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May
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comment OpenGL ES 2.0: Perspective Projection for 2D Games
Set up a perspection projection matrix and multiply following vectors (representing corners of two quads) with it: (-1,-1,1,1), (1,1,1,1) and (-1000, -1000, 1,1), (-998, -998, 1,1). Now, if you calculate differences between first two vectors and last two vectors (and I mean after projection) you will get the same result, meaning that their areas are equal even after the projection (also, remember to divide projected vectors with their w component).
May
30
comment OpenGL ES 2.0: Perspective Projection for 2D Games
@bunkai: I really don't know about your case but it seems that you are doing something wrong. I'm 100% sure that you should not get any deformation if your sprites are really perpendicular to the camera. And no, you're not viewing them from "slight angle". Here is a simple proof (see next comment):
May
27
comment OpenGL ES 2.0: Perspective Projection for 2D Games
About the maths: You have to find a plane in view frustum with an area equal to the area of viewport. This is very easy to calculate: plane = (1/2)*viewportHeight/tan(verticalFOV/2). Note that if you are using FOV=90 this simplifies to plane = (1/2)*viewportHeight
May
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May
27
comment OpenGL ES 2.0: Perspective Projection for 2D Games
1) Currently we are not using mipmapping since we are not placing objects very far or very close to camera. Of course we have things like background etc. but we calculate their size so that they are pixel-perfect. However, I don't see any reason why mipmapping couldn't be used. 2) As I mentioned in my answer, geometry does not change if the sprites are facing the camera. In this case they are just like billboards and they will not certainly deform.
May
26
revised OpenGL ES 2.0: Perspective Projection for 2D Games
added 362 characters in body
May
26
answered OpenGL ES 2.0: Perspective Projection for 2D Games
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answered Component based entity system API naming problems
Apr
11
comment From camera coordinates to world coordinates
But that does not mean that view * invView equals identity in shader. That's why I recommended you to check that you have set uniform values correctly to the used effect. If view * invView = I in shader there is no reason why your first case would work and the last one would not.
Apr
11
comment From camera coordinates to world coordinates
Check that you are setting uniform values (view and invView) to the used effect correctly. If the first case you mention works and the last one does not there must be something wrong with uniforms.
Apr
7
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revised Fastest way to draw quads in OpenGL ES?
added 565 characters in body; deleted 2 characters in body; added 4 characters in body
Apr
7
answered Fastest way to draw quads in OpenGL ES?