Axiom.Core.BillboardSet.CreateBuffers C# (CSharp) Method

		private void CreateBuffers()
		{
			/* Alloc positions   ( 1 or 4 verts per billboard, 3 components )
					 colours     ( 1 x RGBA per vertex )
					 indices     ( 6 per billboard ( 2 tris ) if not point rendering )
					 tex. coords ( 2D coords, 1 or 4 per billboard )
			*/

			//             LogManager.Instance.Write(string.Format("BillBoardSet.CreateBuffers entered; vertexData {0}, indexData {1}, mainBuffer {2}",
			//                     vertexData == null ? "null" : vertexData.ToString(),
			//                     indexData == null ? "null" : indexData.ToString(),
			//                     mainBuffer == null ? "null" : mainBuffer.ToString()));

			// Warn if user requested an invalid setup
			// Do it here so it only appears once
			if ( this.pointRendering && this.billboardType != BillboardType.Point )
			{
				LogManager.Instance.Write(
						"Warning: BillboardSet {0} has point rendering enabled but is using a type " +
						"other than BillboardType.Point, this may not give you the results you " +
						"expect.",
						this.name );
			}

			this.vertexData = new VertexData();
			if ( this.pointRendering )
			{
				this.vertexData.vertexCount = this.poolSize;
			}
			else
			{
				this.vertexData.vertexCount = this.poolSize * 4;
			}

			this.vertexData.vertexStart = 0;

			// Vertex declaration
			VertexDeclaration decl = this.vertexData.vertexDeclaration;
			VertexBufferBinding binding = this.vertexData.vertexBufferBinding;

			int offset = 0;
			decl.AddElement( 0, offset, VertexElementType.Float3, VertexElementSemantic.Position );
			offset += VertexElement.GetTypeSize( VertexElementType.Float3 );
			decl.AddElement( 0, offset, VertexElementType.Color, VertexElementSemantic.Diffuse );
			offset += VertexElement.GetTypeSize( VertexElementType.Color );
			// Texture coords irrelevant when enabled point rendering (generated
			// in point sprite mode, and unused in standard point mode)
			if ( !this.pointRendering )
			{
				decl.AddElement( 0, offset, VertexElementType.Float2, VertexElementSemantic.TexCoords, 0 );
			}

			this.mainBuffer =
					HardwareBufferManager.Instance.CreateVertexBuffer( decl.Clone( 0 ), this.vertexData.vertexCount, BufferUsage.DynamicWriteOnlyDiscardable );

			// bind position and diffuses
			binding.SetBinding( 0, this.mainBuffer );

			if ( !this.pointRendering )
			{
				this.indexData = new IndexData();

				// calc index buffer size
				this.indexData.indexStart = 0;
				this.indexData.indexCount = this.poolSize * 6;

				// create the index buffer
				this.indexData.indexBuffer =
						HardwareBufferManager.Instance.CreateIndexBuffer(
								IndexType.Size16,
								this.indexData.indexCount,
								BufferUsage.StaticWriteOnly );

				/* Create indexes (will be the same every frame)
				   Using indexes because it means 1/3 less vertex transforms (4 instead of 6)

				   Billboard layout relative to camera:

					0-----1
					|    /|
					|  /  |
					|/    |
					2-----3
				*/

				// lock the index buffer
				IntPtr idxPtr = this.indexData.indexBuffer.Lock( BufferLocking.Discard );

				unsafe
				{
					ushort* pIdx = (ushort*)idxPtr.ToPointer();

					for ( int idx, idxOffset, bboard = 0; bboard < this.poolSize; ++bboard )
					{
						// Do indexes
						idx = bboard * 6;
						idxOffset = bboard * 4;

						pIdx[ idx ] = (ushort)idxOffset; // + 0;, for clarity
						pIdx[ idx + 1 ] = (ushort)( idxOffset + 2 );
						pIdx[ idx + 2 ] = (ushort)( idxOffset + 1 );
						pIdx[ idx + 3 ] = (ushort)( idxOffset + 1 );
						pIdx[ idx + 4 ] = (ushort)( idxOffset + 2 );
						pIdx[ idx + 5 ] = (ushort)( idxOffset + 3 );
					} // for
				} // unsafe

				// unlock the buffers
				this.indexData.indexBuffer.Unlock();
			}
			this.buffersCreated = true;
		}