TRIANGLE DIVIDING/DRAWING SYSTEM FOR CONVEX POLYGON

摘要

PURPOSE:To increase the painting out speed of triangles by drawing only the left side, the left and right sides, or only the right side based on the minimum value (or maximum value) at drawing of triangles obtained by dividing a convex polygon with the maximum or minimum value of the X or Y axis direction defined as a fixed point. CONSTITUTION:A triangle dividing part 1 detects the maximum or minimum value of the X or Y axis direction from a list of apex coordinates of the convex polygon and defines the maximum or minimum value as a fixed point to divide successively a polygon into triangles. A processing part 2 draws only the left side, the left and right sides, or only the right side in terms of the coordinates of the sides opposite to the fixed points of those divided triangles based on the maximum (or minimum) value. Thus it is possible to avoid the double painting out operations for the adjacent sides when a convex polygon is divided into triangles and undergoes the painting out processes. As a result, the painting out process can be applied to a convex polygon at a high speed.