sampotter
commented
4 years ago This wrapper attempts to mimic the Embree C API closely. So, if you want to figure out how to do something, my goal is for a user to be able to consult the Embree API first.
That said, this wrapper is in a prototype stage and hasn't been used or tested thoroughly yet.
Here's some code that I'm using currently for raytracing, somewhat out of context:
device = embree.Device()
geometry = device.make_geometry(embree.GeometryType.Triangle)
scene = device.make_scene()
vertex_buffer = geometry.set_new_buffer(
embree.BufferType.Vertex, # buf_type
0, # slot
embree.Format.Float3, # fmt
3*np.dtype('float32').itemsize, # byte_stride
V.shape[0], # item_count
)
vertex_buffer[:] = V[:]
index_buffer = geometry.set_new_buffer(
embree.BufferType.Index, # buf_type
0, # slot
embree.Format.Uint3, # fmt
3*np.dtype('uint32').itemsize, # byte_stride,
F.shape[0]
)
index_buffer[:] = F[:]
geometry.commit()
geom_id = scene.attach_geometry(geometry)
geometry.release()
scene.commit()
n0, p0 = N[i0], P[i0]
dP = P - p0
mask = np.logical_and(dP@n0 >= 0, np.sum(dP*N, axis=1) <= 0)
P_mask = P[mask]
M = sum(mask)
rayhit = embree.RayHit1M(M)
rayhit.tnear[:] = 0
rayhit.tfar[:] = np.inf
rayhit.prim_id[:] = embree.INVALID_GEOMETRY_ID
rayhit.geom_id[:] = embree.INVALID_GEOMETRY_ID
rayhit.org[:] = p0 + eps*n0
rayhit.dir[:] = P_mask - p0
context = embree.IntersectContext()
scene.intersect1M(context, rayhit)
H = np.zeros((P.shape[0],), dtype=bool)
I_mask = np.where(mask)[0]
H[I_mask] = rayhit.prim_id == I_maskIn this example, I'm shooting some rays from perturbed triangle centroids to other triangles and seeing which rays actually hit their target triangles. In this case, I've loaded an OBJ using another Python library (doesn't really matter which), and then used Embree's API to tell it about the mesh's vertices and faces.
If you aren't familiar with Embree, if you consult the Embree API, you'll find that the code above matches what is done in Embree's provided examples.
Please let me know if you run into any trouble, and feel free to post code and mesh files here.
Please note: the entire API isn't wrapped yet, but should be very easy to wrap more functions. If a function from the Embree API that you need is missing, please say so. You can check embree.pyx to see if a function has been wrapped.
ttsesm
aluo-x
adamgranthendry
adam-grant-hendry
@sampotter I would like to use the embree lib for raycasting since it provides a nice accelerated solution. However, I am not quite sure how to use your wrapper. Would be possible to write a small example showing some use case. For example considering that someone has the indices and faces of a mesh object in numpy arrays how to create the corresponding mesh in embree by using this wrapper?