Switch from #ifdef to uniform branches for decals

Makes code much smaller & simpler, and shader locker constant folding
should make it just as efficient.

1 files changed, 44 insertions, 192 deletions

diff --git a/decal.cginc b/decal.cginc
index 5f60fe7..aee7cf0 100644
--- a/decal.cginc
+++ b/decal.cginc
@@ -27,206 +27,58 @@ float2 decal_rotate(float2 uv, float rotation) {
   return float2(d.x * c - d.y * s, d.x * s + d.y * c) + 0.5;
 }
 
+#define APPLY_DECAL(N) \
+  { \
+    float2 uv = get_uv_by_channel(i, _Decal##N##_UV_Channel); \
+    uv -= _Decal##N##_MainTex_ST.zw; \
+    uv *= _Decal##N##_MainTex_ST.xy; \
+    if (_Decal##N##_Rotation_Enabled) \
+      uv = decal_rotate(uv, _Decal##N##_Rotation); \
+    float4 albedo = decal_sample(_Decal##N##_MainTex, uv, _Decal##N##_UV_Mode); \
+    albedo *= _Decal##N##_Color; \
+    albedo.a *= _Decal##N##_Opacity; \
+    if (_Decal##N##_Mask_Enabled) { \
+      float2 mask_uv = get_uv_by_channel(i, _Decal##N##_Mask_UV_Channel); \
+      mask_uv -= _Decal##N##_Mask_ST.zw; \
+      mask_uv *= _Decal##N##_Mask_ST.xy; \
+      float mask = decal_sample(_Decal##N##_Mask, mask_uv, _Decal##N##_UV_Mode); \
+      if (_Decal##N##_Mask_Invert) mask = 1 - mask; \
+      albedo.a *= mask; \
+    } \
+    if (_Decal##N##_Albedo_Clamp) albedo.rgb = saturate(albedo.rgb); \
+    [forcecase] \
+    switch (_Decal##N##_Mix_Mode) { \
+      case DECAL_MIX_MODE_ALPHA_BLEND: \
+        pbr.albedo = alpha_blend(albedo, pbr.albedo); \
+        break; \
+      case DECAL_MIX_MODE_MULTIPLY: \
+        pbr.albedo.rgb *= lerp(1, albedo.rgb, albedo.a); \
+        break; \
+      case DECAL_MIX_MODE_ADD_PRODUCT: \
+        pbr.albedo.rgb += lerp(0, albedo.rgb * pbr.albedo.rgb, albedo.a); \
+        break; \
+    } \
+    if (_Decal##N##_Metallic_Gloss_Enabled) { \
+      float4 mg = decal_sample(_Decal##N##_Metallic_Gloss, uv, _Decal##N##_UV_Mode); \
+      pbr.metallic = lerp(pbr.metallic, mg.r, albedo.a); \
+      pbr.smoothness = lerp(pbr.smoothness, mg.a, albedo.a); \
+      pbr.roughness_perceptual = clamp(1 - pbr.smoothness, MIN_PERCEPTUAL_ROUGHNESS, 1); \
+      pbr.roughness = clamp(pbr.roughness_perceptual * pbr.roughness_perceptual, MIN_ROUGHNESS, 1); \
+    } \
+  }
+
 void applyDecals(v2f i, inout Pbr pbr) {
 #if defined(_DECAL0)
-  {
-    float2 uv = get_uv_by_channel(i, _Decal0_UV_Channel);
-    uv -= _Decal0_MainTex_ST.zw;
-    uv *= _Decal0_MainTex_ST.xy;
-#if defined(_DECAL0_ROTATION)
-    uv = decal_rotate(uv, _Decal0_Rotation);
-#endif
-    float4 albedo = decal_sample(_Decal0_MainTex, uv, _Decal0_UV_Mode);
-    albedo *= _Decal0_Color;
-    albedo.a *= _Decal0_Opacity;
-
-#if defined(_DECAL0_MASK)
-    float2 mask_uv = get_uv_by_channel(i, _Decal0_Mask_UV_Channel);
-    mask_uv -= _Decal0_Mask_ST.zw;
-    mask_uv *= _Decal0_Mask_ST.xy;
-    // For now, mask gets the same sampling mode as the decal.
-    float mask = decal_sample(_Decal0_Mask, mask_uv, _Decal0_UV_Mode);
-#if defined(_DECAL0_MASK_INVERT)
-    mask = 1 - mask;
-#endif  // _DECAL0_MASK_INVERT
-    albedo.a *= mask;
-#endif  // _DECAL0_MASK
-
-#if defined(_DECAL0_ALBEDO_CLAMP)
-    albedo.rgb = saturate(albedo.rgb);
-#endif  // _DECAL0_ALBEDO_CLAMP
-
-    [forcecase]
-    switch (_Decal0_Mix_Mode) {
-      case DECAL_MIX_MODE_ALPHA_BLEND:
-        pbr.albedo = alpha_blend(albedo, pbr.albedo);
-        break;
-      case DECAL_MIX_MODE_MULTIPLY:
-        pbr.albedo.rgb *= lerp(1, albedo.rgb, albedo.a);
-        break;
-      case DECAL_MIX_MODE_ADD_PRODUCT:
-        pbr.albedo.rgb += lerp(0, albedo.rgb * pbr.albedo.rgb, albedo.a);
-        break;
-    }
-
-#if defined(_DECAL0_METALLIC_GLOSS)
-    float4 mg = decal_sample(_Decal0_Metallic_Gloss, uv, _Decal0_UV_Mode);
-    pbr.metallic = lerp(pbr.metallic, mg.r, albedo.a);
-    pbr.smoothness = lerp(pbr.smoothness, mg.a, albedo.a);
-    pbr.roughness_perceptual = clamp(1 - pbr.smoothness, MIN_PERCEPTUAL_ROUGHNESS, 1);
-    pbr.roughness = clamp(pbr.roughness_perceptual * pbr.roughness_perceptual, MIN_ROUGHNESS, 1);
-#endif  // _DECAL0_METALLIC_GLOSS
-  }
+  APPLY_DECAL(0)
 #endif
-
 #if defined(_DECAL1)
-  {
-    float2 uv = get_uv_by_channel(i, _Decal1_UV_Channel);
-    uv -= _Decal1_MainTex_ST.zw;
-    uv *= _Decal1_MainTex_ST.xy;
-#if defined(_DECAL1_ROTATION)
-    uv = decal_rotate(uv, _Decal1_Rotation);
-#endif
-    float4 albedo = decal_sample(_Decal1_MainTex, uv, _Decal1_UV_Mode);
-    albedo *= _Decal1_Color;
-    albedo.a *= _Decal1_Opacity;
-
-#if defined(_DECAL1_MASK)
-    float2 mask_uv = get_uv_by_channel(i, _Decal1_Mask_UV_Channel);
-    mask_uv -= _Decal1_Mask_ST.zw;
-    mask_uv *= _Decal1_Mask_ST.xy;
-    float mask = decal_sample(_Decal1_Mask, mask_uv, _Decal1_UV_Mode);
-#if defined(_DECAL1_MASK_INVERT)
-    mask = 1 - mask;
-#endif  // _DECAL1_MASK_INVERT
-    albedo.a *= mask;
-#endif  // _DECAL1_MASK
-
-#if defined(_DECAL1_ALBEDO_CLAMP)
-    albedo.rgb = saturate(albedo.rgb);
-#endif  // _DECAL1_ALBEDO_CLAMP
-
-    [forcecase]
-    switch (_Decal1_Mix_Mode) {
-      case DECAL_MIX_MODE_ALPHA_BLEND:
-        pbr.albedo = alpha_blend(albedo, pbr.albedo);
-        break;
-      case DECAL_MIX_MODE_MULTIPLY:
-        pbr.albedo.rgb *= lerp(1, albedo.rgb, albedo.a);
-        break;
-      case DECAL_MIX_MODE_ADD_PRODUCT:
-        pbr.albedo.rgb += lerp(0, albedo.rgb * pbr.albedo.rgb, albedo.a);
-        break;
-    }
-
-#if defined(_DECAL1_METALLIC_GLOSS)
-    float4 mg = decal_sample(_Decal1_Metallic_Gloss, uv, _Decal1_UV_Mode);
-    pbr.metallic = lerp(pbr.metallic, mg.r, albedo.a);
-    pbr.smoothness = lerp(pbr.smoothness, mg.a, albedo.a);
-    pbr.roughness_perceptual = clamp(1 - pbr.smoothness, MIN_PERCEPTUAL_ROUGHNESS, 1);
-    pbr.roughness = clamp(pbr.roughness_perceptual * pbr.roughness_perceptual, MIN_ROUGHNESS, 1);
-#endif  // _DECAL1_METALLIC_GLOSS
-  }
+  APPLY_DECAL(1)
 #endif
-
 #if defined(_DECAL2)
-  {
-    float2 uv = get_uv_by_channel(i, _Decal2_UV_Channel);
-    uv -= _Decal2_MainTex_ST.zw;
-    uv *= _Decal2_MainTex_ST.xy;
-#if defined(_DECAL2_ROTATION)
-    uv = decal_rotate(uv, _Decal2_Rotation);
-#endif
