Drawing on the 3D Reconstruction

[TotoLulu94]

Hi,

I would like to draw a 3D bounding box in the 3D reconstruction. And I don't really know how to do that.
For now, I have the (x,y,z) world coordinate for each corner of the bouding box. I was thinking about finding the corresponding voxel and assigning them a color. However, I don't really know how to proceed. do you have any Ideas/directions to achieve that ?
Thanks for any reply.

[sgolodetz]

The voxel reconstruction is rendered by using raycasting to produce an image of the scene and then drawing a quad textured with that image. By default, rendering the quad will then write the depth values for the quad (not the scene) into the depth buffer.

If you instead write the correct depth values for the reconstruction into the depth buffer, you can use e.g. OpenGL to simply draw a bounding box over the top of the reconstruction, with correct depth testing. To fill the depth buffer with the correct depth values, you can render a depth image of the scene (again, using raycasting), and then use e.g. a GLSL shader to write the depth values into the depth buffer. It will take a bit of work to do this (I thought about doing it once but never got round to it), but should work ok.

More simply, if you don't care about depth testing then you can just turn it off and draw the bounding box directly over the reconstruction using OpenGL - that will mean that bits of it that should be occluded by the scene aren't properly occluded, but that may not necessarily be important for your application.