Why is my collision not working

Hey guys, I am creating a mario platformer, but for some weird reason my collision isn't working.
Here is my code:
main ino file:

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#include <SPI.h>
#include <Gamebuino.h>

#include "mario_bitmaps.h"
#include "player.h"

#define MAX_LEVEL_WIDTH  30
#define MAX_LEVEL_HEIGHT 6

extern const byte PROGMEM levels[];

const byte *block = NULL;
int cameraPos = 0;
byte lvldata[MAX_LEVEL_WIDTH * MAX_LEVEL_HEIGHT];
byte lvl = 1;
Gamebuino gb;
Player player(0, LCDHEIGHT - 24);

byte i = 0, j = 0; // for loop variables

void loadLevel(int curLev) {
  for(i = 0; i<MAX_LEVEL_WIDTH * MAX_LEVEL_HEIGHT; i++){//Loops through the level
    lvldata[i] = pgm_read_byte(levels + (MAX_LEVEL_WIDTH * MAX_LEVEL_HEIGHT) * (curLev - 1) + i);
  }
}

void renderLevel() {
  for(i = 0;i < MAX_LEVEL_HEIGHT;i++) {
    for(j = 0;j < MAX_LEVEL_WIDTH;j++) {
      switch(lvldata[j + i * MAX_LEVEL_WIDTH]) {
        case 0:
        block = empty;
        break;
        case 1:
        block = sand_ground;
        break;
        case 2:
        block = diagonal_right;
        break;
        case 3:
        block = diagonal_left;
        break;
        default:
        break;
      }
      if(block != NULL) {
        if((j << 3) - cameraPos >= -8 && (j << 3) - cameraPos < LCDWIDTH ||
        (i << 3) > 0 && (i << 3) < LCDHEIGHT) {
          gb.display.drawBitmap((j << 3) - cameraPos, i << 3, block);
        }
      } else {
        gb.display.drawBitmap((j << 3) - cameraPos, i << 3, empty);
      }
    }
  }
  cameraPos = player.x * 2;
}

void setup() {
  gb.begin();
  gb.titleScreen(F("Super Mario Bros"));
  loadLevel(lvl);
}

void loop() {
  if(gb.update()) {
    gb.display.clear();
    renderLevel();
    player.render(gb);
    if(gb.buttons.pressed(BTN_C)) {
        gb.titleScreen(F("Super Mario Bros"));
        loadLevel(1);
    }
  }
}


Levels.ino

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const byte levels[] PROGMEM = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 3, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 2, 0, 0, 0, 0,
3, 2, 0, 0, 3, 0, 0, 0, 0, 2, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
};

const byte collision_levels[] PROGMEM = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
};

////////Tile Map IDS:////////
// NULL        0
// Sand Ground 1
// Diagonal Right 2
// Diagonal Left 3


marioBitmaps.h

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#ifndef MARIO_BITMAPS_H
#define MARIO_BITMAPS_H

byte mario_still[] PROGMEM = {16,16,
0x1F,0x0,
0x20,0xC0,
0x4F,0x20,
0x72,0xC0,
0xB2,0x20,
0xB1,0x20,
0x63,0xC0,
0x30,0x80,
0x4F,0x0,
0x86,0x80,
0xBF,0x80,
0x4F,0x80,
0x53,0x80,
0x21,0x0,
0x3E,0x0,
0x3E,0x0,
};

byte mario_walking_1[] PROGMEM = {16,16,
0x1F,0x0,
0x20,0xC0,
0x4F,0x20,
0x72,0xC0,
0xB2,0x20,
0xB1,0x20,
0x63,0xC0,
0x30,0x80,
0x4F,0x0,
0x86,0x80,
0xBF,0x80,
0x4F,0x80,
0x5B,0x80,
0xBE,0x40,
0x96,0x40,
0x61,0x80,
};

byte sand_ground[] PROGMEM = {8,8,
0xFF,
0x0,
0xFF,
0xFF,
0x10,
0x0,
0x80,
0x21,
};

const byte diagonal_right[] PROGMEM = {8,8,
0x80,
0x40,
0x20,
0x10,
0x8,
0x4,
0x2,
0x1,
};

const byte diagonal_left[] PROGMEM = {8,8,
0x1,
0x2,
0x4,
0x8,
0x10,
0x20,
0x40,
0x80,
};

const byte empty[] PROGMEM = {8,8,
0x0,
0x0,
0x0,
0x0,
0x0,
0x0,
0x0,
0x0,
};

#endif /* MARIO_BITMAPS_H */


Player.h

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#ifndef PLAYER_H
#define PLAYER_H

#include "mario_bitmaps.h"

#define MAX_COLLISION_LEVEL_WIDTH  30
#define MAX_COLLISION_LEVEL_HEIGHT 6

extern const byte PROGMEM collision_levels[];
extern byte lvl;
extern int cameraPos;
byte collvldata[MAX_COLLISION_LEVEL_WIDTH * MAX_COLLISION_LEVEL_HEIGHT];

void loadColLevel(int curLev) {
  for(byte i = 0; i<MAX_COLLISION_LEVEL_WIDTH * MAX_COLLISION_LEVEL_HEIGHT; i++){//Loops through the level
    collvldata[i] = pgm_read_byte(collision_levels + (MAX_COLLISION_LEVEL_WIDTH * MAX_COLLISION_LEVEL_HEIGHT) * (curLev - 1) + i);
  }
}

class Player {
public:
  Player(float x, float y) {
    this->x = x;
    this->y = y;
    this->velX = 0.0f;
    this->velY = 0.0f;
    this->bitMap = mario_still;
    this->flip = false;
    this->walking = false;
    this->lives = 3;
    loadColLevel(lvl);
  }
  float x, y;
  float velX, velY;
  byte *bitMap;
  boolean flip;
  boolean walking;
  byte lives;
 
