Hi, I have a cloud rendering shader that uses 3d noise and raymarching. It's a screen-wide frag shader, base on this tutorial: https://www.youtube.com/watch?v=4QOcCGI6xOU
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Currently, I illuminate the clouds using yet more raymarching. I have two problems with that, first it's expensive, second my clouds don't cast any shadows.
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I want to basically tell Unity to write to the dynamic lightmap, and use it to abort the lightmarching if I know I'm the shadow of the cloud.
I have little idea on how to do that, except vaguely that adding a shadow pass to the shader will tell unity to do that.
Here's my current code structure, minus the very long raymarching code:
Shader "Jupiter/Clouds"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
// No culling or depth
Cull Off ZWrite Off ZTest Always
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "Assets/Scripts/Clouds/Shaders/CloudDebug.cginc"
// vertex input: position, UV
struct appdata {
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float3 viewVector : TEXCOORD1;
};
v2f vert (appdata v) {
v2f output;
output.pos = UnityObjectToClipPos(v.vertex);
output.uv = v.uv;
// Camera space matches OpenGL convention where cam forward is -z. In unity forward is positive z.
// (https://docs.unity3d.com/ScriptReference/Camera-cameraToWorldMatrix.html)
float3 viewVector = mul(unity_CameraInvProjection, float4(v.uv * 2 - 1, 0, -1));
output.viewVector = mul(unity_CameraToWorld, float4(viewVector,0));
return output;
}
// Textures
Texture3D NoiseTex;
Texture3D DetailNoiseTex;
Texture2D WeatherMap;
Texture2D BlueNoise;
SamplerState samplerNoiseTex;
SamplerState samplerDetailNoiseTex;
SamplerState samplerWeatherMap;
SamplerState samplerBlueNoise;
sampler2D _MainTex;
sampler2D _CameraDepthTexture;
//tons of parameters
float4 frag (v2f i) : SV_Target
{
//blablabla
return float4(col,0);
}
ENDCG
}
}
}
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