Terrain: use 32-bit indices if necessary

components/terrain/buffercache.cpp

@@ -4,6 +4,162 @@
 
 #include "defs.hpp"
 
+namespace
+{
+
+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));
+
+    size_t lodDeltas[4];
+    for (int i=0; i<4; ++i)
+        lodDeltas[i] = (flags >> (4*i)) & (0xf);
+
+    bool anyDeltas = (lodDeltas[Terrain::North] || lodDeltas[Terrain::South] || lodDeltas[Terrain::West] || lodDeltas[Terrain::East]);
+
+    size_t increment = 1 << lodLevel;
+    assert(increment < verts);
+    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;
+    // If any edge needs stitching we'll skip all edges at this point,
+    // mainly because stitching one edge would have an effect on corners and on the adjacent edges
+    if (anyDeltas)
+    {
+        colStart += increment;
+        colEnd -= increment;
+        rowEnd -= increment;
+        rowStart += increment;
+    }
+    for (size_t row = rowStart; row < rowEnd; row += increment)
+    {
+        for (size_t col = colStart; col < colEnd; col += increment)
+        {
+            indices.push_back(verts*col+row);
+            indices.push_back(verts*(col+increment)+row+increment);
+            indices.push_back(verts*col+row+increment);
+
+            indices.push_back(verts*col+row);
+            indices.push_back(verts*(col+increment)+row);
+            indices.push_back(verts*(col+increment)+row+increment);
+        }
+    }
+
+    size_t innerStep = increment;
+    if (anyDeltas)
+    {
+        // Now configure LOD transitions at the edges - this is pretty tedious,
+        // and some very long and boring code, but it works great
+
+        // South
+        size_t row = 0;
+        size_t outerStep = 1 << (lodDeltas[Terrain::South] + lodLevel);
+        for (size_t col = 0; col < verts-1; col += outerStep)
+        {
+            indices.push_back(verts*col+row);
+            indices.push_back(verts*(col+outerStep)+row);
+            // Make sure not to touch the right edge
+            if (col+outerStep == verts-1)
+                indices.push_back(verts*(col+outerStep-innerStep)+row+innerStep);
+            else
+                indices.push_back(verts*(col+outerStep)+row+innerStep);
+
+            for (size_t i = 0; i < outerStep; i += innerStep)
+            {
+                // Make sure not to touch the left or right edges
+                if (col+i == 0 || col+i == verts-1-innerStep)
+                    continue;
+                indices.push_back(verts*(col)+row);
+                indices.push_back(verts*(col+i+innerStep)+row+innerStep);
+                indices.push_back(verts*(col+i)+row+innerStep);
+            }
+        }
+
+        // North
+        row = verts-1;
+        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);
+            indices.push_back(verts*col+row);
+            // Make sure not to touch the left edge
+            if (col == 0)
+                indices.push_back(verts*(col+innerStep)+row-innerStep);
+            else
+                indices.push_back(verts*col+row-innerStep);
+
+            for (size_t i = 0; i < outerStep; i += innerStep)
+            {
+                // Make sure not to touch the left or right edges
+                if (col+i == 0 || col+i == verts-1-innerStep)
+                    continue;
+                indices.push_back(verts*(col+i)+row-innerStep);
+                indices.push_back(verts*(col+i+innerStep)+row-innerStep);
+                indices.push_back(verts*(col+outerStep)+row);
+            }
+        }
+
+        // West
+        size_t col = 0;
+        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);
+            indices.push_back(verts*col+row);
+            // Make sure not to touch the top edge
+            if (row+outerStep == verts-1)
+                indices.push_back(verts*(col+innerStep)+row+outerStep-innerStep);
+            else
+                indices.push_back(verts*(col+innerStep)+row+outerStep);
+
+            for (size_t i = 0; i < outerStep; i += innerStep)
+            {
+                // Make sure not to touch the top or bottom edges
+                if (row+i == 0 || row+i == verts-1-innerStep)
+                    continue;
+                indices.push_back(verts*col+row);
+                indices.push_back(verts*(col+innerStep)+row+i);
+                indices.push_back(verts*(col+innerStep)+row+i+innerStep);
+            }
+        }
+
+        // East
+        col = verts-1;
+        outerStep = size_t(1) << (lodDeltas[Terrain::East] + lodLevel);
+        for (size_t row = 0; row < verts-1; row += outerStep)
+        {
+            indices.push_back(verts*col+row);
+            indices.push_back(verts*col+row+outerStep);
+            // Make sure not to touch the bottom edge
+            if (row == 0)
+                indices.push_back(verts*(col-innerStep)+row+innerStep);
+            else
+                indices.push_back(verts*(col-innerStep)+row);
+
+            for (size_t i = 0; i < outerStep; i += innerStep)
+            {
+                // Make sure not to touch the top or bottom edges
+                if (row+i == 0 || row+i == verts-1-innerStep)
+                    continue;
+                indices.push_back(verts*col+row+outerStep);
+                indices.push_back(verts*(col-innerStep)+row+i+innerStep);
+                indices.push_back(verts*(col-innerStep)+row+i);
+            }
+        }
+    }
+
+    Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
+    Ogre::HardwareIndexBufferSharedPtr buffer = mgr->createIndexBuffer(type,
+                                                                       indices.size(), Ogre::HardwareBuffer::HBU_STATIC);
+    buffer->writeData(0, buffer->getSizeInBytes(), &indices[0], true);
+    return buffer;
+}
+
+}
+
 namespace Terrain
 {
 
