From bde81269130c31c93cbb0f0f3ac8f23560751cac Mon Sep 17 00:00:00 2001
From: Jules Blok <jules.blok@gmail.com>
Date: Tue, 21 Feb 2017 16:15:22 +0100
Subject: [PATCH] VideoBackends: Remove depth range clamping hacks.

Oversized depth ranges are handled correctly now, we don't need to hack around them with clamps anymore.
---
 Source/Core/VideoBackends/D3D/Render.cpp      |  6 ++----
 Source/Core/VideoBackends/D3D12/Render.cpp    |  6 ++----
 Source/Core/VideoBackends/OGL/Render.cpp      | 16 +++++++++-------
 Source/Core/VideoBackends/Vulkan/Renderer.cpp |  6 ++----
 4 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/Source/Core/VideoBackends/D3D/Render.cpp b/Source/Core/VideoBackends/D3D/Render.cpp
index 431690ca25..a100fb5616 100644
--- a/Source/Core/VideoBackends/D3D/Render.cpp
+++ b/Source/Core/VideoBackends/D3D/Render.cpp
@@ -561,10 +561,8 @@ void Renderer::SetViewport()
   float Y = Renderer::EFBToScaledYf(xfmem.viewport.yOrig + xfmem.viewport.ht - scissorYOff);
   float Wd = Renderer::EFBToScaledXf(2.0f * xfmem.viewport.wd);
   float Ht = Renderer::EFBToScaledYf(-2.0f * xfmem.viewport.ht);
-  float range = MathUtil::Clamp<float>(xfmem.viewport.zRange, 0.0f, 16777215.0f);
-  float min_depth =
-      MathUtil::Clamp<float>(xfmem.viewport.farZ - range, 0.0f, 16777215.0f) / 16777216.0f;
-  float max_depth = MathUtil::Clamp<float>(xfmem.viewport.farZ, 0.0f, 16777215.0f) / 16777216.0f;
+  float min_depth = (xfmem.viewport.farZ - xfmem.viewport.zRange) / 16777216.0f;
+  float max_depth = xfmem.viewport.farZ / 16777216.0f;
   if (Wd < 0.0f)
   {
     X += Wd;
diff --git a/Source/Core/VideoBackends/D3D12/Render.cpp b/Source/Core/VideoBackends/D3D12/Render.cpp
index d72ab7497a..d5bdaeb07a 100644
--- a/Source/Core/VideoBackends/D3D12/Render.cpp
+++ b/Source/Core/VideoBackends/D3D12/Render.cpp
@@ -466,10 +466,8 @@ void Renderer::SetViewport()
   float y = Renderer::EFBToScaledYf(xfmem.viewport.yOrig + xfmem.viewport.ht - scissor_y_offset);
   float width = Renderer::EFBToScaledXf(2.0f * xfmem.viewport.wd);
   float height = Renderer::EFBToScaledYf(-2.0f * xfmem.viewport.ht);
-  float range = MathUtil::Clamp<float>(xfmem.viewport.zRange, 0.0f, 16777215.0f);
-  float min_depth =
-      MathUtil::Clamp<float>(xfmem.viewport.farZ - range, 0.0f, 16777215.0f) / 16777216.0f;
-  float max_depth = MathUtil::Clamp<float>(xfmem.viewport.farZ, 0.0f, 16777215.0f) / 16777216.0f;
+  float min_depth = (xfmem.viewport.farZ - xfmem.viewport.zRange) / 16777216.0f;
+  float max_depth = xfmem.viewport.farZ / 16777216.0f;
   if (width < 0.0f)
   {
     x += width;
diff --git a/Source/Core/VideoBackends/OGL/Render.cpp b/Source/Core/VideoBackends/OGL/Render.cpp
index abee545ba4..f8405250d7 100644
--- a/Source/Core/VideoBackends/OGL/Render.cpp
+++ b/Source/Core/VideoBackends/OGL/Render.cpp
@@ -1111,6 +1111,8 @@ void Renderer::SetViewport()
                           (float)scissorYOff);
   float Width = EFBToScaledXf(2.0f * xfmem.viewport.wd);
   float Height = EFBToScaledYf(-2.0f * xfmem.viewport.ht);
+  float min_depth = (xfmem.viewport.farZ - xfmem.viewport.zRange) / 16777216.0f;
+  float max_depth = xfmem.viewport.farZ / 16777216.0f;
   if (Width < 0)
   {
     X += Width;
@@ -1136,17 +1138,10 @@ void Renderer::SetViewport()
   // Set the reversed depth range.
   if (g_ActiveConfig.backend_info.bSupportsOversizedDepthRanges)
   {
-    float min_depth = (xfmem.viewport.farZ - xfmem.viewport.zRange) / 16777216.0f;
-    float max_depth = xfmem.viewport.farZ / 16777216.0f;
     glDepthRangedNV(max_depth, min_depth);
   }
   else
   {
-    float range = MathUtil::Clamp<float>(xfmem.viewport.zRange, -16777216.0f, 16777216.0f);
-    float min_depth =
-        MathUtil::Clamp<float>(xfmem.viewport.farZ - range, 0.0f, 16777215.0f) / 16777216.0f;
-    float max_depth = MathUtil::Clamp<float>(xfmem.viewport.farZ, 0.0f, 16777215.0f) / 16777216.0f;
-
     // If an oversized depth range is used, we need to calculate the depth range in the
     // vertex shader.
     if (g_ActiveConfig.backend_info.bSupportsDepthClamp &&
@@ -1165,6 +1160,13 @@ void Renderer::SetViewport()
         max_depth = GX_MAX_DEPTH;
       }
     }
+    else
+    {
+      // There's no way to support oversized depth ranges in this situation. Let's just clamp the
+      // range to the maximum value supported by the console GPU and hope for the best.
+      min_depth = MathUtil::Clamp(min_depth, 0.0f, GX_MAX_DEPTH);
+      max_depth = MathUtil::Clamp(max_depth, 0.0f, GX_MAX_DEPTH);
+    }
 
     glDepthRangef(max_depth, min_depth);
   }
diff --git a/Source/Core/VideoBackends/Vulkan/Renderer.cpp b/Source/Core/VideoBackends/Vulkan/Renderer.cpp
index 765601b329..ebfc755327 100644
--- a/Source/Core/VideoBackends/Vulkan/Renderer.cpp
+++ b/Source/Core/VideoBackends/Vulkan/Renderer.cpp
@@ -1641,10 +1641,8 @@ void Renderer::SetViewport()
   float y = Renderer::EFBToScaledYf(xfmem.viewport.yOrig + xfmem.viewport.ht - scissor_y_offset);
   float width = Renderer::EFBToScaledXf(2.0f * xfmem.viewport.wd);
   float height = Renderer::EFBToScaledYf(-2.0f * xfmem.viewport.ht);
-  float range = MathUtil::Clamp<float>(xfmem.viewport.zRange, -16777215.0f, 16777215.0f);
-  float min_depth =
-      MathUtil::Clamp<float>(xfmem.viewport.farZ - range, 0.0f, 16777215.0f) / 16777216.0f;
-  float max_depth = MathUtil::Clamp<float>(xfmem.viewport.farZ, 0.0f, 16777215.0f) / 16777216.0f;
+  float min_depth = (xfmem.viewport.farZ - xfmem.viewport.zRange) / 16777216.0f;
+  float max_depth = xfmem.viewport.farZ / 16777216.0f;
   if (width < 0.0f)
   {
     x += width;