Patent ID: 6903741

Claim:
A method for rendering soft shadows in a frame representing a three-dimensional scene, which is defined by a list of polygons and comprises a plurality of three-dimensional objects, said method comprising the steps of: from a light source's point of view: determining edges casting shadows from said list of polygons; computing shadow volumes and computing soft shadow edges from said edges casting shadows; creating up to six squared empty textures of the same size, each of them becoming a face of a cubemap representing a cube centered at the light source's point of view, said faces of said cubemap being aligned with orthogonal major axes with the light source's position as origin; rendering into at least one face of said cubemap an appropriate part of said scene with full brightness color and rendering a representation of soft shadows into said at least one face of said cubemap using said edges casting shadows and said soft shadow edges computed; from a point of view of a viewer viewing said scene: rendering a visible part of the scene into a z-buffer with colors, lighting and texture information disabled for generating depth information; rendering said shadow volumes into a stencil buffer in combination with said z-buffer information; and in a single pass, rendering said scene with colors, lighting and texture information enabled and applying said cubemap to said scene for rendering said representation of said soft shadows into said scene using a texture coordinate generation while performing a stencil test operation for preventing the scene to be drawn in shadowed areas, to produce a soft shadowed image.