Group Members and tasks:

• Brandon Tipp: Project leader, game design, and graphics rendering & engine
• Mike Soukup: Game play, physics, and computer AI
• James Papp: User interface - keyboard, mouse, menus
• Kevin Slanicky: Networking
• Marcin Chwierut: Graphics and sound

Problem Description

This project combines challenges seen in previous MPs such as graphics rendering, player movement, input/output, as well as new challenges like networking and sound integration.  It also adds the most obvious and probably the hardest challenge - working as a group to complete the project.  Completing and testing an individual section of the program, such as all the tasks that were assigned to a member, does not mean that section is complete.  It must still be integrated with the routines written by the other members.  After integration, the whole program must be thoroughly tested to ensure that the combined procedures interact and function properly with all the other procedurs.  We are planning on finishing the individual routines a week before demonstration to allow a full week for integration.  If all goes well, we will finish integration early and have some extra days before the demonstration to add a few features we had to hold off on during planning.

We will have to design our own engines for every aspect of the game.  The hardest of them being the graphics engine.  It will have to render the overhead view, side view, and of course the hardest part, the forward looking view.  Another difficult aspect will be integrating the networking with the rest of the program.  Juggling packets from multiple players and interpreting all of them within a given time period will require excellent programming and thorough testing.  Another challenge, the user interface, needs to combine ease of use with functionality.  After all, if no one can get past the main menu, the can't play the game.  Another difficult part of the program will be the game play itself.  Keeping track of up to ten tanks and ten weapons along with a constantly changing terrain all at the same time is difficlut a task.   Add to that the control of the computer AI, and you've got quite a challenge.   Mixing the correct sound effects to flow smoothly with the action adds an important aspect that is needed for any good game.  All good games also require an introduction sequence that grabs the user's attention.  Creating the correct sequence is another formidable task.

Game Description and Operation

This project implements an improved version of the classic Scorched Earth game.  It combines a real time game taking place in a 3D world with 320x200 VGA graphics, sound, single player against the computer, or multi-player over a network.   The game starts with an introduction screen followed by the main menu with game type options and game setup options.  The actual game screen is divided into a large display showing the view from the front of the tank, two smaller displays showing an overhead shot of the whole battlefield and a side view much like the original Scorched Earth screen, along with a section dedicated to tank status such as turret angle, weapon power, inventory, health, fuel, etc.

The play will use both the mouse and keyboard (with user defined keys) to control all aspects of the game play.  During the game, the user will be able to change the view angle, switch weapons, adjust turret angle and weapon velocity, and navigate the terrain with the mouse and keyboard controls.  After targeting an enemy, the player can select from an arsenal of purchased weapons and let one fly.  The real time nature of the game is somewhat limited in order to preserve the strategic element of the original game.  Due to reload time, players may only shoot their weapons every 10 seconds.  Another complication with the weapon system, which is still left unexplained by the tank's engineers, prevents two weapons from the same player to be in flight at the same time.  Attempting to fire a second weapon causes the first one to be destructed.  If utilized correctly, this "feature" as the engineers prefer to call it can be used to detonate a near miss directly over an enemy's head, causing considerable damage.

The battle continues until only one tank is left standing, at which point the winner of that round is declared, and players receive their money based on performance in the previous round.  The game then enters the buying screen where players may spend their hard earned money on better weapons, increased shields, and fuel.  After all players (including the computer) have replenished and upgraded their stockpile of weapons and supplies, the next round begins.  Battle after battle are fought until the previously determined number of rounds have been played, after which the overall winner is decided and rewarded with a congradulations screen.  After the battles, all the players are returned to the main menu where another battle may be set up to settle once and for all who the best player is.

Implementation

This program was written entirely in assembly, completely from scratch (excluding a few adapted functions), including all graphics.  The first task was to divide the game areas between all the members, and each come up with procedures, variables, and data structures necessary to complete our part of the game.  We came up with five major sections (which is good becaue we have five people in our group) to break the game into: User interface - I/O & menues, Graphics and sound, Networking, Game play & AI, and the Game play graphics - 3D rendering.

Next we started on a preliminary game loop that tied together everyone's functions and gave a good idea exactly what needs to be done.  The next task was to split up and each write our functions, keeping in mind that they need to interact with eachother's procedures.  The main goal for the first week of programming was to get basic working functions so they can be put together as early as possible.  But that phase ran over the first week, and into the second.  We were finally ready to start integrading code on the Saturday before the project was due.  The integration turned up countless bugs in everyone's procedures that had to be fixed before we could continue.   This continuous integration of new code with the already functional base code continued until the due date.

We had a playable, yet very buggy alpha version finished by Tuesday night.  It didn't include the forward looking 3D screen, any type of AI (all computers took the same shot every time), or sound.  The 3D rendering was completed late Wednesday night, the AI was finialized around 4:00 Thursday morning, and the sound was integrated around 7:00 Thursday morning.  Other additions to the alpha were an improved menu structure, game play that included a dynamic terrain, and other fixes with the tank and weapon movement and calculation.  The beta version came together at 8:45 Thursday morning, just in time for the 9:00 handin.   This beta still didn't include tanks in the main 3D screen (although they were visible in the two side screens), networking, or economics.  Our demonstration of the beta Thursday night was flawless.

Screen Shots

One of the first working alpha's	First playable alpha. All the numbers in the main scren are for debugging the tanks and weapons
Another shot of the playable alpha. This time the numbers are used for debugging the AI.	The playable beta
Another of the beta	Yet another one
This is the last one, don't worry

Main Procedure

• Owners: Brandon Tipp, Mike Soukup, Jim Papp, Kevin Slanicky, Marcin Chwierut
• Purpose: Main game engine that calls and controlls everything.
• Description: It needs to make calls to introduce the game, start the main menu, drive the game, keep track of type of game, keep track of network or AI depending on game type, draw the screen, and exit the game.
• Inputs:
  • none
• Outputs:
  • none
• Calls: almost everything
• Flow of Main:
  1) Set up the game - interrupts, tables, etc.
  2) Show the introduction and enter the main menu where options can be set, game type can be selected, and program can be exited.
  3) Starts the actual game by asking for the player's name and setting up either a network or single player game.
  4) Give player the option to purchace weapons, and have computer buy weapons (if single player).
  5) Generate the random terrain for the next battle.
  6) Enter Battle loop where all player's and computer's (if single player) movements, shots, and hits are calculated, packets are transmitted and received, and the screen is rendered and drawn.   Stay in loop until only one tank remains.
  7) Repeat Battles until desired amount has been reached, and return to the main menu.
  8) If player chooses exit, show credits and exit the game.

Miscellaneous Procedures

_SetUpTables

• Owner: Brandon Tipp
• Purpose: To fill in the _SinTable, _CosTable, _CotTable, and the _DeltaZTable.
• Description: C function that generates look-up tables for functions so the index into the table will give that function of the angle.
• Variables: none
• Inputs: none
• Outputs:
  • _SinTable
  • _CosTable
  • _CotTable
  • _DeltaZTable
• Calls: none

SetUpProgram

• Owner: Brandon Tipp
• Purpose: To set the environment so we can run the game.
• Description: Places computer in 320x200x256 graphics mode and installs the interrupts.
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • InstallKey
  • InstallTimer

FinishProgram

• Owner: Brandon Tipp
• Purpose: To reset the environment when the game is done.
• Description: Places the computer back into text mode and deinstalls the interrupts.
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • DeInstallKey
  • DeInstallTimer

RandVal

• Owner: BrandonTipp
• Purpose: Generates a random number.
• Description: Makes a BIOS call to the computer's clock to return the number of ticks past midnight.  This value is then used to initialize _RandSeed.
• Variables:
  • _RandSeed
• Inputs:
  • System clock
• Outputs: none
• Calls: none

QuickRand

• Owner: Brandon Tipp
• Purpose: Generate a random number quickly.
• Description: Multiplies _RandSeed by a prime number and adds in another prime number to generate a pseudo random number.
• Variables:
  • _RandSeed
• Inputs: none
• Outputs:
  • ax - a number between 0000h and FFFFh
• Calls: none

WorldHeight

• Owner: Brandon Tipp
• Purpose: Determine the height of the world at a point.
• Description: If dx is 0, determine the height of the world at the nearest world cell.  If dx is 1, determine the height of the position by interpolating the four nearest ponts.
• Variables:
  • _WorldArray
• Inputs:
  • ax - x position (in 256ths of a cell)
  • bx - y position (in 256ths of a cell)
  • dx - method of calculation, 0 returns nearest value, 1 interpolates
• Outputs:
  • ax - the height (in 256ths of a cell)
• Calls: none

