Screen space effects utilizing the alpha channel and the alpha buffer

A graphics accelerator with a frame buffer, used in a real time simulation system, comprising:

• (a) an alpha processing channel;
• (b) an alpha memory coupled to the alpha processing channel, wherein screen effect data rendered in the alpha processing channel is stored in the alpha memory and then applied to the frame buffer;
• and
• (c) a post processor wherein screen effects are applied to frame buffer color data.

A method for simulating night scenes and own-ship lighting using a graphics accelerator with a frame buffer, comprising:

• (a) storing a ship mounted lighting pattern in an alpha memory of the frame buffer;
• (b) generating range values for pixels based on a range calculated for vertices of a polygon and interpolated through the alpha channel when the polygon is rendered;
• (c) processing the range values and applying range attenuation to the own-ship lighting pattern as a post process to the frame buffer when pixels are scanned out of the frame buffer for display;
• and
• (d) avoiding attenuation of point lights and luminous polygons by checking a luminous bit stored in the alpha memory at a subpixel level and not attenuating the respective subpixels.