# US 8,275,138 B2 · Dynamic acoustic rendering > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,275,138 B2 - Document ID: US8275138B2 - Status: Granted - Kind: B2 - Application number: 11/827,085 - Filed: 2007-07-09 - Published: 2008-03-20 - Granted: 2012-09-25 - Earliest claimed: 1999-05-04 - Assignees: Creative Technology Ltd - Inventors: Alan Gerrard; Nam Do - Web page: https://patentgrep.com/patent/US8275138B2 ## CPC - H04S 3/00: Systems employing more than two channels, e.g. quadraphonic (H04S5/00, H04S7/00 take precedence) - H04S 7/30: {Control circuits for electronic adaptation of the sound field} - H04S: STEREOPHONIC SYSTEMS ## Abstract A method of acoustically rendering a virtual environment is described. The method includes receiving a subset of polygons derived for an acoustic display from a set of polygons generated for a graphical display. Acoustic reflections are determined from a sound source that bounce off of polygons in the subset of polygons to a listener position in the virtual environment. It is determined whether a polygon in the subset of polygons causes an occlusion of the sound source at the listener position, and a play list of sounds is generated based on the reflections and occlusions. ## Claims ### Claim 1 A method for acoustically rendering a virtual environment including: receiving a set of polygons associated with an acoustic display; determining whether one or more polygons in the set cause acoustic reflections of a sound source at a listener position in the virtual environment, wherein one or more polygons is located between the sound source and the listener position; determining whether one or more polygons in the set cause occlusions of the sound source at the listener position; and generating a play list of sounds based on the reflections and occlusions, wherein a reflected sound causes the generation of a first sound and a second sound, the first sound corresponding to a direct path between the sound source and the listener and a second sound corresponding to an extra path length traveled by the reflected sound from the sound source to the listener. ### Claim 2 (depends on 1) A method as recited in claim 1, wherein the set of polygons associated with the acoustic display is derived from a set of polygons generated for a graphical display. ### Claim 3 (depends on 1) A method as recited in claim 1, wherein the set of polygons associated with the acoustic display is derived by applying a size filter to a set of polygons generated for a graphical display. ### Claim 4 (depends on 1) A method as recited in claim 1, further comprising inflating a size of a polygon in the set relative to an original size of the polygon generated for a graphical display. ### Claim 5 (depends on 1) A method as recited in claim 1, wherein a polygon in the set comprises a of one or polygons generated for a graphical display. ### Claim 6 (depends on 1) A method as recited in claim 1, wherein different size filters are defined for reflections and occlusions. ### Claim 7 (depends on 1) A method as recited in claim 1, wherein a rendering mode is specified for one or more polygons in the set of polygons, the rendering mode determining whether each is considered for occlusion or reflection determinations. ### Claim 8 (depends on 1) A method as recited in claim 1, wherein each polygon in the set is associated with an acoustic material type. ### Claim 9 (depends on 8) A method as recited in claim 8, wherein the acoustic material type of each polygon is associated with one or more of a reflection factor for acoustical reflections and an attenuation factor for acoustical occlusions. ### Claim 10 (depends on 1) A method as recited in claim 1, wherein a polygon in the set includes a subsurface which is associated with a subsurface factor. ### Claim 11 (depends on 1) A method as recited in claim 1, wherein acoustic reflections, if present, cause sound from the sound source to arrive to the listener position via a path that is not a direct path. ### Claim 12 (depends on 1) A method as recited in claim 1, wherein acoustic reflections comprise one or more of first order and second order acoustic reflections. ### Claim 13 (depends on 1) A method as recited in claim 1, wherein the play list includes one or more of a sound associated with a direct path from the sound source to the listener position, a sound from the sound source to the listener position adjusted by an attenuation factor due to an occlusion resulting from a polygon situated in between the sound source and the listener position, a sound from the sound source to the listener position adjusted by an attenuation factor and a subsurface factor due to an occlusion resulting from a subsurface of a polygon situated in between the sound source and the listener position, and a sound resulting from an acoustic reflection of the sound source by a polygon at the listener position. ### Claim 14 (depends on 1) A method as recited in claim 1, wherein the set of polygons is associated with a frame of the virtual environment. ### Claim 15 A method performed by a system for acoustically rendering a polygon between a sound source having a strength and a listener position including: determining whether a polygon generated by a graphics rendering application intersects a ray extending from the sound source to the listener position, wherein the polygon is located between the sound source and the listener position; and in the event that the polygon intersects the ray, attenuating the strength of the sound source, wherein attenuating the strength of the sound source includes determining an attenuation factor from a graphics texture associated with the polygon in the graphics rendering application; determining whether a polygon generated by the graphics rendering application creates an acoustic reflection of the sound source to the listener position; and in the event that the polygon creates an acoustic reflection, including in a play list of sounds a sound associated with the acoustic reflection, wherein a reflected sound causes the generation of a first sound and a second sound, the first sound corresponding to a direct path between the sound source and the listener and a second sound corresponding to an extra path length traveled by the reflected sound from the sound source to the listener. ### Claim 16 (depends on 15) A method as recited in claim 15, further comprising adjusting an attenuation factor by a subsurface factor if the ray intersects a subsurface of the polygon. ### Claim 17 A method performed by a system for acoustically rendering a polygon in a virtual environment, comprising: receiving a rendering mode variable that enables reflections or occlusions; determining whether a polygon generated by a graphics rendering application creates an acoustic reflection of a sound source at a listener position, wherein the polygon is located between the sound source and the listener position; in the event that the polygon creates an acoustic reflection, including in a play list of sounds a sound associated with the acoustic reflection, wherein a reflected sound causes the generation of a first sound and a second sound, the first sound corresponding to a direct path between the sound source and the listener and a second sound corresponding to an extra path length traveled by the reflected sound from the sound source to the listener. ### Claim 18 A system for acoustically rendering a virtual environment including: a processor configured to: receive a set of polygons associated with an acoustic display; determine whether one or more polygons in the set cause acoustic reflections of a sound source at a listener position in the virtual environment, wherein one or more polygons is located between the sound source and the listener position; determine whether one or more polygons in the set cause occlusions of the sound source at the listener position; and generate a play list of sounds based on the reflections and occlusions; and a memory coupled to the processor and configured to provide instructions to the processor, wherein a reflected sound causes the generation of a first sound and a second sound, the first sound corresponding to a direct path between the sound source and the listener and a second sound corresponding to an extra path length traveled by the reflected sound from the sound source to the listener. ### Claim 19 A computer program product for acoustically rendering a virtual environment, the computer program product being embodied in a non-transitory computer readable medium and comprising computer instructions for: receiving a set of polygons associated with an acoustic display; determining whether one or more polygons in the set cause acoustic reflections of a sound source at a listener position in the virtual environment, wherein one or more polygons is located between the sound source and the listener position; determining whether one or more polygons in the set cause occlusions of the sound source at the listener position; and generating a play list of sounds based on the reflections and occlusions, wherein a reflected sound causes the generation of a first sound and a second sound, the first sound corresponding to a direct path between the sound source and the listener and a second sound corresponding to an extra path length traveled by the reflected sound from the sound source to the listener.