Timer Memory access violation
Archives Forums/Blitz3D Bug Reports/Timer Memory access violation
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| I have been looking all over and i can't find a solution so maybe this will help: The problem is that when i run the code i get a memory access violation CODE: Graphics3D 800,600,0,2 SetBuffer BackBuffer() timer = (30) font=LoadFont("Arial",15) SetFont font Type bullet Field x Field y End Type Type bomb Field x Field y End Type Type alien Field x Field y End Type While result=0 result=MainMenu() ;put these options inside the menu loop, as these ;return 0 - continuing the mainmenu loop. If result=2 Then result=Options() If result=3 Then result=Credits() Wend If result=1 Then StartGame() ;if the result isn't 1, then it must be 4 - hence QUIT End Function MainMenu() Cls Text 400,50,"Start Menu",1,1 Rect 300,100,200,50,0 Text 400,125,"Start Game",1,1 Rect 300,200,200,50,0 Text 400,225,"Options",1,1 Rect 300,300,200,50,0 Text 400,325,"Credits",1,1 Rect 300,400,200,50,0 Text 400,425,"Quit",1,1 Flip result=0 While result=0 mx=MouseX():my=MouseY() If MouseHit(1) Then If RectsOverlap(300,100,200,50,mx,my,1,1) Then result = 1 If RectsOverlap(300,200,200,50,mx,my,1,1) Then result = 2 If RectsOverlap(300,300,200,50,mx,my,1,1) Then result = 3 If RectsOverlap(300,400,200,40,mx,my,1,1) Then result = 4 End If Wend Return result End Function Function Options() Cls Text 400,300,"Options Screen! Any key to return to main menu",1,1 Flip WaitKey() Return 0 End Function Function Credits() Cls Text 400,300,"Credits!!",1,1 Text 400,330,"Intro Made by: BlackD",1,1 Text 400,350,"Everything Else: linkjay1", 1, 1 Text 400,400,"Any key to return",1,1 Flip WaitKey() Return 0 End Function Function StartGame() Cls AutoMidHandle True img_ship = LoadImage("ship.png") img_bullet = LoadImage("bullet.png") img_alien = LoadImage("alien.png") wav_music = LoadSound("music.wav") wav_explode = LoadSound("explode.wav") wav_shoot = LoadSound("shoot.wav") wav_shiphit = LoadSound("shiphit.wav") wav_alienshoot = LoadSound("alienshoot.wav") x = 320 y = 400 lives = 3 score = 0 aspeed = 2 amx = aspeed chdir = False SetBuffer BackBuffer() For z = 1 To 7 For w = 1 To 2 a.alien = New alien a\x = 100 + 50*z a\y = 150 + 50*w Next Next While Not KeyDown(1) Cls DrawImage img_ship,x,y If KeyDown(30) Then x = x - 3 If KeyDown(32) Then x = x + 3 If KeyHit(57) Then PlaySound(wav_shoot) b.bullet = New bullet b\x = x b\y = y - 5 EndIf For b.bullet = Each bullet b\y = b\y - 5 DrawImage img_bullet,b\x,b\y If b\y < 0 Then Delete b Next If chdir = True Then amx = -amx EndIf chdir = False For a.alien = Each alien a\x = a\x + amx If a\x > 620 Then chdir = True If a\x < 20 Then chdir = True If Rand(500) = 25 Then PlaySound(wav_alienshoot) bombs.bomb = New bomb bombs\x = a\x bombs\y = a\y EndIf DrawImage img_alien,a\x,a\y For b.bullet = Each bullet If ImagesCollide(img_bullet,b\x,b\y,0,img_alien,a\x,a\y,0) Then PlaySound(wav_explode) Delete b Delete a score = score + 10 Exit EndIf Next Next For bombs.bomb = Each bomb bombs\y = bombs\y + 4 DrawImage img_bullet,bombs\x,bombs\y If ImagesCollide(img_bullet,bombs\x,bombs\y,0,img_ship,x,y,0) Then PlaySound(wav_shiphit) lives = lives - 1 Delete bombs ElseIf bombs\y > 500 Then Delete bombs EndIf Next Text 50,420,"Lives: " + lives Text 530, 420, "SCORE: " + score If score = 140 Then Text 320, 100, "YOU WIN!!!", 1, 1 Flip Delay 3000 End EndIf If lives = 0 Then Text 320, 100, "GAME OVER", 1, 1 Flip Delay 3000 End EndIf Flip WaitTimer(timer) Wend End End Function |
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| Timer Memory access violation How to use a timer: myTimer = CreateTimer( 4 ) ; four times per second While Not KeyHit( 1 ) Cls WaitTimer( myTimer ) ticks = ticks + 1 Text 60, 120, "ESCAPE quits, timer ticks = " + ticks Flip Wend |
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| This is not a Blitz bug, just an error in your coding. There are two main problems: 1: You are declaring timer in your 'main program' scope timer=(30) but referencing it inside the StartGame Function WaitTimer(timer) The scope of this function assumes 'timer' to be a local variable, which by default is undeclared and therefore = 0 Your error occurs because you try to call WaitTimer on a null timer handle. - 2: Your declaration: tiemr=(30) Is incorrect syntax for declaring a timer handle. What you are actually doing is simply defining a local integer variable called "timer" with a value of 30 _______________________________________ Making the following alteration will solve the problem completely: Change timer = (30) Into Global timer = CreateTimer(30) Firstly, it now actual defines "timer" as a Timer handle with a parameter of 30 hz, rather than just a numeric variable with an arbitrary value of 30. Also ensures that scope is global so 'timer' used anywhere will refer to this actual timer handle. Read up on the differences between Handles and Variables, also how Scope affects references to these values inside functions and outside of them. |
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