4 files changed, 83 insertions, 36 deletions

diff --git a/Source/Core/VideoCommon/PostProcessing.cpp b/Source/Core/VideoCommon/PostProcessing.cpp
index c3a245629f..49b05e6762 100644
--- a/Source/Core/VideoCommon/PostProcessing.cpp
+++ b/Source/Core/VideoCommon/PostProcessing.cpp
@@ -419,9 +419,9 @@ std::vector<std::string> PostProcessing::GetPassiveShaderList()
 bool PostProcessing::Initialize(AbstractTextureFormat format)
 {
   m_framebuffer_format = format;
-  // CompilePixelShader must be run first if configuration options are used.
+  // CompilePixelShader() must be run first if configuration options are used.
   // Otherwise the UBO has a different member list between vertex and pixel
-  // shaders, which is a link error.
+  // shaders, which is a link error on some backends.
   if (!CompilePixelShader() || !CompileVertexShader() || !CompilePipeline())
     return false;
 
@@ -486,23 +486,29 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
 
   MathUtil::Rectangle<int> src_rect = src;
   g_gfx->SetSamplerState(0, RenderState::GetLinearSamplerState());
+  g_gfx->SetSamplerState(1, RenderState::GetPointSamplerState());
   g_gfx->SetTexture(0, src_tex);
+  g_gfx->SetTexture(1, src_tex);
 
-  const bool is_color_correction_active = IsColorCorrectionActive();
+  const bool needs_color_correction = IsColorCorrectionActive();
+  // Rely on the default (bi)linear sampler with the default mode
+  // (it might not be gamma corrected).
+  const bool needs_resampling =
+      g_ActiveConfig.output_resampling_mode > OutputResamplingMode::Default;
   const bool needs_intermediary_buffer = NeedsIntermediaryBuffer();
+  const bool needs_default_pipeline = needs_color_correction || needs_resampling;
   const AbstractPipeline* final_pipeline = m_pipeline.get();
   std::vector<u8>* uniform_staging_buffer = &m_default_uniform_staging_buffer;
   bool default_uniform_staging_buffer = true;
+  const MathUtil::Rectangle<int> present_rect = g_presenter->GetTargetRectangle();
 
   // Intermediary pass.
-  // We draw to a high quality intermediary texture for two reasons:
+  // We draw to a high quality intermediary texture for a couple reasons:
+  // -Consistently do high quality gamma corrected resampling (upscaling/downscaling)
   // -Keep quality for gamma and gamut conversions, and HDR output
   //  (low bit depths lose too much quality with gamma conversions)
-  // -We make a texture of the exact same res as the source one,
-  //  because all the post process shaders we already had assume that
-  //  the source texture size (EFB) is different from the swap chain
-  //  texture size (which matches the window size).
-  if (m_default_pipeline && is_color_correction_active && needs_intermediary_buffer)
+  // -Keep the post process phase in linear space, to better operate with colors
+  if (m_default_pipeline && needs_default_pipeline && needs_intermediary_buffer)
   {
     AbstractFramebuffer* const previous_framebuffer = g_gfx->GetCurrentFramebuffer();
 
@@ -512,13 +518,18 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
     // so it would be a waste to allocate two layers (see "bUsesExplictQuadBuffering").
     const u32 target_layers = copy_all_layers ? src_tex->GetLayers() : 1;
 
+    const u32 target_width =
+        needs_resampling ? present_rect.GetWidth() : static_cast<u32>(src_rect.GetWidth());
+    const u32 target_height =
+        needs_resampling ? present_rect.GetHeight() : static_cast<u32>(src_rect.GetHeight());
+
     if (!m_intermediary_frame_buffer || !m_intermediary_color_texture ||
-        m_intermediary_color_texture.get()->GetWidth() != static_cast<u32>(src_rect.GetWidth()) ||
-        m_intermediary_color_texture.get()->GetHeight() != static_cast<u32>(src_rect.GetHeight()) ||
+        m_intermediary_color_texture.get()->GetWidth() != target_width ||
+        m_intermediary_color_texture.get()->GetHeight() != target_height ||
         m_intermediary_color_texture.get()->GetLayers() != target_layers)
     {
       const TextureConfig intermediary_color_texture_config(
-          src_rect.GetWidth(), src_rect.GetHeight(), 1, target_layers, src_tex->GetSamples(),
+          target_width, target_height, 1, target_layers, src_tex->GetSamples(),
           s_intermediary_buffer_format, AbstractTextureFlag_RenderTarget);
       m_intermediary_color_texture = g_gfx->CreateTexture(intermediary_color_texture_config,
                                                           "Intermediary post process texture");
@@ -530,8 +541,8 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
     g_gfx->SetFramebuffer(m_intermediary_frame_buffer.get());
 
