deferred pbr shading

Effects/DeferredPBREffect.cs

@@ -0,0 +1,88 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace Kav
+{
+    public class DeferredPBREffect : Effect
+    {
+        EffectParameter gPositionParam;
+        EffectParameter gAlbedoParam;
+        EffectParameter gNormalParam;
+        EffectParameter gMetallicRoughnessParam;
+
+        EffectParameter eyePositionParam;
+        PointLightCollection pointLightCollection;
+
+        public Texture2D GPosition { get; set; }
+        public Texture2D GAlbedo { get; set; }
+        public Texture2D GNormal { get; set; }
+        public Texture2D GMetallicRoughness { get; set; }
+
+        public Vector3 EyePosition { get; set; }
+
+        public int MaxPointLights { get; } = 64;
+
+        public PointLightCollection PointLights
+        {
+            get { return pointLightCollection; }
+            private set { pointLightCollection = value; }
+        }
+
+        public DeferredPBREffect(GraphicsDevice graphicsDevice) : base(graphicsDevice, Resources.DeferredPBREffect)
+        {
+            CacheEffectParameters();
+
+            pointLightCollection = new PointLightCollection(
+                Parameters["PointLightPositions"],
+                Parameters["PointLightColors"],
+                MaxPointLights
+            );
+        }
+
+        protected DeferredPBREffect(DeferredPBREffect cloneSource) : base(cloneSource)
+        {
+            GPosition = cloneSource.GPosition;
+            GAlbedo = cloneSource.GAlbedo;
+            GNormal = cloneSource.GNormal;
+            GMetallicRoughness = cloneSource.GMetallicRoughness;
+
+            EyePosition = cloneSource.EyePosition;
+
+            PointLights = new PointLightCollection(
+                Parameters["LightPositions"],
+                Parameters["PositionLightColors"],
+                MaxPointLights
+            );
+
+            for (int i = 0; i < MaxPointLights; i++)
+            {
+                PointLights[i] = cloneSource.PointLights[i];
+            }
+        }
+
+        public override Effect Clone()
+        {
+            return new DeferredPBREffect(this);
+        }
+
+        protected override void OnApply()
+        {
+            gPositionParam.SetValue(GPosition);
+            gAlbedoParam.SetValue(GAlbedo);
+            gNormalParam.SetValue(GNormal);
+            gMetallicRoughnessParam.SetValue(GMetallicRoughness);
+
+            eyePositionParam.SetValue(EyePosition);
+        }
+
+        void CacheEffectParameters()
+        {
+            gPositionParam = Parameters["gPosition"];
+            gAlbedoParam = Parameters["gAlbedo"];
+            gNormalParam = Parameters["gNormal"];
+            gMetallicRoughnessParam = Parameters["gMetallicRoughness"];
+
+            eyePositionParam = Parameters["EyePosition"];
+        }
+    }
+}

