Author Topic: Player pointing at mouse? (Read 4080 times)

Makuto · « **on:** March 22, 2011, 05:26:02 pm »

How do I make my player sprite point at the mouse? Originally I used the equation atan((mousey-playery)/(mousex-playerx)). I looked on the internet, and this equation is supposed to return the angle of the player, in degrees. I was then planning on putting the result in for the player.SetRotation. However, this doesn't return the angle, just a weird decimal negative number. What should I do?

Lo-X · « **Reply #1 on:** March 22, 2011, 08:16:55 pm »

I think the return is in radian, try to multiplicate by 180 and divide by PI

Makuto · « **Reply #2 on:** March 23, 2011, 03:56:59 am »

Because the Y-axis goes upwards while the object goes downwards in relation to the screen, and the X-axis is at the top, the window is basically in the fourth quadrant, which has a negative Y and a positive X. Do I need to convert the Y-coordinates to negative numbers to get the correct angle?

kalgon · « **Reply #3 on:** March 23, 2011, 02:48:23 pm »

try atan2 ?

Walker · « **Reply #4 on:** March 23, 2011, 04:23:06 pm »

cmath functions use radians, you will need to invert/negate/thingy (y = 0 - y) the y coordinate and atan2 is more suited for this. Everyone is right! Gold stars!

Makuto · « **Reply #5 on:** March 23, 2011, 04:32:47 pm »

I got it working. Thanks, guys!

Jove · « **Reply #6 on:** March 24, 2011, 07:21:58 am »

Hey Makuto.

Would you mind sharing the solution to this? It might be useful for something I would like to do.

(I'm lousy at maths :? )

mimipim · « **Reply #7 on:** March 24, 2011, 08:56:21 am »

To get the angle you must know your player position and mouse position:

float angle = atan2(mouseY-plrY,mouseX-plrX)*(180/3.1415f);
spr_myplr.SetRotation(angle);

Jove · « **Reply #8 on:** March 24, 2011, 09:25:01 am »

Many thanks.

Makuto · « **Reply #9 on:** March 24, 2011, 01:29:07 pm »

Great code!