Mario Collisions

BlitzMax Forums/BlitzMax Programming/Mario Collisions

Torrente (Posted 2006) [#1]

I've been thinking about creating a simple platform game, and am already having trouble with the collisions. I took some .bb source code that someone posted on CodersWorkshop, ported it to blitzmax, giving me this: SuperStrict '********************************** screen constants Const SCREEN_WIDTH:Int = 800 Const SCREEN_HEIGHT:Int = 600 Const FULL_SCREEN:Int = False Const HERTZ:Int = 60 '********************************** grid constants Const MAP_WIDTH:Int = 20 Const MAP_HEIGHT:Int = 15 Global map:Int[MAP_WIDTH,MAP_HEIGHT] '********************************** player state enumeration Const ST_NORMAL:Int = 0 Const ST_FALLING:Int = 1 Const ST_JUMPING:Int = 2 '********************************** Const GRAVITY:Float = .2 Const TILE_SIZE:Int = 40 Const DIR_RIGHT:Int = 2 Const DIR_LEFT:Int = 1 Graphics SCREEN_WIDTH,SCREEN_HEIGHT,FULL_SCREEN,HERTZ Global player:Tplayer = New Tplayer player.x = 200 player.y = 200 'player.state = ST_FALLING player.bg_width = 40 player.bg_height = 40 fillmap() While Not KeyDown(KEY_ESCAPE) drawmap() player.update() DrawText("x: " + player.x,50,50) DrawText("y: " + player.y,50,70) DrawText("state: " + player.state,50,90) Flip Cls Wend Function drawmap() For Local loop_x:Int = 0 To MAP_WIDTH - 1 For Local loop_y:Int = 0 To MAP_HEIGHT - 1 SetColor map[loop_x,loop_y] * 255,60,60 DrawRect loop_x*TILE_SIZE,loop_y * TILE_SIZE,TILE_SIZE,TILE_SIZE Next Next End Function Type Tplayer Field x:Float Field y:Float Field xv:Float Field yv:Float Field id:String Field state:Int Field direction:Int Field distance:Int Field bg_width:Int 'bounding box width Field bg_height:Int 'bounding box height Method Update() checkkeys() draw() End Method Method draw() SetColor 255,255,255 DrawRect x,y,bg_width,bg_height End Method Method RightCollision:Int(speed:Float) For Local loop_x:Int = 0 To MAP_WIDTH - 1 For Local loop_y:Int = 0 To MAP_HEIGHT - 1 If rectsoverlap(x + speed + 1, y, bg_width, bg_height, loop_x * TILE_SIZE, loop_y * TILE_SIZE, TILE_SIZE, TILE_SIZE) Select map[loop_x,loop_y] Case 1 distance = (loop_x * TILE_SIZE) - (x + bg_width) Return True End Select EndIf Next Next End Method Method LeftCollision:Int(speed:Float) For Local loop_x:Int = 0 To MAP_WIDTH - 1 For Local loop_y:Int = 0 To MAP_HEIGHT - 1 If rectsoverlap(x + speed - 1, y, bg_width, bg_height, loop_x * TILE_SIZE, loop_y * TILE_SIZE, TILE_SIZE, TILE_SIZE) Select map[loop_x,loop_y] Case 1 distance = x - ((loop_x + 1) * bg_width) Return True End Select EndIf Next Next End Method Method BottomCollision:Int(speed:Float) For Local loop_x:Int = 0 To MAP_WIDTH - 1 For Local loop_y:Int = 0 To MAP_HEIGHT - 1 If rectsoverlap(x, y + speed + 1, bg_width, bg_height, loop_x * TILE_SIZE, loop_y * TILE_SIZE, TILE_SIZE, TILE_SIZE) Select map[loop_x,loop_y] Case 1 distance = (loop_y * TILE_SIZE) - (Y + bg_width) Return True End Select EndIf Next Next End Method Method TopCollision:Int(speed:Float) For Local loop_x:Int = 0 To MAP_WIDTH - 1 For Local loop_y:Int = 0 To MAP_HEIGHT - 1 If rectsoverlap(x, y + speed - 1, bg_width, bg_height, loop_x * TILE_SIZE, loop_y * TILE_SIZE, TILE_SIZE, TILE_SIZE) Select map[loop_x,loop_y] Case 1 distance = ((loop_y + 1) * TILE_SIZE) - (y) Return True End Select EndIf Next Next End Method Method checkkeys() Select state Case ST_NORMAL If Not bottomCollision(yv) state = ST_FALLING EndIf Case ST_FALLING yv = yv + GRAVITY If bottomCollision(yv) And state <> ST_JUMPING yv = 0 y = y + distance state = ST_NORMAL EndIf Case ST_JUMPING If topCollision(yv) yv = 0 y = y + distance state = ST_FALLING EndIf yv = yv + GRAVITY If yv >= 0 state = ST_FALLING EndIf End Select If KeyHit(KEY_UP) And (Not topCollision(yv)) And (state = ST_NORMAL) state = ST_JUMPING yv = -8 EndIf If yv > 10 yv = 10 EndIf If xv > 5 xv = 5 ElseIf xv < -5 xv = -5 EndIf x = x + xv y = y + yv If KeyDown(KEY_RIGHT) direction = DIR_RIGHT If rightCollision(xv) xv = 0 x = x + distance Else If xv > 0 If leftCollision(xv) xv = 0 x = x - distance EndIf xv = xv + 0.5 Else xv = xv + 0.2 EndIf EndIf EndIf If KeyDown(KEY_LEFT) direction = DIR_LEFT If leftCollision(xv) xv = 0 x = x - distance Else If xv < 0 If rightCollision(xv) xv = 0 x = x + distance EndIf xv = xv - 0.5 Else xv = xv - 0.2 EndIf EndIf EndIf If (xv > 0 Or xv < 0) And ((Not KeyDown(KEY_RIGHT)) And (Not KeyDown(KEY_LEFT))) Select direction Case DIR_LEFT If leftCollision(xv) xv = 0 x = x - distance Else xv = xv + GRAVITY If xv >= 0 xv = 0 EndIf EndIf Case DIR_RIGHT If rightCollision(xv) xv = 0 x = x + distance Else xv = xv - GRAVITY If xv <= 0 xv = 0 EndIf EndIf End Select EndIf End Method End Type Function fillmap() Local line:String For Local y:Int = 0 To MAP_HEIGHT - 1 ReadData line For Local x:Int = 0 To MAP_WIDTH - 1 map[x,y] = Int(Mid(line,x+1,1)) Next Next End Function Function RectsOverlap:Int(x0:Float, y0:Float, w0:Float, h0:Float, x2:Float, y2:Float, w2:Float, h2:Float) If x0 > (x2 + w2) Or (x0 + w0) < x2 Then Return False If y0 > (y2 + h2) Or (y0 + h0) < y2 Then Return False Return True End Function DefData "11111111111111111111" DefData "11010101010101010101" DefData "10000000000000000001" DefData "11110000000000111111" DefData "10000000000000000001" DefData "10000000000000000001" DefData "10000000111100000001" DefData "10000000000000000001" DefData "11110000000000000001" DefData "10000000000000000001" DefData "10000000001110001111" DefData "10000000000000000001" DefData "10000000000000000001" DefData "10000000000000000001" DefData "11111111111111111111" It works, in a sense, but is far from perfect. At times, it will put me off of the screen for no apparent reason, along with a few other quirks. I was wondering, for one, can anyone tell me what I can improve/fix to make the collisions work better? Even better, does anyone have some blitzmax code already written that shows basic collision detection? All help is appreciated.

