'Raycaster with definekey.bas for SmallBASIC 0.12.6 [B+=MGA] 2016-06-17 ' Raycaster maze Ricks copy from SB 2016-06-17 ' MGA modified with definekey all inkey stuff removed ' still quits with esc and now q ' uses a simple ray casting technique (see lodev.org for tutorial) to draw ' vertical stripes down the graphics window. ' Each stripe is drawn to a size dependent upon the distance of the wall from the viewer. ' "Rays" are cast across a viewing plane in front of the viewer, from left to right. ' the height of the wall stripe depends on the distance of the wall from the viewer. 'InitialSetup ' set up screen width and height ' values also used to determine the width and height of the "viewing plane" ' "size" is used to determine the width of each vertical line drawn. ' a smaller value makes the walls sharper, but draws slower (there are more lines) ' a larger value makes the walls blockier, but draws more quickly 'these replace INKEY catching definekey 0xFF04, moveLeft 'press left arrow or ccw definekey 0xFF05, moveRight 'press right arrow or cw definekey 0xFF09, moveForward 'press up arrow, forward definekey 0xFF0A, moveBack 'press down arrow, back definekey 0x0071, quit 'press q definekey 0x001B, quit 'press esc w = xmax-1 h = ymax-1 ' default size was 8 size = 2.0 'intensity of light source. The lower the number the further you can see. intensity = .2 dim worldMap(21,21) dim mapLine(21) ' ' set up the player's start position and direction ' these are the x/y co-ordinates of the world map ' nb absolute values place the player at grid intersections!! posX = 2.5 '5.5 posY = 2.5 '10.5 dirX = 1 dirY = 0 planeX = 0 ' ' plane y is the size of the viewing plane in degrees ' (altering this gives different perspective views) planeY = 0.66 completed = 1 ' ' moveSpeed is how far forward you move each step. ' bigger values create bigger steps, lower values mean smaller (smoother) steps ' RotSpeed is how much you rotate left/right when you turn ' a value of 1/3 of RotSpeed seems about right moveSpeed = 0.2 RotSpeed = 0.07 cx = XMAX/2 : cy = YMAX /2 'View ( cx-400,cy-330,cx+400,cy+330,Rgb(0,0,0),Rgb(100,200,255) ) '========================================================================= sub main completed = 0 local x = 0 For x = 0 To w / size ' calculate ray position and direction cameraX = 2 * x / (w / size ) - 1 ' x-coordinate in camera space Added fix for divide by 0 error (Rick3137) rayPosX = posX rayPosY = posY rayDirX = dirX + planeX * cameraX rayDirY = dirY + planeY * cameraX ' 'which box of the map we're in mapX = Floor(rayPosX) mapY = Floor(rayPosY) ' length of ray from current position to next x or y-side sideDistX = 0 sideDistY = 0 ' length of ray from one x or y-side to next x or y-side deltaDistX = Sqr(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX)) deltaDistY = Sqr(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY)) perpWallDist = 0 'what direction to step in x or y-direction (either +1 or -1) stepX = 0 stepY = 0 hit = 0 ' was there a wall hit? side = 0 ' was a NS or a EW wall hit? ' calculate step and initial sideDist If rayDirX < 0 Then stepX = -1 sideDistX = (rayPosX - mapX) * deltaDistX Else stepX = 1 sideDistX = (mapX + 1.0 - rayPosX) * deltaDistX End If If rayDirY < 0 then stepY = -1 sideDistY = (rayPosY - mapY) * deltaDistY Else stepY = 1 sideDistY = (mapY + 1.0 - rayPosY) * deltaDistY End If ' perform DDA ' trace a "ray" until it hits a wall, and determine if it's an "X" (horizontal) or "Y" (vertical) wall While hit = 0 ' jump to next map square, OR in x-direction, OR in y-direction If sideDistX < sideDistY Then sideDistX = sideDistX + deltaDistX mapX = mapX + stepX side = 0 Else sideDistY = sideDistY + deltaDistY mapY = mapY + stepY side = 1 End If ' Check if ray has hit a wall If worldMap(mapX,mapY) > 0 Then hit = 1 Wend ' Calculate distance projected on camera direction. If side = 0 Then perpWallDist = Abs((mapX - rayPosX + (1 - stepX) / 2) / rayDirX) Else perpWallDist = Abs((mapY - rayPosY + (1 - stepY) / 2) / rayDirY) End If ' Calculate height of line to draw on screen lineHeight = Abs(h / perpWallDist) lineHeight = int(lineHeight) 'if height if