Terrain: use 32-bit indices if necessary

components/terrain/buffercache.cpp

@@ -4,50 +4,12 @@
 
 #include "defs.hpp"
 
-namespace Terrain
+namespace
 {
 
-    Ogre::HardwareVertexBufferSharedPtr BufferCache::getUVBuffer()
-    {
-        if (mUvBufferMap.find(mNumVerts) != mUvBufferMap.end())
-        {
-            return mUvBufferMap[mNumVerts];
-        }
-
-        int vertexCount = mNumVerts * mNumVerts;
-
-        std::vector<float> uvs;
-        uvs.reserve(vertexCount*2);
-
-        for (unsigned int col = 0; col < mNumVerts; ++col)
-        {
-            for (unsigned int row = 0; row < mNumVerts; ++row)
-            {
-                uvs.push_back(col / static_cast<float>(mNumVerts-1)); // U
-                uvs.push_back(row / static_cast<float>(mNumVerts-1)); // V
-            }
-        }
-
-        Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
-        Ogre::HardwareVertexBufferSharedPtr buffer = mgr->createVertexBuffer(
-                    Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT2),
-                                                vertexCount, Ogre::HardwareBuffer::HBU_STATIC);
-
-        buffer->writeData(0, buffer->getSizeInBytes(), &uvs[0], true);
-
-        mUvBufferMap[mNumVerts] = buffer;
-        return buffer;
-    }
-
-    Ogre::HardwareIndexBufferSharedPtr BufferCache::getIndexBuffer(unsigned int flags)
-    {
-        unsigned int verts = mNumVerts;
-
-        if (mIndexBufferMap.find(flags) != mIndexBufferMap.end())
-        {
-            return mIndexBufferMap[flags];
-        }
-
+template <typename IndexType>
+Ogre::HardwareIndexBufferSharedPtr createIndexBuffer(unsigned int flags, unsigned int verts, Ogre::HardwareIndexBuffer::IndexType type)
+{
     // LOD level n means every 2^n-th vertex is kept
     size_t lodLevel = (flags >> (4*4));
 
@@ -55,11 +17,11 @@ namespace Terrain
     for (int i=0; i<4; ++i)
         lodDeltas[i] = (flags >> (4*i)) & (0xf);
 
-        bool anyDeltas = (lodDeltas[North] || lodDeltas[South] || lodDeltas[West] || lodDeltas[East]);
+    bool anyDeltas = (lodDeltas[Terrain::North] || lodDeltas[Terrain::South] || lodDeltas[Terrain::West] || lodDeltas[Terrain::East]);
 
     size_t increment = 1 << lodLevel;
     assert(increment < verts);
-        std::vector<short> indices;
+    std::vector<IndexType> indices;
     indices.reserve((verts-1)*(verts-1)*2*3 / increment);
 
     size_t rowStart = 0, colStart = 0, rowEnd = verts-1, colEnd = verts-1;
@@ -94,7 +56,7 @@ namespace Terrain
 
         // South
         size_t row = 0;
-            size_t outerStep = 1 << (lodDeltas[South] + lodLevel);
+        size_t outerStep = 1 << (lodDeltas[Terrain::South] + lodLevel);
         for (size_t col = 0; col < verts-1; col += outerStep)
         {
             indices.push_back(verts*col+row);
@@ -118,7 +80,7 @@ namespace Terrain
 
         // North
         row = verts-1;
-            outerStep = size_t(1) << (lodDeltas[North] + lodLevel);
+        outerStep = size_t(1) << (lodDeltas[Terrain::North] + lodLevel);
         for (size_t col = 0; col < verts-1; col += outerStep)
         {
             indices.push_back(verts*(col+outerStep)+row);
@@ -142,7 +104,7 @@ namespace Terrain
 
         // West
         size_t col = 0;
-            outerStep = size_t(1) << (lodDeltas[West] + lodLevel);
+        outerStep = size_t(1) << (lodDeltas[Terrain::West] + lodLevel);
         for (size_t row = 0; row < verts-1; row += outerStep)
         {
             indices.push_back(verts*col+row+outerStep);
@@ -166,7 +128,7 @@ namespace Terrain
 
         // East
         col = verts-1;
-            outerStep = size_t(1) << (lodDeltas[East] + lodLevel);
+        outerStep = size_t(1) << (lodDeltas[Terrain::East] + lodLevel);
         for (size_t row = 0; row < verts-1; row += outerStep)
         {
             indices.push_back(verts*col+row);
@@ -190,9 +152,64 @@ namespace Terrain
     }
 
     Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
-        Ogre::HardwareIndexBufferSharedPtr buffer = mgr->createIndexBuffer(Ogre::HardwareIndexBuffer::IT_16BIT,
+    Ogre::HardwareIndexBufferSharedPtr buffer = mgr->createIndexBuffer(type,
                                                                        indices.size(), Ogre::HardwareBuffer::HBU_STATIC);
     buffer->writeData(0, buffer->getSizeInBytes(), &indices[0], true);
+    return buffer;
+}
+
+}
+
+namespace Terrain
+{
+
+    Ogre::HardwareVertexBufferSharedPtr BufferCache::getUVBuffer()
+    {
+        if (mUvBufferMap.find(mNumVerts) != mUvBufferMap.end())
+        {
+            return mUvBufferMap[mNumVerts];
+        }
+
+        int vertexCount = mNumVerts * mNumVerts;
+
+        std::vector<float> uvs;
+        uvs.reserve(vertexCount*2);
+
+        for (unsigned int col = 0; col < mNumVerts; ++col)
+        {
+            for (unsigned int row = 0; row < mNumVerts; ++row)
+            {
+                uvs.push_back(col / static_cast<float>(mNumVerts-1)); // U
+                uvs.push_back(row / static_cast<float>(mNumVerts-1)); // V
+            }
+        }
+
+        Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
+        Ogre::HardwareVertexBufferSharedPtr buffer = mgr->createVertexBuffer(
+                    Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT2),
+                                                vertexCount, Ogre::HardwareBuffer::HBU_STATIC);
+
+        buffer->writeData(0, buffer->getSizeInBytes(), &uvs[0], true);
+
+        mUvBufferMap[mNumVerts] = buffer;
+        return buffer;
+    }
+
+    Ogre::HardwareIndexBufferSharedPtr BufferCache::getIndexBuffer(unsigned int flags)
+    {
+        unsigned int verts = mNumVerts;
+
+        if (mIndexBufferMap.find(flags) != mIndexBufferMap.end())
+        {
+            return mIndexBufferMap[flags];
+        }
+
+        Ogre::HardwareIndexBufferSharedPtr buffer;
+        if (verts*verts > (0xffffu))
+            buffer = createIndexBuffer<unsigned int>(flags, verts, Ogre::HardwareIndexBuffer::IT_32BIT);
+        else
+            buffer = createIndexBuffer<unsigned short>(flags, verts, Ogre::HardwareIndexBuffer::IT_16BIT);
+
         mIndexBufferMap[flags] = buffer;
         return buffer;
     }