Resconstruction World Position from Depth Buffer

Unity Engine
1

Not having much luck with this. I am aware that Internal-PrepassLigthing.shader is doing this, but when I simply copy the code over, I didn’t get what I want.

Do I need to do anything on the script side (such as setting the matrix parameter _CameraToWorld)?

Thanks

2

Can you post the code you’ve got so far?

3

Sure can.

Shader "fog" {
Properties {
	_MainTex ("Base (RGB)", 2D) = "white" {}
	}

SubShader {
	Pass {
		ZTest Always Cull Off ZWrite Off
		Fog { Mode off }
		
CGPROGRAM
#pragma target 3.0
#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

struct appdata {
	float4 vertex : POSITION;
	float3 texcoord : TEXCOORD0;
};

struct v2f {
	float4 pos : SV_POSITION;
	float4 uv : TEXCOORD0;
	float3 ray : TEXCOORD1;
};

float4 MyComputeScreenPos (float4 pos) {
	float4 o = pos * 0.5f;
	#if defined(UNITY_HALF_TEXEL_OFFSET)
	o.xy = float2(o.x, o.y*_ProjectionParams.x) + o.w * _ScreenParams.zw;
	#else
	o.xy = float2(o.x, o.y*_ProjectionParams.x) + o.w;
	#endif
	o.zw = pos.zw;
	return o;
}	

v2f vert (appdata v)
{
	v2f o;
	o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
	o.uv = MyComputeScreenPos (o.pos);
	o.ray = mul (UNITY_MATRIX_MV, v.vertex).xyz * float3(-1,-1,1);
	
	// v.texcoord is equal to 0 when we are drawing 3D light shapes and
	// contains a ray pointing from the camera to one of near plane's
	// corners in camera space when we are drawing a full screen quad.
	o.ray = lerp(o.ray, v.texcoord, v.texcoord.z != 0);
	
	return o;
}

uniform sampler2D _MainTex;
sampler2D _CameraDepthTexture;
float4x4 _CameraToWorld;

float4 frag (v2f i) : COLOR
{
	float4 original = tex2D(_MainTex, i.uv.xy);
	
	i.ray = i.ray * (_ProjectionParams.z / i.ray.z);
	float2 uv = i.uv.xy / i.uv.w;
	
	float depth = tex2D (_CameraDepthTexture, uv).r;
	depth = Linear01Depth (depth);
	float4 viewPos = float4(i.ray * depth,1);
	float3 worldPos = mul (_CameraToWorld, viewPos).xyz;
	
	float4 output;
	
	if (worldPos.y < 20.0)
		output.rgb = original.rgb * 0.5f;
	else
		output.rgb = original.rgb;

	output.a = 1.0;
	
	return output;
}
ENDCG

	}
}

Fallback off

}

And the script side is just this

Graphics.Blit (source, destination, material);

For some reason the output image is upside down.

4

Have you found a solution?