Apparatus for displaying a three dimensional object which appears substantially the same in different display directions by modifying stored image data by a scale factor

• US 5,295,234 A
• Filed: 01/15/1993
• Issued: 03/15/1994
• Est. Priority Date: 12/29/1988
• Status: Expired due to Term

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Ishida, Koichi, Watanabe, Nobutake
• Primary Examiner(s): Harkcom, Gary V.
• Assistant Examiner(s): SMITH, MICHAEL
• Application Number:
  US08/005,172
• Time in Patent Office: 424 Days
• Field of Search: 395/121, 395/119, 395/120, 395/122, 395/124, 364/413.19
• US Class Current: 345/421
• CPC Class Codes: G06T 15/405 using Z-buffer

Abstract

Image data including depth data on a pixel basis representing a sphere or column are previously generated and stored in a mapping memory. When the sphere or column is to be displayed on a display screen, the image data are read out from the mapping memory. The image data thus read out are mapped to a predetermined region of a memory for display and are processed for hidden surface removal simultaneously.

Claims

1. An apparatus for displaying three dimensional objects on a display screen, comprising:

frame memory means for holding destination image data to be displayed, the destination image data including destination color data and destination depth data;

mapping memory means for holding source image data on a pixel basis, the source image data representing a three dimensional object which is not substantially influenced by display direction and including source color data and source depth data;

data holding means for storing first data which designate an area in said frame memory means, the area in said frame memory means being an area in which the source image data are to be displayed;

first address generation means for generating first addresses which belong to the area, based upon the first data;

scale factor obtaining means for obtaining a scale factor based upon the first data and upon source image data size;

second address generation means for generating second addresses based upon the first address, the first data and the scale factor, the second address being applied to said mapping memory means as a reading address;

depth data generation means for generating first depth data based upon the first data, the source depth data and the scale factor; and

write control means for reading the source color data, for performing hidden surface removal based upon the first depth data and the destination depth data, and for writing the source color data in said frame memory means based upon the first address, depending upon hidden surface removal performance.