VECTOR SCANNED VIDEO GAME METHOD AND APPARATUS

Abstract: A system for directly painting the vectors which in combination comprises symbols (80, 82, 84, 86) on the display of a video game. Memory space dedicated to the game symbols is kept to a minimum in order to permit maximum utilization of memory for game operation. A symbol definition list (94) is employed to maintain pre-defined game symbols. The game itself only manipulates a display status list (92). A separate asynchronous logic system (96) creates the display from the two lists.

Description: VECTORSCANNEDVIDEOGAMEMETHODANDAPPARATUS TECHNICAL FIELD This invention relates to cathode ray tube (CRT) display systems and, more particularly, to CRT display employed in video games. BRIEF DESCRIPTION OF DRAWINGS The invention and prior art are described with respect to the drawings which comprise: Figure 1 is a front elevation of a CRT as employed in a display system. Figure 2 is a partially cutaway side elevation through the CRT of Figure 2. Figure 3 is a front elevation of a CRT indicating the development of a raster display- Figure 4 is a simplified view of a raster display displaying an "A". Figure 5 is a simplified drawing of a display painting an "A" with an X-Y scan system. Figure β is a graph showing the decay of the phosphors employed in a CRT display with respect to the refresh rate necessary to prevent flicker. Figure 7 is a block diagram showing one method of prior art generation of displays with an X-Y scan system. Figure 8 shows an alternate prior art method of X-Y display generation. Figure 9 is a simplified block diagram showing a video game environment as wherein the present invention is employed. Figure 10 is a drawing showing a typical symbol as employed with the present invention. Figure 11 shows the construction of entries on the symbol definition list as employed in the present invention. Figure 12 shows the construction of an entry on the OMPI display status list as employed in the present invention. Figure 13 is a block diagram showing a video gam system as constructed according to the present invention. Figure 14 is a block diagram of X-Y scan monito system logic according to the present invention. BACKGROUND ART A typical CRT as employed in a display system i shown in front and cutaway side views respectively i Figures 1 and 2 . The CRT 10 comprises an evacuated glas envelope 12 having a phosphor surface 14 on the inside o the viewing area. Vertical and horizontal deflectors, 1 and 18, respectively, are affixed about the neck 20 of th envelope 12. A. cathode 22 emits electrons 24 which ar drawn towards the phosphor surface 14. Electrons 24 striking the phosphor surface 14 cause illuminatio thereof. By selectively energizing the deflectors 16, 18, the path 26 followed by the electrons 24 can be moved horizontally and vertically. Referring to Figure 3, the most common video displa is shown. Such a display has a "raster scan". The beam of electrons 24 is made to move horizontally in electron-width strips from one side of the phosphor surface 14 to the other and from the top to the bottom, as indicated by the solid and dashed arrows in Figure 3. A first horizontal raster line is scanned from left to right along the top as indicated by the solid arrow 28. With the electron bea intensity turned off, the non-illuminating beam is then moved down one raster line and back to the left side of the screen as viewed in Figure 3 and as represented by the dashed arrow 30. The next raster line, as represented by the solid arrow 32, is then displayed across the screen. This process repeats from top to bottom until the last raster line, as represented by the solid arrow 34, is displayed. The display then begins at the top left by moving the non-illuminated beam, as represented by the dashed arrow 36, from the ending point to the beginning point. During the traversing of the raster lines by the electron beam, images are created by varying the intensity of the beam. The type of image created is shown in Figure 4 in simplified form. The number of actual raster lines in a typical display is greater than that shown in Figure 4, but the overall effect is the same. That is, as represented by the figure "A" shown, accurate horizontal lines can be created because the raster lines are horizontal. By contrast, diagonal lines such as the legs of the "A" are created by a sequence of staggered points as a best possible representation of a true diagonal line under the circumstances. Video games which are employed in the home market for use with the CRT of a television set must use the raster drive of the television set. By contrast, video games created for the stand-alone game market are not so restricted. They can employ what is referred to as an "X-Y" scan system. Such a system is shown in Figure 5. If one were to create the same "A" display as shown in Figure 4 using an X-Y scan system, it would be created as shown by the arrows of Figure 5. The "X" and "Y" refer to moving positions of the electron beam with reference to the typical X,Y coordinates of a two dimensional graph