[d3d11] Add option to control sampler LOD bias

dxvk.conf

@@ -169,6 +169,16 @@
 # d3d9.samplerAnisotropy = -1
 
 
+# Changes the mipmap LOD bias for all samplers. The given number will be
+# added to the LOD bias provided by the application, rather than replacing
+# it entirely. Positive values will reduce texture detail, while negative
+# values may increase sharpness at the cost of shimmer.
+#
+# Supported values: Any number between -2.0 and 1.0
+
+# d3d11.samplerLodBias = 0.0
+
+
 # Declares vertex positions as invariant in order to solve
 # potential Z-fighting issues at a small performance cost.
 #

src/d3d11/d3d11_options.cpp

@@ -1,4 +1,4 @@
-#include <unordered_map>
+#include "../util/util_math.h"
 
 #include "d3d11_options.h"
 
@@ -13,6 +13,7 @@ namespace dxvk {
     this->ignoreGraphicsBarriers = config.getOption<bool>("d3d11.ignoreGraphicsBarriers", false);
     this->maxTessFactor         = config.getOption<int32_t>("d3d11.maxTessFactor", 0);
     this->samplerAnisotropy     = config.getOption<int32_t>("d3d11.samplerAnisotropy", -1);
+    this->samplerLodBias        = config.getOption<float>("d3d11.samplerLodBias", 0.0f);
     this->invariantPosition     = config.getOption<bool>("d3d11.invariantPosition", true);
     this->floatControls         = config.getOption<bool>("d3d11.floatControls", true);
     this->disableMsaa           = config.getOption<bool>("d3d11.disableMsaa", false);
@@ -23,6 +24,9 @@ namespace dxvk {
     this->syncInterval          = config.getOption<int32_t>("dxgi.syncInterval", -1);
     this->tearFree              = config.getOption<Tristate>("dxgi.tearFree", Tristate::Auto);
 
+    // Clamp LOD bias so that people don't abuse this in unintended ways
+    this->samplerLodBias = dxvk::fclamp(this->samplerLodBias, -2.0f, 1.0f);
+
     int32_t maxImplicitDiscardSize = config.getOption<int32_t>("d3d11.maxImplicitDiscardSize", 256);
     this->maxImplicitDiscardSize = maxImplicitDiscardSize >= 0
       ? VkDeviceSize(maxImplicitDiscardSize) << 10

src/d3d11/d3d11_options.h

@@ -62,6 +62,11 @@ namespace dxvk {
     /// given anisotropy value for all samplers.
     int32_t samplerAnisotropy;
 
+    /// Mipmap LOD bias
+    ///
+    /// Enforces the given LOD bias for all samplers.
+    float samplerLodBias;
+
     /// Declare vertex positions in shaders as invariant
     bool invariantPosition;
 

src/d3d11/d3d11_sampler.cpp

@@ -44,6 +44,10 @@ namespace dxvk {
     if (desc.MaxAnisotropy <  1) info.maxAnisotropy =  1.0f;
     if (desc.MaxAnisotropy > 16) info.maxAnisotropy = 16.0f;
     
+    // Enforce LOD bias specified in the device options
+    if (info.minFilter == VK_FILTER_LINEAR && info.magFilter == VK_FILTER_LINEAR)
+      info.mipmapLodBias += device->GetOptions()->samplerLodBias;
+
     // Enforce anisotropy specified in the device options
     int32_t samplerAnisotropyOption = device->GetOptions()->samplerAnisotropy;