koobas.hobune.stream
What are Splat maps - this is from Bootcamp
From bootcamp
Shader "Misc/Mesh Terrain 4 Splats" {
Properties { _Control ("SplatMap (RGBA)", 2D) = "red" {} _Splat0 ("Layer 0 (R)", 2D) = "white" {} _Splat1 ("Layer 1 (G)", 2D) = "white" {} _Splat2 ("Layer 2 (B)", 2D) = "white" {} _Splat3 ("Layer 3 (A)", 2D) = "white" {} _BaseMap ("BaseMap (RGB)", 2D) = "white" {} }
// Fragment program SubShader { Tags { "RenderType" = "Opaque" } Pass { Tags { "LightMode" = "Always" }
CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma fragmentoption ARB_precision_hint_fastest #pragma multi_compile LIGHTMAP_ON LIGHTMAP_OFF
#include "UnityCG.cginc"
struct appdata_lightmap {
float4 vertex : POSITION;
float2 texcoord : TEXCOORD0;
float2 texcoord1 : TEXCOORD1;
};
struct v2f_vertex {
float4 pos : SV_POSITION;
float4 uv[3] : TEXCOORD0;
};
uniform sampler2D _Control;
uniform float4 _Control_ST;
#ifdef LIGHTMAP_ON
uniform float4 unity_LightmapST;
uniform sampler2D unity_Lightmap;
#endif
uniform sampler2D _Splat0,_Splat1,_Splat2,_Splat3;
uniform float4 _Splat0_ST,_Splat1_ST,_Splat2_ST,_Splat3_ST;
v2f_vertex vert (appdata_lightmap v)
{
v2f_vertex o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.uv[0].xy = TRANSFORM_TEX (v.texcoord.xy, _Control);
#ifdef LIGHTMAP_ON
o.uv[0].zw = v.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
#else
o.uv[0].zw = half2(0,0);
#endif
o.uv[1].xy = TRANSFORM_TEX (v.texcoord.xy, _Splat0);
o.uv[1].zw = TRANSFORM_TEX (v.texcoord.xy, _Splat1);
o.uv[2].xy = TRANSFORM_TEX (v.texcoord.xy, _Splat2);
o.uv[2].zw = TRANSFORM_TEX (v.texcoord.xy, _Splat3);
return o;
}
half4 frag (v2f_vertex i) : COLOR
{
half4 splat_control = tex2D(_Control, i.uv[0].xy);
half3 splat_color = splat_control.r * tex2D (_Splat0, i.uv[1].xy).rgb;
splat_color += splat_control.g * tex2D (_Splat1, i.uv[1].zw).rgb;
splat_color += splat_control.b * tex2D (_Splat2, i.uv[2].xy).rgb;
splat_color += splat_control.a * tex2D (_Splat3, i.uv[2].zw).rgb;
#ifdef LIGHTMAP_ON
splat_color *= DecodeLightmap (tex2D (unity_Lightmap, i.uv[0].zw));
#endif
return half4 (splat_color, 0.0);
}
ENDCG
}
}
// Fixed function SubShader { Tags { "RenderType" = "Opaque" } Pass { Tags { "LightMode" = "Vertex" } SetTexture [_BaseMap] { constantColor(0,0,0,0) combine texture, constant } } Pass { Tags { "LightMode" = "VertexLM" } SetTexture [unity_Lightmap] { combine texture } SetTexture [_BaseMap] { constantColor(0,0,0,0) combine texture previous, constant } } Pass { Tags { "LightMode" = "VertexLMRGBM" } SetTexture [unity_Lightmap] { combine texture texture alpha DOUBLE } SetTexture [_BaseMap] { constantColor(0,0,0,0) combine texture * previous DOUBLE, constant } } } }
What do they do and how to make them.
Plus if you try to use bootcamp Splat by importing the material and textures and applying to a mesh does not work.
A "splat" mixes two or more textures using data from a third one (or elsewhere). In this case, Splats 1-4 are the textures to be displayed/mixed, and the splatmap has the colours that determine which of the 4 are displayed (red shows splat 1, green splat2, etc). As to why it doesn't work on any old mesh, I don't know. IMHO unity shaderlab doccumentation is despicable.
