1 2 Consider three squares, A, B and C in 3D world coordinates as shown in left figure. The square A has four vertexes (2, 2, 2), (0, 2, 2), (0, 0, 2), (2, 0, 2), square B has four vertexes (1, 1, 1), (-1, 1, 1), (-1,-1, 1), (1,-1, 1), and square C has four vertexes (1,1,0),(-1,1,0),(-1,-1, 0), (1,-1, 0). They are defined by connecting their vertexes in this order. Now computer draws 3D scene using Z-buffer method. Viewing point The viewpoint of scene is placed at infinity point of the world coordinate z axis and looks down at the origin. 2D window buffer is placed on X-Y plane. Answer to the following questions. Here, color of the square A, B, C, and background has different color each other. ) When the computer draws this scene, the color of each pixel on a display is stored in frame buffer (set of RGB value of each pixel) on drawing process. Initially, the frame buffer is filled with initial Background color. If the computer draws three squares in the order of A+B+C, how many times is the frame buffer updated in maximum? Here, if pixel is left the initial state (background color) to the end of the drawing process, the update count is 0. ) If the computer draws three squares in the order of C B+ A, how many times is the frame buffer updated in maximum? Here if pixel is left the initial state (background color) to the end of the drawing process, the update time is 0. ) ) Sketch final rendered scene from this viewpoint. (Indicate the squares with subscript.) 1 2 Consider three squares, A, B and C in 3D world coordinates as shown in left figure. The square A has four vertexes (2, 2, 2), (0, 2, 2), (0, 0, 2), (2, 0, 2), square B has four vertexes (1, 1, 1), (-1, 1, 1), (-1,-1, 1), (1,-1, 1), and square C has four vertexes (1,1,0),(-1,1,0),(-1,-1, 0), (1,-1, 0). They are defined by connecting their vertexes in this order. Now computer draws 3D scene using Z-buffer method. Viewing point The viewpoint of scene is placed at infinity point of the world coordinate z axis and looks down at the origin. 2D window buffer is placed on X-Y plane. Answer to the following questions. Here, color of the square A, B, C, and background has different color each other. ) When the computer draws this scene, the color of each pixel on a display is stored in frame buffer (set of RGB value of each pixel) on drawing process. Initially, the frame buffer is filled with initial Background color. If the computer draws three squares in the order of A+B+C, how many times is the frame buffer updated in maximum? Here, if pixel is left the initial state (background color) to the end of the drawing process, the update count is 0. ) If the computer draws three squares in the order of C B+ A, how many times is the frame buffer updated in maximum? Here if pixel is left the initial state (background color) to the end of the drawing process, the update time is 0. ) ) Sketch final rendered scene from this viewpoint. (Indicate the squares with subscript.)