Effects/HLSL/DeferredPBREffect.fx

@@ -0,0 +1,167 @@
+#include "Macros.fxh" //from FNA
+
+static const float PI = 3.141592653589793;
+static const int MAX_POINT_LIGHTS = 64;
+
+DECLARE_TEXTURE(gPosition, 0);
+DECLARE_TEXTURE(gAlbedo, 1);
+DECLARE_TEXTURE(gNormal, 2);
+DECLARE_TEXTURE(gMetallicRoughness, 3);
+
+BEGIN_CONSTANTS
+
+    float3 EyePosition                              _ps(c0)      _cb(c0);
+    
+    float3 PointLightPositions[MAX_POINT_LIGHTS]    _ps(c1)      _cb(c1);
+    float3 PointLightColors[MAX_POINT_LIGHTS]       _ps(c65)     _cb(c65);
+
+MATRIX_CONSTANTS
+
+END_CONSTANTS
+
+struct PixelInput
+{
+    float4 Position : SV_POSITION;
+    float2 TexCoord : TEXCOORD0;
+};
+
+// Pixel Shader
+
+float3 FresnelSchlick(float cosTheta, float3 F0)
+{
+    return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
+}
+
+float DistributionGGX(float3 N, float3 H, float roughness)
+{
+    float a = roughness * roughness;
+    float a2 = a * a;
+    float NdotH = max(dot(N, H), 0.0);
+    float NdotH2 = NdotH * NdotH;
+
+    float num = a2;
+    float denom = (NdotH2 * (a2 - 1.0) + 1.0);
+    denom = PI * denom * denom;
+
+    return num / denom;
+}
+
+float GeometrySchlickGGX(float NdotV, float roughness)
+{
+    float r = (roughness + 1.0);
+    float k = (r * r) / 8.0;
+
+    float num = NdotV;
+    float denom = NdotV * (1.0 - k) + k;
+
+    return num / denom;
+}
+
+float GeometrySmith(float3 N, float3 V, float3 L, float roughness)
+{
+    float NdotV = max(dot(N, V), 0.0);
+    float NdotL = max(dot(N, L), 0.0);
+    float ggx2 = GeometrySchlickGGX(NdotV, roughness);
+    float ggx1 = GeometrySchlickGGX(NdotL, roughness);
+
+    return ggx1 * ggx2;
+}
+
+float3 ComputeLight(
+    float3 lightDir,
+    float3 radiance,
+    float3 F0,
+    float3 V,
+    float3 N,
+    float3 albedo,
+    float metallic,
+    float roughness
+) {
+    float3 L = normalize(lightDir);
+    float3 H = normalize(V + L);
+
+    float NDF = DistributionGGX(N, H, roughness);
+    float G = GeometrySmith(N, V, L, roughness);
+    float3 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
+
+    float3 numerator = NDF * G * F;
+    float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
+    float3 specular = numerator / max(denominator, 0.001);
+
+    float3 kS = F;
+    float3 kD = float3(1.0, 1.0, 1.0) - kS;
+
+    kD *= 1.0 - metallic;
+
+    float NdotL = max(dot(N, L), 0.0);
+    return (kD * albedo / PI + specular) * radiance * NdotL;
+}
+
+float4 ComputeColor(
+    float3 worldPosition,
+    float3 worldNormal,
+    float3 albedo,
+    float metallic,
+    float roughness
+) {
+    float3 V = normalize(EyePosition - worldPosition);
+    float3 N = normalize(worldNormal);
+
+    float3 F0 = float3(0.04, 0.04, 0.04);
+    F0 = lerp(F0, albedo, metallic);
+
+    float3 Lo = float3(0.0, 0.0, 0.0);
+
+    // point light
+    for (int i = 0; i < MAX_POINT_LIGHTS; i++)
+    {
+        float3 lightDir = PointLightPositions[i] - worldPosition;
+        float distance = length(lightDir);
+        float attenuation = 1.0 / (distance * distance);
+        float3 radiance = PointLightColors[i] * attenuation;
+
+        Lo += ComputeLight(lightDir, radiance, F0, V, N, albedo, metallic, roughness);
+    }
+
+    // // directional light
+    // for (int i = 0; i < 4; i++)
+    // {
+    //     float3 lightDir = LightDirections[i];
+    //     float3 radiance = DirectionLightColors[i];
+
+    //     Lo += ComputeLight(lightDir, radiance, F0, V, N, albedo, metallic, roughness);
+    // }
+
+    float3 ambient = float3(0.03, 0.03, 0.03) * albedo; // * AO;
+    float3 color = ambient + Lo;
+
+    color = color / (color + float3(1.0, 1.0, 1.0));
+    float exposureConstant = 1.0 / 2.2;
+    color = pow(color, float3(exposureConstant, exposureConstant, exposureConstant));
+
+    return float4(color, 1.0);
+}
+
+float4 main_ps(PixelInput input) : SV_TARGET0
+{
+    float3 fragPosition = SAMPLE_TEXTURE(gPosition, input.TexCoord).rgb;
+    float3 normal = SAMPLE_TEXTURE(gNormal, input.TexCoord).xyz;
+    float3 albedo = SAMPLE_TEXTURE(gAlbedo, input.TexCoord).rgb;
+    float2 metallicRoughness = SAMPLE_TEXTURE(gMetallicRoughness, input.TexCoord).rg;
+
+    return ComputeColor(
+        fragPosition,
+        normal,
+        albedo,
+        metallicRoughness.r,
+        metallicRoughness.g
+    );
+}
+
+Technique DeferredPBR
+{
+    Pass
+    {
+        PixelShader = compile ps_3_0 main_ps();
+    }
+}

Effects/PBREffect.cs

@@ -3,48 +3,6 @@ using Microsoft.Xna.Framework.Graphics;
 
 namespace Kav
 {
-    public class PointLightCollection
-    {
-        private readonly Vector3[] positions = new Vector3[4];
-        private readonly Vector3[] colors = new Vector3[4];
-        private readonly float[] intensities = new float[4];
-
-        readonly EffectParameter lightPositionsParam;
-        readonly EffectParameter lightColorsParam;
-
-        public PointLightCollection(EffectParameter lightPositionsParam, EffectParameter lightColorsParam)
-        {
-            this.lightPositionsParam = lightPositionsParam;
-            this.lightColorsParam = lightColorsParam;
-        }
-
-        public PointLight this[int i]
-        {
-            get
-            {
-                var color = colors[i] / intensities[i];
-                return new PointLight(
-                    positions[i],
-                    new Color(
-                        color.X,
-                        color.Y,
-                        color.Z,
-                        1f
-                    ),
-                    intensities[i]
-                );
-            }
-            set
-            {
-                positions[i] = value.Position;
-                colors[i] = value.Color.ToVector3() * value.Intensity;
-                intensities[i] = value.Intensity;
-                lightPositionsParam.SetValue(positions);
-                lightColorsParam.SetValue(colors);
-            }
-        }
-    }
-
     public class DirectionalLightCollection
     {
         private readonly Vector3[] directions = new Vector3[4];
@@ -285,7 +243,8 @@ namespace Kav
 
