once again given this is a tetris type program, I was looking for a way to determine wether or not a square that is constantly dropping has reached a certain point on the opengl screen. I made 2 lines on the open gl window that look like this... the bottoms of the lines equal -20.0f(y axis).... | . | //box drops from top. and my square which is made up of glVertex3f(-1.0f, 1.0f, 0.0f); //top left glVertex3f( 1.0f, 1.0f, 0.0f); //top right glVertex3f( 1.0f,-1.0f, 0.0f); //bottom left glVertex3f(-1.0f,-1.0f, 0.0f); //Bottom right the box drops constantly, and what I want to do, is when it gets to a certain point...I want the box to stop right where it is. the code that makex the box drop looks like this... if(count>50) { count=0; //This counter makes the box drop down about //a little less than every 1 second yposy--; //This is the boxes y position } I tried using an if, that said ....if(yposy == -20.0f) { yposy-=0.0; } but this just made the box start at -20.0f in the begginning of program. Any suggestions? [edited by - skittlez on February 12, 2003 10:29:44 PM] [edited by - skittlez on February 12, 2003 10:30:31 PM]

what you want to do is test if it is greater than or equal to 20k, that way if you aren''t always moving it down at 1 unit per second, then it will stop, so you''ll want to have something like this:

if(ypos<=-20)
ypos+=1.0f; //or whatever value you''re incrementing it by

that will make it so the box just stays at the bottom, however, I would suggest that you look in to using a bool variable to say whether or not to move it:

bool move=true; //put this at the top of your program

// inside of the drawglscene function, put this:

if(move==true && count>50)
{
ypos--;
count=0;
}

if(move)
count++;

if(ypos<=-20)
move=false;



and that code will effectively move, test, and stop the block once it reaches -20

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But you must remember that most Tetris - type games allow you to move the block for a certain amount of time even after it hits something. Don''t forget about that skittle