system. Assuming the undeflected position of the beam is at the center of the screen as viewed in Figure 5, the beam would first be moved (i.e., its X, Y position established) to the bottom of the left leg of the "A" in an un-illuminated mode as indicated by the dashed arrow 38. The beam would then be illuminated and its X,Y position moved by use of the deflectors 16, 18 to the apex of the "A" as indicated by the solid arrow 40. It would then be moved from the apex to the bottom of the right leg as indicated by the solid arrow 42. It would then be moved in its un-illuminated mode as indicated by the dashed arrow 44 in preparation for drawing or "painting" the horizontal bar of the "A" as indicated by the solid arrow 46. As can be seen, the "A" as painted by the X-Y display system is comprised of pur straight lines. In" a raster scan system, the raster scans rapidl across the screen from top to bottom and then repeats. The screen, therefore, is in a constant state of illumination as determined by the intensity modulation of the electro beam. The phosphors of the phosphor surface 14, however, do not remain illuminated. Once energized by being struck by an electron, they glow and then begin to rapidly decay. This is illustrated in Figure 6 by line 48. If the phosphor surface 14 is struck by an electron, it will glow and eventually the intensity will diminish to zero. If the intensity is allowed to diminish below the level indicated by dashed line 50 before being re-illuminated, the viewer will perceive a flicker in the display. If the display is re-energized before that level is reached, no flicker will be seen. Such re-energizing or repainting is referred to as "refreshing" the display. In typical prior art systems employing X-Y scan systems, this has been done in several ways. Referring first to Figure 7, a system where the operating programs dynamically creating the vectors of the display and the refl esh program are all contained within a main computer is shown. The main computer is symbolized by the dashed box 52. On a time-sharing basis, the operating programs 54 place vector descriptions in memory area 56. The refresh program 58 accesses the memory area 56 and uses the descriptions therein to create and refresh the display on the CRT of display 60. Figure 8 shows an alternate approach where the display contains its own logic portions for refreshing the display. The operating programs 54 are once again within the main computer indicated by the dashed box 52. In this case, however, the vector descriptions are contained in a commonly accessible memory area 62. The display compute represented by the dashed box 64 contains the refres program 58 and can also access the common memory 62. Turning now to Figure 9, the environment of th present invention is shown. The computer 66 contains game program 68 and a display creation and refresh progra 70. The display refresh program 70 is connected to the CR display 72 while the game program is connected to playe consoles 74 (usually one or two) containing such inpu devices as balltabs 76 and buttons 78. The foregoing elements are all placed in a convenient housing having appropriate mechanisms for coin operation thereof. The game consists of, for example, a "player 1" fighter symbol 80 and a "player 2" fighter symbol 82 controlled by the two control panels 74, respectively. As the game program 68 senses the changes in the balltabs 76 and buttons 78 of panels 74, the position of the symbols 80, 82 are moved about display 72 in a manner to simulate controlled flight thereof. Each symbol 80, 82 is capable of firing a simulated "missile" 84 which, if placed into coincidence with the position of the opponents symbol 80, 82, will cause that symbol 80, 82 to be "destroyed" with an attendant awarding -of points. In such video games to date, the operation has been primarily as shown in Figure 7. That is, the game program 68 continuously calculates and places in memory the individual refresh vector descriptions of the game in progress for the refresh program 70. A typical video game in an arcade has a limited life expectancy. As a game loses appeal, the amount of play quickly drops below a point of financial viability. Thus, it is desirable to provide a video gaming system which is easily converted to a new game. Because of the components required to be employed, the amount of memory available is fixed. Obviously, therefore, the more memory dedicated to the continued recalculation of vectors in order to produce the displa symbols of the dynamic game, the less memory is availabl for the logic of the game itself and, therefore, the gam cannot be as complex and graphic as desired to impart high interest level to the players. Wherefore, it is als desirable to provide a video display scan system whic employs a minimum amount of available memory whil preserving a maximum amount of available memory for use i the game logic of the program itself. The time and cost of programming new games is als directly related to the complexity of the task. Spatia orientation of displayed symbols can occupy a significan