJ_COORD(i.scrPos);
            float depthValue = 1 - Linear01Depth(tex2Dproj(_CameraDepthTexture, uv).r);
            return float4(depthValue, depthValue, depthValue, 1.0f);
        }
        return float4(0.0f, 0.0f, 0.0f, 1.0f);
        }
            ENDCG
        }
    }
    FallBack "Diffuse"
}

?