![]() ![]() So you would have to take only the nearest OBB ! Exercise left to the reader… Pros and cons ![]() But if this OBB is behind another OBB, this is wrong. Note that this algorithm has a problem : it picks the first OBB it finds. Our Ray - OBB intersection function will look like this :įor ( int i = 0 i < 100 i ++ ) ![]() #RAY BOX INTERSECTION CODE#(full source code is available in Misc05/misc05_picking_custom.cpp) This means that there is no intersection.īut if this order changes (you enter the green area -> you enter the red area), then you know there is an intersection ! Notice how the intersections are ordered : you enter the green area -> you leave the green area -> you enter the red area -> you leave the red area. When the ray intersects the 2 others planes that delimit the Y axis (in green), it gives 2 more intersections. When intersected with the ray (a very simple operation), it gives 2 intersections, one “near” and one “far” : On the X axis, this is delimited by 2 vertical planes, colored in red here. ( The algorithm and the pictures are largely inspired from Real-Time Rendering 3. There are quite precise (but it depends on your input geometry), and quite cheap to compute.Īn OBB is a box that fits the mesh, and when the mesh is translated or rotated, the same transformation is applied to the box : A good middleground are OBB : Oriented Bounding Boxes. On the other side, intersecting the ray with each triangle of the original mesh is way to costly. Spheres are very easy to intersect, but for many object, they represent the original mesh very poorly. Instead of relying to Bullet intersect a ray with a Collision Shape, we’re going to do this ourselves.Īs we have seen, there are many possible collision shapes. This tutorial uses concepts and functions from the Bullet tutorial, so make sure you read it first. This last method is a nice middleground between the “hacky” pure-OpenGL implementation, and having to integrate a fully-featured physics engine just to do raycasts and picking. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |