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Question regarding Field of View

Started by superkent Feb 6, 2011 at 1:17 PM 1 replies 4.5k views

Original Post

Feb 6, 2011 at 1:17 PM

I am having a little trouble understanding how the field of view and aspect ratio are related. When we set our FOV when we create our perspective matrix, lets say to 45 degrees, does this mean that the system will create a frustum that is 45 degrees both horizontally and virtically? And if so, how does it compensate for aspect ratios that arent 1:1? I have been looking at different frustum class implementations and I dont ever get the same numbers as the examples for the coordinates of the near and far planes, though my math is a bit shaky.

SiCrane

Feb 6, 2011 at 2:07 PM

According to the documentation for Matrix.CreatePerspectiveFieldOfView the field of view parameter is the field of view in the y direction.

kiwibonga

Feb 6, 2011 at 4:07 PM

One important detail: the FoV setting in that function is the angle from the center of the screen to the edge. That means setting a 45 degree (pi/4) angle will actually result in a 90 degree (pi/2) FoV.

In a single player game, it's appropriate to set the FoV angle depending on the aspect ratio of the screen -- closer to 90 degrees (pi/2) on 4:3, and closer to 120 degrees (2pi/3) on 16:9/16:10.

In multiplayer, users will complain about the game balance implications of widescreen players being able to see more, so find a sweet spot between the two

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