GPU: Add downsample scale option

src/core/fullscreen_ui.cpp

@@ -3907,6 +3907,17 @@ void FullscreenUI::DrawDisplaySettingsPage()
                   "GPU", "DownsampleMode", Settings::DEFAULT_GPU_DOWNSAMPLE_MODE, &Settings::ParseDownsampleModeName,
                   &Settings::GetDownsampleModeName, &Settings::GetDownsampleModeDisplayName, GPUDownsampleMode::Count,
                   (renderer != GPURenderer::Software));
+  if (Settings::ParseDownsampleModeName(
+        GetEffectiveStringSetting(bsi, "GPU", "DownsampleMode",
+                                  Settings::GetDownsampleModeName(Settings::DEFAULT_GPU_DOWNSAMPLE_MODE))
+          .c_str())
+        .value_or(Settings::DEFAULT_GPU_DOWNSAMPLE_MODE) == GPUDownsampleMode::Box)
+  {
+    DrawIntRangeSetting(bsi, FSUI_CSTR("Downsampling Display Scale"),
+                        FSUI_CSTR("Selects the resolution scale that will be applied to the final image. 1x will "
+                                  "downsample to the original console resolution."),
+                        "GPU", "DownsampleScale", 1, 1, GPU::MAX_RESOLUTION_SCALE, "%dx");
+  }
 
   DrawEnumSetting(
     bsi, FSUI_CSTR("Scaling"),

src/core/gpu_hw.cpp

@@ -19,6 +19,7 @@
 #include "common/scoped_guard.h"
 #include "common/string_util.h"
 
+#include "IconsFontAwesome5.h"
 #include "imgui.h"
 
 #include <cmath>
@@ -50,6 +51,14 @@ ALWAYS_INLINE static u32 GetMaxResolutionScale()
   return g_gpu_device->GetMaxTextureSize() / VRAM_WIDTH;
 }
 
+ALWAYS_INLINE_RELEASE static u32 GetBoxDownsampleScale()
+{
+  u32 scale = std::min<u32>(g_settings.gpu_resolution_scale, g_settings.gpu_downsample_scale);
+  while ((g_settings.gpu_resolution_scale % scale) != 0)
+    scale--;
+  return scale;
+}
+
 ALWAYS_INLINE static bool ShouldUseUVLimits()
 {
   // We only need UV limits if PGXP is enabled, or texture filtering is enabled.
@@ -166,38 +175,7 @@ bool GPU_HW::Initialize()
   m_wireframe_mode = g_settings.gpu_wireframe_mode;
   m_disable_color_perspective = features.noperspective_interpolation && ShouldDisableColorPerspective();
 
-  if (m_multisamples != g_settings.gpu_multisamples)
-  {
-    Host::AddFormattedOSDMessage(Host::OSD_CRITICAL_ERROR_DURATION,
-                                 TRANSLATE("OSDMessage", "%ux MSAA is not supported, using %ux instead."),
-                                 g_settings.gpu_multisamples, m_multisamples);
-  }
-  if (!m_per_sample_shading && g_settings.gpu_per_sample_shading)
-  {
-    Host::AddOSDMessage(TRANSLATE_STR("OSDMessage", "SSAA is not supported, using MSAA instead."), 20.0f);
-  }
-  if (!features.dual_source_blend && TextureFilterRequiresDualSourceBlend(m_texture_filtering))
-  {
-    Host::AddFormattedOSDMessage(
-      Host::OSD_CRITICAL_ERROR_DURATION,
-      TRANSLATE("OSDMessage", "Texture filter '%s' is not supported with the current renderer."),
-      Settings::GetTextureFilterDisplayName(m_texture_filtering));
-    m_texture_filtering = GPUTextureFilter::Nearest;
-  }
-
-  if (!features.noperspective_interpolation && !ShouldDisableColorPerspective())
-    Log_WarningPrint("Disable color perspective not supported, but should be used.");
-
-  if (!features.geometry_shaders && m_wireframe_mode != GPUWireframeMode::Disabled)
-  {
-    Host::AddOSDMessage(
-      TRANSLATE("OSDMessage",
-                "Geometry shaders are not supported by your GPU, and are required for wireframe rendering."),
-      Host::OSD_CRITICAL_ERROR_DURATION);
-    m_wireframe_mode = GPUWireframeMode::Disabled;
-  }
-
-  m_pgxp_depth_buffer = g_settings.UsingPGXPDepthBuffer();
+  CheckSettings();
 
   UpdateSoftwareRenderer(false);
 
@@ -316,14 +294,18 @@ void GPU_HW::UpdateSettings(const Settings& old_settings)
 
   // TODO: Use old_settings
   const bool framebuffer_changed =
-    (m_resolution_scale != resolution_scale || m_multisamples != multisamples || m_downsample_mode != downsample_mode);
+    (m_resolution_scale != resolution_scale || m_multisamples != multisamples || m_downsample_mode != downsample_mode ||
+     (m_downsample_mode == GPUDownsampleMode::Box &&
+      g_settings.gpu_downsample_scale != old_settings.gpu_downsample_scale));
   const bool shaders_changed =
     (m_resolution_scale != resolution_scale || m_multisamples != multisamples ||
      m_true_color != g_settings.gpu_true_color || m_per_sample_shading != per_sample_shading ||
      m_scaled_dithering != g_settings.gpu_scaled_dithering || m_texture_filtering != g_settings.gpu_texture_filter ||
      m_using_uv_limits != use_uv_limits || m_chroma_smoothing != g_settings.gpu_24bit_chroma_smoothing ||
-     m_downsample_mode != downsample_mode || m_wireframe_mode != wireframe_mode ||
-     m_pgxp_depth_buffer != g_settings.UsingPGXPDepthBuffer() ||
+     m_downsample_mode != downsample_mode ||
+     (m_downsample_mode == GPUDownsampleMode::Box &&
+      g_settings.gpu_downsample_scale != old_settings.gpu_downsample_scale) ||
+     m_wireframe_mode != wireframe_mode || m_pgxp_depth_buffer != g_settings.UsingPGXPDepthBuffer() ||
      m_disable_color_perspective != disable_color_perspective);
 
   if (m_resolution_scale != resolution_scale)
@@ -369,8 +351,7 @@ void GPU_HW::UpdateSettings(const Settings& old_settings)
   m_wireframe_mode = wireframe_mode;
   m_disable_color_perspective = disable_color_perspective;
 
-  if (!m_supports_dual_source_blend && TextureFilterRequiresDualSourceBlend(m_texture_filtering))
-    m_texture_filtering = GPUTextureFilter::Nearest;
+  CheckSettings();
 
   if (m_pgxp_depth_buffer != g_settings.UsingPGXPDepthBuffer())
   {
@@ -404,6 +385,72 @@ void GPU_HW::UpdateSettings(const Settings& old_settings)
   }
 }
 
+void GPU_HW::CheckSettings()
+{
+  const GPUDevice::Features features = g_gpu_device->GetFeatures();
+
+  if (m_multisamples != g_settings.gpu_multisamples)
+  {
+    Host::AddIconOSDMessage("MSAAUnsupported", ICON_FA_PAINT_BRUSH,
+                            fmt::format(TRANSLATE_FS("OSDMessage", "{}x MSAA is not supported, using {}x instead."),
+                                        g_settings.gpu_multisamples, m_multisamples),
+                            Host::OSD_CRITICAL_ERROR_DURATION);
+  }
+  else
+  {
+    Host::RemoveKeyedOSDMessage("MSAAUnsupported");
+  }
+
+  if (!m_per_sample_shading && g_settings.gpu_per_sample_shading)
+  {
+    Host::AddOSDMessage(TRANSLATE_STR("OSDMessage", "SSAA is not supported, using MSAA instead."), 20.0f);
+  }
+  if (!features.dual_source_blend && TextureFilterRequiresDualSourceBlend(m_texture_filtering))
+  {
+    Host::AddFormattedOSDMessage(
+      Host::OSD_CRITICAL_ERROR_DURATION,
+      TRANSLATE("OSDMessage", "Texture filter '%s' is not supported with the current renderer."),
+      Settings::GetTextureFilterDisplayName(m_texture_filtering));
+    m_texture_filtering = GPUTextureFilter::Nearest;
+  }
+
+  if (!features.noperspective_interpolation && !ShouldDisableColorPerspective())
+    Log_WarningPrint("Disable color perspective not supported, but should be used.");
+
+  if (!features.geometry_shaders && m_wireframe_mode != GPUWireframeMode::Disabled)
+  {
+    Host::AddOSDMessage(
+      TRANSLATE("OSDMessage",
+                "Geometry shaders are not supported by your GPU, and are required for wireframe rendering."),
+      Host::OSD_CRITICAL_ERROR_DURATION);
+    m_wireframe_mode = GPUWireframeMode::Disabled;
+  }
+
+  if (m_downsample_mode == GPUDownsampleMode::Box)
+  {
+    const u32 scale = GetBoxDownsampleScale();
+    if (scale != g_settings.gpu_downsample_scale || scale == g_settings.gpu_resolution_scale)
+    {
+      Host::AddIconOSDMessage(
+        "BoxDownsampleUnsupported", ICON_FA_PAINT_BRUSH,
+        fmt::format(
+          TRANSLATE_FS("OSDMessage",
+                       "Resolution scale {0}x is not divisible by downsample scale {1}x, using {2}x instead."),
+          g_settings.gpu_resolution_scale, g_settings.gpu_downsample_scale, scale),
+        Host::OSD_ERROR_DURATION);
+    }
+    else
+    {
+      Host::RemoveKeyedOSDMessage("BoxDownsampleUnsupported");
+    }
+
+    if (scale == g_settings.gpu_resolution_scale)
+      m_downsample_mode = GPUDownsampleMode::Disabled;
+  }
+
+  m_pgxp_depth_buffer = g_settings.UsingPGXPDepthBuffer();
+}
+
 u32 GPU_HW::CalculateResolutionScale() const
 {
   const u32 max_resolution_scale = GetMaxResolutionScale();
@@ -580,8 +627,10 @@ bool GPU_HW::CreateBuffers()
   }
   else if (m_downsample_mode == GPUDownsampleMode::Box)
   {
-    if (!(m_downsample_render_texture = g_gpu_device->CreateTexture(VRAM_WIDTH, VRAM_HEIGHT, 1, 1, 1,
-                                                                    GPUTexture::Type::RenderTarget, VRAM_RT_FORMAT)) ||
+    const u32 downsample_scale = GetBoxDownsampleScale();
+    if (!(m_downsample_render_texture =
+            g_gpu_device->CreateTexture(VRAM_WIDTH * downsample_scale, VRAM_HEIGHT * downsample_scale, 1, 1, 1,
+                                        GPUTexture::Type::RenderTarget, VRAM_RT_FORMAT)) ||
         !(m_downsample_framebuffer = g_gpu_device->CreateFramebuffer(m_downsample_render_texture.get())))
     {
       return false;
@@ -1056,8 +1105,9 @@ bool GPU_HW::CompilePipelines()
   }
   else if (m_downsample_mode == GPUDownsampleMode::Box)
   {
-    std::unique_ptr<GPUShader> fs =
-      g_gpu_device->CreateShader(GPUShaderStage::Fragment, shadergen.GenerateBoxSampleDownsampleFragmentShader());
+    std::unique_ptr<GPUShader> fs = g_gpu_device->CreateShader(
+      GPUShaderStage::Fragment,
+      shadergen.GenerateBoxSampleDownsampleFragmentShader(m_resolution_scale / GetBoxDownsampleScale()));
     if (!fs)
       return false;
 
@@ -2642,10 +2692,11 @@ void GPU_HW::DownsampleFramebufferAdaptive(GPUTexture* source, u32 left, u32 top
 
 void GPU_HW::DownsampleFramebufferBoxFilter(GPUTexture* source, u32 left, u32 top, u32 width, u32 height)
 {
-  const u32 ds_left = left / m_resolution_scale;
-  const u32 ds_top = top / m_resolution_scale;
-  const u32 ds_width = width / m_resolution_scale;
-  const u32 ds_height = height / m_resolution_scale;
+  const u32 factor = m_resolution_scale / GetBoxDownsampleScale();
+  const u32 ds_left = left / factor;
+  const u32 ds_top = top / factor;
+  const u32 ds_width = width / factor;
+  const u32 ds_height = height / factor;
 
   source->MakeReadyForSampling();
 

src/core/gpu_hw.h

@@ -347,4 +347,5 @@ private:
   }
 
   void PrintSettingsToLog();
+  void CheckSettings();
 };

src/core/gpu_hw_shadergen.cpp

@@ -1558,24 +1558,26 @@ std::string GPU_HW_ShaderGen::GenerateAdaptiveDownsampleCompositeFragmentShader(
   return ss.str();
 }
 
-std::string GPU_HW_ShaderGen::GenerateBoxSampleDownsampleFragmentShader()
+std::string GPU_HW_ShaderGen::GenerateBoxSampleDownsampleFragmentShader(u32 factor)
 {
   std::stringstream ss;
   WriteHeader(ss);
   WriteCommonFunctions(ss);
   DeclareTexture(ss, "samp0", 0, false);
 
+  ss << "#define FACTOR " << factor << "\n";
+
   DeclareFragmentEntryPoint(ss, 0, 1, {}, true, 1, false, false, false, false);
   ss << R"(
 {
   float3 color = float3(0.0, 0.0, 0.0);
-  uint2 base_coords = uint2(v_pos.xy) * uint2(RESOLUTION_SCALE, RESOLUTION_SCALE);
-  for (uint offset_x = 0u; offset_x < RESOLUTION_SCALE; offset_x++)
+  uint2 base_coords = uint2(v_pos.xy) * uint2(FACTOR, FACTOR);
+  for (uint offset_x = 0u; offset_x < FACTOR; offset_x++)
   {
-    for (uint offset_y = 0u; offset_y < RESOLUTION_SCALE; offset_y++)
+    for (uint offset_y = 0u; offset_y < FACTOR; offset_y++)
       color += LOAD_TEXTURE(samp0, int2(base_coords + uint2(offset_x, offset_y)), 0).rgb;
   }
-  color /= float(RESOLUTION_SCALE * RESOLUTION_SCALE);
+  color /= float(FACTOR * FACTOR);
   o_col0 = float4(color, 1.0);
 }
 )";

src/core/gpu_hw_shadergen.h

@@ -30,7 +30,7 @@ public:
   std::string GenerateAdaptiveDownsampleMipFragmentShader(bool first_pass);
   std::string GenerateAdaptiveDownsampleBlurFragmentShader();
   std::string GenerateAdaptiveDownsampleCompositeFragmentShader();
-  std::string GenerateBoxSampleDownsampleFragmentShader();
+  std::string GenerateBoxSampleDownsampleFragmentShader(u32 factor);
 
