From db8f7fc72d6abd6df84200e1917672ec0b9a6d08 Mon Sep 17 00:00:00 2001
From: Nick Renieris <velocityra@gmail.com>
Date: Mon, 14 Oct 2019 18:20:48 +0200
Subject: [PATCH] retroplayer/gl: Don't allocate render buffers every frame

Fixes stuttering (occasional black frames every few seconds).
---
 .../VideoRenderers/RPRendererOpenGL.cpp       | 38 +++++++++++++------
 .../VideoRenderers/RPRendererOpenGL.h         | 11 ++++++
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.cpp b/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.cpp
index 4cdb706bed375..93d06c712f54e 100644
--- a/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.cpp
+++ b/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.cpp
@@ -293,11 +293,31 @@ void CRPRendererOpenGL::Render(uint8_t alpha)
 
   const uint32_t color = (alpha << 24) | 0xFFFFFF;
 
-  const std::unique_ptr<CGLTexture> sourceTexture(new CGLTexture(
-          static_cast<unsigned int>(renderBuffer->GetWidth()),
-          static_cast<unsigned int>(renderBuffer->GetHeight()),
-          GL_RGB,
-          renderBuffer->TextureID()));
+  RenderBufferTextures *rbTextures;
+  const auto it = m_RBTexturesMap.find(renderBuffer);
+  if (it != m_RBTexturesMap.end())
+  {
+    rbTextures = it->second.get();
+  } else {
+    // We can't copy or move CGLTexture, so construct source/target in-place
+    rbTextures = new RenderBufferTextures{
+      {   // source texture
+        static_cast<unsigned int>(renderBuffer->GetWidth()),
+        static_cast<unsigned int>(renderBuffer->GetHeight()),
+        GL_RGB,
+        renderBuffer->TextureID()
+      },
+      {
+        // target texture
+        static_cast<unsigned int>(m_context.GetScreenWidth()),
+        static_cast<unsigned int>(m_context.GetScreenHeight())
+      }
+    };
+    m_RBTexturesMap.emplace(renderBuffer, rbTextures);
+  }
+
+  const auto sourceTexture = &rbTextures->source;
+  const auto targetTexture = &rbTextures->target;
 
   glBindTexture(m_textureTarget, sourceTexture->getMTexture());
 
@@ -320,14 +340,10 @@ void CRPRendererOpenGL::Render(uint8_t alpha)
             m_rotatedDestCoords[3]
     };
 
-    const std::unique_ptr<CGLTexture> renderTargetTexture(new CGLTexture(
-            static_cast<unsigned int>(m_context.GetScreenWidth()),
-            static_cast<unsigned int>(m_context.GetScreenHeight())));
-
-    renderTargetTexture->CreateTextureObject();
+    targetTexture->CreateTextureObject();
 
     SHADER::CShaderTextureGL source(*sourceTexture);
-    SHADER::CShaderTextureGL target(*renderTargetTexture);
+    SHADER::CShaderTextureGL target(*targetTexture);
     if (!m_shaderPreset->RenderUpdate(destPoints, &source, &target))
     {
       m_shadersNeedUpdate = false;
diff --git a/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.h b/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.h
index 6ebd4b81009ad..92bd0299285d7 100644
--- a/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.h
+++ b/xbmc/cores/RetroPlayer/rendering/VideoRenderers/RPRendererOpenGL.h
@@ -10,14 +10,19 @@
 
 #include "RPBaseRenderer.h"
 #include "cores/RetroPlayer/process/RPProcessInfo.h"
+#include "guilib/TextureGL.h"
 
 #include "system_gl.h"
 
+#include <map>
+
 namespace KODI
 {
 namespace RETRO
 {
   class CRenderContext;
+  class CRenderBufferOpenGL;
+
 
   class CRendererFactoryOpenGL : public IRendererFactory
   {
@@ -54,6 +59,10 @@ namespace RETRO
       float y;
       float z;
     };
+    struct RenderBufferTextures {
+        CGLTexture source;
+        CGLTexture target;
+    };
     
     // implementation of CRPBaseRenderer
     bool ConfigureInternal() override;
@@ -76,6 +85,8 @@ namespace RETRO
 
     virtual void Render(uint8_t alpha);
 
+    std::map<CRenderBufferOpenGL*, std::unique_ptr<RenderBufferTextures>> m_RBTexturesMap;
+
     GLuint m_mainVAO;
     GLuint m_mainVertexVBO;
     GLuint m_mainIndexVBO;