2d triangle-mesh optimization

[miko]

i've got a plenty of 2d-triangles (non-overlapping, together filling possibly non-convex and non-continuos 2d-area). i need to reduce their number. the area must remain exactly same. is there any lovely alghoritm for this ? (often i have 20 tris for a simple square and that's a bit stupid i think )

[ZbuffeR]

It doesn't sound too hard to me :

1) find the vertices and edges that are on the contour (check if an edge is shared by to triangles : not the silhouette)

2) for each polygon found in 1), split it in several convex polygons (angle between 2 successive edges must be positive for ex)

3) rebuild triangles for each convex polygon, from each contour edge and the first vertex.

Only 2) seem a bit tricky to me. But I do not have to implement this, so it's much easier

Good luck !