Thread: C++ collision detection

hello I have been writing a side scrolling shooter in visual studio with opengl. I draw the level with GL_QUADSTRIP that reads its points in from a .dat file.

the dat file looks like this
# level length
20
# level speed (used for development/testing)
1.2
# ground data
10
0.0 0.0
1.0 0.25
2.0 0.0
#ceiling data
10
0.0 1.0
1.0 0.75
2.0 1.0
#end
I am trying to use this to try and implement collision detection between the ship(which is just a basic triangle drawn with opengl) and the floor and ceiling data

Code:

for(int i= 0;i<=level.groundLength; i++){
		if (ship.position.x < level.ground[i].x){
			gameState = GAME_QUIT;
		}
}

This isnt working obviously so my question is can anyone help me work out how to read the data form the .dat to check if the ship is collidiing with the level and ending the game.

Any help is appreciated
Thanking You

Originally Posted by ForeverAndOne

# level length
20
# level speed (used for development/testing)
1.2
# ground data
10
0.0 0.0
1.0 0.25
2.0 0.0
#ceiling data
10
0.0 1.0
1.0 0.75
2.0 1.0
#end

If this file remains constant, it's as easy as reading certain lines while discarding the rest.
But if this is a general form of a more complex format, ( e.g comments, assignment, arbitrary data position ), you need to implement a parser that will retrieve the data for you.

Originally Posted by ForeverAndOne

I am trying to use this to try and implement collision detection between the ship(which is just a basic triangle drawn with opengl) and the floor and ceiling data

Code:

for(int i= 0;i<=level.groundLength; i++){
		if (ship.position.x < level.ground[i].x){
			gameState = GAME_QUIT;
		}
}

Since we're talking about ground, I think you messed the meaning of "x" in your mind.
Say (shipX, shipY) are the coords of the ship, (gndX, gndY) are the coords of a piece of ground, also "shipLen" and "groundLen" the lenghts of the ship and ground piece respectively:
This is a way to check for collision properly:

Code:

if (shipY <= gndY)
{
    if ((shipX >= gndX && shipX < gndX+groundLen) ||
        (shipX+shipLen >= gndX && shipX+shipLen < gndX+groundLen) ||
        (shipX < gndX && shipX+shipLen > gndX+groundLen))
        cout << "There was a collision!\n";
}