I want to create an effect that looks like this: https://www.youtube.com/watch?v=i__ZPdR47uk
So I made a Particle2D, set the texture to a thin triangle that I made, and set the emission mask to be a rectangle sprite with the same dimensions as the screen and set it to spawn particles on the border. Then Radial Accel is set to -1 in hopes that the triangles would point to the center, but it actually points to the top left. Is there a way to center the emission mask or set it up some other way so that the triangles would go to the center?
Edit: More of a workaround than a solution. I set up the emission mask texture to just cover the bottom and right borders of the image, then set it as the emission mask of the Particle2D. This will make the triangles only spawn on the bottom and right sides and they'll all point to the top left corner. Then make 3 copies of the Particle2D and flip them, and now you have all 4 pointing to the middle!