CalculateWorldPosition

• Owner: Brandon Tipp
• Purpose: Calculate the X, Y, and Z position in the world given a starting point, a heading, a declination, and a range.
• Description:
• Variables: none
• Inputs:
  • _X, _Y, _Z - starting points of tank
  • _ViewAngle - heading (in 1/3 degrees from +x)
  • ax - offset from heading (signed in 1/3 degrees from +x)
  • dx - declination (signed in 1/3 degrees from the horizon
  • bx - range (index into the Range array pointing to the range)
  • WorldArray
• Outputs:
  • ax - the x position in 256ths of a cell
  • bx - the y position in 256ths of a cell
  • cx - the z position in 256ths of a cell
• Calls: none

ChooseHostRandoms

• Owner: Kevin Slanicky
• Purpose: Choose random values for terrain and tank positions.
• Description: Selects random values used to generate the terrain, and selects random values for placing the host computer.
• Variables:
  • TankArray
  • _XScale1
  • _YScale1
  • _XScale2
  • _YScale2
  • _XPhi1
  • _YPhi1
  • _XPhi2
  • _YPhi2
• Inputs: none
• Outputs: none
• Calls:
  • QuickRand

ChooseClientRandoms

• Owner: Kevin Slanicky
• Purpose: Choose random values for the Client's position.
• Description: Selects a position for the tank.
• Variables:
  • TankNumber
  • TankArray
• Inputs: none
• Outputs: none
• Calls:
  • QuickRand

ChooseSingleRandoms

• Owner: Kevin Slanicky
• Purpose: Choose random values for a single player game.
• Description: Selects random values used to generate the terrain, and selects random values for placing the players.
• Variables:
  • TankArray
  • NumberOfPlayers
  • _XScale1
  • _YScale1
  • _XScale2
  • _YScale2
  • _XPhi1
  • _YPhi1
  • _XPhi2
  • _YPhi2
• Inputs: none
• Outputs: none
• Calls:
  • QuickRand

_CalculateTerrain

• Owner: Brandon Tipp
• Purpose: From the chosen random values, use sine functions to generate the terrain.
• Description: For a given X and Y coordinate in the world array, the value of 128 + 128 * {(XScale1/FFFFh*sin(X*pi/125+_XPhi1) + (_XScale2/FFFFh*sin(X*pi/250+_XPhi2)} * {(YScale1/FFFFh*sin(Y*pi/125+_YPhi1) + (_YScale2/FFFFh*sin(Y*pi/250+_YPhi2)  It does this by filling in the XTable and YTable, then multiplying the waves stored in these tables by each other.
• Variables:
  • XTable
  • YTable
  • _XScale1
  • _YScale1
  • _XScale2
  • _YScale2
  • _XPhi1
  • _YPhi1
  • _XPhi2
  • _YPhi2
  • _WorldArray
• Inputs: none
• Outputs: none
• Calls: none

Graphics Procedures

Intro

• Owner: Marcin Chwierut
• Purpose: Introduces the game.
• Description: Displays the introduction screens allowing the procedure to be interrupted by pressing ESC buton
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • _InstKey
  • _DeInstallKey
  • MLoadPCX
  • MShowScreenBuffer
  • ZoomLogo
  • Fade
  • MoveScreendn

Outro

• Owner: Marcin Chwierut
• Purpose: Display ending screens.
• Description: Displays ending screens, allows the procedure to be interrupted by pressing ESC button.
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • _InstKey
  • _DeInstallKey
  • MLoadPCX
  • MShowScreenBuffer
  • Fade
  • MoveScreendn

ZoomLogo

• Owner: Marcin Chwierut
• Purpose: Zooms the logo in.
• Description: By taking the starting position and the starting scale factor, the pcx is scaled to fit the 320x200 screen
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

MLoadPCX

• Owner: Marcin Chwierut
• Purpose: Loads and decodes PCX file into memory.
• Description: Given the offset of the pcx file, and the destination segment the pcx is loaded to the given buffer.
• Variables: none
• Inputs:
  • ax - destination segment address
  • dx - offset of the pcx file
• Outputs:
  • Fills destination segment with image data
• Calls: none

MShowScreenBuffer

• Owner: Marcin Chwierut
• Purpose: Move 320x200 pixels of screen data from ScreenBuffer to the screen
• Description: Moves the information in ScreenBuffer to the screen.
• Variables: none
• Inputs:
  • ScreenBuffer
• Outputs:
  • writes data to the screen
• Calls: none

MoveScreenDn

• Owner: Marcin Chwierut
• Purpose: Scroll the screen down.
• Description: Scrolls the screen down by putting the number of lines into the background buffer and the moving it to screenbuffer after displaying that data.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

Fade

• Owner: Marcin Chwierut
• Purpose: Fades out the screen
• Description: Fades out the screen by decrementing the intensities of each color in the color palette of the video card until they reach 0.
• Variables: none
• Inputs: none
• Outputs:
  • writes to the color palette in video card
• Calls: none

_InstKey

• Owner: Marcin Chwierut
• Purpose: Install new keyboard interrupt.
• Description: Replaces the old interrupt vecor to the new one.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

_DeInstallKey

• Owner: Marcin Chwierut
• Purpose: Reinstall the old keyboard interrupt.
• Description: Replaces the new interrupt vector by the old one.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

MyKeyInt

• Owner: Marcin Chwierut
• Purpose: The acutal key interrupt vector.
• Description: The only key accepted is the ESC key.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

_ClearBuffer

• Owner: Marcin Chwierut
• Purpose: Clears a buffer
• Description: This procedure is used to clear the screen buffer in orer to output it to the screen between different screens are loaded.
• Variables: none
• Inputs: Segment to be cleared
• Outputs: clean buffer
• Calls: none

DelayProc

• Owner: Marcin Chwierut
• Purpose: Delay
• Description: Used to delay various operations.
• Variables: none
• Inputs: delay amount
• Outputs: none
• Calls: none

Sound Procedures

ProgramDSP

• Owner: Marcin Chwierut
• Purpose: Make appropriate writes to the DSP in order to output the sound file through the speakers.
• Description: First the speaker is turned on by writing 0D1h to the dsp, next the output frequency is written to the sound card, then the time constant is written, and finally the file length is written to the sound card - at this point sound card is ready to output the file.
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • DSPWrite

ProgramDMA

• Owner: Marcin Chwierut
• Purpose: Setup DMA for data transfer
• Description: This procedure first calculates the page and offset, then disables the dma channel, writes the length of the file in order for the dma to transfer the right amount of data to the sound card, then it enables the dma channel.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

DSP_Reset

• Owner: Marcin Chwierut
• Purpose: Resets the sound card.
• Description: This procedure writes 1 to the reset port, than it waits for 3 microseconds, next it writes 0 to the reset port, then it polls the read-buffer status port, and finally polls the read data port.
• Variables: none
• Inputs:
  • Sound Blaster address
• Outputs:
  • ax - 00h if sound card was sent successfully, AAh if reset was unsuccessful
• Calls: none

PlayWave

• Owner: Marcin Chwierut
• Purpose: Calls appropriate procedures in order to output the wav files
• Description: Main sound effects procedure.  First it makes a call to RESET_DSP, then it sets appropriate volume level, loads the wave file into the appropriate buffer, calls ProgramDMA.  Next it calls ProgramDSP procedure, after that last call wave file is sent to the sound card and heard through the speakers
• Variables: none
• Inputs:
  • ax - offset of the wav file
  • cl - LSB left channel volume level, MSB right channel volume level
• Outputs:
  • plays sound
• Calls:
  • DSP_reset
  • ProgramDMA
  • ProgramDSP

InstallSBISR

• Owner: Marcin Chwierut
• Purpose: Install the new sound card ISR.
• Description: Based on sound card's interrupt, the new ISR is installed.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

DeinstallSBISR

• Owner: Marcin Chwierut
• Purpose: De-install the sound's ISR
• Description: The old interrupt service routine is set in its oritinal place
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

DSP_IRQdone

• Owner: Marcin Chwierut
• Purpose: The actual new interrupt routine
• Description: Outputs the value 20h to the interrupt coutroller port 20h
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

PlayMidi

• Owner: Marcin Chwierut
• Purpose: Output the midi file to the sound card.
• Description: Making appropriate int66h calls this procedure sends the file to the sound card
• Variables: none
• Inputs:
  • ax - offset of the midi file
• Outputs: midi file is played
• Calls: none

GetSBSettings

• Owner: Marcin Chwierut
• Purpose: Extract the DMA, IRQ, and sound blaster base address values from the DOS environment variables.
• Description: Searches for the word BLASTER in the DOS env vars, after which the IRQ, DMA, and sound blaster base address vlues are located.
• Variables: none
• Inputs: none
• Outputs:
  • irq, dmachannel, & sb_addr values are updated
• Calls: none

SetDMA

• Owner: Marcin Chwierut
• Purpose: Set appropriate DMApage, DMAaddress, and DMAcount variables.
• Description: Based on the DMAchannel extracte by the GetSBSettings procedure, the DAMpage, DAMaddress, and DMAcount values are updated.
• Variables:
  • DMAchannel
  • DMApage
  • DMAaddres
  • DMAcount
• Inputs: none
• Outputs: none
• Calls: none

GamePlay Procedures

CalculateMovement

• Owner: Mike Soukup
• Purpose : Controls the movement and firing of a tank.
• Description: Based on the keyboard variables, determines what actions the tank should perform, and creates a weapon in WeaponArray if necessary.  Is also responsible for playing sound effects.
• Variables:
  • Keyboard state variables: TurnRight, TurnLeft, GoForward, GoBack, TurretUp, TurretDown, VelocityUp, VelocityDown, Shoot, Recharge, SpeedUp, Suicide)
  • TankArray - X position, Y position, Z position, View Angle, TurretAngle, Projectile Velocity, Fuel, Ammunition, and Time Until Next Shot
  • WeaponArray (if shot is fired) - all
• Inputs:
  • cx - Tank number
• Outputs: none
• Calls:
  • WorldHeight
  • Sound functions

CalculateWeapon

• Owner: Mike Soukup
• Purpose: Controls the flight of a weapon.
• Description: Calculates where the weapon will be in the next frame using current position and velocity.  Checks if weapon hits a tank or the ground, if so, detonate it.  Also calculates any damage done to tanks or the ground..
• Variables:
  • WeaponArray - all
  • NukeOnScreen
  • WindX
  • WindY
  • Gravity
• Inputs:
  • cx - Weapon number
• Outputs: none
• Calls:
  • WorldHeight

CalculateWorldDamage

• Owner: Mike Soukup
• Purpose: Calculates any changes (addition or subtraction of dirt) to the terrain due to weapon explosions.
• Description: Takes the current blast radius of the exploding weaon and subtracts or adds dirt to the terrain by iterating through an array containing dirt decrements/increments and adding/subtracting the value.
• Variables:
  • NumberOfPlayers
  • WeaponArray
  • Radius5, Radius10, Radius15, Radius20, Radius25
  • WorldArray
• Inputs: none
• Outputs: none
• Calls: none

SetUpWar

• Owner: Mike Soukup
• Purpose: Reset the variables to starting values.
• Description: Resets the weapon & shield inventory, RoundsWon, and LastKilledBy fields in the TankArray back to the starting values.
• Variables:
  • TankArray
  • Rounds
  • RoundsLeft
• Inputs: none
• Outputs: none
• Calls: none

SetUpBattle

• Owner: Mike Soukup
• Purpose: Reset TankArray and WeaponArray for the start of a Battle.
• Description: Places tank in a random position on the map, resets the view agle, turret angle, projectile velocity, heath, and time until next shot.
• Variables:
  • TankArray - X position, Y position, Z position, View Angle, Turret Angle, Projectile Velocity, Health, and Time Until Next Shot
  • WeaponArray - all
• Inputs: none
• Outputs: none
• Calls:
  • QuickRand

ResetBattleLoop

• Owner: Mike Soukup
• Purpose: Resets variables used in battle loop.
• Description: Resets to 0 variables set by CalculateTank and CalculateWeapon and used by graphics and rendering.
• Variables:
  • Selected_Weapon
  • WeaponSelect
  • Shield_Selected
  • ShieldSelect
  • NukeOnScreen
  • DamageTaken
  • NumberOfPlayers
  • DamageArray
• Inputs: none
• Outputs: none
• Calls: none

CheckBattleDone

• Owner: Mike Soukup
• Purpose: Check if the battle is over.
• Description: Check if only one tank is alive, and all weapons have been detonated, which means the battle is over.
• Variables:
  • TankArray
  • WeaponArray
  • NumberOfPlayers
• Inputs: none
• Outputs:
  • ax - 1 if battle is finished, 0 if battle is still going
• Calls: none

AI Procedures

ComputerBuy

• Owner: Mike Soukup
• Purpose: Determines what weapons and shields the computer player purchases.
• Description: Simply picks random weapons for the computer to buy, but makes sure not to go bankrupt.
• Variables:
  • TankArray - Money, Ammunition
• Inputs:
  • cx - Tank number
• Outputs:  none
• Calls: none

