WIP

src/core/host_display.h

@@ -72,6 +72,7 @@ public:
   virtual bool CreateResources() = 0;
   virtual void DestroyResources() = 0;
 
+  virtual bool SetScalingShader(const std::string_view& config) = 0;
   virtual bool SetPostProcessingChain(const std::string_view& config) = 0;
 
   /// Call when the window size changes externally to recreate any resources.

src/core/host_interface.cpp

@@ -461,6 +461,7 @@ void HostInterface::SetDefaultSettings(SettingsInterface& si)
   si.SetBoolValue("Display", "ShowResolution", false);
   si.SetBoolValue("Display", "Fullscreen", false);
   si.SetBoolValue("Display", "VSync", true);
+  si.SetStringValue("Display", "ScaleShader", "");
   si.SetStringValue("Display", "PostProcessChain", "");
 
   si.SetBoolValue("CDROM", "ReadThread", true);

src/core/settings.cpp

@@ -175,6 +175,7 @@ void Settings::Load(SettingsInterface& si)
   display_show_speed = si.GetBoolValue("Display", "ShowSpeed", false);
   display_show_resolution = si.GetBoolValue("Display", "ShowResolution", false);
   video_sync_enabled = si.GetBoolValue("Display", "VSync", true);
+  display_scale_shader = si.GetStringValue("Display", "ScaleShader", "");
   display_post_process_chain = si.GetStringValue("Display", "PostProcessChain", "");
 
   cdrom_read_thread = si.GetBoolValue("CDROM", "ReadThread", true);
@@ -298,6 +299,11 @@ void Settings::Save(SettingsInterface& si) const
   si.SetBoolValue("Display", "ShowSpeed", display_show_speed);
   si.SetBoolValue("Display", "ShowResolution", display_show_speed);
   si.SetBoolValue("Display", "VSync", video_sync_enabled);
+  if (display_scale_shader.empty())
+    si.DeleteValue("Display", "ScaleShader");
+  else
+    si.SetStringValue("Display", "ScaleShader", display_scale_shader.c_str());
+
   if (display_post_process_chain.empty())
     si.DeleteValue("Display", "PostProcessChain");
   else

src/core/settings.h

@@ -91,6 +91,7 @@ struct Settings
 
   GPURenderer gpu_renderer = GPURenderer::Software;
   std::string gpu_adapter;
+  std::string display_scale_shader;
   std::string display_post_process_chain;
   u32 gpu_resolution_scale = 1;
   u32 gpu_multisamples = 1;

src/frontend-common/common_host_interface.cpp

@@ -177,6 +177,7 @@ void CommonHostInterface::DestroySystem()
   SetTimerResolutionIncreased(false);
   m_save_state_selector_ui->Close();
   m_display->SetPostProcessingChain({});
+  m_display->SetScalingShader({});
 
   HostInterface::DestroySystem();
 }
@@ -715,6 +716,9 @@ void CommonHostInterface::OnSystemCreated()
 {
   HostInterface::OnSystemCreated();
 
+  if (!g_settings.display_scale_shader.empty() && !m_display->SetScalingShader(g_settings.display_scale_shader))
+    AddOSDMessage(TranslateStdString("OSDMessage", "Failed to load scaling shader."), 20.0f);
+
   if (g_settings.display_post_processing && !m_display->SetPostProcessingChain(g_settings.display_post_process_chain))
     AddOSDMessage(TranslateStdString("OSDMessage", "Failed to load post processing shader chain."), 20.0f);
 }
@@ -2082,6 +2086,12 @@ void CommonHostInterface::CheckForSettingsChanges(const Settings& old_settings)
       UpdateSpeedLimiterState();
     }
 
+    if (g_settings.display_scale_shader != old_settings.display_scale_shader)
+    {
+      if (!m_display->SetScalingShader(g_settings.display_post_process_chain))
+        AddOSDMessage(TranslateStdString("OSDMessage", "Failed to load scaling shader."), 20.0f);
+    }
+
     if (g_settings.display_post_processing != old_settings.display_post_processing ||
         g_settings.display_post_process_chain != old_settings.display_post_process_chain)
     {
@@ -2469,13 +2479,24 @@ void CommonHostInterface::TogglePostProcessing()
 
 void CommonHostInterface::ReloadPostProcessingShaders()
 {
-  if (!m_display || !g_settings.display_post_processing)
+  if (!m_display)
     return;
 
