From 19abb62586a0210d9e7828fdcbbebf159c9e10c5 Mon Sep 17 00:00:00 2001
From: Philip Goto <philip.goto@gmail.com>
Date: Sun, 5 Nov 2017 16:08:25 +0100
Subject: [PATCH] Add Smooth NN scaling to OpenGL renderer

---
 src/openrct2-ui/UiContext.cpp                  |  6 ++++--
 .../engines/HardwareDisplayDrawingEngine.cpp   |  7 +------
 .../engines/opengl/OpenGLDrawingEngine.cpp     | 18 +++++++++++++++++-
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/src/openrct2-ui/UiContext.cpp b/src/openrct2-ui/UiContext.cpp
index bc45a153c6..5c92cccaa1 100644
--- a/src/openrct2-ui/UiContext.cpp
+++ b/src/openrct2-ui/UiContext.cpp
@@ -497,11 +497,13 @@ public:
         {
             _scaleQuality = SCALE_QUALITY_NN;
         }
+        
+        sint32 scaleQuality = _scaleQuality;
         if (_scaleQuality == SCALE_QUALITY_SMOOTH_NN)
         {
-            _scaleQuality = SCALE_QUALITY_LINEAR;
+            scaleQuality = SCALE_QUALITY_LINEAR;
         }
-        snprintf(scaleQualityBuffer, sizeof(scaleQualityBuffer), "%u", _scaleQuality);
+        snprintf(scaleQualityBuffer, sizeof(scaleQualityBuffer), "%u", scaleQuality);
         SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, scaleQualityBuffer);
 
         sint32 width, height;
diff --git a/src/openrct2-ui/drawing/engines/HardwareDisplayDrawingEngine.cpp b/src/openrct2-ui/drawing/engines/HardwareDisplayDrawingEngine.cpp
index ad68d1a365..7a5798c677 100644
--- a/src/openrct2-ui/drawing/engines/HardwareDisplayDrawingEngine.cpp
+++ b/src/openrct2-ui/drawing/engines/HardwareDisplayDrawingEngine.cpp
@@ -103,12 +103,7 @@ public:
             }
         }
 
-        sint32 scaleQuality = gConfigGeneral.scale_quality;
-        if (gConfigGeneral.use_nn_at_integer_scales &&
-            gConfigGeneral.window_scale == std::floor(gConfigGeneral.window_scale))
-        {
-            scaleQuality = SCALE_QUALITY_NN;
-        }
+        sint32 scaleQuality = GetContext()->GetUiContext()->GetScaleQuality();
         if (scaleQuality == SCALE_QUALITY_SMOOTH_NN)
         {
             scaleQuality = SCALE_QUALITY_LINEAR;
diff --git a/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp b/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
index c72cb56da1..2ab5deb49e 100644
--- a/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
+++ b/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
@@ -142,6 +142,7 @@ private:
     ApplyPaletteShader *    _applyPaletteShader     = nullptr;
     OpenGLFramebuffer *     _screenFramebuffer      = nullptr;
     OpenGLFramebuffer *     _scaleFramebuffer       = nullptr;
+    OpenGLFramebuffer *     _smoothScaleFramebuffer = nullptr;
 
 public:
     SDL_Color Palette[256];
@@ -258,7 +259,12 @@ public:
         _applyPaletteShader->SetTexture(_drawingContext->GetFinalFramebuffer().GetTexture());
         _applyPaletteShader->Draw();
 
-        if (_scaleFramebuffer != nullptr)
+        if (_smoothScaleFramebuffer != nullptr)
+        {
+            _smoothScaleFramebuffer->Copy(*_scaleFramebuffer, GL_NEAREST);
+            _screenFramebuffer->Copy(*_smoothScaleFramebuffer, GL_LINEAR);
+        }
+        else if (_scaleFramebuffer != nullptr)
         {
             _screenFramebuffer->Copy(*_scaleFramebuffer, GL_LINEAR);
         }
@@ -395,10 +401,20 @@ private:
             delete _scaleFramebuffer;
             _scaleFramebuffer = nullptr;
         }
+        if (_smoothScaleFramebuffer != nullptr)
+        {
+            delete _smoothScaleFramebuffer;
+            _smoothScaleFramebuffer = nullptr;
+        }
         if (GetContext()->GetUiContext()->GetScaleQuality() > 0)
         {
             _scaleFramebuffer = new OpenGLFramebuffer(_width, _height, false, false);
         }
+        if (GetContext()->GetUiContext()->GetScaleQuality() == SCALE_QUALITY_SMOOTH_NN)
+        {
+            uint32 scale = std::ceil(gConfigGeneral.window_scale);
+            _smoothScaleFramebuffer = new OpenGLFramebuffer(_width * scale, _height * scale, false, false);
+        }
     }
 
     void Display()