From fc1fe0672bd4179a9af3ebc55b180e19cefcd65a Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Mon, 26 Feb 2018 21:01:21 +1000
Subject: [PATCH] OGL: Add some basic state tracking

We would want to improve the granularity here in the future, but for
now, this should avoid any performance loss from switching to the
VideoCommon shader cache.
---
 Source/Core/VideoBackends/OGL/Render.cpp | 27 ++++++++++++++++++------
 Source/Core/VideoBackends/OGL/Render.h   |  9 +++++---
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/Source/Core/VideoBackends/OGL/Render.cpp b/Source/Core/VideoBackends/OGL/Render.cpp
index 5319e41cbd..945dbadcf1 100644
--- a/Source/Core/VideoBackends/OGL/Render.cpp
+++ b/Source/Core/VideoBackends/OGL/Render.cpp
@@ -1290,8 +1290,11 @@ void Renderer::SetAndClearFramebuffer(const AbstractFramebuffer* framebuffer,
   glClear(clear_mask);
 }
 
-void Renderer::ApplyBlendingState(const BlendingState& state)
+void Renderer::ApplyBlendingState(const BlendingState state, bool force)
 {
+  if (!force && m_current_blend_state == state)
+    return;
+
   bool useDualSource =
       state.usedualsrc && g_ActiveConfig.backend_info.bSupportsDualSourceBlend &&
       (!DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DUAL_SOURCE_BLENDING) || state.dstalpha);
@@ -1364,6 +1367,7 @@ void Renderer::ApplyBlendingState(const BlendingState& state)
   }
 
   glColorMask(state.colorupdate, state.colorupdate, state.colorupdate, state.alphaupdate);
+  m_current_blend_state = state;
 }
 
 // This function has the final picture. We adjust the aspect ratio here.
@@ -1561,15 +1565,19 @@ void Renderer::RestoreAPIState()
     glEnable(GL_CLIP_DISTANCE0);
     glEnable(GL_CLIP_DISTANCE1);
   }
-  BPFunctions::SetGenerationMode();
   BPFunctions::SetScissor();
   BPFunctions::SetViewport();
-  BPFunctions::SetDepthMode();
-  BPFunctions::SetBlendMode();
+
+  ApplyRasterizationState(m_current_rasterization_state, true);
+  ApplyDepthState(m_current_depth_state, true);
+  ApplyBlendingState(m_current_blend_state, true);
 }
 
-void Renderer::ApplyRasterizationState(const RasterizationState& state)
+void Renderer::ApplyRasterizationState(const RasterizationState state, bool force)
 {
+  if (!force && m_current_rasterization_state == state)
+    return;
+
   // none, ccw, cw, ccw
   if (state.cullmode != GenMode::CULL_NONE)
   {
@@ -1581,10 +1589,15 @@ void Renderer::ApplyRasterizationState(const RasterizationState& state)
   {
     glDisable(GL_CULL_FACE);
   }
+
+  m_current_rasterization_state = state;
 }
 
-void Renderer::ApplyDepthState(const DepthState& state)
+void Renderer::ApplyDepthState(const DepthState state, bool force)
 {
+  if (!force && m_current_depth_state == state)
+    return;
+
   const GLenum glCmpFuncs[8] = {GL_NEVER,   GL_LESS,     GL_EQUAL,  GL_LEQUAL,
                                 GL_GREATER, GL_NOTEQUAL, GL_GEQUAL, GL_ALWAYS};
 
@@ -1602,6 +1615,8 @@ void Renderer::ApplyDepthState(const DepthState& state)
     glDisable(GL_DEPTH_TEST);
     glDepthMask(GL_FALSE);
   }
+
+  m_current_depth_state = state;
 }
 
 void Renderer::SetPipeline(const AbstractPipeline* pipeline)
diff --git a/Source/Core/VideoBackends/OGL/Render.h b/Source/Core/VideoBackends/OGL/Render.h
index 3f1277a0c2..d8882e2111 100644
--- a/Source/Core/VideoBackends/OGL/Render.h
+++ b/Source/Core/VideoBackends/OGL/Render.h
@@ -154,12 +154,15 @@ private:
   void CheckForSurfaceChange();
   void CheckForSurfaceResize();
 
-  void ApplyBlendingState(const BlendingState& state);
-  void ApplyRasterizationState(const RasterizationState& state);
-  void ApplyDepthState(const DepthState& state);
+  void ApplyBlendingState(const BlendingState state, bool force = false);
+  void ApplyRasterizationState(const RasterizationState state, bool force = false);
+  void ApplyDepthState(const DepthState state, bool force = false);
   void UploadUtilityUniforms(const void* uniforms, u32 uniforms_size);
 
   std::array<const AbstractTexture*, 8> m_bound_textures{};
   const OGLPipeline* m_graphics_pipeline = nullptr;
+  RasterizationState m_current_rasterization_state = {};
+  DepthState m_current_depth_state = {};
+  BlendingState m_current_blend_state = {};
 };
 }