+  if (!g_settings.display_scale_shader.empty())
+  {
+    if (!m_display->SetScalingShader(g_settings.display_scale_shader))
+      AddOSDMessage(TranslateStdString("OSDMessage", "Failed to load scaling shader."), 20.0f);
+    else
+      AddOSDMessage(TranslateStdString("OSDMessage", "Scaling shader reloaded."), 10.0f);
+  }
+
+  if (g_settings.display_post_processing)
+  {
     if (!m_display->SetPostProcessingChain(g_settings.display_post_process_chain))
       AddOSDMessage(TranslateStdString("OSDMessage", "Failed to load post-processing shader chain."), 20.0f);
     else
       AddOSDMessage(TranslateStdString("OSDMessage", "Post-processing shaders reloaded."), 10.0f);
+  }
 }
 
 bool CommonHostInterface::ParseFullscreenMode(const std::string_view& mode, u32* width, u32* height,

src/frontend-common/d3d11_host_display.cpp

@@ -724,19 +724,38 @@ void D3D11HostDisplay::RenderDisplay(s32 left, s32 top, s32 width, s32 height, v
                                      s32 texture_view_height, bool linear_filter)
 {
   m_context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
-  m_context->VSSetShader(m_display_vertex_shader.Get(), nullptr, 0);
-  m_context->PSSetShader(m_display_pixel_shader.Get(), nullptr, 0);
   m_context->PSSetShaderResources(0, 1, reinterpret_cast<ID3D11ShaderResourceView**>(&texture_handle));
-  m_context->PSSetSamplers(0, 1, linear_filter ? m_linear_sampler.GetAddressOf() : m_point_sampler.GetAddressOf());
+  m_context->PSSetSamplers(0, 1,
+                           (linear_filter && !m_scale_stage.has_value()) ? m_linear_sampler.GetAddressOf() :
+                                                                           m_point_sampler.GetAddressOf());
 
+  if (!m_scale_stage)
+  {
     const float uniforms[4] = {static_cast<float>(texture_view_x) / static_cast<float>(texture_width),
                                static_cast<float>(texture_view_y) / static_cast<float>(texture_height),
                                (static_cast<float>(texture_view_width) - 0.5f) / static_cast<float>(texture_width),
                                (static_cast<float>(texture_view_height) - 0.5f) / static_cast<float>(texture_height)};
-  const auto map = m_display_uniform_buffer.Map(m_context.Get(), m_display_uniform_buffer.GetSize(), sizeof(uniforms));
+    const auto map =
+      m_display_uniform_buffer.Map(m_context.Get(), m_display_uniform_buffer.GetSize(), sizeof(uniforms));
     std::memcpy(map.pointer, uniforms, sizeof(uniforms));
     m_display_uniform_buffer.Unmap(m_context.Get(), sizeof(uniforms));
+    m_context->VSSetShader(m_display_vertex_shader.Get(), nullptr, 0);
     m_context->VSSetConstantBuffers(0, 1, m_display_uniform_buffer.GetD3DBufferArray());
+    m_context->PSSetShader(m_display_pixel_shader.Get(), nullptr, 0);
+  }
+  else
+  {
+    const auto map =
+      m_display_uniform_buffer.Map(m_context.Get(), m_display_uniform_buffer.GetSize(), m_scale_stage->uniforms_size);
+    m_scale_shader->FillUniformBuffer(map.pointer, texture_width, texture_height, texture_view_x, texture_view_y,
+                                      texture_view_width, texture_view_height, width, height, 0.0f);
+    m_display_uniform_buffer.Unmap(m_context.Get(), m_scale_stage->uniforms_size);
+    m_context->VSSetShader(m_scale_stage->vertex_shader.Get(), nullptr, 0);
+    m_context->VSSetConstantBuffers(0, 1, m_display_uniform_buffer.GetD3DBufferArray());
+    m_context->PSSetShader(m_scale_stage->pixel_shader.Get(), nullptr, 0);
+    m_context->PSSetConstantBuffers(0, 1, m_display_uniform_buffer.GetD3DBufferArray());
+  }
+
 
   const CD3D11_VIEWPORT vp(static_cast<float>(left), static_cast<float>(top), static_cast<float>(width),
                            static_cast<float>(height));
@@ -862,6 +881,43 @@ D3D11HostDisplay::AdapterInfo D3D11HostDisplay::GetAdapterInfo(IDXGIFactory* dxg
   return adapter_info;
 }
 
