Instantly share code, notes, and snippets.

Embed
What would you like to do?
Example depicting applying Unity lightmapping data to a simple diffuse shader.
Shader "Diffuse Lightmap" {
Properties {
_MainTex ("Texture 1", 2D) = "white" {}
}
SubShader {
Tags { "RenderType" = "Opaque" }
Pass {
// Disable lighting, we're only using the lightmap
Lighting Off
CGPROGRAM
// Must be a vert/frag shader, not a surface shader: the necessary variables
// won't be defined yet for surface shaders.
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct v2f {
float4 pos : SV_POSITION;
float2 uv0 : TEXCOORD0;
float2 uv1 : TEXCOORD1;
};
struct appdata_lightmap {
float4 vertex : POSITION;
float2 texcoord : TEXCOORD0;
float2 texcoord1 : TEXCOORD1;
};
// These are prepopulated by Unity
sampler2D unity_Lightmap;
float4 unity_LightmapST;
sampler2D _MainTex;
float4 _MainTex_ST; // Define this since its expected by TRANSFORM_TEX; it is also pre-populated by Unity.
v2f vert(appdata_lightmap i) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, i.vertex);
// UnityCG.cginc - Transforms 2D UV by scale/bias property
// #define TRANSFORM_TEX(tex,name) (tex.xy * name##_ST.xy + name##_ST.zw)
o.uv0 = TRANSFORM_TEX(i.texcoord, _MainTex);
// Use `unity_LightmapST` NOT `unity_Lightmap_ST`
o.uv1 = i.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
return o;
}
half4 frag(v2f i) : COLOR {
half4 main_color = tex2D(_MainTex, i.uv0);
// Decodes lightmaps:
// - doubleLDR encoded on GLES
// - RGBM encoded with range [0;8] on other platforms using surface shaders
// inline fixed3 DecodeLightmap(fixed4 color) {
// #if defined(SHADER_API_GLES) && defined(SHADER_API_MOBILE)
// return 2.0 * color.rgb;
// #else
// return (8.0 * color.a) * color.rgb;
// #endif
// }
main_color.rgb *= DecodeLightmap(tex2D(unity_Lightmap, i.uv1));
return main_color;
}
ENDCG
}
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment