From d5379935301cec61239421f5f59dd14a2b063b23 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Sat, 12 Dec 2020 02:36:53 -0800
Subject: [PATCH] flat sprite lighting in deferred pipeline

---
 Effects/DeferredPBR_PointLightEffect.cs      | 14 +--------
 Effects/FXB/DeferredPBR_PointLightEffect.fxb |  4 +--
 Effects/HLSL/DeferredPBR_PointLightEffect.fx | 31 ++++++++++++--------
 3 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/Effects/DeferredPBR_PointLightEffect.cs b/Effects/DeferredPBR_PointLightEffect.cs
index 6a85806..63e4af2 100644
--- a/Effects/DeferredPBR_PointLightEffect.cs
+++ b/Effects/DeferredPBR_PointLightEffect.cs
@@ -18,8 +18,6 @@ namespace Kav
 
         EffectParameter farPlaneParam;
 
-        EffectParameter worldParam;
-        EffectParameter worldInverseParam;
         EffectParameter worldViewProjectionParam;
 
         public Texture2D GPosition { get; set; }
@@ -47,7 +45,7 @@ namespace Kav
             set
             {
                 world = value;
-                dirtyFlags |= EffectDirtyFlags.WorldViewProj | EffectDirtyFlags.World;
+                dirtyFlags |= EffectDirtyFlags.WorldViewProj;
             }
         }
 
@@ -114,14 +112,6 @@ namespace Kav
 
             farPlaneParam.SetValue(FarPlane);
 
-            if ((dirtyFlags & EffectDirtyFlags.World) != 0)
-            {
-                worldParam.SetValue(world);
-                worldInverseParam.SetValue(Matrix.Invert(world));
-
-                dirtyFlags &= ~EffectDirtyFlags.World;
-            }
-
             if ((dirtyFlags & EffectDirtyFlags.WorldViewProj) != 0)
             {
                 worldViewProjectionParam.SetValue(world * view * projection);
@@ -145,8 +135,6 @@ namespace Kav
 
             farPlaneParam                  = Parameters["FarPlane"];
 
-            worldParam                     = Parameters["World"];
-            worldInverseParam              = Parameters["WorldInverse"];
             worldViewProjectionParam       = Parameters["WorldViewProjection"];
         }
     }
diff --git a/Effects/FXB/DeferredPBR_PointLightEffect.fxb b/Effects/FXB/DeferredPBR_PointLightEffect.fxb
index f7cfc76..010f5d6 100644
--- a/Effects/FXB/DeferredPBR_PointLightEffect.fxb
+++ b/Effects/FXB/DeferredPBR_PointLightEffect.fxb
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:19dd54568190283d2d0137af4489bc1478fc4901f62dd64421bceb4f2980645c
-size 5192
+oid sha256:b98c96aaebb45d196293e1be3716517eaca204dd83eb17768653bd060954ec45
+size 4144
diff --git a/Effects/HLSL/DeferredPBR_PointLightEffect.fx b/Effects/HLSL/DeferredPBR_PointLightEffect.fx
index c9d5643..5e7eed1 100644
--- a/Effects/HLSL/DeferredPBR_PointLightEffect.fx
+++ b/Effects/HLSL/DeferredPBR_PointLightEffect.fx
@@ -21,8 +21,6 @@ BEGIN_CONSTANTS
 
 MATRIX_CONSTANTS
 
-    float4x4 WorldInverse                   _ps(c4)     _cb(c8);
-    float4x4 World                          _ps(c8)     _cb(c12);
     float4x4 WorldViewProjection _vs(c0)                _cb(c4);
 
 END_CONSTANTS
@@ -88,17 +86,26 @@ float4 main_ps(PixelInput input) : SV_TARGET0
     float3 albedo = SAMPLE_TEXTURE(gAlbedo, texCoord).rgb;
     float2 metallicRoughness = SAMPLE_TEXTURE(gMetallicRoughness, texCoord).rg;
 
-    float3 objectZNormal = mul(normal, WorldInverse);
-    objectZNormal.xz *= -1;
-    float3 invertedZNormalWorld = mul(objectZNormal, World);
+    if (isSprite == 1.0)
+    {
+        float3 lightDir = PointLightPosition - worldPosition;
+        float3 L = normalize(lightDir);
+        float distance = length(lightDir);
+        float attenuation = 1.0 / (distance * distance);
+        float3 radiance = PointLightColor * attenuation;
 
-    return ComputeColor(
-        worldPosition,
-        normal,
-        albedo,
-        metallicRoughness.r,
-        metallicRoughness.g
-    ) + (isSprite * ComputeColor(worldPosition, invertedZNormalWorld, albedo, metallicRoughness.r, metallicRoughness.g));
+        return float4(albedo * radiance * 0.1, 1.0);
+    }
+    else
+    {
+        return ComputeColor(
+            worldPosition,
+            normal,
+            albedo,
+            metallicRoughness.r,
+            metallicRoughness.g
+        );
+    }
 }
 
 Technique DeferredPBR_Point