CalculateAI

• Owner: Mike Soukup
• Purpose: Does all the AI work
• Description: Function that is called by main, so it is responsible for all the AI calls.   Calculates any computer movement as a result of terrain changes, determines who the computer targets, calculates a correct shot, deviates a bit from the shot, and shoots.
• Variables:
  • TankArray
  • NumberOfPlayers
  • Rounds
  • RoundsLeft
  • OverallWinner
  • WinnerOfLastRound
• Inputs:
  • cx - Tank number
• Outputs: none
• Calls:
  • WorldHeight
  • CalculateCloseShot
  • CalculateBetterShot
  • ComputerShot
  • QuickRand

CalculateCloseShot

• Owner: Mike Soukup
• Purpose: Given a target tank, calculate a shot that will come close to its target.
• Description: Takes the tank position and target position and calculates a shot that will hit the target if wind and altitude changes are disregarded.
• Variables:
  • TankArray
• Inputs:
  • cx - Tank number
• Outputs: none
• Calls: none

CalculateBetterShot

• Owner: Mike Soukup
• Purpose: Change the starting velocity, angle, and turret angle, so a closer shot is generated.
• Description: By figuring out the distance and angle the previous shot missed its target by, adjust the velocity, angle, and turret angle, based on how close the previous shot came.
• Variables:
  • TankArray
• Inputs:
  • cx - Tank number
• Outputs: none
• Calls: none

ComputerShot

• Owner: Mike Soukup
• Purpose: Have the computer shoot its weapon.
• Description: Creates a weapon in WeaponArray.
• Variables:
  • TankArray
  • WeaponArray
  • _SinTable
  • _CosTable
• Inputs:
  • cx - Tank number
• Outputs: none
• Calls:
  • QuickRand

Graphics and Rendering Procedures

RenderGameText

• Owner: Jim Papp
• Purpose: Display any text on the battle screen.
• Description: Writes text to the screen.  Fills in numbers next to the weapons to indicate number left.  Writes the message in ScreenTextBuffer to the bottom of the 3D window.
• Variables:
  • TankArray
  • ScreenTextBuffer
  • SBseg
• Inputs: none
• Outputs: none
• Calls:
  • RenderString

RenderOverhead

• Owner: Brandon Tipp
• Purpose: Fill in the 50x50 overhead view of the batle screen.
• Description: Writes to the screen an overhead of the world with tanks.  Shows your position in white and each of the other living tanks in a different color.  All moving weapons on the screen are rendered in red, while exploding weapons are rendered as an intense red circle.
• Variables:
  • WorldArray
  • TankArray
  • WeaponArray
  • SBseg
• Inputs: none
• Outputs: none
• Calls:
  • ScaleSprite

RenderSide

• Owner: Brandon Tipp
• Purpose: Fill in the 50x50 side view box.
• Description: Writes to the screen a side view of everything in front of you including tanks and weapons, limited to a range of MaxRange.  (The world is 2500m across)  The weapon is rendered as a red dot when not exploding, and as an intense red circle when exploding.
• Variables:
  • WorldArray
  • TankArray
  • WeaponArray
  • SBseg
• Inputs: none
• Outputs: none
• Calls:
  • ScaleSprite

Render3D

• Owner: Brandon Tipp
• Purpose: Fill in the 180x180 forward 3D view box.
• Description: Calls functions that determine the proper color of each pixel on the screen, and draws the points.
• Variables: SBseg
• Inputs: none
• Outputs: none
• Calls:
  • CalculateWorldPosition
  • ScaleSprite
  • CastBack

CastBack

• Owner: Brandon Tipp
• Purpose: Determine the relative angle, and declination of an object.
• Description: Determines the position on the screen where an object would be drawn using trig.  Since it is a wrap around world, the function attempts to wrap the object around so ax will be between -30*3 and 30*3.  di points to the location in the screenbuffer where a point would be drawn on the screen at these coordinates.
• Variables:
  • _X, _Y, _Z - tank position to cast from
  • _ViewAngle - reference heading to start from
• Inputs:
  • ax - X position of the object
  • bx - Y position of the object
  • dx - Z position of the object
• Outputs:
  • ax - the angle to the object relative to the view angle (-180*3 to 180*3)
  • bx - the declination to the object relative to the horizon (-90*3 to 90*3)
  • dx
    • 0 - |ax| > 30*3 or |bx| > 30*3
    • 1 - otherwise
  • di - if dx = 1, 320 * 189 + (bx +30*3) * 320 + (ax +30*3)
• Calls: none

