glespiral(3gle) [debian man page]

gleSpiral(3GLE) 							GLE							   gleSpiral(3GLE)

NAME

       gleSpiral - Sweep an arbitrary contour along a helical path.

SYNTAX

       void gleSpiral (int ncp,
		       gleDouble contour[][2],
		       gleDouble cont_normal[][2],
		       gleDouble up[3],
		       gleDouble startRadius,	  /* spiral starts in x-y plane */
		       gleDouble drdTheta,	  /* change in radius per revolution */
		       gleDouble startZ,	  /* starting z value */
		       gleDouble dzdTheta,	  /* change in Z per revolution */
		       gleDouble startXform[2][3], /* starting contour affine xform */
		       gleDouble dXformdTheta[2][3], /* tangent change xform per revoln */
		       gleDouble startTheta,	  /* start angle in x-y plane */
		       gleDouble sweepTheta);	  /* degrees to spiral around */

ARGUMENTS

       ncp	 number of contour points

       contour	 2D contour

       cont_normal
		 2D contour normals

       up	 up vector for contour

       startRadius
		 spiral starts in x-y plane

       drdTheta  change in radius per revolution

       startZ	 starting z value

       dzdTheta  change in Z per revolution

       startXform
		 starting contour affine transformation

       dXformdTheta
		 tangent change xform per revolution

       startTheta
		 start angle in x-y plane

       sweepTheta
		 degrees to spiral around

DESCRIPTION

       Sweep an arbitrary contour along a helical path.

       The axis of the helix lies along the modeling coordinate z-axis.

       An affine transform can be applied as the contour is swept. For most ordinary usage, the affines should be given as NULL.

       The "startXform[][]" is an affine matrix applied to the contour to deform the contour. Thus, "startXform" of the form

	    |  cos     sin    0   |
	    |  -sin    cos    0   |

       will rotate the contour (in the plane of the contour), while

	    |  1    0	 tx   |
	    |  0    1	 ty   |

       will translate the contour, and

	    |  sx    0	  0   |
	    |  0    sy	  0   |

       scales along the two axes of the contour. In particular, note that

	    |  1    0	 0   |
	    |  0    1	 0   |

       is the identity matrix.

       The  "dXformdTheta[][]"	is  a  differential  affine matrix that is integrated while the contour is extruded.  Note that this affine matrix
       lives in the tangent space, and so it should have the form of a generator.  Thus, dx/dt's of the form

	    |  0     r	  0   |
	    |  -r    0	  0   |

       rotate the the contour as it is extruded (r == 0 implies no rotation, r == 2*PI implies that the contour is rotated once, etc.), while

	    |  0    0	 tx   |
	    |  0    0	 ty   |

       translates the contour, and

	    |  sx    0	  0   |
	    |  0    sy	  0   |

       scales it. In particular, note that

	    |  0    0	 0   |
	    |  0    0	 0   |

       is the identity matrix -- i.e. the derivatives are zero, and therefore the integral is a constant.

SEE ALSO

       gleLathe

AUTHOR

       Linas Vepstas (linas@linas.org)

GLE
									3.0							   gleSpiral(3GLE)

Check Out this Related Man Page

gleSuperExtrusion(3GLE) 						GLE						   gleSuperExtrusion(3GLE)

NAME

       gleSuperExtrusion - Extrude arbitrary 2D contour along arbitrary 3D path, specifying local affine transformations.

SYNTAX

       void gleSuperExtrusion (int ncp,
		       gleDouble contour[][2],
		       gleDouble cont_normal[][2],
		       gleDouble up[3],
		       int npoints,
		       gleDouble point_array[][3],
		       float color_array[][3],
		 gleDouble xform_array[][2][3]);

ARGUMENTS

       ncp	 number of contour points

       contour	 2D contour

       cont_normal
		 2D contour normals

       up	 up vector for contour

       npoints	 numpoints in poly-line

       point_array
		 polyline vertices

       color_array
		 colors at polyline verts

       xform_array
		 2D contour affine transforms

DESCRIPTION

       Extrude	arbitrary 2D contour along arbitrary 3D path, specifying local affine transformations. As the contour is extruded, the affine will
       be applied to the points in the contour.

       The argument "contour" specifies the 2D contour to be extruded, while the argument "point_array" specifies the path along which to extrude.
       The vector "up" defines the orientation of the contour y-axis in real 3D space.

       Note  that  neither the very first segment, nor the very last segment are drawn. The first and last segments serve only to define the angle
       of the join at the very ends of the polyline. Thus, to draw one segment, three must be specified. To draw two segments, four must be speci-
       fied, etc.

       The normal array may be NULL. If it is, normal vectors will NOT be automatically generated, and the object will look terrible when lit.

       The  color array may be NULL. If NULL, the current color is used. If not NULL, the glColor3f() routine is used to set the color; therefore,
       specifying the glColorMaterial() subroutine before this primitive can be used to set diffuse, specular, ambient, etc. colors.

SEE ALSO

       gleExtrusion, gleTwistExtrusion

AUTHOR

       Linas Vepstas (linas@linas.org)

GLE
									3.0						   gleSuperExtrusion(3GLE)

Linux and UNIX Man Pages

glespiral(3gle) [debian man page]

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