+bool D3D11HostDisplay::SetScalingShader(const std::string_view& config)
+{
+  if (config.empty())
+  {
+    m_scale_shader.reset();
+    m_scale_stage.reset();
+    return true;
+  }
+
+  m_scale_shader = PostProcessingShader();
+  if (!PostProcessingChain::CreateSingleShader(&m_scale_shader.value(), config))
+  {
+    m_scale_shader.reset();
+    return false;
+  }
+
+  m_scale_stage = PostProcessingStage();
+  if (!CompilePostProcessingStage(m_scale_shader.value(), &m_scale_stage.value()))
+  {
+    Log_ErrorPrintf("Failed to compile resize shader");
+    m_scale_stage.reset();
+    m_scale_shader.reset();
+    return false;
+  }
+
+  if (m_display_uniform_buffer.GetSize() < m_scale_stage->uniforms_size &&
+      !m_display_uniform_buffer.Create(m_device.Get(), D3D11_BIND_CONSTANT_BUFFER, m_scale_stage->uniforms_size))
+  {
+    Log_ErrorPrintf("Failed to allocate %u byte constant buffer for scaling", m_scale_stage->uniforms_size);
+    m_scale_stage.reset();
+    m_scale_shader.reset();
+    return false;
+  }
+
+  return true;
+}
+
 bool D3D11HostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   if (config.empty())
@@ -882,17 +938,10 @@ bool D3D11HostDisplay::SetPostProcessingChain(const std::string_view& config)
 
   for (u32 i = 0; i < m_post_processing_chain.GetStageCount(); i++)
   {
-    const PostProcessingShader& shader = m_post_processing_chain.GetShaderStage(i);
-    const std::string vs = shadergen.GeneratePostProcessingVertexShader(shader);
-    const std::string ps = shadergen.GeneratePostProcessingFragmentShader(shader);
-
     PostProcessingStage stage;
-    stage.uniforms_size = shader.GetUniformsSize();
+
-    stage.vertex_shader =
+    const PostProcessingShader& shader = m_post_processing_chain.GetShaderStage(i);
-      D3D11::ShaderCompiler::CompileAndCreateVertexShader(m_device.Get(), vs, g_settings.gpu_use_debug_device);
+    if (!CompilePostProcessingStage(shader, &stage))
-    stage.pixel_shader =
-      D3D11::ShaderCompiler::CompileAndCreatePixelShader(m_device.Get(), ps, g_settings.gpu_use_debug_device);
-    if (!stage.vertex_shader || !stage.pixel_shader)
     {
       Log_ErrorPrintf("Failed to compile one or more post-processing shaders, disabling.");
       m_post_processing_stages.clear();
@@ -944,6 +993,21 @@ bool D3D11HostDisplay::CheckPostProcessingRenderTargets(u32 target_width, u32 ta
   return true;
 }
 
+bool D3D11HostDisplay::CompilePostProcessingStage(const PostProcessingShader& shader, PostProcessingStage* stage)
+{
+  FrontendCommon::PostProcessingShaderGen shadergen(HostDisplay::RenderAPI::D3D11, true);
+
+  const std::string vs = shadergen.GeneratePostProcessingVertexShader(shader);
+  const std::string ps = shadergen.GeneratePostProcessingFragmentShader(shader);
+
+  stage->uniforms_size = shader.GetUniformsSize();
+  stage->vertex_shader =
+    D3D11::ShaderCompiler::CompileAndCreateVertexShader(m_device.Get(), vs, g_settings.gpu_use_debug_device);
+  stage->pixel_shader =
+    D3D11::ShaderCompiler::CompileAndCreatePixelShader(m_device.Get(), ps, g_settings.gpu_use_debug_device);
+  return stage->vertex_shader && stage->pixel_shader;
+}
+
 void D3D11HostDisplay::ApplyPostProcessingChain(ID3D11RenderTargetView* final_target, s32 final_left, s32 final_top,
                                                 s32 final_width, s32 final_height, void* texture_handle,
                                                 u32 texture_width, s32 texture_height, s32 texture_view_x,
@@ -1013,6 +1077,11 @@ void D3D11HostDisplay::ApplyPostProcessingChain(ID3D11RenderTargetView* final_ta
 
 #else // LIBRETRO
 
+bool D3D11HostDisplay::SetScalingShader(const std::string_view& config)
+{
+  return false;
+}
+
 bool D3D11HostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   return false;

src/frontend-common/d3d11_host_display.h

@@ -8,6 +8,7 @@
 #include <d3d11.h>
 #include <dxgi.h>
 #include <memory>
+#include <optional>
 #include <string>
 #include <string_view>
 #include <vector>
@@ -49,6 +50,7 @@ public:
   virtual bool SetFullscreen(bool fullscreen, u32 width, u32 height, float refresh_rate) override;
   virtual void DestroyRenderSurface() override;
 
+  virtual bool SetScalingShader(const std::string_view& config) override;
   virtual bool SetPostProcessingChain(const std::string_view& config) override;
 
   std::unique_ptr<HostDisplayTexture> CreateTexture(u32 width, u32 height, const void* initial_data,
@@ -108,6 +110,7 @@ protected:
   };
 
   bool CheckPostProcessingRenderTargets(u32 target_width, u32 target_height);
+  bool CompilePostProcessingStage(const PostProcessingShader& shader, PostProcessingStage* stage);
   void ApplyPostProcessingChain(ID3D11RenderTargetView* final_target, s32 final_left, s32 final_top, s32 final_width,
                                 s32 final_height, void* texture_handle, u32 texture_width, s32 texture_height,
                                 s32 texture_view_x, s32 texture_view_y, s32 texture_view_width,
@@ -142,6 +145,8 @@ protected:
   bool m_using_allow_tearing = false;
   bool m_vsync = true;
 
