Watertight ray triangle intersection

A method implemented by a hardware-based traversal coprocessor coupled to a streaming multiprocessor, the method comprising:

• storing, in memory, at least a portion of an accelerated data structure including a plurality of hierarchical nodes, at least one node identifying a plurality of primitives of a virtual scene;
• determine whether a ray intersects the primitives;
• and
• when the ray is determined to intersect an edge or a vertex shared by two or more primitives, identifying, to the streaming multiprocessor, only one primitive of the plurality of primitives sharing the edge or the vertex as being intersected by the ray.

A hardware-based traversal coprocessor configured to:

• receive, from a streaming multiprocessor, a query identifying a ray and a tree data structure to test for primitive intersections with the ray;
• retrieve, from memory outside of the traversal coprocessor, portions of the tree data structure, each portion identifying one or more bounding volumes of a hierarchy of bounding volumes identified in the tree data structure;
• determine smallest subdivisions of the hierarchy of bounding volumes which are intersected by the ray;
• push onto a stack a range of primitives identified in smallest subdivision of the hierarchy of bounding volumes intersected by the ray;
• determine whether the ray going through a surface formed by two or more primitives intersects an edge or a vertex shared by the two or more primitives;
• when the ray is determined to intersect the shared edge or a vertex, store, in a result queue, a single primitive of the two or more primitives as being intersected by the ray;
• and
• transmit, to the streaming multiprocessor, intersection information of the intersected primitives stored in the result queue.

A device including hardware circuitry configured to:

• receive a ray and a plurality of primitives;
• determine, using an arithmetic unit, whether the ray going thought a surface formed by the primitives intersects an edge or vertex shared by two or more the primitives;
• and
• when the ray is determined to intersect the edge or vertex shared by two or more primitives, identify a single one of the two or more primitives sharing the edge or vertex as being intersected by the ray.