GS: Add new filtering mode to reduce UI blur.

Author: TJnotJT

pcsx2-qt/Settings/GraphicsHardwareRenderingSettingsTab.ui

@@ -121,6 +121,11 @@
        <string>Bilinear (Forced excluding sprite)</string>
       </property>
      </item>
+     <item>
+      <property name="text">
+       <string>Bilinear (PS2 except flat nearest)</string>
+      </property>
+     </item>
     </widget>
    </item>
    <item row="4" column="0">

pcsx2-qt/Settings/GraphicsSettingsWidget.cpp

@@ -497,7 +497,8 @@ GraphicsSettingsWidget::GraphicsSettingsWidget(SettingsWindow* settings_dialog,
 			   "Nearest: Makes no attempt to blend colors.<br> "
 			   "Bilinear (Forced): Will blend colors together to remove harsh edges between different colored pixels even if the game told the PS2 not to.<br> "
 			   "Bilinear (PS2): Will apply filtering to all surfaces that a game instructs the PS2 to filter.<br> "
-			   "Bilinear (Forced Excluding Sprites): Will apply filtering to all surfaces, even if the game told the PS2 not to, except sprites."));
+			   "Bilinear (Forced Excluding Sprites): Will apply filtering to all surfaces, even if the game told the PS2 not to, except sprites.<br>",
+			   "Bilinear (PS2 Except Flat Nearest): Will apply filtering to all surfaces that a game instructs the PS2 to filter, with the exception of flat draws that will be forced to nearest."));
 
 		dialog()->registerWidgetHelp(m_hw.trilinearFiltering, tr("Trilinear Filtering"), tr("Automatic (Default)"),
 			tr("Reduces blurriness of large textures applied to small, steeply angled surfaces by sampling colors from the two nearest Mipmaps. Requires Mipmapping to be 'on'.<br> "

pcsx2/Config.h

@@ -317,6 +317,7 @@ enum class BiFiltering : u8
 	Forced,
 	PS2,
 	Forced_But_Sprite,
+	PS2_But_Flat_Nearest,
 };
 
 enum class TriFiltering : s8

pcsx2/GS/Renderers/Common/GSVertexTrace.cpp

@@ -112,6 +112,11 @@ void GSVertexTrace::Update(const void* vertex, const u16* index, int v_count, in
 				m_filter.opt_linear = (m_primclass == GS_SPRITE_CLASS) ? m_filter.linear : 1;
 				break;
 
+			case BiFiltering::PS2_But_Flat_Nearest:
+				// Special case to reduce UI blurriness when upscaling is enabled
+				m_filter.opt_linear = m_eq.z ? 0 : m_filter.linear;
+				break;
+
 			case BiFiltering::Forced:
 				m_filter.opt_linear = 1;
 				break;