Figure drawing device and method

Abstract

A figure drawing device includes; a device 2 for increasing/decreasing the number of pixels on a scanning line up to the final painting pixel by one pixel; a device 3 for increasing/decreasing the number of scanning lines for drawing by one line; a device 4 for outputting drawing pixel data based on the control by the devices 1 and 2; a stencil buffer 5 for holding figure data in an intermediate stage of sequentially drawing a figure; a device 6 for holding pixel data read from the buffer 5 and consecutive as plural pieces of pixel data; a device 7 for detecting the transit state of the data value in the device 6; and a device 8 for inverting/non-inverting the logical operation result of the output data of the device 4 and the data in the device 6 and writing a result to the buffer 5.

1 . A figure drawing device which draws a figure by painting pixels on a scanning line, comprising:
 at least one processor to perform   painted pixel increase/decrease control to increase or decrease a number of painting pixels up to a final painting pixel on the scanning line by one pixel;   scanning line increase/decrease control to increase or decrease a number of scanning lines to draw a figure by one scanning line; and   pixel data output to output pixel data to draw a figure on a basis of control of the painted pixel increase/decrease control and the scanning line increase/decrease control, wherein   a figure is drawn by dividing the figure into a plurality of triangles;   the at least one processor further to perform a painting target side determination to determine which side of a newly drawn triangle is to be painted when the divided triangles are sequentially drawn;   the painted pixel increase/decrease control and the scanning line increase/decrease control to control increasing or decreasing painted pixels and scanning lines depending on a determination request of the painting target side determination, and wherein   the painting target side determination inputs
 first information for identifying whether the divided triangle is a leading triangle to be first drawn, 
 second information for identifying whether the divided triangle is a final triangle to be last drawn, 
 third information indicating an order in which vertexes of the divided triangle provided as a stream are provided, 
 fourth information indicating which of an upper side and a lower side parallel to a scanning line for the figure drawing or which of a left side and a right side crossing the scanning line a side of the divided triangle is classified into, and indicating whether each of the vertexes of the divided triangle belongs to a lower side of the triangle, and 
 fifth information indicating whether each of the vertexes of the divided triangle belongs to the right side as an ending point of painted pixels on the scanning line, and 
   the painting target side determination outputs
 sixth information indicating whether or not each side of the divided triangle needs to be painted. 
   
     
     
         2 . The device according to  claim 1 , wherein the painting target side determination comprises:
 first logic to input the first, second and third information and to output seventh information indicating whether each side of the divided triangle is in the figure to be drawn or whether each side of the divided triangle is a contour side to an external portion of the figure to be drawn,
 second logic to input the fourth and fifth information and to output eighth information indicating whether each side of the divided triangle is the lower side or whether each side of the divided triangle is the right side, and 
 third logic to input the seventh and eighth information and to output the sixth information.