gellyware (Posted 2006) [#2]

This might interest you: http://www.codersworkshop.com/viewshowcase.php?id=897

Torrente (Posted 2006) [#3]

GellyWare: Yup, I already had a look at that. To put it simply, I was lost. I followed a few source files around and tried to figure out a few unknown variable before I gave up. Thanks for the suggestion, although the code is too confusing for me to make out quite what it's doing.

Curtastic (Posted 2006) [#4]

Here you go, I made this. Tell me if anything is confusing. Oh I stole your map :P SuperStrict Graphics 800 , 600 , 0 Const Gravity:Float = .1 Type TPlayer Field x:Float,y:Float Field width:Float , height:Float Field speedx:Float , speedy:Float Method Draw() DrawRect x , y , width , height EndMethod Method Update() 'ground friction speedx:* .85 'x conrtols If KeyDown(key_left) Then speedx = - 2 If KeyDown(key_right) Then speedx = 2 'x movement x:+ speedx 'if you ran into a wall If map.rectcollide(x , y , width , height) Then 'move back out of the wall x:- speedx 'stop your speed speedx = 0 EndIf 'y controls (jump) If KeyHit(key_up) Then 'make sure you are on the ground If map.rectcollide(x , y + 1 , width , height) Then 'jump! speedy = - 5 EndIf EndIf 'y movement speedy:+ gravity y:+ speedy 'if you hit a wall If map.rectcollide(x , y , width , height) Then 'move back out of the wall y:- speedy 'stop your speed speedy = 0 EndIf EndMethod EndType Type TMap Field width:Int , height:Int Field array:Int[,] Const tilesize:Int = 30 Method Load() Local x:Int,y:Int Local line:String ReadData width ReadData height array=New Int[width,height] For y = 0 Until height ReadData line For x = 0 Until width array[x , y] = Int(Mid(line , x + 1 , 1) ) Next Next EndMethod Method Draw() Local x:Int , y:Int For y = 0 Until height For x = 0 Until width If array[x , y] = 1 Then DrawRect x * tilesize , y * tilesize , tilesize , tilesize EndIf Next Next EndMethod 'Returns True if the rectangle collides with the map. 'This one and only collision function can be used for everything. Method RectCollide:Int(x:Float , y:Float , width:Float , height:Float) Local x1:Int , y1:Int Local x2:Int , y2:Int 'convert pixel positions to tile positions x1 = x / tilesize y1 = y / tilesize x2 = (x + width) / tilesize y2 = (y + height) / tilesize Local tilex:Int , tiley:Int 'check each tile that the rect is in For tiley = y1 To y2 For tilex = x1 To x2 If array[tilex , tiley] = 1 Then Return True EndIf Next Next Return False EndMethod EndType Global You:tplayer = New tplayer you.x = 200 you.y = 100 you.width = 20 you.height = 25 Global Map:tmap = New tmap map.load() Repeat you.update() you.draw() map.draw() Flip Cls If KeyHit(key_escape) Then End Forever DefData 20,15 DefData "11111111111111111111" DefData "11010101010101010101" DefData "10000000000000000001" DefData "11110000000000111111" DefData "10000000000000000001" DefData "10000000000000000001" DefData "10000000111100000001" DefData "10000000000000000001" DefData "11110000000000000001" DefData "10000000000000000001" DefData "10000000001110001111" DefData "10000000000000000001" DefData "10000000000000000001" DefData "10000000000000000001" DefData "11111111111111111111"

Torrente (Posted 2006) [#5]

Thanks for the help, it works like a charm. Plus, I understand what's going on, which is a rare occurence in itself. :)