Skip to content

Instantly share code, notes, and snippets.

@baobao
Last active Sep 29, 2021
Embed
What would you like to do?
using UnityEngine;
[ExecuteInEditMode]
public class ShadowMap : MonoBehaviour
{
[SerializeField]
Material m_mat;
void OnWillRenderObject ()
{
var lightCamera = Camera.current;
// ライトにくっつけたCameraでライトから見たDepthRenderTextureに焼き込む
if (cam.name == "Light")
{
var lightVMatrix = lightCamera.worldToCameraMatrix;
var lightPMatrix = GL.GetGPUProjectionMatrix(cam.projectionMatrix, false);
var lightVP = lightPMatrix * lightVMatrix;
// [-1, 1] => [0, 1]に補正する行列
var biasMat = new Matrix4x4();
biasMat.SetRow(0, new Vector4(0.5f, 0.0f, 0.0f, 0.5f));
biasMat.SetRow(1, new Vector4(0.0f, 0.5f, 0.0f, 0.5f));
biasMat.SetRow(2, new Vector4(0.0f, 0.0f, 0.5f, 0.5f));
biasMat.SetRow(3, new Vector4(0.0f, 0.0f, 0.0f, 1.0f));
// ライトから見た射影変換行列をシェーダい渡す
m_mat.SetMatrix("_LightVP", biasMat * lightVP);
}
}
}
Shader "ShadowMap"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
// 光源視点からのDepthTexture(RenderTexture)
_LightDepthTex("LightDepth",2D) = "white" {}
// 影の濃さ
_ShadowValue("ShadowValue",Range(0.001,1)) = 1
}
SubShader
{
CGINCLUDE
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
float4 shadowVertex : TEXCOORD1;
};
sampler2D _MainTex;
float4 _MainTex_ST;
// 光源視点からのDepthTexture(RenderTexture)
sampler2D _LightDepthTex;
// 光源視点から射影変換行列
float4x4 _LightVP;
// 影の濃さ
float _ShadowValue;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
// 光源視点の変換座標
o.shadowVertex = mul(_LightVP, v.vertex);
// debug
//o.vertex = mul(_LightVP, v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float shadowRatio = 1;
// ライトから見た時のDepth
float4 lightDepth = tex2D(_LightDepthTex, i.shadowVertex.xy);
// Debug Code
// return lightDepth.r;
// Debug Code
// return i.shadowVertex.z;
// DepthTextureのDepthとライトから見た時のライトからの距離を比べてDepthTextureのDepthの方が小さかったら影と判断
float diff = i.shadowVertex.z - lightDepth.r;
if (diff >= 0)
{
shadowRatio = _ShadowValue;
}
return tex2D(_MainTex, i.uv.xy) * shadowRatio;
}
ENDCG
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
ENDCG
}
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment