System and method for coloring polygon using dithering

• US 5,573,402 A
• Filed: 11/21/1994
• Issued: 11/12/1996
• Est. Priority Date: 05/22/1992
• Status: Expired due to Fees

• Current Assignee: Midway Games West, Inc. (Scientific Games Corporation)
• Original Assignee: Atari Incorporated (Infogrames Entertainment SA)
• Inventors: Gray, Alan S.
• Primary Examiner(s): CHENG, JOE H
• Application Number:
  US08/342,711
• Time in Patent Office: 722 Days
• Field of Search: 434/62, 434/65, 434/69, 434/71, 434/307 R, 434/308, 434/365, 434/373, 434/118, 364/410, 364/578, 273/148 B, 273/438, 273/442, 345/145, 345/118, 345/121, 345/150, 345/199, 395/126, 395/130, 395/131, 395/500
• US Class Current: 434/69
• CPC Class Codes: A63F 13/245 specially adapted to a particular type of game, e.g. steering wheels
• CPC Class Codes: A63F 13/803 Driving vehicles or craft, e.g. cars, airplanes, ships, robots or tanks
• CPC Class Codes: A63F 13/90 Constructional details or arrangements of video game devices not provided for in groups A63F13/20 or A63F13/25, e.g. housing, wiring, connections or cabinets
• CPC Class Codes: A63F 2300/1037 being specially adapted for converting control signals received from the game device into a haptic signal, e.g. using force feedback
• CPC Class Codes: A63F 2300/302 specially adapted for receiving control signals not targeted to a display device or game input means, e.g. vibrating driver's seat, scent dispenser
• CPC Class Codes: A63F 2300/636 involving process of starting or resuming a game
• CPC Class Codes: A63F 2300/64 for computing dynamical parameters of game objects, e.g. motion determination or computation of frictional forces for a virtual car
• CPC Class Codes: A63F 2300/66 for rendering three dimensional images
• CPC Class Codes: A63F 2300/8017 Driving on land or water; Flying
• CPC Class Codes: G06T 15/00 3D [Three Dimensional] image rendering
• CPC Class Codes: G06T 15/50 Lighting effects
• CPC Class Codes: G09B 9/04 for teaching control of land vehicles
• CPC Class Codes: G09B 9/05 the view from a vehicle being simulated G09B9/052, G09B9/058 take precedence

Abstract

A driver training system for a user of a simulated vehicle. The system includes input devices for controlling the simulated vehicle, a video display having three-dimensional graphics, modeling software for determining position information based on the input devices, atmospheric effects software to simulate time-of-day and weather conditions, and recursive training software to display a previous route through an environment simultaneously with a present route through the environment together with associated performance data. Another aspect of the recursive training software replays either the previous route or present route and controls one of the input devices to provide "hands-on" feedback to the user. The user then incrementally and recursively maximizes parameters associated with vehicle operation skill. The driver training system may be embodied as a vehicle simulator.

Claims

1. In a computer having a video display and a storage, a method of hazing a plurality of polygons, comprising the steps of:

selecting one of the polygons from the storage;

calculating a haze value as;

space="preserve" listing-type="equation">haze value=(z*kval)/dimval

where

z is the distance between a camera position and the selected polygon,

kval is a constant, and

dimval is the distance for full hazing;

calculating a shade value as the dot product of a sun vector and the normal to the polygonal plane;

indexing a dither table with the haze and shade values for dither color offsets;

adding a base color to the dither color offsets for dither colors;

determining a dither pattern of dither colors based on the position of the selected polygon; and

drawing the selected polygon on the video display using the dither pattern.

2. The method of claim 1, wherein the constant (kval) is selected based upon a rate at which colors change in a particular hazing condition.

3. The method of claim 1, wherein the step of determining the dither pattern comprises the steps of:

selecting a first dither pattern if the selected polygon begins on an even scan line of the video display; and

selecting a second dither pattern if the selected polygon begins on an odd scan line of the video display.

4. The method of claim 1, further including the step of comparing the polygon distance (z) to the hazing distance (dimval), wherein the shade value is calculated if the polygon distance (z) is less than the hazing distance (dimval).

5. A computerized method of modifying a base color of a polygon in a computer accessing a storage and a visual display to indicate a hazing condition, the method comprising the steps of:

selecting a polygon from the storage of the computer;

selecting a first distance representing a distance for full hazing;

calculating a second distance representing a distance between an observer and the polygon;

calculating a haze value from the first and second distances;

determining a shade value for the selected polygon based upon the position of the polygon in the video display and the relative position of at least one light source;

indexing a lookup table, stored in the computer, based upon the haze value and the shade value to obtain at least one color offset;

adding the at least one color offset to the base color of the polygon to determine dither colors for the polygon; and

drawing the selected polygon on the video display using the dither colors.

6. The method of claim 5, wherein the step of calculating the haze value comprises multiplying the second distance by a constant and then dividing the result by the first distance.

7. The method of claim 6, wherein the constant is selected based upon a rate at which colors change in said hazing condition.

8. The method of claim 5, wherein the at least one light source comprises two light sources.

9. The method of claim 8, wherein the step of determining the shade value comprises:

calculating a first dot product of a vector of the first light source and a normal to the polygonal plane;

calculating a second dot product of a vector of the second light source and the normal to the polygonal plane;

summing components of the first and second dot products; and

adding a translation factor to the summed components to produce a range of positive values representative of intensity.