     FillUniformBuffer(src_rect, src_tex, src_layer, g_gfx->GetCurrentFramebuffer()->GetRect(),
-                      g_presenter->GetTargetRectangle(), uniform_staging_buffer->data(),
-                      !default_uniform_staging_buffer);
+                      present_rect, uniform_staging_buffer->data(), !default_uniform_staging_buffer,
+                      true);
     g_vertex_manager->UploadUtilityUniforms(uniform_staging_buffer->data(),
                                             static_cast<u32>(uniform_staging_buffer->size()));
 
@@ -544,6 +555,7 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
     src_rect = m_intermediary_color_texture->GetRect();
     src_tex = m_intermediary_color_texture.get();
     g_gfx->SetTexture(0, src_tex);
+    g_gfx->SetTexture(1, src_tex);
     // The "m_intermediary_color_texture" has already copied
     // from the specified source layer onto its first one.
     // If we query for a layer that the source texture doesn't have,
@@ -557,7 +569,7 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
     // If we have no custom user shader selected, and color correction
     // is active, directly run the fixed pipeline shader instead of
     // doing two passes, with the second one doing nothing useful.
-    if (m_default_pipeline && is_color_correction_active)
+    if (m_default_pipeline && needs_default_pipeline)
     {
       final_pipeline = m_default_pipeline.get();
     }
@@ -580,8 +592,8 @@ void PostProcessing::BlitFromTexture(const MathUtil::Rectangle<int>& dst,
   if (final_pipeline)
   {
     FillUniformBuffer(src_rect, src_tex, src_layer, g_gfx->GetCurrentFramebuffer()->GetRect(),
-                      g_presenter->GetTargetRectangle(), uniform_staging_buffer->data(),
-                      !default_uniform_staging_buffer);
+                      present_rect, uniform_staging_buffer->data(), !default_uniform_staging_buffer,
+                      false);
     g_vertex_manager->UploadUtilityUniforms(uniform_staging_buffer->data(),
                                             static_cast<u32>(uniform_staging_buffer->size()));
 
@@ -609,7 +621,11 @@ std::string PostProcessing::GetUniformBufferHeader(bool user_post_process) const
   // The first (but not necessarily only) source layer we target
   ss << "  int src_layer;\n";
   ss << "  uint time;\n";
+  ss << "  int graphics_api;\n";
+  // If true, it's an intermediary buffer (including the first), if false, it's the final one
+  ss << "  int intermediary_buffer;\n";
 
+  ss << "  int resampling_method;\n";
   ss << "  int correct_color_space;\n";
   ss << "  int game_color_space;\n";
   ss << "  int correct_gamma;\n";
@@ -742,6 +758,7 @@ void SetOutput(float4 color)
 
 #define GetOption(x) (x)
 #define OptionEnabled(x) ((x) != 0)
+#define OptionDisabled(x) ((x) == 0)
 
 )";
   return ss.str();
@@ -752,13 +769,9 @@ std::string PostProcessing::GetFooter() const
   return {};
 }
 
-bool PostProcessing::CompileVertexShader()
+std::string GetVertexShaderBody()
 {
   std::ostringstream ss;
-  // We never need the user selected post process custom uniforms in the vertex shader
-  const bool user_post_process = false;
-  ss << GetUniformBufferHeader(user_post_process);
-
   if (g_ActiveConfig.backend_info.bSupportsGeometryShaders)
   {
     ss << "VARYING_LOCATION(0) out VertexData {\n";
@@ -779,21 +792,34 @@ bool PostProcessing::CompileVertexShader()
 