WorldHeight

• Owner: Brandon Tipp
• Purpose: Determine the height of the world at a point.
• Description: If cx is 0, determine the height of the world at the nearest world cell.   If cx is 1, determine the height of the position by interpolating the four nearest points.
• Variables: none
• Inputs:
  • ax - X position (in 256ths of a cell)
  • bx - Y position (in 256ths of a cell)
  • cx - method of calculation, 0 returns nearest value, 1 interpolates
• Outputs:
  • dx - the height (in 256ths of a cell)
• Calls: none

ScaleSprite

• Owner: to be assigned
• Purpose: Scale a sprite
• Description:
• Variables: none
• Inputs:
  • ax - the sprite number to scale
  • bx - the square dimensions of the final sprite image
• Outputs:
  • ScratchSeg - a square matrix (starting at offset 0) bx*bx large, containing the scaled sprite with 0's as the invisible color.  The maximum size that will be taken up is 180x180, with the image scaled and cropped to fit.
  • bx - the actual size of the scaled bitmap.  This equals the input if it was less than 180, and 180 otherwise
• Calls: none

Network Procedures

ProcessInfo

• Owner: Kevin Slanicky
• Purpose: Processes all incoming packets
• Description: First determines which type packet is, the based on type processes all the information contained in the packet.
• Variables:
  • TankArray
  • WeaponArray
  • RXBuffer
• Inputs: none
• Outputs: none
• Calls: none

GenerateGame

• Owner: Kevin Slanicky
• Purpose: Responsible for setting up a server on the computer that wants to host a game.
• Description: Adds the group name "ScorchedFinalPrj" then adds the unique name "ScorchedFina00$$" as the first player.  Then it sends out a packet every 1/18th of a second waiting for NumberOfPlayers more people to join the game.  It then responds back acknowledging their admittance into the game.
• Variables:
  • NumberOfPlayers
• Inputs: none
• Outputs: none
• Calls: none

JoinGame

• Owner: Kevin Slanicky
• Purpose: Allow other players to search for a game to play in.
• Description: The new player waits to receive data from a host that is sending out its information.  Once it has found a game, it returns 1 for success.
• Variables: none
• Inputs: none
• Outputs:
  • ax - 1 for success, 0 for failure to locate game
• Calls: none

SendRandoms

• Owner: Kevin Slanicky
• Purpose: Send random numbers used to generate terrain.
• Description: Sends the random variables that the host generated in order to have one terrain in use by all players.
• Variables:
  • Terrain variables
• Inputs: none
• Outputs: none
• Calls: none

GetHostRandoms

• Owner: Kevin Slanicky
• Purpose: Recieve terrain information from host.
• Description: Allows client players to get the data that the host created in regards to the terrain.
• Variables:
  • Terrain variables
• Inputs: none
• Outputs: none
• Calls: none

CheckNetworkReady

• Owner: Kevin Slanicky
• Purpose: Make sure all players are ready for battle to start.
• Description: Waits until the host has received a packet from all players indicating they are ready to play.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

WaitNetworkReady

• Owner: Kevin Slanicky
• Purpose: Make hosts wait for game to begin.
• Description: The function the clients use to wait for the host to finish up.  It will receive information that is generated in the CheckNetworkReady function.
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

SendPosition

• Owner: Kevin Slanicky
• Purpose: Inform host of position in terrain.
• Description: Sends out to all computers the information regarding its present location.
• Variables:
  • TankArray
• Inputs: none
• Outputs: none
• Calls: none

SendBattlePacket

• Owner: Kevin Slanicky
• Purpose: Inform everyone about the tank's current position as well as the position of its weapon.
• Description: The information is sent to all computers so that each client can determine if it is affected by the tank that is sending data.
• Variables:
  • TankArray
  • WeaponArray
• Inputs: none
• Outputs: none
• Calls: none

I/O Procedures

_InstKey

• Owner: Jim Papp
• Purpose: Installs the keyboard interrupt, and saves the old vector.
• Description:
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

_DeInstallKey

• Owner: Jim Papp
• Purpose: Restores the default keyboard interrupt.
• Description:
• Variables: none
• Inputs: none
• Outputs: none
• Calls: none

_MyKeyInt

• Owner: Jim Papp
• Purpose: Interprets keyboard interrupts.
• Description: Called by vector table on interrupt 9 ( IRQ 1).
• Variables:
  • KeyStateTable
• Inputs: none
• Outputs: none
• Calls: none

_UpdateGlobalIO

• Owner: Jim Papp
• Purpose: Sets all the globals that are controlled by user I/O.
• Description: Monitors KeyStateTable for user input, and updates global I/O variables accordingly.  Allows for customizable controls.
• Variables:
  • KeyStateTable
  • Global I/O variables
• Inputs: none
• Outputs: none
• Calls: none