             pointLightCollection = new PointLightCollection(
                 Parameters["LightPositions"],
-                Parameters["PositionLightColors"]
+                Parameters["PositionLightColors"],
+                MaxPointLights
             );
 
             directionalLightCollection = new DirectionalLightCollection(
@@ -304,7 +263,8 @@ namespace Kav
 
             PointLights = new PointLightCollection(
                 Parameters["LightPositions"],
-                Parameters["PositionLightColors"]
+                Parameters["PositionLightColors"],
+                MaxPointLights
             );
 
             for (int i = 0; i < MaxPointLights; i++)

Effects/PointLightCollection.cs

@@ -0,0 +1,49 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace Kav
+{
+    public class PointLightCollection
+    {
+        private readonly Vector3[] positions;
+        private readonly Vector3[] colors;
+        private readonly float[] intensities = new float[4];
+
+        readonly EffectParameter lightPositionsParam;
+        readonly EffectParameter lightColorsParam;
+
+        public PointLightCollection(EffectParameter lightPositionsParam, EffectParameter lightColorsParam, int maxLights)
+        {
+            this.positions = new Vector3[maxLights];
+            this.colors = new Vector3[maxLights];
+            this.lightPositionsParam = lightPositionsParam;
+            this.lightColorsParam = lightColorsParam;
+        }
+
+        public PointLight this[int i]
+        {
+            get
+            {
+                var color = colors[i] / intensities[i];
+                return new PointLight(
+                    positions[i],
+                    new Color(
+                        color.X,
+                        color.Y,
+                        color.Z,
+                        1f
+                    ),
+                    intensities[i]
+                );
+            }
+            set
+            {
+                positions[i] = value.Position;
+                colors[i] = value.Color.ToVector3() * value.Intensity;
+                intensities[i] = value.Intensity;
+                lightPositionsParam.SetValue(positions);
+                lightColorsParam.SetValue(colors);
+            }
+        }
+    }
+}

Kav.Core.csproj

@@ -18,6 +18,9 @@
     <EmbeddedResource Include="Effects\FXB\GBufferEffect.fxb">
       <LogicalName>Kav.Resources.GBufferEffect.fxb</LogicalName>
     </EmbeddedResource>
+    <EmbeddedResource Include="Effects\FXB\DeferredPBREffect.fxb">
+      <LogicalName>Kav.Resources.DeferredPBREffect.fxb</LogicalName>
+    </EmbeddedResource>
     <EmbeddedResource Include="Effects\FXB\PBREffect.fxb">
       <LogicalName>Kav.Resources.PBREffect.fxb</LogicalName>
 		</EmbeddedResource>

Kav.Framework.csproj

@@ -18,6 +18,9 @@
     <EmbeddedResource Include="Effects\FXB\GBufferEffect.fxb">
       <LogicalName>Kav.Resources.GBufferEffect.fxb</LogicalName>
     </EmbeddedResource>
+    <EmbeddedResource Include="Effects\FXB\DeferredPBREffect.fxb">
+      <LogicalName>Kav.Resources.DeferredPBREffect.fxb</LogicalName>
+    </EmbeddedResource>
     <EmbeddedResource Include="Effects\FXB\PBREffect.fxb">
       <LogicalName>Kav.Resources.PBREffect.fxb</LogicalName>
 		</EmbeddedResource>

Renderer.cs

@@ -17,10 +17,11 @@ namespace Kav
         private RenderTarget2D gNormal { get; }
         private RenderTarget2D gAlbedo { get; }
         private RenderTarget2D gMetallicRoughness { get; }
+        private RenderTarget2D deferredRenderTarget { get; }
 
         private RenderTargetBinding[] GBuffer { get; }
 
-        private GBufferEffect GBufferEffect { get; }
+        private DeferredPBREffect DeferredPBREffect { get; }
 
         private SpriteBatch SpriteBatch { get; }
 
@@ -35,7 +36,7 @@ namespace Kav
                 renderDimensionsX,
                 renderDimensionsY,
                 false,
-                SurfaceFormat.Color,
+                SurfaceFormat.HalfSingle, // unused
                 DepthFormat.Depth24
             );
 