   // Vulkan Y needs to be inverted on every pass
   if (g_ActiveConfig.backend_info.api_type == APIType::Vulkan)
+  {
     ss << "  opos.y = -opos.y;\n";
-
-  std::string s2 = ss.str();
-  s2 += "}\n";
-  m_default_vertex_shader = g_gfx->CreateShaderFromSource(ShaderStage::Vertex, s2,
-                                                          "Default post-processing vertex shader");
-
-  // OpenGL Y needs to be inverted once only (in the last pass)
-  if (g_ActiveConfig.backend_info.api_type == APIType::OpenGL)
-    ss << "  opos.y = -opos.y;\n";
+  }
+  // OpenGL Y needs to be inverted in all passes except the last one
+  else if (g_ActiveConfig.backend_info.api_type == APIType::OpenGL)
+  {
+    ss << "  if (intermediary_buffer != 0)\n";
+    ss << "    opos.y = -opos.y;\n";
+  }
 
   ss << "}\n";
+  return ss.str();
+}
 
+bool PostProcessing::CompileVertexShader()
+{
+  std::ostringstream ss_default;
+  ss_default << GetUniformBufferHeader(false);
+  ss_default << GetVertexShaderBody();
+  m_default_vertex_shader = g_gfx->CreateShaderFromSource(ShaderStage::Vertex, ss_default.str(),
+                                                          "Default post-processing vertex shader");
+
+  std::ostringstream ss;
+  ss << GetUniformBufferHeader(true);
+  ss << GetVertexShaderBody();
   m_vertex_shader =
       g_gfx->CreateShaderFromSource(ShaderStage::Vertex, ss.str(), "Post-processing vertex shader");
+
   if (!m_default_vertex_shader || !m_vertex_shader)
   {
     PanicAlertFmt("Failed to compile post-processing vertex shader");
@@ -816,6 +842,9 @@ struct BuiltinUniforms
   std::array<float, 4> src_rect;
   s32 src_layer;
   u32 time;
+  s32 graphics_api;
+  s32 intermediary_buffer;
+  s32 resampling_method;
   s32 correct_color_space;
   s32 game_color_space;
   s32 correct_gamma;
@@ -839,7 +868,7 @@ void PostProcessing::FillUniformBuffer(const MathUtil::Rectangle<int>& src,
                                        const AbstractTexture* src_tex, int src_layer,
                                        const MathUtil::Rectangle<int>& dst,
                                        const MathUtil::Rectangle<int>& wnd, u8* buffer,
-                                       bool user_post_process)
+                                       bool user_post_process, bool intermediary_buffer)
 {
   const float rcp_src_width = 1.0f / src_tex->GetWidth();
   const float rcp_src_height = 1.0f / src_tex->GetHeight();
@@ -860,7 +889,10 @@ void PostProcessing::FillUniformBuffer(const MathUtil::Rectangle<int>& src,
                                static_cast<float>(src.GetHeight()) * rcp_src_height};
   builtin_uniforms.src_layer = static_cast<s32>(src_layer);
   builtin_uniforms.time = static_cast<u32>(m_timer.ElapsedMs());
+  builtin_uniforms.graphics_api = static_cast<s32>(g_ActiveConfig.backend_info.api_type);
+  builtin_uniforms.intermediary_buffer = static_cast<s32>(intermediary_buffer);
 
+  builtin_uniforms.resampling_method = static_cast<s32>(g_ActiveConfig.output_resampling_mode);
   // Color correction related uniforms.
   // These are mainly used by the "m_default_pixel_shader",
   // but should also be accessible to all other shaders.
@@ -883,6 +915,8 @@ void PostProcessing::FillUniformBuffer(const MathUtil::Rectangle<int>& src,
   std::memcpy(buffer, &builtin_uniforms, sizeof(builtin_uniforms));
   buffer += sizeof(builtin_uniforms);
 
+  // Don't include the custom pp shader options if they are not necessary,
+  // having mismatching uniforms between different shaders can cause issues on some backends
   if (!user_post_process)
     return;
 
@@ -1000,8 +1034,7 @@ bool PostProcessing::CompilePipeline()
   const bool needs_intermediary_buffer = NeedsIntermediaryBuffer();
 
