Patent ID: 6392643
Filing Date: 2002-05-21
Classification: G06T

Abstract:
An image generation apparatus wherein draw commands generated by a CPU are transferred to a drawing device which generates an image in a frame buffer by drawing sequentially in accordance with said draw commands, said drawing device comprising:a read means for reading pixel data of an image which has been previously drawn from said frame buffer; a mixing circuit for mixing the pixel data read from said frame buffer with pixel data of a corresponding position where a next drawing operation is to be performed in a specified mixing ratio; a write means for writing the pixel data mixed in the corresponding pixel position in said frame buffer; a mixing ratio memory for storing said mixing ratio supplied to said mixing circuit; a flag determination means for extracting a flag associated with a draw command and for determining the state of said flag; and a control means for performing control based on a result of the flag determination means such that, if said flag is in one state, reading of pixel data from said frame buffer by said read means is omitted and the pixel data of the corresponding position where the next drawing operation is to be performed is written as it is in the corresponding pixel position in said frame buffer by said write means and such that, if said flag is in another state, the reading of the pixel data from said frame buffer by said read means and the writing into said frame buffer by said write means are omitted.