protected new void FillArrays(out HeightMapTerrainShader.Vertex[] vertices, out int[] indices)
{
// Create the vertex array.
vertices = new HeightMapTerrainShader.Vertex[VertexCount];
// Create the index array.
indices = new int[IndexCount];
var index = 0;
for (var j = 0; j < TerrainHeight - 1; j++)
{
for (var i = 0; i < TerrainWidth - 1; i++)
{
var indexBottomLeft = TerrainHeight * j + i;
var indexBottomRight = TerrainHeight * j + (i + 1);
var indexUpperLeft = TerrainHeight * (j + 1) + i;
var indexUpperRight = TerrainHeight * (j + 1) + (i + 1);
#region First Triangle
// Upper left
vertices[index] = HeightMap[indexUpperLeft];
indices[index] = index++;
// Upper right
vertices[index] = HeightMap[indexUpperRight];
indices[index] = index++;
// Bottom Left
vertices[index] = HeightMap[indexBottomLeft];
indices[index] = index++;
#endregion
#region Second Triangle
// Bottom Left
vertices[index] = HeightMap[indexBottomLeft];
indices[index] = index++;
// Upper right
vertices[index] = HeightMap[indexUpperRight];
indices[index] = index++;
// Bottom right
vertices[index] = HeightMap[indexBottomRight];
indices[index] = index++;
#endregion
}
}
}
private Node?CreateTreeNode(Device device, float positionX, float positionZ, float width)
{
var node = new Node();
// Store the node position and size.
node.PositionX = positionX;
node.PositionZ = positionZ;
node.Width = width;
// Initialize the triangle count to zero for the node.
node.TriangleCount = 0;
// Initialize the vertex and index buffers
node.VertexBuffer = null;
node.IndexBuffer = null;
// Initialize the nodes
node.Nodes = new Node?[4];
// Count the number of the triangle that are inside this node.
var numTriangles = CountTriangles(positionX, positionZ, width);
// Case 1: If there are no triangles in this node then return as it is empty and requires no processing.
if (numTriangles == 0)
{
return(null);
}
// Case 2: If there are too many triangles in this node then split it into four equal sized smaller tree nodes.
if (numTriangles > MaxTriangles)
{
for (int i = 0; i < 4; i++)
{
// Calculate the position offsets for the new child node.
var offsetX = (((i % 2) < 1) ? -1 : 1) * (width / 4);
var offsetZ = (((i % 4) < 2) ? -1 : 1) * (width / 4);
// See if there are triangles in the new node.
var count = CountTriangles((positionX + offsetX), (positionZ + offsetZ), width / 2);
if (count > 0)
{
// If there are triangles inside where this node would be then create the child node.
// Extend the tree starting from this child node now.
node.Nodes[i] = CreateTreeNode(device, (positionX + offsetX), (positionZ + offsetZ), width / 2);
}
}
}
// Case 3: If this node is not empty and the triangle count for it is less than the max then
// this node is at the bottom of the tree so create the list of triangles to store in it.
node.TriangleCount = numTriangles;
// Calculate the number of vertices
var vertexCount = numTriangles * 3;
// Create the vertex array
var vertices = new HeightMapTerrainShader.Vertex[vertexCount];
// Create the index array
var indices = new int[vertexCount];
// Create the vertex array
node.VertexArray = new Vector3[vertexCount];
// Initialize the index for this new vertex and index array.
var index = 0;
// Go through all the triangles in the vertex list.
for (int i = 0; i < TriangleCount; i++)
{
// If the triangle is inside this node then add it to the vertex array.
var result = IsTriangleContained(i, positionX, positionZ, width);
if (result)
{
// Calculate the index into the terrain vertex list
var vertexIndex = i * 3;
// Get the three vertices of this triangle from the vertex list
vertices[index] = VertexList[vertexIndex];
indices[index] = index;
node.VertexArray[index] = VertexList[vertexIndex].position;
index++;
vertexIndex++;
vertices[index] = VertexList[vertexIndex];
indices[index] = index;
node.VertexArray[index] = VertexList[vertexIndex].position;
index++;
vertexIndex++;
vertices[index] = VertexList[vertexIndex];
indices[index] = index;
node.VertexArray[index] = VertexList[vertexIndex].position;
index++;
}
}
// Create the vertex buffer.
node.VertexBuffer = Buffer.Create(device, BindFlags.VertexBuffer, vertices);
// Create the index buffer.
node.IndexBuffer = Buffer.Create(device, BindFlags.IndexBuffer, indices);
return(node);
}
protected void FillArrays()
{
// Create the vertex array.
Vertices = new HeightMapTerrainShader.Vertex[VertexCount];
// Create the index array.
Indices = new int[IndexCount];
var index = 0;
for (var j = 0; j < TerrainHeight - 1; j++)
{
for (var i = 0; i < TerrainWidth - 1; i++)
{
var indexBottomLeft = TerrainHeight * j + i;
var indexBottomRight = TerrainHeight * j + (i + 1);
var indexUpperLeft = TerrainHeight * (j + 1) + i;
var indexUpperRight = TerrainHeight * (j + 1) + (i + 1);
#region First Triangle
// Upper left
Vertices[index] = HeightMap[indexUpperLeft];
// Modify the texture coordinates to cover the top edge.
if (Vertices[index].texture.Y == 1.0f)
{
Vertices[index].texture.Y = 0.0f;
}
Indices[index] = index++;
// Upper right
Vertices[index] = HeightMap[indexUpperRight];
// Modify the texture coordinates to cover the top and right edges.
if (Vertices[index].texture.X == 0.0f)
{
Vertices[index].texture.X = 1.0f;
}
if (Vertices[index].texture.Y == 1.0f)
{
Vertices[index].texture.Y = 0.0f;
}
Indices[index] = index++;
// Bottom Left
Vertices[index] = HeightMap[indexBottomLeft];
Indices[index] = index++;
#endregion
#region Second Triangle
// Bottom Left
Vertices[index] = HeightMap[indexBottomLeft];
Indices[index] = index++;
// Upper right
Vertices[index] = HeightMap[indexUpperRight];
// Modify the texture coordinates to cover the top and right edges.
if (Vertices[index].texture.X == 0.0f)
{
Vertices[index].texture.X = 1.0f;
}
if (Vertices[index].texture.Y == 1.0f)
{
Vertices[index].texture.Y = 0.0f;
}
Indices[index] = index++;
// Bottom right
Vertices[index] = HeightMap[indexBottomRight];
// Modify the texture coordinates to cover the right edge.
if (Vertices[index].texture.X == 0.0f)
{
Vertices[index].texture.X = 1.0f;
}
Indices[index] = index++;
#endregion
}
}
}
