Why are my two classes sharing variables? C++

ISDCaptain01 · 2014-04-07T23:31:05

Okay I have two classes: SWORDBEAM: This one basically handles the projectiles that come out of the player, its pretty simple: class SWORDBEAM { public: int x, y; int alive; int dir; int xspeed, yspeed; //COnstructor SWORDBEAM() { x = 0; y = 0; alive = 0; dir = 0; xspeed = 0; yspeed = 0; } //Core Functions void drawbeam() { int n; int px, py; px = x; py = y; //Is the beam active if(!alive) return; //Draw sword beam sprite if(dir == UP) al_draw_bitmap(swordbeamUp, px - mapxoff, py - mapyoff, NULL); if(dir == DOWN) al_draw_bitmap(swordbeamDown, px - mapxoff, py - mapyoff, NULL); if(dir == LEFT) al_draw_bitmap(swordbeamLeft, px - mapxoff, py - mapyoff, NULL); if(dir == RIGHT) al_draw_bitmap(swordbeamRight, px - mapxoff, py - mapyoff, NULL); } void movebeam() { int px, py; px = x; py = y; //Is the beam active? if(!alive) return; //Move the beam x += xspeed; y += yspeed; px = x; py = y; //Stay within the screen if(px < link->x - (gameBufferWidth/3) || px > link->x + (gameBufferWidth/3) || py < link->y - (gameBufferHeight/2) || py > link->y + (gameBufferHeight/2)) { //If it goes off screen, than kill it explosionSprite->alive = 1; alive = 0; return; } } void fireweapon() { //Ready to fire again if(!alive) { alive = 1; al_play_sample_instance(swordcomboInstance); //Fire the beam in the direction that link is facing switch(link->dir) { //Up case 0: x = link->x + link->width/2; y = link->y + link->height/2; xspeed = 0; yspeed = -swordspeed; dir = 0; break; //Down case 1: x = link->x + link->width/2; y = link->y + link->height/2; xspeed = 0; yspeed = swordspeed; dir = 1; break; //Left case 2: x = link->x + link->width/2; y = link->y + link->height/2 - 3; xspeed = -swordspeed; yspeed = 0; dir = 2; break; //Right case 3: x = link->x + link->width/2; y = link->y + link->height/2 - 3; xspeed = swordspeed; yspeed = 0; dir = 3; break; } } } }; //Declare a swordbeam SWORDBEAM swordbeam; My other class is the enemy, It basically moves in a path I set for it: class OCTOROCK { private: int x, y; int width, height; int curframe, maxframe; int framecount, framedelay; int dir; int alive; int pathx1, pathx2; int pathy1, pathy2; int speed; public: //Constructor OCTOROCK() { x, y = 0; width, height = 0; curframe, maxframe = 0; framecount, framedelay = 0; dir = 0; int speed = 0; alive = 0; pathx1, pathx2 = 0; pathy1, pathy2 = 0; } void setUp(int px, int py, int pwidth, int pheight, int pcurframe, int pmaxframe, int pframecount, int pframedelay, int pdir, int pspeed, int palive, int ppathx1, int ppathx2, int ppathy1, int ppathy2) { x = px; y = py; width = pwidth; height = pheight; curframe = pcurframe; maxframe = pmaxframe; framecount = pframecount; framedelay = pframedelay; dir = pdir; speed = pspeed; alive = palive; pathx1 = ppathx1; pathx2 = ppathx2; pathy1 = ppathy1; pathy2 = ppathy2; } //Responsible for updating the octorock void updateOctorock() { if(alive) { //Give octorock a path to follow, only dealing with x axis for now if(x > pathx2) { dir = LEFT; } else if(x < pathx1) { dir = RIGHT; } //Move the octorock if(dir == UP) { x += 0; y -= speed; } if(dir == DOWN) { x += 0; y += speed; } if(dir == LEFT) { x -= speed; y += 0; } if(dir == RIGHT) { x += speed; y += 0; } } } //Responsible for drawing the octorock; void drawOctorock() { //Is it alive? if(alive) { //South if(dir == DOWN) { if(++framecount > framedelay) { framecount = 0; if(++curframe > 1) { curframe = 0; } } } //North /*else if(dir == UP) { if(++framecount > framedelay) { framecount = 0; if(++curframe > 3) { curframe = 2; } } }*/ //Left else if(dir == LEFT) { if(++framecount > framedelay) { framecount = 0; if(++curframe > 5) { curframe = 4; } } } //Right else if(dir == RIGHT) { if(++framecount > framedelay) { framecount = 0; if(++curframe > 5) { curframe = 4; } } } if(dir == RIGHT) { al_draw_bitmap_region(octorock_images[curframe], 0, 0, al_get_bitmap_width(octorock_images[curframe]), al_get_bitmap_height(octorock_images[curframe]), x - mapxoff, y - mapyoff, NULL); } else { al_draw_bitmap_region(octorock_images[curframe], 0, 0, al_get_bitmap_width(octorock_images[curframe]), al_get_bitmap_height(octorock_images[curframe]), x - mapxoff, y - mapyoff, ALLEGRO_FLIP_HORIZONTAL); } } } //Sees if the octorock got attacked by link void detectCollision() { int playerx; int playery; int x1; int x2; int y1; int y2; if(alive) { playerx = link->x; playery = link->y; x1 = x; y1 = y; x2 = x1 + width; y2 = y1 + height; if(inside(playerx, playery, x1, y1, x2, y2)) { if(link->curframe == 0 || link->curframe == 1 || link->curframe == 2 || link->curframe == 3 || link->curframe == 4 || link->curframe == 5 || link->curframe == 6 || link->curframe == 7) { hearts -= 1; } else if(link->curframe == 9 || link->curframe == 10 || link->curframe == 11 || link->curframe == 12) { alive = 0; } } } } void octoPosition() { cout << "X Pos: " << x << endl; cout << "Y Pos: " << y << endl; } }; OCTOROCK octorock[1]; The problem is that when I shoot my projectiles, my enemy gets shot out along with the projectile sprite. I have no clue why this is happening. I have console window running keeping track of all postions and it seems like the swordbeam and octorock are sharing variables. If they are separate classes then how so?

