Functions | |
void | Rotate_Texture (double theta, double phi, double psi) |
Moves the represented texture about its U-, V-, or W-axis. More... | |
Detailed Description
Function Documentation
◆ Rotate_Texture()
void Rotate_Texture | ( | double | theta, |
double | phi, | ||
double | psi | ||
) |
Moves the represented texture about its U-, V-, or W-axis.
- Parameters
-
theta - Angle, in degrees, to rotate about the U-axis. phi - Angle to rotate about the V-axis. psi - Angle to rotate about the W-axis.
DETAILS
Rotate_Texture() modifies a segment's "texture matrix" attribute (see Set_Texture_Matrix() ) that is applied to the (u, v, w) vertex parameters of shells and meshes. In order to give the appearance that a texture is being rotated, the vertex parameters (which don't change their geometric locations) are transformed by the opposite rotation (the matrix adjoint).
If more than one degree of rotation is requested, the effect is of theta being performed first, then phi, then psi.
All rotations in HOOPS, no matter whether "texture" or "object", are performed by default using a left-hand rule. A positive rotation is represented by the direction curved fingers of the left hand are pointing when the thumb points in the positive direction along the axis in question, i.e., counter-clockwise. A negative rotation angle goes the other way. This definition can be reversed with the "Handedness" attribute.
The mathematical transform that is supplied to Append_Texture_Matrix() is

NOTES
The system doesn't actually labor over a general concatenation of all those matrices.