GS-GUI: Add tooltip for Dithering

The PS2 and PS1 supported dithering where-as PCSX2 didn't support hardware dithering till 1.7 dev builds. Some games have no dithering, others have dithering in the shadows or others like baroque just smear it full with this affect so it's an extreme example: https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=ab92a0e0-f91e-11ea-bf88-a15b6c7adf9a

pcsx2/GS/Window/GSLinuxDialog.cpp

@@ -309,6 +309,7 @@ void populate_hw_table(GtkWidget* hw_table)
 	AddTooltip(mipmap_label, IDC_MIPMAP_HW);
 	AddTooltip(mipmap_combo_box, IDC_MIPMAP_HW);
 	AddTooltip(acc_bld_label, acc_bld_combo_box, IDC_ACCURATE_BLEND_UNIT);
+	AddTooltip(dither_label, dither_combo_box, IDC_DITHERING);
 
 	s_table_line = 0;
 	InsertWidgetInTable(hw_table, hack_enable_check, acc_date_check);

pcsx2/GS/Window/GSSetting.cpp

@@ -196,6 +196,13 @@ const char* dialog_message(int ID, bool* updateText)
 				   "Disabling this can amplify stuttering due to low RAM/VRAM.\n\n"
 				   "Note: It should be enabled for Armored Core, Destroy All Humans, Gran Turismo and possibly others.\n"
 				   "This option does not improve the graphics or the FPS.");
+		case IDC_DITHERING:
+			return cvtString("In the PS2's case, it reduces banding between colors and improves the perceived color depth.\n"
+				   "In the PS1's case, it was used more aggressively due to 16-bit colour.\n"
+				   "Sit far enough and don't examine it too closely for the best effect.\n\n"
+				   "Off:\nDisables any dithering.\n\n"
+				   "Unscaled:\nNative Dithering / Lowest dithering effect does not increase size of squares when upscaling.\n\n"
+				   "Scaled:\nUpscaling-aware / Highest dithering effect.");
 			// Windows only options.
 #ifdef _WIN32
 		case IDC_ACCURATE_BLEND_UNIT_D3D11:

pcsx2/GS/Window/GSSetting.h

@@ -41,48 +41,52 @@ const char* dialog_message(int ID, bool* updateText = NULL);
 #ifndef _WIN32
 enum
 {
+	// Renderer
 	IDC_FILTER,
+	// Hardware Renderer
+	IDC_ACCURATE_DATE,
+	IDC_PALTEX,
+	IDC_CONSERVATIVE_FB,
+	IDC_AFCOMBO,
+	IDC_DITHERING,
+	IDC_MIPMAP_HW,
+	IDC_CRC_LEVEL,
+	IDC_ACCURATE_BLEND_UNIT,
+	// Rendering Hacks
+	IDC_AUTO_FLUSH_HW,
+	IDC_TC_DEPTH,
+	IDC_SAFE_FEATURES,
+	IDC_FAST_TC_INV,
+	IDC_CPU_FB_CONVERSION,
+	IDC_MEMORY_WRAPPING,
+	IDC_PRELOAD_GS,
 	IDC_HALF_SCREEN_TS,
 	IDC_TRI_FILTER,
 	IDC_SKIPDRAWHACK,
 	IDC_SKIPDRAWHACKEDIT,
 	IDC_SKIPDRAWOFFSET,
 	IDC_SKIPDRAWOFFSETEDIT,
-	IDC_OFFSETHACK,
-	IDC_WILDHACK,
+	// Upscaling Hacks
 	IDC_ALIGN_SPRITE,
+	IDC_MERGE_PP_SPRITE,
+	IDC_WILDHACK,
+	IDC_OFFSETHACK,
 	IDC_ROUND_SPRITE,
 	IDC_TCOFFSETX,
 	IDC_TCOFFSETX2,
 	IDC_TCOFFSETY,
 	IDC_TCOFFSETY2,
-	IDC_PALTEX,
-	IDC_ACCURATE_BLEND_UNIT,
-	IDC_ACCURATE_DATE,
-	IDC_TC_DEPTH,
-	IDC_CPU_FB_CONVERSION,
-	IDC_CRC_LEVEL,
-	IDC_AFCOMBO,
+	// Software Renderer
+	IDC_AUTO_FLUSH_SW,
 	IDC_AA1,
+	IDC_MIPMAP_SW,
 	IDC_SWTHREADS,
 	IDC_SWTHREADS_EDIT,
-	IDC_SHADEBOOST,
-	IDC_SHADER_FX,
-	IDC_FXAA,
-	IDC_MIPMAP_SW,
-	IDC_MIPMAP_HW,
-	IDC_PRELOAD_GS,
-	IDC_FAST_TC_INV,
-	IDC_CONSERVATIVE_FB,
-	IDC_LINEAR_PRESENT,
-	IDC_AUTO_FLUSH_HW,
-	IDC_AUTO_FLUSH_SW,
-	IDC_SAFE_FEATURES,
-	IDC_MEMORY_WRAPPING,
-	IDC_MERGE_PP_SPRITE,
+	// OpenGL Advanced Settings
 	IDC_GEOMETRY_SHADER_OVERRIDE,
 	IDC_IMAGE_LOAD_STORE,
 	IDC_SPARSE_TEXTURE,
+	// On-screen Display
 	IDC_OSD_LOG,
 	IDC_OSD_MONITOR,
 	IDC_OSD_MAX_LOG,
@@ -97,7 +101,12 @@ enum
 	IDR_TFX_VGS_GLSL,
 	IDR_TFX_FS_GLSL,
 	IDR_TFX_CL,
-	// fonts
+	// Shader Configuration
+	IDC_SHADEBOOST,
+	IDC_SHADER_FX,
+	IDC_FXAA,
+	IDC_LINEAR_PRESENT,
+	// Fonts
 	IDR_FONT_ROBOTO,
 };
 #endif

pcsx2/GS/Window/GSSettingsDlg.cpp

@@ -120,6 +120,7 @@ void GSSettingsDlg::OnInit()
 	AddTooltip(IDC_SWTHREADS_EDIT);
 	AddTooltip(IDC_AUTO_FLUSH_SW);
 	AddTooltip(IDC_CONSERVATIVE_FB);
+	AddTooltip(IDC_DITHERING);
 
 	UpdateControls();
 }