-    float4 albedo = decal_sample(_Decal2_MainTex, uv, _Decal2_UV_Mode);
-    albedo *= _Decal2_Color;
-    albedo.a *= _Decal2_Opacity;
-
-#if defined(_DECAL2_MASK)
-    float2 mask_uv = get_uv_by_channel(i, _Decal2_Mask_UV_Channel);
-    mask_uv -= _Decal2_Mask_ST.zw;
-    mask_uv *= _Decal2_Mask_ST.xy;
-    float mask = decal_sample(_Decal2_Mask, mask_uv, _Decal2_UV_Mode);
-#if defined(_DECAL2_MASK_INVERT)
-    mask = 1 - mask;
-#endif  // _DECAL2_MASK_INVERT
-    albedo.a *= mask;
-#endif  // _DECAL2_MASK
-
-#if defined(_DECAL2_ALBEDO_CLAMP)
-    albedo.rgb = saturate(albedo.rgb);
-#endif  // _DECAL2_ALBEDO_CLAMP
-
-    [forcecase]
-    switch (_Decal2_Mix_Mode) {
-      case DECAL_MIX_MODE_ALPHA_BLEND:
-        pbr.albedo = alpha_blend(albedo, pbr.albedo);
-        break;
-      case DECAL_MIX_MODE_MULTIPLY:
-        pbr.albedo.rgb *= lerp(1, albedo.rgb, albedo.a);
-        break;
-      case DECAL_MIX_MODE_ADD_PRODUCT:
-        pbr.albedo.rgb += lerp(0, albedo.rgb * pbr.albedo.rgb, albedo.a);
-        break;
-    }
-
-#if defined(_DECAL2_METALLIC_GLOSS)
-    float4 mg = decal_sample(_Decal2_Metallic_Gloss, uv, _Decal2_UV_Mode);
-    pbr.metallic = lerp(pbr.metallic, mg.r, albedo.a);
-    pbr.smoothness = lerp(pbr.smoothness, mg.a, albedo.a);
-    pbr.roughness_perceptual = clamp(1 - pbr.smoothness, MIN_PERCEPTUAL_ROUGHNESS, 1);
-    pbr.roughness = clamp(pbr.roughness_perceptual * pbr.roughness_perceptual, MIN_ROUGHNESS, 1);
-#endif  // _DECAL2_METALLIC_GLOSS
-  }
+  APPLY_DECAL(2)
 #endif
-
 #if defined(_DECAL3)
-  {
-    float2 uv = get_uv_by_channel(i, _Decal3_UV_Channel);
-    uv -= _Decal3_MainTex_ST.zw;
-    uv *= _Decal3_MainTex_ST.xy;
-#if defined(_DECAL3_ROTATION)
-    uv = decal_rotate(uv, _Decal3_Rotation);
-#endif
-    float4 albedo = decal_sample(_Decal3_MainTex, uv, _Decal3_UV_Mode);
-    albedo *= _Decal3_Color;
-    albedo.a *= _Decal3_Opacity;
-
-#if defined(_DECAL3_MASK)
-    float2 mask_uv = get_uv_by_channel(i, _Decal3_Mask_UV_Channel);
-    mask_uv -= _Decal3_Mask_ST.zw;
-    mask_uv *= _Decal3_Mask_ST.xy;
-    float mask = decal_sample(_Decal3_Mask, mask_uv, _Decal3_UV_Mode);
-#if defined(_DECAL3_MASK_INVERT)
-    mask = 1 - mask;
-#endif  // _DECAL3_MASK_INVERT
-    albedo.a *= mask;
-#endif  // _DECAL3_MASK
-
-#if defined(_DECAL3_ALBEDO_CLAMP)
-    albedo.rgb = saturate(albedo.rgb);
-#endif  // _DECAL3_ALBEDO_CLAMP
-
-    [forcecase]
-    switch (_Decal3_Mix_Mode) {
-      case DECAL_MIX_MODE_ALPHA_BLEND:
-        pbr.albedo = alpha_blend(albedo, pbr.albedo);
-        break;
-      case DECAL_MIX_MODE_MULTIPLY:
-        pbr.albedo.rgb *= lerp(1, albedo.rgb, albedo.a);
-        break;
-      case DECAL_MIX_MODE_ADD_PRODUCT:
-        pbr.albedo.rgb += lerp(0, albedo.rgb * pbr.albedo.rgb, albedo.a);
-        break;
-    }
-
-#if defined(_DECAL3_METALLIC_GLOSS)
-    float4 mg = decal_sample(_Decal3_Metallic_Gloss, uv, _Decal3_UV_Mode);
-    pbr.metallic = lerp(pbr.metallic, mg.r, albedo.a);
-    pbr.smoothness = lerp(pbr.smoothness, mg.a, albedo.a);
-    pbr.roughness_perceptual = clamp(1 - pbr.smoothness, MIN_PERCEPTUAL_ROUGHNESS, 1);
-    pbr.roughness = clamp(pbr.roughness_perceptual * pbr.roughness_perceptual, MIN_ROUGHNESS, 1);
-#endif  // _DECAL3_METALLIC_GLOSS
-  }
+  APPLY_DECAL(3)
 #endif
 }