public void SetCustomParameter(int index, Axiom.MathLib.Vector4 val)
{
throw new NotImplementedException();
}
public override void ApplyObliqueDepthProjection(ref Axiom.MathLib.Matrix4 projMatrix, Axiom.MathLib.Plane plane, bool forGpuProgram)
{
// Thanks to Eric Lenyel for posting this calculation at www.terathon.com
// Calculate the clip-space corner point opposite the clipping plane
// as (sgn(clipPlane.x), sgn(clipPlane.y), 1, 1) and
// transform it into camera space by multiplying it
// by the inverse of the projection matrix
/* generalised version
Vector4 q = matrix.inverse() *
Vector4(Math::Sign(plane.normal.x), Math::Sign(plane.normal.y), 1.0f, 1.0f);
*/
Axiom.MathLib.Vector4 q = new Axiom.MathLib.Vector4();
q.x = Math.Sign(plane.Normal.x) / projMatrix.m00;
q.y = Math.Sign(plane.Normal.y) / projMatrix.m11;
q.z = 1.0f;
// flip the next bit from Lengyel since we're right-handed
if (forGpuProgram) {
q.w = (1.0f - projMatrix.m22) / projMatrix.m23;
}
else {
q.w = (1.0f + projMatrix.m22) / projMatrix.m23;
}
// Calculate the scaled plane vector
Axiom.MathLib.Vector4 clipPlane4d =
new Axiom.MathLib.Vector4(plane.Normal.x, plane.Normal.y, plane.Normal.z, plane.D);
Axiom.MathLib.Vector4 c = clipPlane4d * (1.0f / (clipPlane4d.Dot(q)));
// Replace the third row of the projection matrix
projMatrix.m20 = c.x;
projMatrix.m21 = c.y;
// flip the next bit from Lengyel since we're right-handed
if (forGpuProgram) {
projMatrix.m22 = c.z;
}
else {
projMatrix.m22 = -c.z;
}
projMatrix.m23 = c.w;
}
