Terrain: decoupled Chunk from QuadTreeNode.
scrawl
11 years ago
parent
2a4e99c069
commit
97c3efb3ba
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#include "buffercache.hpp"
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#include <OgreHardwareBufferManager.h>
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#include "defs.hpp"
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namespace Terrain
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{
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Ogre::HardwareVertexBufferSharedPtr BufferCache::getUVBuffer()
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{
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if (mUvBufferMap.find(mNumVerts) != mUvBufferMap.end())
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{
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return mUvBufferMap[mNumVerts];
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}
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int vertexCount = mNumVerts * mNumVerts;
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std::vector<float> uvs;
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uvs.reserve(vertexCount*2);
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for (unsigned int col = 0; col < mNumVerts; ++col)
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{
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for (unsigned int row = 0; row < mNumVerts; ++row)
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{
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uvs.push_back(col / static_cast<float>(mNumVerts-1)); // U
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uvs.push_back(row / static_cast<float>(mNumVerts-1)); // V
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}
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}
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Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
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Ogre::HardwareVertexBufferSharedPtr buffer = mgr->createVertexBuffer(
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Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT2),
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vertexCount, Ogre::HardwareBuffer::HBU_STATIC);
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buffer->writeData(0, buffer->getSizeInBytes(), &uvs[0], true);
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mUvBufferMap[mNumVerts] = buffer;
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return buffer;
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}
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Ogre::HardwareIndexBufferSharedPtr BufferCache::getIndexBuffer(int flags)
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{
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unsigned int verts = mNumVerts;
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if (mIndexBufferMap.find(flags) != mIndexBufferMap.end())
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{
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return mIndexBufferMap[flags];
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}
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// LOD level n means every 2^n-th vertex is kept
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size_t lodLevel = (flags >> (4*4));
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size_t lodDeltas[4];
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for (int i=0; i<4; ++i)
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lodDeltas[i] = (flags >> (4*i)) & (0xf);
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bool anyDeltas = (lodDeltas[North] || lodDeltas[South] || lodDeltas[West] || lodDeltas[East]);
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size_t increment = 1 << lodLevel;
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assert(increment < verts);
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std::vector<short> indices;
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indices.reserve((verts-1)*(verts-1)*2*3 / increment);
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size_t rowStart = 0, colStart = 0, rowEnd = verts-1, colEnd = verts-1;
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// If any edge needs stitching we'll skip all edges at this point,
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// mainly because stitching one edge would have an effect on corners and on the adjacent edges
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if (anyDeltas)
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{
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colStart += increment;
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colEnd -= increment;
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rowEnd -= increment;
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rowStart += increment;
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}
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for (size_t row = rowStart; row < rowEnd; row += increment)
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{
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for (size_t col = colStart; col < colEnd; col += increment)
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{
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indices.push_back(verts*col+row);
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indices.push_back(verts*(col+increment)+row+increment);
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indices.push_back(verts*col+row+increment);
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indices.push_back(verts*col+row);
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indices.push_back(verts*(col+increment)+row);
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indices.push_back(verts*(col+increment)+row+increment);
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}
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}
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size_t innerStep = increment;
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if (anyDeltas)
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{
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// Now configure LOD transitions at the edges - this is pretty tedious,
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// and some very long and boring code, but it works great
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// South
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size_t row = 0;
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size_t outerStep = 1 << (lodDeltas[South] + lodLevel);
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for (size_t col = 0; col < verts-1; col += outerStep)
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{
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indices.push_back(verts*col+row);
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indices.push_back(verts*(col+outerStep)+row);
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// Make sure not to touch the right edge
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if (col+outerStep == verts-1)
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indices.push_back(verts*(col+outerStep-innerStep)+row+innerStep);
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else
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indices.push_back(verts*(col+outerStep)+row+innerStep);
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for (size_t i = 0; i < outerStep; i += innerStep)
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{
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// Make sure not to touch the left or right edges
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if (col+i == 0 || col+i == verts-1-innerStep)
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continue;
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indices.push_back(verts*(col)+row);
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indices.push_back(verts*(col+i+innerStep)+row+innerStep);
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indices.push_back(verts*(col+i)+row+innerStep);
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}
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}
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// North
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row = verts-1;
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outerStep = 1 << (lodDeltas[North] + lodLevel);
