Convert to much faster (Big O) 2D bin packing algorithm

MaxRects time increases exponentially, after adding 18000 items MaxRects takes 1000 times longer than Skyline. This is unacceptable with ~110,000 sprites. Skyline packing efficiency is pretty good too
wheybags · Mar 18, 2019 · efadd7e · efadd7e
1 parent 8ce51e6
commit efadd7e
Show file tree

Hide file tree

Showing 10 changed files with 1,343 additions and 620 deletions.
diff --git a/components/CMakeLists.txt b/components/CMakeLists.txt
@@ -73,10 +73,12 @@ set(RenderFiles
     render/misc.h
     render/atlastexture.cpp
     render/atlastexture.h
-    ../extern/RectangleBinPack/MaxRectsBinPack.cpp
-    ../extern/RectangleBinPack/MaxRectsBinPack.h
+    ../extern/RectangleBinPack/GuillotineBinPack.cpp
+    ../extern/RectangleBinPack/GuillotineBinPack.h
     ../extern/RectangleBinPack/Rect.cpp
     ../extern/RectangleBinPack/Rect.h
+    ../extern/RectangleBinPack/SkylineBinPack.cpp
+    ../extern/RectangleBinPack/SkylineBinPack.h
 )
 add_library(Render ${RenderFiles})
 target_link_libraries(Render PUBLIC Cel Levels nuklear SDL2::SDL2 SDL_image::SDL_image ${OPENGL_LIBRARIES})

diff --git a/components/render/atlastexture.cpp b/components/render/atlastexture.cpp
@@ -6,7 +6,7 @@
  * be missing if the array texture was allocated with > 1 depth (layers)... */
 
 #include "atlastexture.h"
-#include "../../extern/RectangleBinPack/MaxRectsBinPack.h"
+#include "../../extern/RectangleBinPack/SkylineBinPack.h"
 
 #include <boost/make_unique.hpp>
 #include <misc/assert.h>
@@ -35,7 +35,7 @@ namespace Render
         glGenTextures(mTextureLayers, &mTextureArrayIds[0]);
 
         for (int32_t layer = 0; layer < mTextureLayers; layer++)
-            mBinPacker.push_back(boost::make_unique<rbp::MaxRectsBinPack>(mTextureWidth, mTextureHeight, false));
+            mBinPacker.push_back(boost::make_unique<rbp::SkylineBinPack>(mTextureWidth, mTextureHeight, false, false));
 
         GLuint fbo;
         glGenFramebuffers(1, &fbo);
@@ -106,7 +106,7 @@ namespace Render
         int32_t layer;
         for (layer = 0; layer < mTextureLayers; layer++)
         {
-            packedPos = mBinPacker[layer]->Insert(paddedWidth, paddedHeight, rbp::MaxRectsBinPack::RectBestAreaFit);
+            packedPos = mBinPacker[layer]->Insert(paddedWidth, paddedHeight, rbp::SkylineBinPack::LevelMinWasteFit);
             if (packedPos.height != 0)
                 break;
         }

diff --git a/components/render/atlastexture.h b/components/render/atlastexture.h
@@ -12,7 +12,7 @@
 
 namespace rbp
 {
-    class MaxRectsBinPack;
+    class SkylineBinPack;
 }
 
 namespace Render
@@ -50,6 +50,6 @@ namespace Render
         GLint mTextureLayers;
         AtlasTextureLookupMap mLookupMap;
         size_t mNextTextureId = 1;
-        std::vector<std::unique_ptr<rbp::MaxRectsBinPack>> mBinPacker;
+        std::vector<std::unique_ptr<rbp::SkylineBinPack>> mBinPacker;
     };
 }
diff --git a/components/render/sdl2backend.cpp b/components/render/sdl2backend.cpp
@@ -23,7 +23,7 @@
 // clang-format off
 #include <misc/disablewarn.h>
 #include "../../extern/jo_gif/jo_gif.cpp"
-#include "../../extern/RectangleBinPack/MaxRectsBinPack.h"
+#include "../../extern/RectangleBinPack/SkylineBinPack.h"
 #include <misc/enablewarn.h>
 // clang-format on