line to be drawn is > than height of graphics window then limit height of line If lineHeight > h Then lineHeight = h ' ' calculate lowest and highest pixel to fill in current stripe drawStart = (lineHeight * -1) / 2 + h / 2 If drawStart < 0 Then drawStart = 0 drawEnd = lineHeight / 2 + h / 2 If drawEnd >= h Then drawEnd = h - 1 ' set up the colours depending on the block numbers ' default colour is grey (RGB values are equal) colAdj2 = (lineHeight / h) * 250 colAdj = (lineHeight / h) * 250 - (intensity - colAdj2) If colAdj < 0 Then colAdj = 0 If colAdj > 200 Then colAdj = 200 colDistR = colAdj colDistG = colAdj colDistB = colAdj ' colours are extracted from the 'setupmap' subroutine Select Case worldMap(mapX, mapY) Case 2 'red colDistR = colAdj colDistG = 0 colDistB = 0 Case 3 'green colDistR = 0 colDistG = colAdj colDistB = 0 Case 4 'blue colDistR = 0 colDistG = 0 colDistB = colAdj Case 5 'magenta colDistR = colAdj colDistG = 0 colDistB = colAdj Case 6 'yellow colDistR = colAdj colDistG = colAdj colDistB = 0 End Select colour = Rgb(colDistR, colDistG, colDistB) If side = 1 Then colour = Rgb(colDistR / 1.3, colDistG / 1.3, colDistB / 1.3) 'Here is what wehave all been waiting for! 'draw the stripe as a vertical line Color colour Line x * size, drawStart, x * size, drawEnd Color Rgb(200, 150, 150) Line x * size, 0, x * size, drawStart Color Rgb(40, 40, 30) Line x * size, drawend, x * size, h Next x completed = 1 End sub sub moveForward if completed = 1 then moveX = dirX * moveSpeed moveY = dirY * moveSpeed If worldMap(floor(posX + moveX),floor(posy)) = 0 Then posX = posX + moveX If worldMap(floor(posx),floor(posY + moveY)) = 0 Then posY = posY + moveY 'main fi end sub moveBack if completed = 1 then moveX = dirX * moveSpeed moveY = dirY * moveSpeed If worldMap(floor(posX - dirX * moveX),floor(posy)) = 0 Then posX = posX - moveX If worldMap(floor(posx),floor(posY - moveY)) = 0 Then posY = posY - moveY fi end sub moveLeft 'counter-clockwise if completed = 1 then oldDirx = dirX cosRotSpeedL = Cos(-1 * RotSpeed) sinRotSpeedL = Sin(-1 * RotSpeed) dirX = dirX * cosRotSpeedL - dirY * sinRotSpeedL dirY = oldDirX * sinRotSpeedL + dirY * cosRotSpeedL oldPlanex = planeX planeX = planeX * cosRotSpeedL - planeY * sinRotSpeedL planeY = oldPlaneX * sinRotSpeedL + planeY * cosRotSpeedL fi end sub moveRight 'clockwise if completed = 1 then oldDirx = dirX COSRotSpeedR = Cos(RotSpeed) SinRotSpeedR = Sin(RotSpeed) dirX = dirX * CosRotSpeedR - dirY * SinRotSpeedR dirY = oldDirX * SinRotSpeedR + dirY * CosRotSpeedR oldPlaneX = planeX planeX = planeX * CosRotSpeedR - planeY * SinRotSpeedR planeY = oldPlaneX * SinRotSpeedR + planeY * CosRotSpeedR fi end Sub setupMap mapwidth = 21 mapheight = 21 'define the map in the mapLine array as strings mapLine(1) = "155555511111111555555" mapLine(2) = "600000000000000000005" mapLine(3) = "600000002000005000051" mapLine(4) = "600000000000305000051" mapLine(5) = "600000002600305022201" mapLine(6) = "604020006000005000001" mapLine(7) = "604031006016604444441" mapLine(8) = "600000000010004000001" mapLine(9) = "600230000010004000001" mapLine(10) = "100000000000004000003" mapLine(11) = "100002200022000000003" mapLine(12) = "100000000000000000033" mapLine(13) = "100002200022000333033" mapLine(14) = "100000000000000033031" mapLine(15) = "103333311111111011011" mapLine(16) = "100000011110000000002" mapLine(17) = "100000001110000000002" mapLine(18) = "100200000110000000002" mapLine(19) = "100000000116543211302" mapLine(20) = "100000000000000000003" mapLine(21) = "111111111116543211222" ' ' define some parameters that state how big the map is mapSizeX = 21 'Text.GetLength (mapLine[1]) mapSizeY = 21 'array.GetItemCount (mapLine) ' 'try to read this in and convert it into a two dimensional array For yLoop = 1 To mapSizeY For xLoop = 1 To mapSizeX worldmap(xloop,yloop) = val(mid(mapLine(yloop),xloop,1)) Next Next End Sub Sub quit stop End sub '========================================================================= ' call the setupmap subroutine to draw the initial map view setupMap() While 1 main Showpage Delay 10 'the right delay here may make your room sweeps smoother Wend