From 06809587e89c04beb2311790c704ac13af882337 Mon Sep 17 00:00:00 2001
From: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Date: Thu, 6 Feb 2020 00:36:57 +0100
Subject: [PATCH] [d3d9] Don't arbitrarily set fog scale to 0

The Witcher 1 sets FOGSTART == FOGEND together with LINEAR fog mode, in
which case we previously set fog_scale to 0 and therefore incorrectly
override the pixel color with the fog color.

Fixes #1401.
---
 src/d3d9/d3d9_device.cpp         | 3 ---
 src/d3d9/d3d9_fixed_function.cpp | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/d3d9/d3d9_device.cpp b/src/d3d9/d3d9_device.cpp
index 315ff6b5..fa6a66fa 100644
--- a/src/d3d9/d3d9_device.cpp
+++ b/src/d3d9/d3d9_device.cpp
@@ -4589,9 +4589,6 @@ namespace dxvk {
       float start = bit::cast<float>(rs[D3DRS_FOGSTART]);
 
       float scale = 1.0f / (end - start);
-      if (!std::isfinite(scale))
-        scale = 0.0f;
-
       UpdatePushConstant<offsetof(D3D9RenderStateInfo, fogScale), sizeof(float)>(&scale);
     }
     else if constexpr (Item == D3D9RenderStateItem::PointSize) {
diff --git a/src/d3d9/d3d9_fixed_function.cpp b/src/d3d9/d3d9_fixed_function.cpp
index e06e187b..04d27b72 100644
--- a/src/d3d9/d3d9_fixed_function.cpp
+++ b/src/d3d9/d3d9_fixed_function.cpp
@@ -129,7 +129,7 @@ namespace dxvk {
           case D3DFOG_LINEAR: {
             uint32_t fogFactor = spvModule.opFSub(floatType, fogEnd, depth);
             fogFactor = spvModule.opFMul(floatType, fogFactor, fogScale);
-            fogFactor = spvModule.opFClamp(floatType, fogFactor, spvModule.constf32(0.0f), spvModule.constf32(1.0f));
+            fogFactor = spvModule.opNClamp(floatType, fogFactor, spvModule.constf32(0.0f), spvModule.constf32(1.0f));
             return fogFactor;
           }