private VertexPositionNormalTangentBinormalTexture[] GenerateTerrainVertices()
{
float terrainWidth = (vertexCountX - 1) * blockScale;
float terrainDepth = (vertexCountZ - 1) * blockScale;
halfTerrainWidth = terrainWidth * 0.5f;
halfTerrainDepth = terrainDepth * 0.5f;
float tu = 0;
float tv = 0;
float tuDerivative = 1.0f / (vertexCountX - 1);
float tvDerivative = 1.0f / (vertexCountZ - 1);
VertexPositionNormalTangentBinormalTexture[] vertices = new VertexPositionNormalTangentBinormalTexture[numVertices];
int count = 0;
for (float i = -halfTerrainDepth; i <= halfTerrainDepth; i += blockScale)
{
tu = 0.0f;
for (float j = -halfTerrainWidth; j <= halfTerrainWidth; j += blockScale)
{
vertices[count].Position = new Vector3(j, heightMap[count].R * heightScale, i);
vertices[count].TextureCoordinate = new Vector2(tu, tv);
tu += tuDerivative;
count++;
}
tv += tvDerivative;
}
return vertices;
}
private void GenerateTerrainNormals(VertexPositionNormalTangentBinormalTexture[] vertices, uint[] indices)
{
for (uint i = 0; i < indices.Length; i += 3)
{
// Get the vertex position (v1, v2, and v3)
Vector3 v1 = vertices[indices[i]].Position;
Vector3 v2 = vertices[indices[i + 1]].Position;
Vector3 v3 = vertices[indices[i + 2]].Position;
// Calculate vectors v1->v3 and v1->v2 and the normal as a cross product
Vector3 vu = v3 - v1;
Vector3 vt = v2 - v1;
Vector3 normal = Vector3.Cross(vu, vt);
normal.Normalize();
vertices[indices[i]].Normal += normal;
vertices[indices[i + 1]].Normal += normal;
vertices[indices[i + 2]].Normal += normal;
}
for (int i = 0; i < vertices.Length; i++)
vertices[i].Normal.Normalize();
}
public void GenerateTerrainTangentBinormal(VertexPositionNormalTangentBinormalTexture[] vertices, uint[] indices)
{
for (uint i = 0; i < vertexCountZ; i++)
{
for (uint j = 0; j < vertexCountX; j++)
{
uint vertexIndex = j + i * vertexCountX;
Vector3 v1 = vertices[vertexIndex].Position;
if (j < vertexCountX - 1)
{
Vector3 v2 = vertices[vertexIndex + 1].Position;
vertices[vertexIndex].Tangent = (v2 - v1);
}
else
{
Vector3 v2 = vertices[vertexIndex - 1].Position;
vertices[vertexIndex].Tangent = (v1 - v2);
}
vertices[vertexIndex].Tangent.Normalize();
vertices[vertexIndex].Binormal = Vector3.Cross(
vertices[vertexIndex].Tangent, vertices[vertexIndex].Normal);
}
}
}