@@ -48,151 +204,12 @@ namespace Terrain
             return mIndexBufferMap[flags];
         }
 
-        // LOD level n means every 2^n-th vertex is kept
+        Ogre::HardwareIndexBufferSharedPtr buffer;
-        size_t lodLevel = (flags >> (4*4));
+        if (verts*verts > (0xffffu))
-
+            buffer = createIndexBuffer<unsigned int>(flags, verts, Ogre::HardwareIndexBuffer::IT_32BIT);
-        size_t lodDeltas[4];
-        for (int i=0; i<4; ++i)
-            lodDeltas[i] = (flags >> (4*i)) & (0xf);
-
-        bool anyDeltas = (lodDeltas[North] || lodDeltas[South] || lodDeltas[West] || lodDeltas[East]);
-
-        size_t increment = 1 << lodLevel;
-        assert(increment < verts);
-        std::vector<short> indices;
-        indices.reserve((verts-1)*(verts-1)*2*3 / increment);
-
-        size_t rowStart = 0, colStart = 0, rowEnd = verts-1, colEnd = verts-1;
-        // If any edge needs stitching we'll skip all edges at this point,
-        // mainly because stitching one edge would have an effect on corners and on the adjacent edges
-        if (anyDeltas)
-        {
-            colStart += increment;
-            colEnd -= increment;
-            rowEnd -= increment;
-            rowStart += increment;
-        }
-        for (size_t row = rowStart; row < rowEnd; row += increment)
-        {
-            for (size_t col = colStart; col < colEnd; col += increment)
-            {
-                indices.push_back(verts*col+row);
-                indices.push_back(verts*(col+increment)+row+increment);
-                indices.push_back(verts*col+row+increment);
-
-                indices.push_back(verts*col+row);
-                indices.push_back(verts*(col+increment)+row);
-                indices.push_back(verts*(col+increment)+row+increment);
-            }
-        }
-
-        size_t innerStep = increment;
-        if (anyDeltas)
-        {
-            // Now configure LOD transitions at the edges - this is pretty tedious,
-            // and some very long and boring code, but it works great
-
-            // South
-            size_t row = 0;
-            size_t outerStep = 1 << (lodDeltas[South] + lodLevel);
-            for (size_t col = 0; col < verts-1; col += outerStep)
-            {
-                indices.push_back(verts*col+row);
-                indices.push_back(verts*(col+outerStep)+row);
-                // Make sure not to touch the right edge
-                if (col+outerStep == verts-1)
-                    indices.push_back(verts*(col+outerStep-innerStep)+row+innerStep);
         else
-                    indices.push_back(verts*(col+outerStep)+row+innerStep);
+            buffer = createIndexBuffer<unsigned short>(flags, verts, Ogre::HardwareIndexBuffer::IT_16BIT);
 