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Started by ISDCaptain01 March 22, 2014 04:39 AM

24 comments, last by BHXSpecter 10 years, 10 months ago

Squared'D

2,428

March 31, 2014 06:27 AM

I think i found out the bug today guys. Basically what happened was that i declared an array of octorocks:
OCTOROCK octorocks[4];
But what i did wrong was that initialized it like this
octorock[1].x =......
octorock[2].x =......
octorock[3].x =......
octorock[4].x =......
What i did wrong is that i didnt access octorock[0] and did a memory violation by going out of bounds in tbe array with octorock[4].

Don't worry. Mistakes like this are quite common. That's why I tend to look to see if I've made silly mistakes first when debugging. I hate it when I end up making major changes when the original bug just turns out to be a missing minus or something. Glad you found the answer.

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Waaayoff

952

March 31, 2014 07:03 AM

Just curious. You set a lot of class variables as private. Any reason why you do that?

wat

In a simple answer, data hiding. It is usually common practice to make class members (variables) private and only allow access by way of constructors(mainly for initializing the class object) and class methods (functions).

Yes.. Except he's asking why they are private, not public. I guess it was a typo.

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BHXSpecter

3,123

April 01, 2014 12:21 AM

My apologies. Meant to quote just Buckeye and didn't realize I had quoted your post. It wasn't aimed at you. Again, I'm sorry, I should have paid closer attention to what I was quoting before submitting it.

DejaimeNeto

4,221

April 01, 2014 05:16 PM

I think i found out the bug today guys. Basically what happened was that i declared an array of octorocks:
[...]
What i did wrong is that i didnt access octorock[0] and did a memory violation by going out of bounds in tbe array with octorock[4].

So it was indeed bad pointer management!
These kind of symptoms are really common in these cases.

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