VideoCommon: Don't process the depth range in the vertex shader if it's not oversized.

2 files changed, 13 insertions, 6 deletions

diff --git a/Source/Core/VideoCommon/VertexShaderGen.cpp b/Source/Core/VideoCommon/VertexShaderGen.cpp
index d3ea2a774a..8f44f1735e 100644
--- a/Source/Core/VideoCommon/VertexShaderGen.cpp
+++ b/Source/Core/VideoCommon/VertexShaderGen.cpp
@@ -30,6 +30,10 @@ VertexShaderUid GetVertexShaderUid()
   uid_data->msaa = g_ActiveConfig.iMultisamples > 1;
   uid_data->ssaa = g_ActiveConfig.iMultisamples > 1 && g_ActiveConfig.bSSAA;
   uid_data->numColorChans = xfmem.numChan.numColorChans;
+  uid_data->vertex_depth =
+      g_ActiveConfig.backend_info.bSupportsDepthClamp &&
+      ((fabs(xfmem.viewport.zRange) > 16777215.0f || fabs(xfmem.viewport.farZ) > 16777215.0f) ||
+       (xfmem.viewport.zRange < 0.0f && !g_ActiveConfig.backend_info.bSupportsReversedDepthRange));
 
   GetLightingShaderUid(uid_data->lighting);
 
@@ -416,13 +420,10 @@ ShaderCode GenerateVertexShaderCode(APIType api_type, const vertex_shader_uid_da
       out.Write("o.colors_1 = color1;\n");
   }
 
-  // Write the true depth value. If the game uses depth textures, then the pixel shader will
-  // override it with the correct values if not then early z culling will improve speed.
+  // If we can disable the incorrect depth clipping planes using depth clamping, then we can do
+  // our own depth clipping and calculate the depth range before the perspective divide.
   if (g_ActiveConfig.backend_info.bSupportsDepthClamp)
   {
-    // If we can disable the incorrect depth clipping planes using depth clamping, then we can do
-    // our own depth clipping and calculate the depth range before the perspective divide.
-
     // Since we're adjusting z for the depth range before the perspective divide, we have to do our
     // own clipping. We want to clip so that -w <= z <= 0, which matches the console -1..0 range.
     // We adjust our depth value for clipping purposes to match the perspective projection in the
@@ -430,7 +431,12 @@ ShaderCode GenerateVertexShaderCode(APIType api_type, const vertex_shader_uid_da
     out.Write("float clipDepth = o.pos.z * (1.0 - 1e-7);\n");
     out.Write("o.clipDist0 = clipDepth + o.pos.w;\n");  // Near: z < -w
     out.Write("o.clipDist1 = -clipDepth;\n");           // Far: z > 0
+  }
 
+  // Write the true depth value. If the game uses depth textures, then the pixel shader will
+  // override it with the correct values if not then early z culling will improve speed.
+  if (uid_data->vertex_depth)
+  {
     // Adjust z for the depth range. We're using an equation which incorperates a depth inversion,
     // so we can map the console -1..0 range to the 0..1 range used in the depth buffer.
     // We have to handle the depth range in the vertex shader instead of after the perspective
diff --git a/Source/Core/VideoCommon/VertexShaderGen.h b/Source/Core/VideoCommon/VertexShaderGen.h
index 4b9e9d1d39..4936ce6ba8 100644
--- a/Source/Core/VideoCommon/VertexShaderGen.h
+++ b/Source/Core/VideoCommon/VertexShaderGen.h
@@ -43,7 +43,8 @@ struct vertex_shader_uid_data
   u32 texMtxInfo_n_projection : 16;  // Stored separately to guarantee that the texMtxInfo struct is
                                      // 8 bits wide
   u32 ssaa : 1;
-  u32 pad : 15;
+  u32 vertex_depth : 1;
+  u32 pad : 14;
 
   struct
   {