-                for (size_t i = 0; i < outerStep; i += innerStep)
-                {
-                    // Make sure not to touch the left or right edges
-                    if (col+i == 0 || col+i == verts-1-innerStep)
-                        continue;
-                    indices.push_back(verts*(col)+row);
-                    indices.push_back(verts*(col+i+innerStep)+row+innerStep);
-                    indices.push_back(verts*(col+i)+row+innerStep);
-                }
-            }
-
-            // North
-            row = verts-1;
-            outerStep = size_t(1) << (lodDeltas[North] + lodLevel);
-            for (size_t col = 0; col < verts-1; col += outerStep)
-            {
-                indices.push_back(verts*(col+outerStep)+row);
-                indices.push_back(verts*col+row);
-                // Make sure not to touch the left edge
-                if (col == 0)
-                    indices.push_back(verts*(col+innerStep)+row-innerStep);
-                else
-                    indices.push_back(verts*col+row-innerStep);
-
-                for (size_t i = 0; i < outerStep; i += innerStep)
-                {
-                    // Make sure not to touch the left or right edges
-                    if (col+i == 0 || col+i == verts-1-innerStep)
-                        continue;
-                    indices.push_back(verts*(col+i)+row-innerStep);
-                    indices.push_back(verts*(col+i+innerStep)+row-innerStep);
-                    indices.push_back(verts*(col+outerStep)+row);
-                }
-            }
-
-            // West
-            size_t col = 0;
-            outerStep = size_t(1) << (lodDeltas[West] + lodLevel);
-            for (size_t row = 0; row < verts-1; row += outerStep)
-            {
-                indices.push_back(verts*col+row+outerStep);
-                indices.push_back(verts*col+row);
-                // Make sure not to touch the top edge
-                if (row+outerStep == verts-1)
-                    indices.push_back(verts*(col+innerStep)+row+outerStep-innerStep);
-                else
-                    indices.push_back(verts*(col+innerStep)+row+outerStep);
-
-                for (size_t i = 0; i < outerStep; i += innerStep)
-                {
-                    // Make sure not to touch the top or bottom edges
-                    if (row+i == 0 || row+i == verts-1-innerStep)
-                        continue;
-                    indices.push_back(verts*col+row);
-                    indices.push_back(verts*(col+innerStep)+row+i);
-                    indices.push_back(verts*(col+innerStep)+row+i+innerStep);
-                }
-            }
-
-            // East
-            col = verts-1;
-            outerStep = size_t(1) << (lodDeltas[East] + lodLevel);
-            for (size_t row = 0; row < verts-1; row += outerStep)
-            {
-                indices.push_back(verts*col+row);
-                indices.push_back(verts*col+row+outerStep);
-                // Make sure not to touch the bottom edge
-                if (row == 0)
-                    indices.push_back(verts*(col-innerStep)+row+innerStep);
-                else
-                    indices.push_back(verts*(col-innerStep)+row);
-
-                for (size_t i = 0; i < outerStep; i += innerStep)
-                {
-                    // Make sure not to touch the top or bottom edges
-                    if (row+i == 0 || row+i == verts-1-innerStep)
-                        continue;
-                    indices.push_back(verts*col+row+outerStep);
-                    indices.push_back(verts*(col-innerStep)+row+i+innerStep);
-                    indices.push_back(verts*(col-innerStep)+row+i);
-                }
-            }
-        }
-
-        Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
-        Ogre::HardwareIndexBufferSharedPtr buffer = mgr->createIndexBuffer(Ogre::HardwareIndexBuffer::IT_16BIT,
-                                                                           indices.size(), Ogre::HardwareBuffer::HBU_STATIC);
-        buffer->writeData(0, buffer->getSizeInBytes(), &indices[0], true);
         mIndexBufferMap[flags] = buffer;
         return buffer;
     }