The TriangleArray

TriangleArrays provide the most basic of all graphics primitives - a collection of individual triangles. Triangles, unsurprisingly, are described by three vertices. As an array of values, the rendering will take each collection of 3 vertices from the array and render them as a triangle.

Construction

    int format = GeometryArray.COORDINATE |
                 GeometryArray.COLOR_3;

    TriangleArray tris = new TriangleArray(6, format);

Figure 9: A triangle array showing the vertex numbering for two triangles

    float[] vertices =
    {
        0,   0,  0,   // v1
        0,   2,  0,   // v2
        1,   5, -3,   // v3
        2,   0,  0,   // v4
        4,   1,  0,   // v5
        5,   5,  1,   // v6
    };

    tris.setCoordinates(0, vertices);

It's impossible to go wrong with triangles. There's only one way of arranging 3 vertices, unlike quads and polygons. However, like quads, there is a clear definition of what is the "front" of the triangle. Just as with quads, if you get the ordering incorrect, you will not be able to see the triangles from your current viewing position. The definition of the "front" of a triangle is the same as that for a quad. If you've forgotten, or not read the Quad intro page then the vertices must be ordered in an anti-clockwise order relative to your current viewing position to see that front face.