private void CalculateTangentBinormal(DTempVertex vertex1, DTempVertex vertex2, DTempVertex vertex3, out DVector tangent, out DVector binormal)
{
float[] vector1 = new float[3];
float[] vector2 = new float[3];
float[] tuVector = new float[2];
float[] tvVector = new float[2];
// Calculate the two vectors for this face.
vector1[0] = vertex2.x - vertex1.x;
vector1[1] = vertex2.y - vertex1.y;
vector1[2] = vertex2.z - vertex1.z;
vector2[0] = vertex3.x - vertex1.x;
vector2[1] = vertex3.y - vertex1.y;
vector2[2] = vertex3.z - vertex1.z;
// Calculate the tu and tv texture space vectors.
tuVector[0] = vertex2.tu - vertex1.tu;
tvVector[0] = vertex2.tv - vertex1.tv;
tuVector[1] = vertex3.tu - vertex1.tu;
tvVector[1] = vertex3.tv - vertex1.tv;
// Calculate the denominator of the tangent/binormal equation.
float den = 1.0f / (tuVector[0] * tvVector[1] - tuVector[1] * tvVector[0]);
// Calculate the cross products and multiply by the coefficient to get the tangent and binormal.
tangent.x = (tvVector[1] * vector1[0] - tvVector[0] * vector2[0]) * den;
tangent.y = (tvVector[1] * vector1[1] - tvVector[0] * vector2[1]) * den;
tangent.z = (tvVector[1] * vector1[2] - tvVector[0] * vector2[2]) * den;
binormal.x = (tuVector[0] * vector2[0] - tuVector[1] * vector1[0]) * den;
binormal.y = (tuVector[0] * vector2[1] - tuVector[1] * vector1[1]) * den;
binormal.z = (tuVector[0] * vector2[2] - tuVector[1] * vector1[2]) * den;
// Calculate the length of this normal.
float length = (float)Math.Sqrt((tangent.x * tangent.x) + (tangent.y * tangent.y) + (tangent.z * tangent.z));
// Normalize the normal and then store it
binormal.x = binormal.x / length;
binormal.y = binormal.y / length;
binormal.z = binormal.z / length;
}
private void CalculateTangentBinormal(DTempVertex vertex1, DTempVertex vertex2, DTempVertex vertex3, out DVector tangent, out DVector binormal)
{
// Calculate the two vectors for the this face.
float[] vector1 = new[] { vertex2.x - vertex1.x, vertex2.y - vertex1.y, vertex2.z - vertex1.z };
float[] vector2 = new[] { vertex3.x - vertex1.x, vertex3.y - vertex1.y, vertex3.z - vertex1.z };
// Calculate the tu and tv texture space vectors.
float[] tuVector = new[] { vertex2.tu - vertex1.tu, vertex3.tu - vertex1.tu };
float[] tvVector = new[] { vertex2.tv - vertex1.tv, vertex3.tv - vertex1.tv };
// Calculate the denominator of the tangent / binormal equation.
float den = 1.0f / (tuVector[0] * tvVector[1] - tuVector[1] * tvVector[0]);
// Calculate the cross products and multiply by the coefficient to get the tangent and binormal.
tangent.x = (tvVector[1] * vector1[0] - tvVector[0] * vector2[0]) * den;
tangent.y = (tvVector[1] * vector1[1] - tvVector[0] * vector2[1]) * den;
tangent.z = (tvVector[1] * vector1[2] - tvVector[0] * vector2[2]) * den;
binormal.x = (tuVector[0] * vector2[0] - tuVector[1] * vector1[0]) * den;
binormal.y = (tuVector[0] * vector2[1] - tuVector[1] * vector1[1]) * den;
binormal.z = (tuVector[0] * vector2[2] - tuVector[1] * vector1[2]) * den;
// Calculate the length of this Tengent normal.
float length = (float)Math.Sqrt(tangent.x * tangent.x + tangent.y * tangent.y + tangent.z * tangent.z);
// Normalize the normal and the store it.
tangent.x = tangent.x / length;
tangent.y = tangent.y / length;
tangent.z = tangent.z / length;
// Calculate the length of this Bi-Tangent normal.
length = (float)Math.Sqrt(binormal.x * binormal.x + binormal.y * binormal.y + binormal.z * binormal.z);
// Normalize the Bi-Tangent normal and the store it.
binormal.x = binormal.x / length;
binormal.y = binormal.y / length;
binormal.z = binormal.z / length;
}