 private:
   ALWAYS_INLINE bool UsingMSAA() const { return m_multisamples > 1; }

src/core/settings.cpp

@@ -225,6 +225,7 @@ void Settings::Load(SettingsInterface& si)
     ParseDownsampleModeName(
       si.GetStringValue("GPU", "DownsampleMode", GetDownsampleModeName(DEFAULT_GPU_DOWNSAMPLE_MODE)).c_str())
       .value_or(DEFAULT_GPU_DOWNSAMPLE_MODE);
+  gpu_downsample_scale = static_cast<u8>(si.GetUIntValue("GPU", "DownsampleScale", 1));
   gpu_wireframe_mode =
     ParseGPUWireframeMode(
       si.GetStringValue("GPU", "WireframeMode", GetGPUWireframeModeName(DEFAULT_GPU_WIREFRAME_MODE)).c_str())
@@ -466,6 +467,7 @@ void Settings::Save(SettingsInterface& si) const
   si.SetBoolValue("GPU", "ScaledDithering", gpu_scaled_dithering);
   si.SetStringValue("GPU", "TextureFilter", GetTextureFilterName(gpu_texture_filter));
   si.SetStringValue("GPU", "DownsampleMode", GetDownsampleModeName(gpu_downsample_mode));
+  si.SetUIntValue("GPU", "DownsampleScale", gpu_downsample_scale);
   si.SetStringValue("GPU", "WireframeMode", GetGPUWireframeModeName(gpu_wireframe_mode));
   si.SetBoolValue("GPU", "DisableInterlacing", gpu_disable_interlacing);
   si.SetBoolValue("GPU", "ForceNTSCTimings", gpu_force_ntsc_timings);

src/core/settings.h

@@ -106,6 +106,7 @@ struct Settings
   bool gpu_scaled_dithering = true;
   GPUTextureFilter gpu_texture_filter = DEFAULT_GPU_TEXTURE_FILTER;
   GPUDownsampleMode gpu_downsample_mode = DEFAULT_GPU_DOWNSAMPLE_MODE;
+  u8 gpu_downsample_scale = 1;
   GPUWireframeMode gpu_wireframe_mode = DEFAULT_GPU_WIREFRAME_MODE;
   bool gpu_disable_interlacing = true;
   bool gpu_force_ntsc_timings = false;

src/core/system.cpp

@@ -3590,6 +3590,7 @@ void System::CheckForSettingsChanges(const Settings& old_settings)
         g_settings.gpu_force_ntsc_timings != old_settings.gpu_force_ntsc_timings ||
         g_settings.gpu_24bit_chroma_smoothing != old_settings.gpu_24bit_chroma_smoothing ||
         g_settings.gpu_downsample_mode != old_settings.gpu_downsample_mode ||
+        g_settings.gpu_downsample_scale != old_settings.gpu_downsample_scale ||
         g_settings.gpu_wireframe_mode != old_settings.gpu_wireframe_mode ||
         g_settings.display_crop_mode != old_settings.display_crop_mode ||
         g_settings.display_aspect_ratio != old_settings.display_aspect_ratio ||

src/duckstation-qt/enhancementsettingswidget.cpp

@@ -20,6 +20,7 @@ EnhancementSettingsWidget::EnhancementSettingsWidget(SettingsDialog* dialog, QWi
   SettingWidgetBinder::BindWidgetToEnumSetting(sif, m_ui.gpuDownsampleMode, "GPU", "DownsampleMode",
                                                &Settings::ParseDownsampleModeName, &Settings::GetDownsampleModeName,
                                                Settings::DEFAULT_GPU_DOWNSAMPLE_MODE);
+  SettingWidgetBinder::BindWidgetToIntSetting(sif, m_ui.gpuDownsampleScale, "GPU", "DownsampleScale", 1);
   SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.trueColor, "GPU", "TrueColor", false);
   SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.scaledDithering, "GPU", "ScaledDithering", false);
   SettingWidgetBinder::BindWidgetToBoolSetting(sif, m_ui.disableInterlacing, "GPU", "DisableInterlacing", true);
@@ -43,7 +44,10 @@ EnhancementSettingsWidget::EnhancementSettingsWidget(SettingsDialog* dialog, QWi
 
   connect(m_ui.resolutionScale, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
           &EnhancementSettingsWidget::updateScaledDitheringEnabled);
+  connect(m_ui.gpuDownsampleMode, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
+          &EnhancementSettingsWidget::updateDownsampleScaleVisible);
   connect(m_ui.trueColor, &QCheckBox::stateChanged, this, &EnhancementSettingsWidget::updateScaledDitheringEnabled);
+  updateDownsampleScaleVisible();
   updateScaledDitheringEnabled();
 
