triangulate-face ( face -- triangles )

Vocabulary

euler.b-rep.triangulation

Inputs

face

an object

Outputs

triangles

an object

Definition

USING: accessors alien.c-types alien.data alien.handles
destructors euler.b-rep.triangulation.private
game.models.half-edge grouping kernel libc opengl.glu sequences
;

IN: euler.b-rep.triangulation

:: triangulate-face ( face -- triangles )
    [
        face dup base-face>> eq?
        [ triangulated-face-must-be-base ] unless
        gluNewTess &gluDeleteTess :> tess
        V{ } clone :> vertices vertices <alien-handle-ptr>
        &release-alien-handle-ptr :> vertices-h tess
        GLU_TESS_BEGIN_DATA tess-begin gluTessCallback
        tess GLU_TESS_END_DATA tess-end gluTessCallback
        tess GLU_TESS_VERTEX_DATA tess-vertex gluTessCallback
        tess GLU_TESS_EDGE_FLAG_DATA tess-edge-flag
        gluTessCallback tess vertices-h gluTessBeginPolygon
        4 double malloc-array &free :> vertex-buf face [| ring |
            tess gluTessBeginContour ring edge>> [
                tess swap vertex>>
                [ position>> double >c-array ]
                [ <alien-handle-ptr> &release-alien-handle-ptr ]
                bi gluTessVertex
            ] each-face-edge tess gluTessEndContour
            ring next-ring>> dup
        ] loop drop tess gluTessEndPolygon vertices { } like
        3 <groups>
    ] with-destructors ;