Circular Line of Sight by Zwarteziel7th Feb 2014 18:25
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Summary Circular Line of Sight: a program that lets a user navigate a map, while highlighting tiles that are in the player's Line of Sight (LOS). Description Circular Line of Sight: a program that generates a map from a file and lets the user navigate it, while highlighting tiles that are in the player's Line of Sight (LOS). The LOS is round (360dg.) but can be modified to check only a part of the circle. (For instance when one should one want to implement a method were a player can only look in the direction it is facing). The code needs a map-file (in \media\maps) which is included in the CodeBase as a .ZIP-file. Code ` This code was downloaded from The Game Creators
` It is reproduced here with full permission
` http://www.thegamecreators.com
//
// Round Line of Sight: a program that generates a map from a file and lets the user
// navigate it, while highlighting tiles that are in the player's Line of Sight (LOS).
// The LOS is round (360dg.), and based on an example from Roguebasin: bit.ly/1duW4dQ
// Needs a map-file (in \media\maps) which is included in the CodeBase as a .ZIP-file.
//
// Zerotown, AGK v1.821
//
`======================================================================================
` Set variables and assign values
`--------------------------------------------------------------------------------------
#constant KeyLeft 37
#constant KeyUp 38
#constant KeyRight 39
#constant KeyDown 40
#constant KeyEsc 27
// variables for the map
global MapLength as integer : MapLength = 64
global MapWidth as integer : MapWidth = 64
type MapUDT
Char$ as string
Visible as integer
Transparent as integer
endtype
dim Map[64, 64] as MapUDT
// variables for the sprites
global SprMap as integer
global SprSize as integer : SprSize = 12
global SprPlayer as integer
global SprPosX as integer
global SprPosZ as integer
// variables for debug information
global DebugInfo as integer : DebugInfo = 1
// variables for setting the screen
global ScreenAspect# as float
global ScreenHeight# as float
global ScreenMax# as float
global ScreenMin# as float
global ScreenWidth# as float
// variables for minimap
global PlayerPosX as integer
global PlayerPosZ as integer
global MapSizeX# as float : MapSizeX# = MapWidth * SprSize
global MapSizeZ# as float : MapSizeZ# = MapLength * SprSize
// variables for the los-function
global GridX as integer
global GridZ as integer
global LOSRange as integer : LOSRange = 8
global SnapX# as float
global SnapZ# as float
// variables for the main loop
global GameState as integer : GameState = 1
`======================================================================================
` Load data and create sprite
`--------------------------------------------------------------------------------------
LoadMap("maps/Dungeon02_64.map")
// create map-sprite
SprMap = CreateSprite(0)
setSpriteSize(SprMap, SprSize, SprSize)
setSpriteTransparency(SprMap, 0)
SetSpriteDepth(SprMap, 11)
// create player-sprite
SprPlayer = CreateSprite(0)
setSpriteSize(SprPlayer, SprSize, SprSize)
setSpriteColor(SprPlayer, 86, 117, 226, 255)
setSpriteTransparency(SprPlayer, 0)
SetSpriteDepth(SprPlayer, 10)
`======================================================================================
` Set the screen
`--------------------------------------------------------------------------------------
SetOrientationAllowed(0, 0, 1, 1)
SetVirtualResolution(1024, 768)
SetResolutionMode(0)
SetPrintSize(18)
SetClearColor(0, 0, 0)
SetScissor(0, 0, 0, 0)
SetSortTextures(1)
SetSyncRate(0, 0)
ScreenWidth# = GetVirtualWidth()
ScreenHeight# = GetVirtualHeight()
if ScreenWidth# > ScreenHeight#
ScreenMin# = ScreenHeight#
ScreenMax# = ScreenWidth#
else
ScreenMin# = ScreenWidth#
ScreenMax# = ScreenHeight#
endif
ScreenAspect# = ScreenMax# / ScreenMin#
`======================================================================================
` Set position of player
`--------------------------------------------------------------------------------------
// find a valid position for a 'player' which is used as a reference in this example
repeat
PlayerPosX = Random(1, MapWidth)
PlayerPosZ = Random(1, MapLength)
until Map[PlayerPosX, PlayerPosZ].Char$ = ":"
`======================================================================================
` Execute main program loop
`--------------------------------------------------------------------------------------
repeat
// calculate player position on grid
GetTilePos(PlayerPosX * SprSize, PlayerPosZ * SprSize, SprSize)
// clear the current LOS
ClearLOS(GridX, GridZ, LOSRange)
// calculate the new LOS
CalcLOS(GridX, GridZ, LOSRange)
// show map
ShowMiniMap(1, 1, MapWidth, MapLength)
// position the player-sprite
SetSpritePosition(SprPlayer, PlayerPosX * SprSize, PlayerPosZ * SprSize)
// check for user input
CheckInput()
// display some debug-information
if DebugInfo = 1
` print("FPS : " + str(Screenfps()))
print("Move with arrow keys")
print("Position X/Y : " + str(GridX) + ", " + str(GridZ))
endif
Sync()
until GameState = 0
SetRawMouseVisible(1)
end
`======================================================================================
` Function to determine position on grid
`--------------------------------------------------------------------------------------
function GetTilePos(PosX#, PosZ#, Size)
GridX = PosX# / Size
GridZ = PosZ# / Size
endfunction
`======================================================================================
` Function to reset the LOS-values
`--------------------------------------------------------------------------------------
function ClearLOS(PosX, PosZ, Range)
// reset all visible tiles within range and edge of range
for z = PosZ - (Range + 1) to PosZ + (Range + 1)
for x = PosX - (Range + 1) to PosX + (Range + 1)
if z => 1 and z <= MapLength
if x => 1 and x <= MapWidth
if Map[x, z].Visible = 1 then Map[x, z].Visible = 0
endif
endif
next x
next z
endfunction
`======================================================================================
` Function to calculate the line of sight for the player
`--------------------------------------------------------------------------------------
function CalcLOS(PosX, PosZ, Range)
// check tiles within range of the player in an expanding circle
for Angle# = 1 to 360 step 0.3 ` decrease stepsize to increase the accuracy with which tiles are checked. (results in slower calculation)
LOSPosX# = PosX + 0.5 ` convert positions of player to a float. Add 0.5 to place player in center of circle
LOSPosZ# = PosZ + 0.5
AngX# = Cos(Angle#)
AngZ# = Sin(Angle#)
Block = 0 ` local variable to check if a position on the grid is blocked (1) or not (0)
Dist = 0 ` local variable to check if distance set with LOSRange has been reached
// check to see if something is blocking the LOS
while Block = 0
LOSPosX# = LOSPosX# + AngX#
LOSPosZ# = LOSPosZ# + AngZ#
Dist = Dist + 1
// check if distance set by LOSRange has been reached
if Dist > Range then Block = 1
// check if edges of the map have been reached
if LOSPosX# < 1 then Block = 1
if LOSPosZ# < 1 then Block = 1
if LOSPosX# > MapWidth then Block = 1
if LOSPosZ# > MapWidth then Block = 1
// round float and convert position back to an integer
if Block = 0
TrcPosX = trunc(LOSPosX#)
TrcPosZ = trunc(LOSPosZ#)
// check if an non-transparent tile is blocking our view
if Map[TrcPosX, TrcPosZ].Transparent = 0
Block = 1
// ***
// *** UNREM the following code below when using the function in a game... it causes the blocking tile to be visible.