10. The method of claim 5, additionally comprising the step of determining a dither pattern based on the position of the polygon in the video display, and wherein the drawing step is based upon the dither colors and the dither pattern.

11. A method of coloring a polygon in a computer having a visual display comprising the steps of:

storing a plurality of color palettes in a memory of the computer;

selecting an atmospheric condition;

selecting one of the color palettes indicative of the atmosphere condition, wherein each color in the palette is associated with a different shade and haze value;

calculating a haze value for the polygon;

determining a shade value for the polygon;

indexing a dither table based upon the haze and shade values so as to provide dither color offsets;

determining dither colors for the polygon based on a base color and the dither color offsets;

selecting a dither pattern based upon the position of the selected polygon on the visual display;

modifying the user perceived color of the selected polygon in response to the selected dither colors and dither pattern; and

displaying the modified polygon on the display device.

12. The method of claim 11, further comprising the steps of:

selecting a hazing distance (dimval) which is the distance that an observer must be from the selected polygon before color of the polygon is fully affected by the atmospheric condition; and

calculating a polygon distance (z) which is the distance between an observer and a selected point on the polygon.

13. The method of claim 12, wherein the haze value is calculated based upon the polygon distance (z)and hazing distance (dimval).

14. The method of claim 12, further including the step of comparing the polygon distance (z) to the hazing distance (dimval), wherein the shade value is calculated if the polygon distance (z) is less than the hazing distance (dimval).

15. The method of claim 11, wherein the shade value is determined based upon the dot product of a light source vector and a normal to the plane of the polygon.

16. The method of claim 11, wherein the step of selecting the dither pattern comprises the step of:

selecting a first dither pattern if the polygon begins on an even scan line of the visual display; and

selecting a second dither pattern if the polygon begins on an odd scan line of the visual display.

17. A method of coloring a polygon in a user-interactive system comprising the steps of:

selecting a simulated universe in response to a user input, wherein the simulated universe comprises a plurality of polygons, a type of haze and a thickness of haze;

selecting a dimming distance value (dimval) and a color change velocity value (kval) corresponding to the thickness of haze and the type of haze positioned between an observer and one of the polygons;

selecting a color palette for the polygon wherein each color of the palette is associated with a unique set of shade and haze values;

storing the color palette in a memory;

selecting characteristics of a plurality of light sources in the simulated universe;

calculating the distance (z) between the observer and a selected point on the polygon;

calculating a haze value based upon the dimming distance value (dimval) and distance (z);

comparing the distance (z) to the dimming distance (dimval);

determining a shade value representative of the relationship between the characteristics of the light sources and a normal to the polygonal plane if the distance (z) is less than the dimming distance value (dimval);

producing an index in response to the shade and haze values;

selecting first and second color offsets by addressing the memory according to the index and the color palette;

selecting a dither pattern based on a position of the polygon; and

displaying the polygon with a color determined by the selected color offsets and dither pattern.

18. The method of claim 17, wherein the haze value is representative of a percentage of full hazing, and wherein each color in the palette is selected to represent a polygon color modified by a different shade and haze percentage.

19. The method of claim 17, wherein the presenting step is performed on a visual display having a plurality of scan lines, and wherein the step of selecting the dither pattern comprises selecting a first dither pattern if the polygon beings on an even scan line and selecting a second dither pattern if the polygon begins on an odd scan line.

20. In a computer having a memory and a visual display, a method of coloring a polygon comprising the steps of:

selecting a color palette for the polygon wherein each color of the palette is associated with a different shade and haze value;

storing the color palette in the memory;

selecting a plurality of light sources in a computer generated universe;

producing a haze value based on a dimming distance value (dimval) and a polygon distance (z) between an observer and the polygon;

producing a shade value representative of the relationship between the light sources and a normal to the polygonal plane;

selecting color offsets into the color palette based upon the haze and shade values;

selecting a dither pattern based on a position of the polygon on the visual display;

modifying the color of the polygon in response to the selected color offsets and dither pattern; and

drawing the polygon on the visual display.

21. The method of claim 20, wherein the step of calculating the haze value comprises multiplying the polygon distance (z) by a constant and then dividing the result by the dimming distance (dimval).

22. The method of claim 21, wherein the constant is selected based upon a rate at which colors change in said hazing condition.

23. The method of claim 21, wherein the step of determining the shade value comprises:

calculating a fist dot product of a vector of a first one of the plurality of light sources and the normal to the polygonal plane;

calculating a second dot product of a vector of a second one of the plurality of light sources and the normal to the polygonal plane;

summing components of the first and second dot products; and

adding a translation factor to the summed components to produce a range of positive values representative of intensity.

24. A system for coloring a polygon to indicate a hazing condition, comprising:

a computer accessing a storage;

an input device connected to the computer capable of selecting a polygon;

a color palette for the polygon wherein each color of the palette is associated with a different shade and haze value, said palette stored in the storage;

a plurality of simulated light sources generated by the computer;

a haze value determined by a dimming distance value (dimval) and a polygon distance (z) between an observer and the polygon;

a shade value representative of the relationship between the light sources and a normal to the polygonal plane;

a selector of color offsets into the color palette using the haze and shade values;

a visual display connected to the computer;

a dither pattern selected by the computer; and

a modifier to change the color of the polygon in response to the selected color offset and dither pattern;

wherein said modified polygon is drawn on the visual display.