  void restart() {
    this->x = 0;
    this->y = 0;
    this->velX = 0.0f;
    this->velY = 0.0f;
    this->bitMap = mario_still;
    this->flip = false;
    this->walking = false;
    loadColLevel(lvl);
  }

  void render(Gamebuino gb) {
    if(lives <= 0) {
      if(!gb.buttons.pressed(BTN_A)) {
        gb.display.clear();
        gb.display.fillScreen(BLACK);
        gb.display.setColor(WHITE, BLACK);
        gb.display.cursorX = (LCDWIDTH / 2) - 15;
        gb.display.cursorY = (LCDHEIGHT / 2) - 5;
        gb.display.println("Game over!");
        gb.display.cursorX = (LCDWIDTH / 2) - 9;
        gb.display.cursorY = (LCDHEIGHT / 2) + 1;
        gb.display.println("Press A");
      } else {
        lives = 3;
        restart();
      }
      return;
    }
    gb.display.print("x");
    gb.display.println(lives);
    gb.display.cursorX = LCDWIDTH / 2 - 3;
    gb.display.cursorY = 0;
    gb.display.print("LEVEL ");
    gb.display.println(lvl);
    if(this->x < 0) this->x = 0;
    if(this->x + 8 > LCDWIDTH) this->x = LCDWIDTH - 8;
    if(this->y < -8) this->y = -8;
    if(this->y + 16 > LCDHEIGHT) {
      restart();
      lives--;
    }
    if(gb.buttons.repeat(BTN_RIGHT, 1)){
      velX = 1.0f;
      flip = false;
      walking = true;
    }
    else if(gb.buttons.repeat(BTN_LEFT, 1)) {
      velX = -1.0f;
      flip = true;
      walking = true;
    }
    else {
      velX = 0;
      walking = false;
    }
    if((collvldata[(int)(((y / 8) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0 &&
    (collvldata[(int)(((y / 8 + 1) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0) {
      x += velX;
    }
 
    if((gb.buttons.timeHeld(BTN_UP) > 0 && gb.buttons.timeHeld(BTN_UP) < 5)){
      if((collvldata[(int)(((y / 8 - 1) * MAX_COLLISION_LEVEL_WIDTH) + (x / 8 + cameraPos / 8))]) == 0) {
        velY = -8.0f;
      }
    }
   
    y += velY;

    if((collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + (x / 8 + cameraPos / 8))]) == 0) {
      velY = 8.0f;
    } else {
      velY = 0;
    }

    if(walking) {
      if(gb.frameCount % 6 >= 0 && gb.frameCount % 6 < 3) {
        this->bitMap = mario_still;
      }
      else {
        this->bitMap = mario_walking_1;
      }
    }
    else {
      this->bitMap = mario_still;
    }
    if(flip) {
      gb.display.drawBitmap(x, y, this->bitMap, NOROT, FLIPH);
    }
    else {
      gb.display.drawBitmap(x, y, this->bitMap, NOROT, NOFLIP);
    }
  }
};

#endif


Thanks in advance
awesome 101

The twenty-first tile on the fifth row isn't working.If you can find the bug I would really appreciate it.
Thanks

You have to keep in mind when doing the collision detection that your x|y are probably from the top-left corner, so you have to check for x+TILEWIDTH and y+TILEWIDTH, and i cannot see such a thing happening here:

if((collvldata[(int)(((y / 8) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0 &&
(collvldata[(int)(((y / 8 + 1) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0) {

Ok thanks for the tip! I have been trying to find this bug for days now.
The reason I say
if((collvldata[(int)(((y / 8) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0 &&
(collvldata[(int)(((y / 8 + 1) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + velX) + cameraPos / 8))]) == 0) {
is because I need to check the upper part of the player and the bottom part of him because his height is two tiles high if that makes sense. Thank you so much! :D

Sorry to bother you again, but my collision still doesnt work
when i go left on some platforms i fall down one tile behind where I am supposed to fall.
here is what i have done:
previous code:
if((collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + (x / 8 + cameraPos / 8))]) == 0) {
velY = 8.0f;
} else {
velY = 0;
}
new code:
if((collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + (((x + 8) / 8 + cameraPos / 8)))]) == 0) {
velY = 8.0f;
} else {
velY = 0;
}

You have to check all the corners, not only one.

I'm sorry to bother you again, but how do I implement that?
Sorry again I'm new to programming

With something like


if((collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + (((x + 8) / 8 + cameraPos / 8)))]) == 0 && (collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + cameraPos / 8)))]) == 0) {

Hi again, but my collsion still doesnt work.
This is what I did:
if((collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + ((x / 8 + cameraPos / 8)))]) == 0 &&
(collvldata[(int)(((y / 8 + 2) * MAX_COLLISION_LEVEL_WIDTH) + (((x + 8) / 8 + cameraPos / 8)))]) == 0) {
velY = 8.0f;
}
else {
velY = 0;
}
I'm sorry for bothering you but I am really desperate to get my collision working. :|
Thanks

I did some intensive debugging sessions, and found out it was because of my cameraPos variable.
I was trying to offset the index of the collision array by the cameraPos variable. This caused problems, as each tile in the collision array were ahead by two tiles rather than at the players position. Right now I am currently trying to fix this. If you know how, please tell me as any help is appreciated. Thanks.

Awesome101

You say you're pretty new but you look good in my book :D . I'm pretty new myself

Topic moved to "Programming Questions". Also please use the code tags when posting code :

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[code]your code here[/code]

Thanks !