Generate NURBS surface
A control matrix may specify the control points. The order of the curve may be specified for both the x and y axes (which are sometimes referred to as the u and v surface axes). The order of the curve must be less than the number of control points across the associated dimension. The default order is 3 (i.e., cubic).
At present, the knots sequence is automatically generated based a sum equal to the curve + number of control points. Control points may be non uniformly weighted if the control matrix has 4 planes (x, y, z, w) where w is the weight value. By default, the control matrix is a random 4x4 matrix of uniformly weighted points.
The jit.gl.nurbs object requires one argument: the name of a drawing context. A named drawing context is a named instance of a jit.window , jit.pwindow , or jit.matrix object that has an instance of the jit.gl.render object associated with it. This value may also be set via the OB3D drawto attribute.
ctlmatrix | matrix-name [symbol] |
Copies the named matrix to the control point matrix. Matrices must have a planecount of 3 or 4, and should be type or |
rand | Generates a random set of control points. |
Name | Type | g/s | Description |
---|---|---|---|
closed | int | The closed flag for each axis inf the form | (default = 0 0). If closed about an axis, the nurbs surface will knot to smoothly close the surface across that axis.|
ctlshow | int | Control point rendering flag (default = 0) When the flag is set, the control points are rendered. | |
dim | int | The dimensions of the grid (default = 20 20) | |
displaylist | int | Cache in displaylist flag (default = 0) This feature may be used to speed up rendering time by creating and storing a list of gl drawing commands on the graphics card. This will have no effect if matrixoutput turned on. | |
order | int | The interpolation order in the form | (default = 3 3). The minimum interpolation order is 1 1. The maximum order is set by the values (control; max = control matrix width-1 height-1)
Name | Description |
---|---|
jit.gl.graph | Open GL floating-point data visualization |
jit.gl.gridshape | Generate simple geometric shapes as a connected grid |
jit.gl.handle | Use mouse movement to control position/rotation |
jit.gl.isosurf | Generates a GL based surface extraction |
jit.gl.mesh | Generates GL geometry from existing data |
jit.gl.model | Read and draw Wavefront .obj models |
jit.gl.plato | Generate platonic solids |
jit.gl.render | Render Open GL |
jit.gl.shader | Manages a GL shader |
jit.gl.sketch | GL parallel to lcd |
jit.gl.slab | Performs a GL accelerated grid-based evaluation |
jit.gl.text2d | Write bitmap text |
jit.gl.text3d | Write vector text |
jit.gl.texture | Manages a GL texture |
jit.gl.videoplane | GL accelerated video plane |
jit.gl.volume | Creates a GL accelerated volume vizualization |