Method and system for improved per-pixel shading in a computer graphics system

Abstract

A method for shading polygon surfaces in a real time rendering system. Providing at least one polygon surface to be shaded. The polygon surface having a plurality of pixels and including at least one surface angle. Providing at least one point light source. Calculating using computer hardware, for substantially each drawn pixel of said polygon surface, a substantially normalized 3D surface direction vector and a 3D point light vector.

I claim:  
     
         1 . A method for shading polygon surfaces in a real time rendering system comprising the steps of: 
 providing at least one polygon surface to be shaded, said polygon surface comprised of a plurality of pixels and including at least one surface angle;    providing at least one point light source; and    calculating using computer hardware, for substantially each drawn pixel of said polygon surface, a substantially normalized 3D surface direction vector and a 3D point light vector.    
     
     
         2 . The method of  claim 1  further comprising the step of using dedicated computer hardware to calculate a substantially normalized 3D surface direction vector and a 3D point light vector.  
     
     
         3 . The method of  claim 2  further comprising the steps of calculating a substantially normalized 3D surface direction vector and a 3D point light vector without the use of a square root type operation.  
     
     
         4 . The method of  claim 3  further comprising the step of calculating a diffuse light value using the surface direction vector and the point light vector.  
     
     
         5 . The method of  claim 4  further comprising the step of calculating a reflection vector.  
     
     
         6 . The method of claims  5  further comprising the step of calculating a specular light value using the point light vector and the reflection vector.  
     
     
         7 . The method of  claim 6  further comprising the step of providing a bump map useful to determine the surface angle vector and the reflection vector.  
     
     
         8 . A method for shading polygon surfaces in a real time rendering system for drawing a plurality of drawn pixels comprising the steps of: 
 providing at least one polygon having a polygon surface to be shaded, said surface comprising a plurality of pixels, and said surface including at least one surface angle;    providing at least one light source, said light source having a corresponding three-dimensional light source vector;    providing a bump map, said bump map having corresponding bump map vectors; and    using a processor to calculate, for substantially each drawn pixel of said surface, a substantially normalized three dimensional (3D) surface direction vector generated from said at least one surface angle and said bump map.    
     
     
         9 . The method of  claim 8  wherein the step of using a processor to calculate the 3D vector comprises using hardware dedicated to lighting calculations.  
     
     
         10 . The method of  claim 8  wherein the step of using a processor to calculate the 3D vector comprises calculating the 3D vector without calculating a square root.  
     
     
         11 . The method of  claim 8  wherein said at least one surface angle comprises a 3D vertex normal vector.  
     
     
         12 . The method of  claim 11  further comprising the step of converting the 3D vertex normal vector to a two dimensional (2D) vector.  
     
     
         13 . The method of  claim 12  wherein a plurality of 2D vectors are converted from a plurality of 3D vertex normal vectors and further comprising interpolating said 2D vectors for a drawn pixel.  
     
     
         14 . The method of  claim 13  further comprising combining said interpolated 2D vectors with bump map vectors to generate 2D composite surface angle vectors.  
     
     
         15 . The method of  claim 14  further comprising converting said 2D composite vectors to substantially normal 3D surface direction vectors.  
     
     
         16 . The method of  claim 15  wherein said step of converting said 2D composite surface vectors comprises using a lookup table.  
     
     
         17 . The method of  claim 14  further comprising calculating 2D reflection vectors from said 2D composite surface angle vectors.  
     
     
         18 . The method of  claim 17  further comprising converting said 2D reflection vectors to 3D reflection vectors.  
     
     
         19 . The method of  claim 17  wherein the step of converting said 2D reflection vectors to 3D reflection vectors comprises using a lookup table.  
     
     
         20 . The method of  claim 11  further comprising rotating said at least one vertex normal vector to a fixed coordinate system; and then converting the 3D vertex normal vector to a two dimensional (2D) vector.  
     
     
         21 . The method of  claim 12  wherein the step of converting the 3D vertex normal vector to a two dimensional (2D) vector comprises converting the 3D vertex vector such that the length of the 2D vector is proportional to the angle between the corresponding 3D vector and a fixed 3D vector.