amount of time with associated expenditure of funds wit respect to the development of a new game which could otherwise be better employed in the development and codin of the game proper. Wherefore, it is also desirable t provide a programming environment for video games wherei the considerations necessary for the production o displayed symbols in the development of new games i minimized. DISCLOSURE OF INVENTION The present invention provides a video display syste for a video gaming system which is easily converted to new game, which uses a minimum amount of the availabl memory, and which minimizes the considerations for production of new symbols in a new or revised game wherei a pre-established series of individual symbols ar selectively displayed in multiple combination as a resul of programmed logic to convey movement of associated object within a defined area by the improvement characterized by means for defining the respective individual possible symbols as a plurality of interconnecting display lines of given angle and length with respect to a common coordinate system; means for maintaining the current status of the symbols to be actually displayed, said means including indication of the individual possible symbol in sai defining means associated with each display symbol and th angle and positional offset thereof in the commo coordinate system; wherein the programmed logic update only the status maintaining means; and, additionally, logi means for accessing the status maintaining means and th symbol defining means and for producing the display as a function thereof. BEST MODE FOR CARRYING OUT THE INVENTION In a display system such as the .stand-alone video game previously described, a number of pre-defined symbols are employed. These symbols are employ.**--.! in combinations to create the dynamic display of moving symbols which represents the display of the game. One such symbol which could be employed in a game according to " the present invention is shown in Figure 10. Such a symbol 86 can represent, for example, a space ship to be controlled either by a game player or the computer. The ship symbol 86 can be represented as shown in Figure 10 as a series of five interconnected vector lines beginning with point "A" at the origin of a polar coordinate system. By beginning at a known origin, the five line vectors which comprise the ship symbol 86 can be described by employing only lengths and angles. The first line A,B is of a given length and at a given angle from the origin. If one begins the electron beam at the origin and paints a straight line for the given length A-B at the given angle thereof, the electron beam will terminate at a position corresponding to point "3". If the beam is then moved along the length of line B—C at the angle thereof, it will terminate at the position of point "C". The same is true for the line segments C-D, D-E, and E-A. If the length and angles of the five lines are properly described, the lines will close upon themselves at point "A" completing the ship symbol 86. The present invention works on this basic premise. Referring now to Figure 11, the individual symbols are described in a symbol definition list having tabular entries of computer words for each individual line vector. In a tested embodiment employing eight bit words, the firs word employs the most significant bit as a "last entry" flag; that is, if bit eight of the first word of a four word entry is "1", this is the last four word entry of the list describing the particular symbol. If "0", it is no the last entry of the list. Similarly, bit one is "display" or "non-display" flag. If the bit is set to "1", the particular vector is to be displayed. That is, the intensity of the beam is to be "on". If the display bit is a"0" the vector is only for moving the position of the beam and the beam is not to be displayed, i.e. the bea intensity is turned off. Such a beam would correspond to the dotted arrows 38 and 44 in Figure 5 needed to generate the "A". Bits two through seven contain indicators concerning the color of the vector if it is a color system as was the case with the tested embodiment being described. The color designation methodology employed as part of the present invention is of particular novelty and importance. Where a color display is being employed, it is particularly usefull .to designate each player's controlled symbol (such as the spaceship 86 of Figure 10) by a different color. This permits rapid identification by a player of his symbol. Of course, color can be employed to convey other information such as a change in point value or playing characteristics of a particular symbol. The color benefits of the present invention will be addressed further shortly. Word two designates the length of the line vector and words three and four designate the angle of the line. In the tested embodiment, a polar coordinate system is used such that word three designate, the angle in degrees and word four designate the quadrant in which the line is to appear. Those skilled in the art will recognize that other word and bit assignments could be employed with equa success. Thus, according to the above description, the shi symbol 86 of Figure 10 would occupy twenty words in th symbol definition list corresponding to Figure 11. Ther would be one four word entry for each of the five line comprising the symbol for a total of twenty. Bit eight o the first word of the first four entries would be a "0" an bit eight of the last four word entry (i.e. bit eight o 10 word 17) would be a "1" to indicate that as being the las line vector description entry for that symbol. In practicing the present invention, each individual symbol to be employed in the display is assigned an entr (i.e. a sequence of 4-word line defining entries) on the -*-5 symbol definition list as defined in Figure 11. Regardless of how many times the symbol may appear dynamically on the display at any one time during the game, only one entry on the symbol definition list is required. Turning now to Figure 12, a single entry from the 0 display status list is shown. Each symbol presently active in the game (whether presently being displayed or not) has an entry of ten words on the display status list. Again, the entry of Figure 12 is shown with reference to a tested embodiment employing an eight bit computer word utilized in 5 a particular manner. Those skilled in the art will recognize that the specifics of the number of words employed and the bit assignments can be modified without the requirement of invention or experimentation. As with the entries of the symbol definition list of 0 Figure 11, word one of the display status list entry contains a "last entry" flag in bit eight, a "display" or "non-display" flag in bit one, and color designation indication in bits two through seven. Words two and three designate, the offset in the X coordinate from the 0,0 5 origin. Words four and five designate the Y offset from the origin. Note that the display screen layout and, therefore, the game logic operates in cartesian coodinates while the symbol— display logic operates in polar coordinates. The unique arrangement of the presen invention makes this beneficial combination possible. Words eight and nine designate an angle offset for th symbol and word ten is a size designation for the symbol when displayed. As will be seen in a more detailed description hereinafter, these offset capabilities provide ease of manipulation and action generation when the present invention is employed in a video game environment. Each entry of the display status list of Figure 12 in words six and seven contains a pointer or address vector to the associated symbol on the symbol definition list of Figure 11. For example, assuming that the five entry (one for each line) symbol definition for the ship symbol 86 of Figure 10 begins at memory location 3456, each entry on the display status list employing the ship symbol 86 would have in words six and seven thereof the vector address 3456. As should now be apparent, using the present invention, the game program logic can create detailed symbol movement on the display by manipulating the entries of Figure 12 on the display status list. For example, to rotate the ship symbol 86 at any .location in which it is an entry on the display status list, that entry need only have the angle designator of words eight and nine progressively increased. In similar manner, the ship can be moved in the X direction by increasing the X offset in words two and three or be moved in the Y direction by increasing the offset in words four and five. Combined movement is obtained by simultaneous changes to these values. Thus, the amount of memory available for the logic of the game itself is greatly increased inasmuch as very little is required for even complex manipulation of the display. The size designator of word ten is of particular importance in that complicated effects can be created by progressively increasing or decreasing the size of a given ? yt symbol alone or in combination with other movements. For example, moving the ship symbol 86 from the bottom of the display to the top and simultaneously increasing its size from a small size to a larger size creates the illusion of motion towards the viewer. ' The amount of movement and the amount of size increase govern the exact illusion created. The smaller the amount of vertical movement coupled with each size increase, the more the object looks like it is coming at the viewer horizontally. The ease of color association and modification achievable with the present invention should now be appreciated. For example, the basic definition of a player symbol (e.g., spaceship 86) employed by all players appears pnly once on the symbol definition list of Figure 11. It can be assigned a basic or universal color in that entry. By contrast, each individual active spaceship 86 of each player will have a separate entry on the display status list of Figure 12. Thus, all the ships of a particular player can be assigned an associated color to override the basic color designation. An individual ship symbol can have its own color designation changed to create special effects