// *** The line is disabled here, because it visualizes the function better in this example.
// ***
` if Map[TrcPosX, TrcPosZ].Visible = 0 then Map[TrcPosX, TrcPosZ].Visible = 1
endif
// set transparent tile to be visible if it isn't already
if Block = 0
if Map[TrcPosX, TrcPosZ].Visible = 0 then Map[TrcPosX, TrcPosZ].Visible = 1
endif
endif
endwhile
next Angle#
endfunction
`======================================================================================
` Function to check user input
`--------------------------------------------------------------------------------------
function CheckInput()
if GetRawKeyState(KeyUp) = 1
PlayerPosZ = PlayerPosZ - 1
if PlayerPosZ < 1 then PlayerPosZ = 1
endif
if GetRawKeyState(KeyDown) = 1
PlayerPosZ = PlayerPosZ + 1
if PlayerPosZ > MapLength then PlayerPosZ = MapLength
endif
if GetRawKeyState(KeyLeft) = 1
PlayerPosX = PlayerPosX - 1
if PlayerPosX < 1 then PlayerPosX = 1
endif
if GetRawKeyState(KeyRight) = 1
PlayerPosX = PlayerPosX + 1
if PlayerPosX > MapWidth then PlayerPosX = MapWidth
endif
if GetRawKeyState(KeyEsc) = 1 then GameState = 0
endfunction
`======================================================================================
` Function to load map-data from file
`--------------------------------------------------------------------------------------
function LoadMap(FileName$)
if GetFileExists(FileName$) = 1
FileId = OpenToRead(FileName$)
for z = 1 to MapLength
for x = 1 to MapWidth
Char$ = chr(ReadByte(FileId))
Map[x, z].Char$ = Char$
Map[x, z].Visible = 0
// determine whether tile can bee 'seen though' by player or not (e.g. a wall blocks the LOS)
if Char$ = "D" then Map[x, z].Transparent = 1
if Char$ = "O" then Map[x, z].Transparent = 0
if Char$ = "U" then Map[x, z].Transparent = 0
if Char$ = ":" then Map[x, z].Transparent = 1
if Char$ = "." then Map[x, z].Transparent = 0
if Char$ = "#" then Map[x, z].Transparent = 0
if Char$ = "S" then Map[x, z].Transparent = 0
next x
next z
CloseFile(FileId)
else
WriteDebugFile("Error in function [LoadMap]: file [FileName$] not found.")
endif
endfunction
`======================================================================================
` Function to show the minimap [StartX, StartZ, EndX, EndZ]
`--------------------------------------------------------------------------------------
function ShowMiniMap(StartX, StartZ, EndX, EndZ)
// display the minimap-sprites
for z = StartZ to EndZ
for x = StartX to EndX
if z => 1 and z <= MapLength
if x => 1 and x <= MapWidth
Char$ = Map[x, z].Char$
// set default sprite color
colR = 20
colG = 20
colB = 20
colA = 255
// set sprite color for door
if Char$ = "D" or Char$ = "O" or Char$ = "U"
colR = 132
colG = 128
colB = 112
colA = 255
endif
// set sprite color for floor
if Char$ = " " or Char$ = ":"
colR = 244
colG = 226
colB = 152
colA = 255
endif
// set sprite color for walls
if Char$ = "#" or Char$ = "S"
colR = 166
colG = 113
colB = 22
colA = 255
endif
// set sprite color for tiles in LOS
if Map[x, z].Visible = 1
colR = 255
colG = 255
colB = 255
colA = 100
endif
// draw sprite
SetSpritePosition(SprMap, (x + SprPosX ) * SprSize, (z + SprPosZ) * SprSize)
SetSpriteColor(SprMap, colR, colG, colB, colA)
DrawSprite(SprMap)
endif
endif
next x
next z
endfunction
`======================================================================================
` Function to write debug file
`--------------------------------------------------------------------------------------
function WriteDebugFile(Error$)
FileId = OpenToWrite("debug.txt", 1)
WriteLine(FileId, Error$)
CloseFile(FileId)
endfunction
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