public void Render(DeviceContext deviceContext, Frustrum frustrum, TerrainShader terrainShader)
{
// Reset the number of the triangles that are drawn for this frame.
DrawCount = 0;
// Render each node that is visible at the parent node and moving down the tree.
RenderNode(deviceContext, ParentNode, frustrum, terrainShader);
}
private void RenderNode(DeviceContext deviceContext, QuadTreeNodeType node, Frustrum frustrum, TerrainShader terrainShader)
{
// Check to see if the node can be viewed, height doesn't matter in a quad tree.
// If it can't be seen then none of its children can either, so don't continue down the tree, this is where the speed is gained.
if (!frustrum.CheckCube(new SharpDX.Vector3(node.positionX, 0.0f, node.positionZ), (node.width / 2.0f))) // 63.7506409
{
return;
}
// If it can be seen then check all four child nodes to see if they can also be seen.
int count = 0;
for (int i = 0; i < 4; i++)
{ // parentNode.width > 0.0f && parentNode.Nodes[i].VertexBuffer != null
if (node.Nodes[i].width > 0.0f) //node.Nodes != null/ parentNode.Nodes[i].width > 0.0f
{
count++;
RenderNode(deviceContext, node.Nodes[i], frustrum, terrainShader);
}
}
// If there were any children nodes then there is no need to continue as parent nodes won't contain any triangles to render.
if (count != 0)
{
return;
}
int vertexCount = node.TriangleCount * 3;
// Otherwise if this node can be seen and has triangles in it then render these triangles.
// Set vertex buffer stride and offset.
// Set the vertex buffer to active in the input assembler so it can be rendered.
deviceContext.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(node.VertexBuffer, SharpDX.Utilities.SizeOf <PositionTextureNormalVertex>(), 0));
// Set the index buffer to active in the input assembler so it can be rendered.
deviceContext.InputAssembler.SetIndexBuffer(node.IndexBuffer, Format.R32_UInt, 0);
// Set the type of primitive that should be rendered from this vertex buffer, in this case triangles.
deviceContext.InputAssembler.PrimitiveTopology = PrimitiveTopology.TriangleList;
// Determine the number of indices in this node.
int indexCount = node.TriangleCount * 3;
// Call the terrain shader to render the polygons in this node.
terrainShader.RenderShader(deviceContext, indexCount);
// Increase the count of the number of polygons that have been rendered during this frame.
DrawCount += node.TriangleCount;
}