Don't mind the mess!
We're currently in the process of migrating the Panda3D Manual to a new service. This is a temporary layout in the meantime.
In general, you do this by first creating a GeomPrimitive of the appropriate type, and then calling addVertex() for each vertex in your primitive, followed by closePrimitive() after each primitive is complete.
Different GeomPrimitive types have different requirements for the number of vertices per primitive. Some always have a fixed amount of vertices, like GeomTriangles, GeomLines and GeomPoints. You should simply add all of the vertices for these primitives. Some people call close_primitive after adding every primitive, but this is not strictly necessary. Other GeomPrimitive types have a variable number of vertices, like GeomTristrips, GeomTrifans and GeomLinestrips. Because you need to tell Panda3D how many vertices are in every primitive, you should call close_primitive() after adding every primitive.
prim = GeomTriangles(Geom.UHStatic) prim.addVertex(0) prim.addVertex(1) prim.addVertex(2) # thats the first triangle # you can also add a few at once prim.addVertices(2, 1, 3) prim.addVertices(0, 5, 6)
Note that the GeomPrimitive constructor requires one parameter, which
is a usage hint, similar to the usage hint required for the
GeomVertexData constructor. Like that usage hint, this tells Panda
whether you will frequently adjust the vertex indices on this
primitive after it has been created. Since it is very unusual to
adjust the vertex indices on a primitive (usually, if you intend to
animate the vertices, you would operate on the vertices, not these
indices), this is almost always
Geom.UH_static, even if the primitive
is associated with a dynamic GeomVertexData. However, there may be
special rendering effects in which you actually do manipulate this
vertex index table in-place every few frames, in which case you should use
Geom.UHDynamic. As with the GeomVertexData, this is only a
performance hint; you're not required to adhere to the usage you
If you are unsure about this parameter, you should use
The above sample code defines a GeomTriangles object that looks like this:
The actual positions of the vertices depends on the values of the vertices numbered 0, 1, 2, 3, and 5 in the associated GeomVertexData (you will associate your GeomPrimitives with a GeomVertexData in the next step, when you attach the GeomPrimitives to a Geom).
Finally, there are a few handy shortcuts for adding multiple vertices at once:
add_vertices(v1, v2) add_vertices(v1, v2, v3) add_vertices(v1, v2, v3, v4)
|Adds 2, 3, or 4 vertices in a single call.|
|Adds numVertices consecutive vertices, beginning at vertex start. For instance, add_consecutive_vertices(5, 3) adds vertices 5, 6, 7.|
|Adds numVertices consecutive vertices, beginning with the next vertex after the last vertex you added, or beginning at vertex 0 if these are the first vertices. For instance, |
None of the above shortcut methods calls
close_primitive() for you; it is still your responsibility to call
close_primitive() each time you add the appropriate number of vertices.