Reflection (Dr.Jit)

These rayd.drjit.Scene methods trace specular reflections. For a walkthrough, see Trace reflection paths.

Per-slot arrays hold ray_count * max_bounces entries, ray-major: slot r * max_bounces + b is bounce b of ray r. Unused slots have a primitive id of -1. Lengths are in scene units.

Scene.trace_reflections#

trace_reflections(ray, max_bounces, active=True, symbolic=True)
trace_reflections(ray, max_bounces, options: ReflectionTraceOptions, active=True, symbolic=True)
trace_reflections(ray, max_bounces, deduplicate=False, canonical_prim_table=[], image_source_tolerance=1e-5, active=True, symbolic=True)

Follows each ray through up to max_bounces specular reflections.

trace = scene.trace_reflections(ray, 2)
first = trace.bounce(0)
chain = scene.trace_reflections(ray, 2, symbolic=False)

ReflectionTraceOptions#

ReflectionTrace#

bounce(i) returns bounces[i]. is_valid() returns the per-ray mask of rays with at least one reflection.

ReflectionBounce#

One bounce for every ray: t (distance from the previous point), hit_points, geo_normals, image_sources (mirror image of the source across this reflector), plane_points, plane_normals, shape_ids, prim_ids, local_prim_ids, global_prim_ids. is_valid() is prim_ids >= 0.

ReflectionChain#

The flat layout. Per-ray fields: bounce_count, discovery_count, representative_ray_index, trailing_t (length of the segment after the last reflection), trailing_prim (primitive it hits), trailing_dir, trailing_origin. Per-slot fields: the ReflectionBounce fields. ray_count and max_bounces give the layout. ReflectionChain is also what SdfGrid, SurfelScene, and MixedScene return from trace_reflections.

Scene.trace_refl_epc#

trace_refl_epc(ray: Ray, receiver: Array3f, max_bounces: int, options: ReflEpcOptions | None = None, active: Bool = True) -> ReflEpc

Solves the exact specular path from each ray's origin to its receiver through the reflectors in options.expected_prim_ids (equivalent-path correction, EPC), then checks the visibility of every segment. No derivatives.

ReflEpcOptions#

ReflEpc#

Per ray: valid (a corrected path exists), bounce_count, path_length, first_blocked_segment, first_blocked_prim, first_blocked_group (-1 when clear). Per slot: reflection_points, plane_normals, prim_ids, trace_prim_ids (primitive actually hit while tracing), resolved_prim_ids (after surface-group resolution), surface_group_ids. Also ray_count, max_bounces.

Scene.trace_refl_epc_field#

trace_refl_epc_field(source, receiver, max_bounces: int, options: ReflEpcFieldOptions | ReflEpcFieldOptionsAD, active=True) -> ReflEpcField | ReflEpcFieldAD

Solves the EPC path and evaluates the complex electric field at the receiver.

Raises RuntimeError when a position source is given without expected_prim_ids of width n_rays * max_bounces.

ReflEpcFieldOptions#

All ReflEpcOptions fields, plus:

ReflEpcField#

Per ray: valid, bounce_count, path_length, and the field components field_x_re, field_x_im, field_y_re, field_y_im, field_z_re, field_z_im. Optional: tx_pos, first_hit, last_hit, and per-slot hit_points, normals, resolved_prim_ids, surface_group_ids. Also ray_count, max_bounces.

Scene.accumulate_reflections#

accumulate_reflections(
    ray, tx_position, grid: AccumGrid, material, max_bounces: int,
    options: AccumOptions = AccumOptions(), active=True,
    tx_polarization=(1.0, 0.0, 0.0),
) -> AccumResult | AccumResultAD

Launches ray from the transmitter, follows reflections, and sums field and power into the cells of grid.

AccumGrid#

An axis-aligned plane of resolution0 * resolution1 cells.

AccumOptions#

Material, MaterialAD#

Per-primitive electromagnetic parameters, each an array with one entry per scene-global primitive.

AccumResult#

WedgeEvents#

capacity, count, and per event: ray_index, hit_points (wedge location), normals, prim_id, directions (incident direction), source_points (virtual source before the event), src_power, initial_directions (primary ray direction), bounce_depth.

Related#

• Diffraction (Dr.Jit)
• Differentiation