Triangle Fans - PRG MBOX User Manual

Triangle Fans

Triangle Fan screen objects are similar to triangle strip objects in that they can create a more complex shape by creating
vertices from the original screen object, and then combining triangles to make the final result. But with triangle fans the
ordering of the vertices is different and every triangle shares the first vertex in the list. In other words, the origin is used
as one point in every triangle. The same screen object from the previous illustrations above becomes more complex
when converted into a triangle fan, requiring six vertices. Instead of being only two triangles, the object is now four
triangles. Each triangle is made up of the first vertex and two other adjacent vertices.
+ Triangle 1 is built from the 1st, 2nd, and 3rd vertices.
+ Triangle 2 is built from the 1st, 3rd, and 4th vertices.
+ Triangle 3 is built from the 1st, 4th, and 5th vertices.
+ Triangle 4 is built from the 1st, 5th, and 6th vertices.
In this manner it is possible to make an object with radial symmetry, and with enough vertices to create a smooth curve,
or to create an arc or circle.
MBOX® USER MANUAL
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