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Help => General => Topic started by: Bonafide on March 05, 2009, 08:21:59 pm

Title: Rect.Intersect() - Driving me mad
Post by: Bonafide on March 05, 2009, 08:21:59 pm

Hey guys,

I've tried searching the forums for a solution, and I've found some helpful threads that have given me some clues as how the Intersect() function works, but I just can't get it to work.

I'm simply trying to get a block to stop moving when it collides with another, stationary block.

Here's the code:

Code: [Select]


float left1, left2, right1, right2, top1, top2, bottom1, bottom2;

left1 = Sprite.GetPosition().x;
left2 = Spr.GetPosition().x;
right1 = left1 - Sprite.GetSize().x;
right2 = left2 - Spr.GetSize().x;
top1 = Sprite.GetPosition().y;
top2 = Spr.GetPosition().y;
bottom1 = top1 + Sprite.GetSize().y;
bottom2 = top2 + Sprite.GetSize().y;

sf::FloatRect Rect(left1, top1, right1, bottom1);
sf::FloatRect Rect2(left2, top2, right2, bottom2);

        // Get elapsed time
        float ElapsedTime = App.GetFrameTime();

        // Move the sprite
if(Rect.Intersects(Rect2))
{
cout << 1;
}
else
{
                        // Key
                }


The collision of the two sprites just won't work, Sprite just runs through Spr.

Title: Rect.Intersect() - Driving me mad
Post by: Laurent on March 05, 2009, 10:20:35 pm

Why are you computing your "right" values as "left - width" instead of "left + width" ??

Title: Rect.Intersect() - Driving me mad
Post by: Bonafide on March 06, 2009, 11:08:46 am

Heh, I did not catch that, but it finally works, thank you!

Title: Rect.Intersect() - Driving me mad
Post by: Bonafide on March 08, 2009, 11:00:03 pm

EDIT: Nevermind, this problem has been resolved.


Bump.

hey guys, I've seem to hit another road bump. Collision is now working, and I have made it so that if the blocks do collide, my moving block will move back a few units from the stationary block. However, if I hold a movement button (say the left key for this example) and make the block "stutter/jitter" (the block wants to continue moving left, but keeps getting pushed back a few units), if I press another movement key at the right time, the moving block will slide across the stationary block on it's corresponding side. I know it's my method of getting the blocks unstuck, so any tips would be appreciated.

Here's essentially what I have:

Code: [Select]


if (App.GetInput().IsKeyDown(sf::Key::Left))
{
if(coll.detectCollision(Sprite, Spr) != true)
{
Sprite.Move(-100 * ElapsedTime, 0);
}
else
{
Sprite.SetPosition((Sprite.GetPosition().x + 3), (Sprite.GetPosition().y));
}
}