   connect(m_ui.pgxpEnable, &QCheckBox::stateChanged, this, &EnhancementSettingsWidget::updatePGXPSettingsEnabled);
@@ -55,6 +59,9 @@ EnhancementSettingsWidget::EnhancementSettingsWidget(SettingsDialog* dialog, QWi
     m_ui.gpuDownsampleMode, tr("Downsampling"), tr("Disabled"),
     tr("Downsamples the rendered image prior to displaying it. Can improve overall image quality in mixed 2D/3D games, "
        "but should be disabled for pure 3D games. Only applies to the hardware renderers."));
+  dialog->registerWidgetHelp(m_ui.gpuDownsampleScale, tr("Downsampling Display Scale"), tr("1x"),
+                             tr("Selects the resolution scale that will be applied to the final image. 1x will "
+                                "downsample to the original console resolution."));
   dialog->registerWidgetHelp(
     m_ui.disableInterlacing, tr("Disable Interlacing (force progressive render/scan)"), tr("Unchecked"),
     tr(
@@ -141,6 +148,29 @@ void EnhancementSettingsWidget::updateScaledDitheringEnabled()
   m_ui.scaledDithering->setEnabled(allow_scaled_dithering);
 }
 
+void EnhancementSettingsWidget::updateDownsampleScaleVisible()
+{
+  const GPUDownsampleMode mode =
+    Settings::ParseDownsampleModeName(
+      m_dialog
+        ->getEffectiveStringValue("GPU", "DownsampleMode",
+                                  Settings::GetDownsampleModeName(Settings::DEFAULT_GPU_DOWNSAMPLE_MODE))
+        .c_str())
+      .value_or(Settings::DEFAULT_GPU_DOWNSAMPLE_MODE);
+
+  const bool visible = (mode == GPUDownsampleMode::Box);
+  if (visible && m_ui.gpuDownsampleLayout->indexOf(m_ui.gpuDownsampleScale) < 0)
+  {
+    m_ui.gpuDownsampleScale->setVisible(true);
+    m_ui.gpuDownsampleLayout->addWidget(m_ui.gpuDownsampleScale, 0);
+  }
+  else if (!visible && m_ui.gpuDownsampleLayout->indexOf(m_ui.gpuDownsampleScale) >= 0)
+  {
+    m_ui.gpuDownsampleScale->setVisible(false);
+    m_ui.gpuDownsampleLayout->removeWidget(m_ui.gpuDownsampleScale);
+  }
+}
+
 void EnhancementSettingsWidget::setupAdditionalUi()
 {
   QtUtils::FillComboBoxWithResolutionScales(m_ui.resolutionScale);

src/duckstation-qt/enhancementsettingswidget.h

@@ -19,6 +19,7 @@ public:
 
 private Q_SLOTS:
   void updateScaledDitheringEnabled();
+  void updateDownsampleScaleVisible();
   void updatePGXPSettingsEnabled();
 
 private:

src/duckstation-qt/enhancementsettingswidget.ui

@@ -88,7 +88,24 @@
        </widget>
       </item>
       <item row="3" column="1">
-       <widget class="QComboBox" name="gpuDownsampleMode"/>
+       <layout class="QHBoxLayout" name="gpuDownsampleLayout" stretch="1,0">
+        <item>
+         <widget class="QComboBox" name="gpuDownsampleMode"/>
+        </item>
+        <item>
+         <widget class="QSpinBox" name="gpuDownsampleScale">
+          <property name="suffix">
+           <string>x</string>
+          </property>
+          <property name="minimum">
+           <number>1</number>
+          </property>
+          <property name="maximum">
+           <number>16</number>
+          </property>
+         </widget>
+        </item>
+       </layout>
       </item>
      </layout>
     </widget>