Implement reverse z

Source/Engine/Core/Math/Matrix.cpp

@@ -506,10 +506,10 @@ void Matrix::OrthoOffCenter(float left, float right, float bottom, float top, fl
     result = Identity;
     result.M11 = 2.0f / (right - left);
     result.M22 = 2.0f / (top - bottom);
-    result.M33 = zRange;
+    result.M33 = -zRange;
     result.M41 = (left + right) / (left - right);
     result.M42 = (top + bottom) / (bottom - top);
-    result.M43 = -zNear * zRange;
+    result.M43 = zFar * zRange;
 }
 
 void Matrix::PerspectiveFov(float fov, float aspect, float zNear, float zFar, Matrix& result)
@@ -525,16 +525,16 @@ void Matrix::PerspectiveFov(float fov, float aspect, float zNear, float zFar, Ma
 
 void Matrix::PerspectiveOffCenter(float left, float right, float bottom, float top, float zNear, float zFar, Matrix& result)
 {
-    const float zRange = zFar / (zFar - zNear);
+    const float zRange = zNear / (zFar - zNear);
 
     result = Zero;
     result.M11 = 2.0f * zNear / (right - left);
     result.M22 = 2.0f * zNear / (top - bottom);
     result.M31 = (left + right) / (left - right);
     result.M32 = (top + bottom) / (bottom - top);
-    result.M33 = zRange;
+    result.M33 = -zRange;
     result.M34 = 1.0f;
-    result.M43 = -zNear * zRange;
+    result.M43 = zFar * zRange;
 }
 
 void Matrix::RotationX(float angle, Matrix& result)

Source/Engine/Core/Math/Matrix.cs

@@ -2176,10 +2176,10 @@ namespace FlaxEngine
             result = Identity;
             result.M11 = 2.0f / (right - left);
             result.M22 = 2.0f / (top - bottom);
-            result.M33 = zRange;
+            result.M33 = -zRange;
             result.M41 = (left + right) / (left - right);
             result.M42 = (top + bottom) / (bottom - top);
-            result.M43 = -znear * zRange;
+            result.M43 = zfar * zRange;
         }
 
         /// <summary>
@@ -2238,14 +2238,14 @@ namespace FlaxEngine
         public static void PerspectiveFov(float fov, float aspect, float znear, float zfar, out Matrix result)
         {
             var yScale = (float)(1.0f / Math.Tan(fov * 0.5f));
-            var q = zfar / (zfar - znear);
+            var zRange = znear / (zfar - znear);
             result = new Matrix
             {
                 M11 = yScale / aspect,
                 M22 = yScale,
-                M33 = q,
+                M33 = -zRange,
                 M34 = 1.0f,
-                M43 = -q * znear,
+                M43 = zRange * zfar,
             };
         }
 
@@ -2275,16 +2275,16 @@ namespace FlaxEngine
         /// <param name="result">When the method completes, contains the created projection matrix.</param>
         public static void PerspectiveOffCenter(float left, float right, float bottom, float top, float znear, float zfar, out Matrix result)
         {
-            float zRange = zfar / (zfar - znear);
+            float zRange = znear / (zfar - znear);
             result = new Matrix
             {
                 M11 = 2.0f * znear / (right - left),
                 M22 = 2.0f * znear / (top - bottom),
                 M31 = (left + right) / (left - right),
                 M32 = (top + bottom) / (bottom - top),
-                M33 = zRange,
+                M33 = -zRange,
                 M34 = 1.0f,
-                M43 = -znear * zRange,
+                M43 = zfar * zRange,
             };
         }
 

Source/Engine/Graphics/GPUContext.h

@@ -186,7 +186,7 @@ public:
     /// </summary>
     /// <param name="depthBuffer">The depth buffer to clear.</param>
     /// <param name="depthValue">The clear depth value.</param>
-    API_FUNCTION() virtual void ClearDepth(GPUTextureView* depthBuffer, float depthValue = 1.0f) = 0;
+    API_FUNCTION() virtual void ClearDepth(GPUTextureView* depthBuffer, float depthValue = 0.0f) = 0;
 
     /// <summary>
     /// Clears an unordered access buffer with a float value.

Source/Engine/Graphics/GPUDevice.cpp

@@ -130,7 +130,7 @@ GPUPipelineState::Description GPUPipelineState::Description::Default =
     true, // DepthEnable
     true, // DepthWriteEnable
     true, // DepthClipEnable
-    ComparisonFunc::Less, // DepthFunc
+    ComparisonFunc::Greater, // DepthFunc
     false, // StencilEnable
     0xff, // StencilReadMask
     0xff, // StencilWriteMask
@@ -154,7 +154,7 @@ GPUPipelineState::Description GPUPipelineState::Description::DefaultNoDepth =
     false, // DepthEnable
     false, // DepthWriteEnable
     false, // DepthClipEnable
-    ComparisonFunc::Less, // DepthFunc
+    ComparisonFunc::Greater, // DepthFunc
     false, // StencilEnable
     0xff, // StencilReadMask
     0xff, // StencilWriteMask
@@ -178,7 +178,7 @@ GPUPipelineState::Description GPUPipelineState::Description::DefaultFullscreenTr
     false, // DepthEnable
     false, // DepthWriteEnable
     false, // DepthClipEnable
-    ComparisonFunc::Less, // DepthFunc
+    ComparisonFunc::Greater, // DepthFunc
     false, // StencilEnable
     0xff, // StencilReadMask
     0xff, // StencilWriteMask

Source/Shaders/GBuffer.hlsl

@@ -27,13 +27,13 @@ Texture2D GBuffer3 : register(t4);
 // Linearize raw device depth
 float LinearizeZ(GBufferData gBuffer, float depth)
 {
-    return gBuffer.ViewInfo.w / (depth - gBuffer.ViewInfo.z);
+    return gBuffer.ViewInfo.w / ((1-depth) - gBuffer.ViewInfo.z);
 }
 
 // Convert linear depth to device depth
 float LinearZ2DeviceDepth(GBufferData gBuffer, float linearDepth)
 {
-    return (gBuffer.ViewInfo.w / linearDepth) + gBuffer.ViewInfo.z;
+    return 1 - ((gBuffer.ViewInfo.w / linearDepth) + gBuffer.ViewInfo.z);
 }
 
 // Get view space position at given pixel coordinate with given device depth