Add angle control to decals

Also:

* Fix decal mipmap calculation
* Decals are now sampled with a clamping sampler, not repeat
* Decal scaling now occurs at center, not bottom left

4 files changed, 76 insertions, 8 deletions

diff --git a/Editor/tooner.cs b/Editor/tooner.cs
index a484bc8..ecad810 100644
--- a/Editor/tooner.cs
+++ b/Editor/tooner.cs
@@ -233,6 +233,10 @@ public class ToonerGUI : ShaderGUI {
         editor.FloatProperty(
             bc,
             "Emission strength");
+        bc = FindProperty($"_Decal{i}_Angle");
+        editor.RangeProperty(
+            bc,
+            "Angle");
       }
 
       EditorGUI.indentLevel -= 1;
diff --git a/globals.cginc b/globals.cginc
index 51f8a2f..9a60bf8 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -4,6 +4,7 @@
 #include "AutoLight.cginc"
 
 SamplerState linear_repeat_s;
+SamplerState linear_clamp_s;
 
 float4 _Color;
 float _Metallic;
@@ -116,21 +117,25 @@ float _PBR_Overlay3_Mask_Invert;
 texture2D _Decal0_BaseColor;
 float4 _Decal0_BaseColor_ST;
 float _Decal0_Emission_Strength;
+float _Decal0_Angle;
 #endif
 #if defined(_DECAL1)
 texture2D _Decal1_BaseColor;
 float4 _Decal1_BaseColor_ST;
 float _Decal1_Emission_Strength;
+float _Decal1_Angle;
 #endif
 #if defined(_DECAL2)
 texture2D _Decal2_BaseColor;
 float4 _Decal2_BaseColor_ST;
 float _Decal2_Emission_Strength;
+float _Decal2_Angle;
 #endif
 #if defined(_DECAL3)
 texture2D _Decal3_BaseColor;
 float4 _Decal3_BaseColor_ST;
 float _Decal3_Emission_Strength;
+float _Decal3_Angle;
 #endif
 
 #if defined(_EMISSION)
diff --git a/tooner.shader b/tooner.shader
index 22cbac2..5a0fea4 100644
--- a/tooner.shader
+++ b/tooner.shader
@@ -74,18 +74,22 @@ Shader "yum_food/tooner"
     _Decal0_Enable("Enable decal", Float) = 0.0
     _Decal0_BaseColor("Base color", 2D) = "white" {}
     _Decal0_Emission_Strength("Emission strength", Float) = 0
+    _Decal0_Angle("Emission strength", Range(0,1)) = 0
 
     _Decal1_Enable("Enable decal", Float) = 0.0
     _Decal1_BaseColor("Base color", 2D) = "white" {}
     _Decal1_Emission_Strength("Emission strength", Float) = 0
+    _Decal1_Angle("Emission strength", Range(0,1)) = 0
 
     _Decal2_Enable("Enable decal", Float) = 0.0
     _Decal2_BaseColor("Base color", 2D) = "white" {}
     _Decal2_Emission_Strength("Emission strength", Float) = 0
+    _Decal2_Angle("Emission strength", Range(0,1)) = 0
 
     _Decal3_Enable("Enable decal", Float) = 0.0
     _Decal3_BaseColor("Base color", 2D) = "white" {}
     _Decal3_Emission_Strength("Emission strength", Float) = 0
+    _Decal3_Angle("Emission strength", Range(0,1)) = 0
 
     [NoScaleOffset] _EmissionTex("Emission map", 2D) = "black" {}
     _EmissionStrength("Emission strength", Range(0, 2)) = 0
diff --git a/tooner_lighting.cginc b/tooner_lighting.cginc
index 2632250..2eb6a47 100644
--- a/tooner_lighting.cginc
+++ b/tooner_lighting.cginc
@@ -464,18 +464,73 @@ void getOverlayAlbedo(inout PbrOverlay ov,
 #endif  // _PBR_OVERLAY3
 }
 