   AbstractPipelineConfig config = {};
-  config.vertex_shader =
-      needs_intermediary_buffer ? m_vertex_shader.get() : m_default_vertex_shader.get();
+  config.vertex_shader = m_default_vertex_shader.get();
   // This geometry shader will take care of reading both layer 0 and 1 on the source texture,
   // and writing to both layer 0 and 1 on the render target.
   config.geometry_shader = UseGeometryShaderForPostProcess(needs_intermediary_buffer) ?
@@ -1018,7 +1051,7 @@ bool PostProcessing::CompilePipeline()
   if (config.pixel_shader)
     m_default_pipeline = g_gfx->CreatePipeline(config);
 
-  config.vertex_shader = m_default_vertex_shader.get();
+  config.vertex_shader = m_vertex_shader.get();
   config.geometry_shader = UseGeometryShaderForPostProcess(false) ?
                                g_shader_cache->GetTexcoordGeometryShader() :
                                nullptr;
diff --git a/Source/Core/VideoCommon/PostProcessing.h b/Source/Core/VideoCommon/PostProcessing.h
index b8b648d2d0..b636f3b133 100644
--- a/Source/Core/VideoCommon/PostProcessing.h
+++ b/Source/Core/VideoCommon/PostProcessing.h
@@ -124,7 +124,8 @@ protected:
   size_t CalculateUniformsSize(bool user_post_process) const;
   void FillUniformBuffer(const MathUtil::Rectangle<int>& src, const AbstractTexture* src_tex,
                          int src_layer, const MathUtil::Rectangle<int>& dst,
-                         const MathUtil::Rectangle<int>& wnd, u8* buffer, bool user_post_process);
+                         const MathUtil::Rectangle<int>& wnd, u8* buffer, bool user_post_process,
+                         bool intermediary_buffer);
 
   // Timer for determining our time value
   Common::Timer m_timer;
diff --git a/Source/Core/VideoCommon/VideoConfig.cpp b/Source/Core/VideoCommon/VideoConfig.cpp
index 42bf178047..83dc5eb53e 100644
--- a/Source/Core/VideoCommon/VideoConfig.cpp
+++ b/Source/Core/VideoCommon/VideoConfig.cpp
@@ -133,6 +133,7 @@ void VideoConfig::Refresh()
 
   texture_filtering_mode = Config::Get(Config::GFX_ENHANCE_FORCE_TEXTURE_FILTERING);
   iMaxAnisotropy = Config::Get(Config::GFX_ENHANCE_MAX_ANISOTROPY);
+  output_resampling_mode = Config::Get(Config::GFX_ENHANCE_OUTPUT_RESAMPLING);
   sPostProcessingShader = Config::Get(Config::GFX_ENHANCE_POST_SHADER);
   bForceTrueColor = Config::Get(Config::GFX_ENHANCE_FORCE_TRUE_COLOR);
   bDisableCopyFilter = Config::Get(Config::GFX_ENHANCE_DISABLE_COPY_FILTER);
diff --git a/Source/Core/VideoCommon/VideoConfig.h b/Source/Core/VideoCommon/VideoConfig.h
index 20f4aa8a28..6e34a43934 100644
--- a/Source/Core/VideoCommon/VideoConfig.h
+++ b/Source/Core/VideoCommon/VideoConfig.h
@@ -52,6 +52,17 @@ enum class TextureFilteringMode : int
   Linear,
 };
 
+enum class OutputResamplingMode : int
+{
+  Default,
+  Bilinear,
+  BSpline,
+  MitchellNetravali,
+  CatmullRom,
+  SharpBilinear,
+  AreaSampling,
+};
+
 enum class ColorCorrectionRegion : int
 {
   SMPTE_NTSCM,
@@ -103,6 +114,7 @@ struct VideoConfig final
   bool bSSAA = false;
   int iEFBScale = 0;
   TextureFilteringMode texture_filtering_mode = TextureFilteringMode::Default;
+  OutputResamplingMode output_resampling_mode = OutputResamplingMode::Default;
   int iMaxAnisotropy = 0;
   std::string sPostProcessingShader;
   bool bForceTrueColor = false;