Main_Menu

• Owner: Jim Papp
• Purpose: Give user access to game.
• Description: Gives access to physics, economics, and other menus.   Each of these will be its own screen, with its own controls and menu, but will essentially be the same, returning to Main_Menu when they are done, and setting their own globals.
• Variables: none
• Inputs: none
• Outputs: none
• Calls:
  • other menu functions

Blit_Char

• Owner: Jim Papp
• Purpose: Displays an 8x8 character to video memory
• Description: Uses the ROM on the video card to display the character
• Variables: none
• Inputs:
  • ax - x position
  • bx - y position
  • ch - character
  • cl - color
  • dl - transparency flag
• Outputs: none
• Calls: none

Blit_Integer

• Owner: Jim Papp
• Purpose: Displays an 8x8 integer to the screen
• Description: Uses the ROM on the video card to display the character
• Variables: none
• Inputs:
  • ax - x position
  • bx - y position
  • ch - integer
  • cl - color
  • dl - transparency flag
• Outputs: none
• Calls: none

DrawBars

• Owner: Mike Soukup
• Purpose: Draws a bar on the screen of varying length, offset, and color
• Description: Given a starting X and Y offset and two numbers, draws a line scaled to represent the fraction CurrNumber/MaxNumber
• Variables: none
• Inptus:
  • ax - Maximum width of bar
  • bx - Current number
  • cx - Maximum number
  • bl - color
  • WordBuffer - XStart
  • WordBuffer2 - YStart
• Outputs: none
• Calls: none

Constants

Tank Related

Global Variables and Structures

Keyboard/Mouse variables

• TurnRight
• TurnLeft
• GoForward
• GoBack
• TurretUp
• TurretDown
• PowerUp
• PowerDown
• Shoot
• Recharge
• SpeedUp
• Suicide

Store information about Tanks and Weapons

• TankArray - holds 10 Tank structures
• WeaponArray - holds 10 Weapon structures
• Tank - Structure that holds all information about a tank

  • Tank	STRUCT
    	BabyMissile_	Word 0FFFFh	; Amount of each weapon left
    	Missile_	Word 0
    	BabyNuke_	Word 0
    	Nuke_	Word 0
    	DirtBall_	Word 0
    	TonOfDirt_	Word 0
    	BabyRiotBomb_	Word 0
    	RiotBomb_	Word 0
    	PlazmaBlast_	Word 0
    	RegShield_	Word 0
    	MedShield_	Word 0
    	HeavyShield_	Word 0
    	Status	Byte 0	; 0 = dead, 1 = alive
    	XPos	Word 0
    	YPos	Word 0
    	ZPos	Word 0
    	ViewAngle	Word 0	; View angle in X-Y plane
    	TurretAngle	Word 0	; View angle from X-Y plane to Z axis
    	Power	Word 0	; Initial velocity of shot
    	Money	DWord 0
    	WeaponSelected	Byte 0	; Which weapon is currently selected
    	Health	Byte 0	; Health of tank
    	ShieldHealth	Byte 0	; Amount of shields left
    	Fuel	Byte 0	; Amount of fuel left
    	Batteries	Word 0
    	Time	Word 0	; Time until next shot
    	ShieldTime	Word 0
    	RoundsWon	Word 0
    	KillsInRound	Word 0
    	; Used in AI
    	Target	Byte 0	; Who the tank is targeting
    	LastKilledBy	Byte -1	; Who killed the tank last
    	CloseVelocity	Word 0	; Shot that will hit target
    	CloseTurret	Word 0
    	CloseAngle	Word 0

• Weapon - Structure that holds all information about a tank's weapon in the air

  • Weapon	STRUCT
    	Status	Word 0	; 0 = none, 1 = in air 2+ = exploding
    	Kind	Word 0	; Type of weapon
    	XPos	Word 0	; Position of weapon
    	YPos	Word 0
    	ZPos	Dword 0
    	XVel	Word 0	; Velocity of weapon
    	YVel	Word 0
    	ZVel	Word 0
    	Increment	Byte 0	; Used to slow explosion rate

Special Thanks:

• Kevin Huffenberger for his help with the physics.
• All the members of other groups who helped us out and kept us entertained during all those long nights/mornings.
• Pepsi-Cola, the makers of Mountain Dew.

This page is created and maintained by Mike Soukup
This page was last updated Friday, May 1, 1998