Thread: Rotating sprites in allegro.

This code works great, but only allows a 90 degree rotation of the sprite. I assume this is because of allegro and I think every other graphics lib assuming top left is 0,0 and going from there so I am only playing in one quad... I am wondering how to make it rotate all 360 degrees do I just make a correction factor based on the screen size or what?

Code:

int main()
{
    ini();

    player = load_bitmap("Player.bmp",NULL);
    BUFFER = create_bitmap(scrx,scry);

    while(!key[KEY_ESC])
    {

        int angle = fixatan2(mouse_y, mouse_x);
        rotate_sprite(BUFFER,player,(scrx/2),(scry/2),angle);
        show_mouse(BUFFER);
        blit(BUFFER,screen,0,0,0,0,scrx,scry);
    }
	return 0;
}
END_OF_MAIN()

Answered my own question. Subtracting half of the screen size from each var allows for 360 degree rotation. center the sprite by subbing half the size in x and y... Now to get a grappling hook working for movement...

he doesn't have to translate...if he wants to simply rotate the sprite..i think he should just
use ftofix(angle) ...allegro has an angle from 0 to 256 i think. And it is fixed floating point something..
just replace ftofix(angle) in the rotate_sprite function

All I was really wanting the code to do was for lack of better terms have my sprite always face my mouse cursor...

Code:

void Player::Set_angle(int x, int y)//x and y are the mouse pointer's x and y coords .
{
    angle = fixatan2(y-(y_coord+32), x-(x_coord+32));
}

For allegro this line works perfectly in the end I will change the 32s to reflect the size of the bitmap that is loaded into memory till then this works great for testing the basics of the game I am trying to make.