A special-purpose hardware device comprising: a camera interface that receives, from a camera device of a head-mounted-display system, image frames of a physical environment surrounding the head-mounted-display system; a positional tracking component communicatively coupled to the camera interface, characterized in that the positional tracking component: is configured to process in a front-end processing component at least a portion of the image frames in-line before image frames are stored within a main memory; wherein the front-end processing component is configured to: detect one or more features of the physical environment within an incoming image frame as the incoming image frame is received, wherein the one or more features are a physical object and/or a portion of a physical object within a physical environment surrounding a head-mounted display system; and pass the features to the main memory of the special-purpose hardware device to be incorporated into an image map that identifies physical locations of the features of the physical environment; track, based at least in part on the portion of the map, a change in a position of the head-mounted-display system within the physical environment; and store the change in the position of the head-mounted-display system for use in generating at least one augmented-reality frame to be presented to a user wearing the head-mounted-display system; and a frame-output interface communicatively coupled to the positional tracking component, wherein the frame-output interface feeds the augmented-reality frame to a display device of the head-mounted-display system for presentation to the user. a camera interface that receives, from a camera device of a head-mounted-display system, image frames of a physical environment surrounding the head-mounted-display system; a positional tracking component communicatively coupled to the camera interface, characterized in that the positional tracking component: is configured to process in a front-end processing component at least a portion of the image frames in-line before image frames are stored within a main memory; wherein the front-end processing component is configured to: detect one or more features of the physical environment within an incoming image frame as the incoming image frame is received, wherein the one or more features are a physical object and/or a portion of a physical object within a physical environment surrounding a head-mounted display system; and pass the features to the main memory of the special-purpose hardware device to be incorporated into an image map that identifies physical locations of the features of the physical environment; track, based at least in part on the portion of the map, a change in a position of the head-mounted-display system within the physical environment; and store the change in the position of the head-mounted-display system for use in generating at least one augmented-reality frame to be presented to a user wearing the head-mounted-display system; and is configured to process in a front-end processing component at least a portion of the image frames in-line before image frames are stored within a main memory; wherein the front-end processing component is configured to: detect one or more features of the physical environment within an incoming image frame as the incoming image frame is received, wherein the one or more features are a physical object and/or a portion of a physical object within a physical environment surrounding a head-mounted display system; and pass the features to the main memory of the special-purpose hardware device to be incorporated into an image map that identifies physical locations of the features of the physical environment; track, based at least in part on the portion of the map, a change in a position of the head-mounted-display system within the physical environment; and store the change in the position of the head-mounted-display system for use in generating at least one augmented-reality frame to be presented to a user wearing the head-mounted-display system; and detect one or more features of the physical environment within an incoming image frame as the incoming image frame is received, wherein the one or more features are a physical object and/or a portion of a physical object within a physical environment surrounding a head-mounted display system; and pass the features to the main memory of the special-purpose hardware device to be incorporated into an image map that identifies physical locations of the features of the physical environment; track, based at least in part on the portion of the map, a change in a position of the head-mounted-display system within the physical environment; and store the change in the position of the head-mounted-display system for use in generating at least one augmented-reality frame to be presented to a user wearing the head-mounted-display system; and a frame-output interface communicatively coupled to the positional tracking component, wherein the frame-output interface feeds the augmented-reality frame to a display device of the head-mounted-display system for presentation to the user.