+  std::optional<PostProcessingShader> m_scale_shader;
+  std::optional<PostProcessingStage> m_scale_stage;
   PostProcessingChain m_post_processing_chain;
   D3D11::Texture m_post_processing_input_texture;
   std::vector<PostProcessingStage> m_post_processing_stages;

src/frontend-common/opengl_host_display.cpp

@@ -572,6 +572,11 @@ void OpenGLHostDisplay::RenderSoftwareCursor(s32 left, s32 bottom, s32 width, s3
 
 #ifndef LIBRETRO
 
+bool OpenGLHostDisplay::SetScalingShader(const std::string_view& config)
+{
+  return false;
+}
+
 bool OpenGLHostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   if (config.empty())
@@ -742,6 +747,11 @@ void OpenGLHostDisplay::ApplyPostProcessingChain(GLuint final_target, s32 final_
 
 #else
 
+bool OpenGLHostDisplay::SetScalingShader(const std::string_view& config)
+{
+  return false;
+}
+
 bool OpenGLHostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   return false;

src/frontend-common/opengl_host_display.h

@@ -49,6 +49,7 @@ public:
   virtual bool SetFullscreen(bool fullscreen, u32 width, u32 height, float refresh_rate) override;
   virtual void DestroyRenderSurface() override;
 
+  virtual bool SetScalingShader(const std::string_view& config) override;
   virtual bool SetPostProcessingChain(const std::string_view& config) override;
 
   std::unique_ptr<HostDisplayTexture> CreateTexture(u32 width, u32 height, const void* initial_data,

src/frontend-common/postprocessing_chain.cpp

@@ -128,6 +128,25 @@ bool PostProcessingChain::CreateFromString(const std::string_view& chain_config)
   return true;
 }
 
+bool PostProcessingChain::CreateSingleShader(PostProcessingShader* shader, const std::string_view& shader_config)
+{
+  size_t first_shader_sep = shader_config.find(';');
+  if (first_shader_sep == std::string::npos)
+    first_shader_sep = shader_config.size();
+
+  const std::string_view shader_name = shader_config.substr(0, first_shader_sep);
+  if (shader_name.empty())
+    return false;
+
+  if (!TryLoadingShader(shader, shader_name))
+    return false;
+
+  if (first_shader_sep < shader_config.size())
+    shader->SetConfigString(shader_config.substr(first_shader_sep + 1));
+
+  return true;
+}
+
 std::vector<std::string> PostProcessingChain::GetAvailableShaderNames()
 {
   std::vector<std::string> names;

src/frontend-common/postprocessing_chain.h

@@ -28,6 +28,7 @@ public:
   bool CreateFromString(const std::string_view& chain_config);
 
   static std::vector<std::string> GetAvailableShaderNames();
+  static bool CreateSingleShader(PostProcessingShader* shader, const std::string_view& shader_config);
 
 private:
   std::vector<PostProcessingShader> m_shaders;

src/frontend-common/vulkan_host_display.cpp

@@ -750,6 +750,11 @@ VulkanHostDisplay::PostProcessingStage::~PostProcessingStage()
     g_vulkan_context->DeferPipelineDestruction(pipeline);
 }
 
+bool VulkanHostDisplay::SetScalingShader(const std::string_view& config)
+{
+  return false;
+}
+
 bool VulkanHostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   g_vulkan_context->ExecuteCommandBuffer(true);
@@ -991,6 +996,11 @@ void VulkanHostDisplay::ApplyPostProcessingChain(s32 final_left, s32 final_top,
 
 #else // LIBRETRO
 
+bool VulkanHostDisplay::SetScalingShader(const std::string_view& config)
+{
+  return false;
+}
+
 bool VulkanHostDisplay::SetPostProcessingChain(const std::string_view& config)
 {
   return false;

src/frontend-common/vulkan_host_display.h

@@ -46,6 +46,7 @@ public:
   virtual bool SetFullscreen(bool fullscreen, u32 width, u32 height, float refresh_rate) override;
   virtual void DestroyRenderSurface() override;
 
+  virtual bool SetScalingShader(const std::string_view& config) override;
   virtual bool SetPostProcessingChain(const std::string_view& config) override;
 
   std::unique_ptr<HostDisplayTexture> CreateTexture(u32 width, u32 height, const void* initial_data,