such as explosions. In a prior art game, the game logic would have had to accomplish that at the display output format level for each symbol. With the system of the present invention, such color manipulation becomes a simple task requiring a minimum of memory in the game logic. Since the designators occupy the same location in a contiguous list of entries, the actual manipulation can be accompished by an index guided subroutine to effect even further savings. This, of course, would not be possible with other more complex prior art approaches. A game system employing the present invention is shown in Figure 13. The game program 88 communicates with the player controls 90 and the display status list 92 which has the active symbol entries as described in Figure 12. The symbol definition list 94 is pre-established in the /' ^ B ^ - f - — £ ■ ■ \ - .' " » . manner of Figure 11. In actual practice, the game program 88 and the symbol definition list 94 are contained i programmable read only memory (PROM) while the displa status list 92 is created at playtime in dynamic memory. Also contained in PROM is the display composition logic 96. The display composition logic 96 accesses the display status list 92 and the symbol definition list 94 and creates therefrom the dynamic visual display on the CRT 98. Turning now to Figure 14 the specific logic employed in display composition logic 96 is shown in block diagram form. As will be well understood by those skilled in the art, the logic of Figure 14 accomplishing the purposes of the present invention can be implemented in many forms to achieve the same functional results. For example, it could be done with software, firmware, or hardwired logic. Any such implementation is easily accomplished by those skilled in the art from the flowchart of Figure 14 without expe imentation and, therefore, no further detail is included herein. Upon initial entry and subsequent re-entry at block 14.01, the logic first starts at the top of the display status list 92, i.e., the first entry according to Figure 12. At block 14.02, it accesses the ten wo-rds comprising the next entry, which, in the first instance, is the first entry. At decision block 14.03, the logic makes a decision as to whether this entry is to be displayed or not. This is accomplished by testing bit one of word one. If the entry is not to be displayed (i.e., bit one of word one is "0"), the logic continues to decision block 14.04 which then tests bit eight of word one to determine if this is the last entry on the display status list. If not, the logic bumps to the next entry. In the illustrated embodiment, this would, of course, mean increasing the address of the first word of the entry by ten. The logic then returns to block 14.02 to repeat the process with the next entry on display status list 92. If at decision block 14.04 the logic finds that this was the last entry, i.e., bit eight of word one is a "1", the logic returns to block 14.01 to scan, once again, the display status list 92. If desired, this latter path could include a time delay 5 assuring that the refresh cycle is repeated no faster than a given frequency. Returning to decision block 14.03, if the logic finds that this entry on the display status list 92 is to be displayed, it proceeds to the logic sequence beginning with 10 block 14.06. At block 14.06, the logic initializes the X,Y position at which the electron beam is to begin painting the particular symbol associated with this entry. It will be remembered that the symbol as defined in the symbol definition list 94 is with reference to an origin position 1.5 of 0,0. Thus, from words two, three, four and five of the entry on the display status list 92, the logic must pick up the X and Y offsets and initialize the position at which it is to begin painting the associated symbol. The logic then moves to block 14.07 where it picks up 0 the vector list address from words 6 and 7. It should be remembered that this is the address of the first word in the sequence of entries (described in detail in Figure 11) on the symbol definition list which define the particular symbol to be associated with this entry on the display 5 status list 92 at this particular time. It should also be appreciated that to create particular effects, the game program 88 can easily change the vector address to that of one or more new "symbols". Having picked up the vector list address, the logic 0 then moves to block 14.08 where it accesses the next entry on the symbol definition list 94. The first time through, of course, it is accessing the first entry. At block 14.09, the logic calculates the angle of the first vector. This angle is a combination of the original angle contained 5 in words three and four of the vector definition and the angle offset contained in words eight and nine of the entry on the display status list 92. Having determined the angle of the vector to be painted, the logic then moves to block 14.10 wherein the length of the vector is calculated. Again, this is a combination of entries from both lists. The basic length as original.lv defined