+void applyDecalAlbedoImpl(
+    inout float3 albedo,
+    inout float decal_emission,
+    v2f i,
+    texture2D tex,
+    float4 tex_st,
+    float emission_strength,
+    float angle)
+{
+  float2 d0_uv = ((i.uv - 0.5) - tex_st.zw) * tex_st.xy + 0.5;
+
+  if (abs(angle) > 1E-6) {
+    float theta = angle * 2.0 * 3.14159265;
+    float2x2 rot = float2x2(
+        cos(theta), -sin(theta),
+        sin(theta), cos(theta));
+    d0_uv = mul(rot, d0_uv - 0.5) + 0.5;
+  }
+
+  float4 d0_c = tex.SampleGrad(linear_clamp_s,
+      saturate(d0_uv),
+      ddx(d0_uv.x) * _Mip_Multiplier,
+      ddy(d0_uv.y) * _Mip_Multiplier);
+
+  float d0_in_range = 1;
+  d0_in_range *= d0_uv.x > 0;
+  d0_in_range *= d0_uv.x < 1;
+  d0_in_range *= d0_uv.y > 0;
+  d0_in_range *= d0_uv.y < 1;
+  d0_c *= d0_in_range;
+
+  albedo.rgb = lerp(albedo.rgb, d0_c.rgb, d0_c.a);
+  decal_emission += d0_c.rgb * emission_strength;
+}
+
 void applyDecalAlbedo(inout float3 albedo,
     inout float decal_emission,
-    v2f i, float iddx, float iddy)
+    v2f i)
 {
 #if defined(_DECAL0)
-  float4 d0_c = _Decal0_BaseColor.SampleGrad(linear_repeat_s,
-      saturate((i.uv - _Decal0_BaseColor_ST.zw) * _Decal0_BaseColor_ST.xy),
-      iddx * _Decal0_BaseColor_ST.x,
-      iddy * _Decal0_BaseColor_ST.y);
-  albedo.rgb = lerp(albedo.rgb, d0_c.rgb, d0_c.a);
-  decal_emission += d0_c.rgb * _Decal0_Emission_Strength;
+  applyDecalAlbedoImpl(albedo, decal_emission, i,
+      _Decal0_BaseColor,
+      _Decal0_BaseColor_ST,
+      _Decal0_Emission_Strength,
+      _Decal0_Angle);
 #endif  // _DECAL0
+#if defined(_DECAL1)
+  applyDecalAlbedoImpl(albedo, decal_emission, i,
+      _Decal1_BaseColor,
+      _Decal1_BaseColor_ST,
+      _Decal1_Emission_Strength,
+      _Decal1_Angle);
+#endif  // _DECAL1
+#if defined(_DECAL2)
+  applyDecalAlbedoImpl(albedo, decal_emission, i,
+      _Decal2_BaseColor,
+      _Decal2_BaseColor_ST,
+      _Decal2_Emission_Strength,
+      _Decal2_Angle);
+#endif  // _DECAL2
+#if defined(_DECAL3)
+  applyDecalAlbedoImpl(albedo, decal_emission, i,
+      _Decal3_BaseColor,
+      _Decal3_BaseColor_ST,
+      _Decal3_Emission_Strength,
+      _Decal3_Angle);
+#endif  // _DECAL3
 }
 
 void mixOverlayAlbedo(inout float3 albedo, PbrOverlay ov) {
@@ -666,7 +721,7 @@ float4 effect(inout v2f i)
   mixOverlayAlbedo(albedo.rgb, ov);
 #if defined(_DECAL0) || defined(_DECAL1) || defined(_DECAL2) || defined(_DECAL3)
   float decal_emission = 0;
-  applyDecalAlbedo(albedo.rgb, decal_emission, i, iddx, iddy);
+  applyDecalAlbedo(albedo.rgb, decal_emission, i);
 #endif
 
 #if defined(_MATCAP0) || defined(_MATCAP1) || defined(_RIM_LIGHTING0) || defined(_RIM_LIGHTING1)