System and method for fast phong shading

A method for assigning color values to image pixels comprising:

• in the geometry stage of a graphics pipeline, precalculating color values based on orientation-dependent color variables, for a sample of normal vector orientations, each color value being associated with scaled first and second angle coordinates that specify a normal vector orientation;
• and
• in a rendering stage of the graphics pipeline, estimating the scaled first and second angle coordinates for the pixels of the image;
• retrieving color values for the pixels according to their scaled estimated angle coordinates;
• and
• generating a display image using the retrieved color values.

A graphics system comprising:

• a geometry engine to associate vector orientation data with vertices of one or more polygons representing an object in an image;
• a color map to store color values for a sample of vector orientations, each color value being referenced by one or more orientation dependent color variables;
• and
• a rendering engine to convert vector orientation data for a polygon to first and second angle coordinates for each pixel of the polygon, to scale the first and second angle coordinates to one or more color variables for each pixel of the polygon, and to assign a color value to each pixel according to its one or more color variables.

A machine readable medium on which are stored instructions that are executable by a system to implement a method for assigning a color value to an image pixel, the method comprising:

• precalculating color values based on orientation-dependent color variables, for a sample of normal vector orientations, each color value being associated with first and second scaled angle coordinates representing a corresponding normal vector orientation;
• estimating first and second scaled angle coordinates for the pixel;
• and
• retrieving a color value for the pixel according to the estimated scaled first and second angle variables.