I also plan to implement some terrain and volumetric rendering functions. If you have every played Mine Craft you have experienced marching cubes in a game, for instance when you dig under ground, the terrain is actually volumetric.
terrain_create(pixelerror, tilesize);
terrain_set_position(id, x, y);
terrain_set_automatic_draw(id, auto);
terrain_set_material(id, mat);
terrain_paint_heights(brush);
terrain_paint_texture(texture);
terrain_get_height(id, x, y);
terrain_draw(id, x, y);
Post any suggestions you may have