private VertexData buildVertexData()
{
VertexData vertexData = new VertexData();
vertexData.vertexCount = numSamples * numSamples;
vertexData.vertexStart = 0;
// set up the vertex declaration
int vDecOffset = 0;
vertexData.vertexDeclaration.AddElement(0, vDecOffset, VertexElementType.Float3, VertexElementSemantic.Position);
vDecOffset += VertexElement.GetTypeSize(VertexElementType.Float3);
vertexData.vertexDeclaration.AddElement(0, vDecOffset, VertexElementType.Float3, VertexElementSemantic.Normal);
vDecOffset += VertexElement.GetTypeSize(VertexElementType.Float3);
vertexData.vertexDeclaration.AddElement(0, vDecOffset, VertexElementType.Float2, VertexElementSemantic.TexCoords);
vDecOffset += VertexElement.GetTypeSize(VertexElementType.Float2);
// create the hardware vertex buffer and set up the buffer binding
HardwareVertexBuffer hvBuffer = HardwareBufferManager.Instance.CreateVertexBuffer(
vertexData.vertexDeclaration.GetVertexSize(0), vertexData.vertexCount,
BufferUsage.StaticWriteOnly, false);
vertexData.vertexBufferBinding.SetBinding(0, hvBuffer);
// lock the vertex buffer
IntPtr ipBuf = hvBuffer.Lock(BufferLocking.Discard);
int bufferOff = 0;
unsafe
{
float *buffer = (float *)ipBuf.ToPointer();
int heightMapOffset = 0;
for (int zIndex = 0; zIndex < numSamples; zIndex++)
{
float z = (zIndex * metersPerSample * WorldManager.oneMeter);
for (int xIndex = 0; xIndex < numSamples; xIndex++)
{
float height = heightMap[heightMapOffset++];
// Position
float x = (xIndex * metersPerSample * WorldManager.oneMeter);
buffer[bufferOff++] = x;
buffer[bufferOff++] = height;
buffer[bufferOff++] = z;
// normals
// XXX - this can be optimized quite a bit
Vector3 norm = tile.GetNormalAt(new Vector3(x + tile.Location.x, height, z + tile.Location.z));
buffer[bufferOff++] = norm.x;
buffer[bufferOff++] = norm.y;
buffer[bufferOff++] = norm.z;
// Texture
// XXX - assumes one unit of texture space is one page.
// how does the vertex shader deal with texture coords?
buffer[bufferOff++] = (x + location.x - tile.Page.Location.x) /
(WorldManager.Instance.PageSize * WorldManager.oneMeter);
buffer[bufferOff++] = (z + location.z - tile.Page.Location.z) /
(WorldManager.Instance.PageSize * WorldManager.oneMeter);
}
}
}
hvBuffer.Unlock();
return(vertexData);
}