is contained in word two of the entry on the symbol definition list. This length is adjusted as a function of the size indicator contained in word 10 of the entry on the display status list 92. Having now calculated the angle and length of the vector, the logic moves to block 14.11 wherein the X,Y coordinates of the beam following the painting of the vector is calculated and stored. It will be noted that this calculation and updating of data is accomplished at this point because the beam may be actively painted or, in the alternative, may be only a case of moving the electron beam between positions without actually illuminating the screen. The logic then moves to decision block 14.12 wherein that latter question is> in fact, asked. By testing bit one of word one of the entry, the logic can determine whether the particular vector is to be displayed or not. If it is, the logic moves to block 14.13 wherein associat »ed color settings are made according to the data contained in bits two through seven of word one of both entries. The exact nature of the actual color adjustment is dependent upon the system and, per se, forms no inventive portion of the present invention. Therefore, no greater detail is given. Having set the appropriate color designations, the logic next paints the vector across the display screen at the angle and for the length calculated. This is accomplished by the digital logic outputting a sequence of commands which causes the actual display driver to have its deflection voltage changed in discrete and equal steps. This approach is well known in the art and results in symbols of uniform intensity being generated regardless of variations in the lengths of the various line segments The logic in either case then moves to decision block 14,1 wherein bit eight of word one is tested to see if this i the last vector of the symbol. If it is not, the logi moves to block 14.16 wherein the address is bumped by fou to the next entry and then returns to block 14.08 to acces the next entry and repeat the process. If it is the las vector, the logic moves to decision block 14.04 to continu as previously described. Wherefore, it should be apparent from the foregoing description that the present invention truly provides a environment for dynamic display systems achieving the stated object. I claim:

Claims: 1. In a video display system wherein pre-established series of individual symbols are selectively displayed in multiple combination as a result of programmed logic to convey movement of associated objects within a defined area, the improvement characterized by: a) means for defining the respective individual possible symbols as a plurality of interconnected display lines of given angle and length with respect to a common coordinate system; b) means for maintaining the current status of the symbols to be actually displayed, said means including an indication of the individual possible symbols in said defining means associated with each display symbol and the angle and positional offset in the common coordinate system; wherein, c) the programmed logic only updates the status maintaining means to manipulate the dynamic display; and additionally comprising, d) logic means connected to the display for accessing said status maintaining means and said symbol defining means and for producing the dynamic display as a function thereof. 2. In a video game system wherein a computerized game program interfaces with player controls and creates a game display as a result of pre-programmed logic and the dynamic positioning of the controls, the improvement characte ized by: a) symbol definition means for defining the respective individual possible symbols to be used in the game as a plurality of interconnected display lines of given angle and length with respect to a common coordinate system; ' b) display status means for maintaining the current status of the symbols to be actually displayed, said display status means including an indication of the individual possible symbol in said symbol definition means associated with each displayed symbol and its angular and positional offset in the common coordinate system; wherein, c) the pre-established logic of the game interfaces only with the display status means and updates it to effect desired changes in the display; and, additionally comprising , d) display composition logic means connected to the display for accessing said display status means and said symbol definition means and for producing the dynamic display of the game as a function thereof. 