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for (size_t col = 0; col < verts-1; col += outerStep)
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{
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indices.push_back(verts*(col+outerStep)+row);
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indices.push_back(verts*col+row);
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// Make sure not to touch the left edge
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if (col == 0)
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indices.push_back(verts*(col+innerStep)+row-innerStep);
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else
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indices.push_back(verts*col+row-innerStep);
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for (size_t i = 0; i < outerStep; i += innerStep)
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{
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// Make sure not to touch the left or right edges
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if (col+i == 0 || col+i == verts-1-innerStep)
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continue;
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indices.push_back(verts*(col+i)+row-innerStep);
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indices.push_back(verts*(col+i+innerStep)+row-innerStep);
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indices.push_back(verts*(col+outerStep)+row);
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}
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}
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// West
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size_t col = 0;
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outerStep = 1 << (lodDeltas[West] + lodLevel);
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for (size_t row = 0; row < verts-1; row += outerStep)
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{
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indices.push_back(verts*col+row+outerStep);
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indices.push_back(verts*col+row);
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// Make sure not to touch the top edge
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if (row+outerStep == verts-1)
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indices.push_back(verts*(col+innerStep)+row+outerStep-innerStep);
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else
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indices.push_back(verts*(col+innerStep)+row+outerStep);
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for (size_t i = 0; i < outerStep; i += innerStep)
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{
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// Make sure not to touch the top or bottom edges
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if (row+i == 0 || row+i == verts-1-innerStep)
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continue;
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indices.push_back(verts*col+row);
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indices.push_back(verts*(col+innerStep)+row+i);
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indices.push_back(verts*(col+innerStep)+row+i+innerStep);
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}
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}
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// East
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col = verts-1;
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outerStep = 1 << (lodDeltas[East] + lodLevel);
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for (size_t row = 0; row < verts-1; row += outerStep)
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{
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indices.push_back(verts*col+row);
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indices.push_back(verts*col+row+outerStep);
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// Make sure not to touch the bottom edge
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if (row == 0)
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indices.push_back(verts*(col-innerStep)+row+innerStep);
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else
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indices.push_back(verts*(col-innerStep)+row);
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for (size_t i = 0; i < outerStep; i += innerStep)
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{
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// Make sure not to touch the top or bottom edges
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if (row+i == 0 || row+i == verts-1-innerStep)
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continue;
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indices.push_back(verts*col+row+outerStep);
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indices.push_back(verts*(col-innerStep)+row+i+innerStep);
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indices.push_back(verts*(col-innerStep)+row+i);
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}
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}
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}
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Ogre::HardwareBufferManager* mgr = Ogre::HardwareBufferManager::getSingletonPtr();
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Ogre::HardwareIndexBufferSharedPtr buffer = mgr->createIndexBuffer(Ogre::HardwareIndexBuffer::IT_16BIT,
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indices.size(), Ogre::HardwareBuffer::HBU_STATIC);
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buffer->writeData(0, buffer->getSizeInBytes(), &indices[0], true);
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mIndexBufferMap[flags] = buffer;
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return buffer;
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}
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}
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@ -0,0 +1,36 @@
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#ifndef COMPONENTS_TERRAIN_BUFFERCACHE_H
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#define COMPONENTS_TERRAIN_BUFFERCACHE_H
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#include <OgreHardwareIndexBuffer.h>
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#include <OgreHardwareVertexBuffer.h>
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#include <map>
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namespace Terrain
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{
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/// @brief Implements creation and caching of vertex buffers for terrain chunks.
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class BufferCache
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{
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public:
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BufferCache(unsigned int numVerts) : mNumVerts(numVerts) {}
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/// @param flags first 4*4 bits are LOD deltas on each edge, respectively (4 bits each)
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/// next 4 bits are LOD level of the index buffer (LOD 0 = don't omit any vertices)
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Ogre::HardwareIndexBufferSharedPtr getIndexBuffer (int flags);
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Ogre::HardwareVertexBufferSharedPtr getUVBuffer ();
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private:
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// Index buffers are shared across terrain batches where possible. There is one index buffer for each
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// combination of LOD deltas and index buffer LOD we may need.
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std::map<int, Ogre::HardwareIndexBufferSharedPtr> mIndexBufferMap;
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std::map<int, Ogre::HardwareVertexBufferSharedPtr> mUvBufferMap;
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unsigned int mNumVerts;
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};
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}
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#endif
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