@@ -44,8 +45,8 @@ namespace Kav
                 renderDimensionsX,
                 renderDimensionsY,
                 false,
-                SurfaceFormat.Color,
+                SurfaceFormat.Vector4,
-                DepthFormat.None
+                DepthFormat.Depth24
             );
 
             gNormal = new RenderTarget2D(
@@ -53,7 +54,7 @@ namespace Kav
                 renderDimensionsX,
                 renderDimensionsY,
                 false,
-                SurfaceFormat.Color,
+                SurfaceFormat.Vector4,
                 DepthFormat.None
             );
 
@@ -71,7 +72,7 @@ namespace Kav
                 renderDimensionsX,
                 renderDimensionsY,
                 false,
-                SurfaceFormat.Color,
+                SurfaceFormat.HalfVector2,
                 DepthFormat.None
             );
 
@@ -82,9 +83,23 @@ namespace Kav
                 new RenderTargetBinding(gMetallicRoughness)
             };
             
+            deferredRenderTarget = new RenderTarget2D(
+                GraphicsDevice,
+                renderDimensionsX,
+                renderDimensionsY
+            );
+
             SimpleDepthEffect = new SimpleDepthEffect(GraphicsDevice);
+            DeferredPBREffect = new DeferredPBREffect(GraphicsDevice);
 
             SpriteBatch = new SpriteBatch(GraphicsDevice);
+
+            Texture2D whitePixel = new Texture2D(GraphicsDevice, 1, 1);
+            whitePixel.SetData(new[] { Color.White });
+
+            GraphicsDevice.SetRenderTarget(deferredRenderTarget);
+            graphicsDevice.Clear(Color.White);
+            GraphicsDevice.SetRenderTarget(null);
         }
 
         public void DeferredRender(
@@ -94,7 +109,9 @@ namespace Kav
             IEnumerable<DirectionalLight> directionalLights
         ) {
             GraphicsDevice.SetRenderTargets(GBuffer);
-            GraphicsDevice.Clear(Color.Black);
+            GraphicsDevice.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1f, 0);
+            GraphicsDevice.DepthStencilState = DepthStencilState.Default;
+            GraphicsDevice.BlendState = BlendState.Opaque;
 
             foreach (var (model, transform) in modelTransforms)
             {
@@ -130,12 +147,24 @@ namespace Kav
             }
 
             GraphicsDevice.SetRenderTarget(null);
-            GraphicsDevice.Clear(Color.Black);
+            GraphicsDevice.Clear(Color.CornflowerBlue);
-            SpriteBatch.Begin(SpriteSortMode.Deferred, null, null, null, null);
+
-            SpriteBatch.Draw(gPosition, new Rectangle(0, 0, 640, 360), Color.White);
+            DeferredPBREffect.GPosition = gPosition;
-            SpriteBatch.Draw(gAlbedo, new Rectangle(640, 0, 640, 360), Color.White);
+            DeferredPBREffect.GAlbedo = gAlbedo;
-            SpriteBatch.Draw(gNormal, new Rectangle(0, 360, 640, 360), Color.White);
+            DeferredPBREffect.GNormal = gNormal;
-            SpriteBatch.Draw(gMetallicRoughness, new Rectangle(640, 360, 640, 360), Color.White);
+            DeferredPBREffect.GMetallicRoughness = gMetallicRoughness;
+            DeferredPBREffect.EyePosition = Matrix.Invert(camera.View).Translation;
+
+            int i = 0;
+            foreach (var pointLight in pointLights)
+            {
+                if (i > DeferredPBREffect.MaxPointLights) { break; }
+                DeferredPBREffect.PointLights[i] = pointLight;
+                i++;
+            }
+
+            SpriteBatch.Begin(SpriteSortMode.Deferred, BlendState.NonPremultiplied, null, null, null, DeferredPBREffect);
+            SpriteBatch.Draw(deferredRenderTarget, Vector2.Zero, Color.White);
             SpriteBatch.End();
         }
 

Resources.cs

@@ -15,6 +15,19 @@ namespace Kav
                 return gBufferEffect;
             }
         }
+
+        public static byte[] DeferredPBREffect
+        {
+            get
+            {
+                if (deferredPBREffect == null)
+                {
+                    deferredPBREffect = GetResource("DeferredPBREffect");
+                }
+                return deferredPBREffect;
+            }
+        }
+
         public static byte[] PBREffect
         {
             get
@@ -40,6 +53,7 @@ namespace Kav
         }
 
         private static byte[] gBufferEffect;
+        private static byte[] deferredPBREffect;
         private static byte[] pbrEffect;
         private static byte[] simpleDepthEffect;