3. The improvement to a video game of claim 2 wherein said display composition logic includes logic to accomplish the following steps: a) start at the top of the display status means; b) access the next entry on the display status means; c) test to see if the entry is to be displayed and if it is, proceed to step (f); d) test to see if the entry is the last entry on the list and if it is, return to step (a); e) bump to the next entry and- return to step (b); f) initialize the beginning X,Y position of the display beam for the particular symbol from data contained in the entry of the display status means; g) pick up the address of the entry on the symbol definition means for the associated symbol from the entry on the display status means; h) access the next entry; i) calculate the angle of the vector from the combined data on the display status means and the symbol definition means; •j) calculate the length of the vector from the combined data on the display status means and the symbol definition means; k) calculate and store the X,Y position of the bea following the display of the vector; 1) test to see if the vector is to be displayed an if not, proceed to step (o); m) set appropriate color designators as necessary; n) paint the vector on the display according to th pre-calculated angle and length data; o) test to see if it is the last vector and, if i is, return to step (d); and, p) bump to the next entry and return to step (h) . 4. The improvement to a video game of claim wherein: said symbol definition means defines each possibl symbol by defining a plurality of individual straight line comprising the symbol. 5. The improvement to a video game of claim 4 wherein: said plurality of straight lines are defined as a interconnected sequence of lines of designated angle an length starting from a given point. 6. The improvement to a video game of claim wherein: all said sequences of lines are started from a origin of 0,0 in an X-Y coordinate system. 7. The improvement to a video game of claim 4 wherein: the definition of each of said plurality of line includes an associated color designator. 3. The improvement to a video game of claim 2 wherein: a) said symbol definition means defines eac possible symbol by defining a plurality of individual straight lines comprising the symbol with reference to common origin point in an X-Y coordinate system; and, b) said display status means includes current X offset, Y offset and angular rotation offset designators. 9 . The improvement to a v ideo . game of claim 8 where in: said displ ay status means also includ es a curr ent size designator for the symbol . 10. The improvement to a video game of claim 8 wherein: said display status means also includes a current associated color designator for the symbol. 11. In a video game wherein pre-established game logic calculates data for the subsequent production of a CRT display including a plurality of moving symbols indicating the progress of the game, the improved method of operation characterized by the inclusion of the steps of: a) predefining the respective individual possible symbols to be used in the game in symbol definition means as a plurality of interconnected display lines of given angle and vector with respect to a common coordinate system; b) providing display status means for maintaining the current status of the sumbols to be actually displayed, said display status means including an indication of the individual possible symbol in said symbol definition means associated with each displayed symbol and the angle and positional offset in the common coordinate system; c) having the pre-established logic of the game interface only with the display status means and update it to indicate desired changes in the display; and, d) having display composition logic means connecte to the display access said display status means and sai symbol definition means and produce the dynamic display o the game as a function thereof. 12. The improved method of a video game of claim 1 wherein said display composition logic includes th following steps: a) starting at the top of the display status means; b) accessing the next entry on the display statu means; c) testing to see if the entry is to be displaye and if it is, proceeding to step (f); d) testing to see if the entry is the last entry o the list and if it is, returning to step (a); e) bumping to the next entry and returning to ste (b); f) initializing the beginning X, Y position of th display beam for the particular symbol from data contained n the entry of the display status means; g) picking up the address of the entry on the symbo definition means for the associated symbol from the entr on the display status means; h) accessing the next entry; i) calculating the angle of the vector from th combined data on the display status means and the symbol definition means; j) calculating the length of the vector from the combined data on the display status means and the symbol definition means; k) calculating and storing the X,Y position of the beam following the display of the vector; 1) testing to see if the vector is to be displayed and if not, proceeding to step (o); m) setting appropriate color designators a necessary; n) painting the vector on the display according t the pre-calculated angle and length data; o) testing to see if it is the last vector and, i it is, returning to step (d); and, p) bumping to the next entry and returning to ste ( ).

Inventors: PECORARO ROBERT A, PECORARO, ROBERT, A.
Applicants: GREMLIN IND INC, GREMLIN INDUSTRIES, INC.
Application year: 1982
Main classification: A63F9
IPC codes: A63F13, G06F3, G09G1, G09G5, H04N3