Method and apparatus for overlaying a bit map image on an environment map

Abstract

The computer system of the present invention generates a view of a scene by storing in memory color values associated with elements of an environment map representing the scene and color values associated with elements of a bit map image that is separate from the environment map. The bit map image is orientated with respect to the coordinate system of the environment map. The environment map is projected onto a view window that comprises an array of pixels. For at least one pixel of the view window covered by the bit map image, the element of the bit map image that corresponds to the pixel of the view plane is determined and a color value of the pixel is derived based upon the color value of the corresponding element of the bit map image. The derived color value of the pixel of the view window is stored for display. The computer system may also store in memory depth values associated with the elements of the bit map image and depth values associated with pixels of the view window. In this scenario, when the depth value associated with the pixel and a depth value associated with the element indicate that the element of the bit map image is nearer to the view point than the pixel of the view window, the computer system derives a color value of the pixel of the view window based upon color value of the corresponding element of the bit map image and stores the derived color value of the pixel for display.