I am rendering bunch of cubes of unit size, but for some reason they look like they are squeezed a bit in the screen-space y axis. Why is this?

My projection matrix:

Projection = Matrix4.CreatePerspectiveFieldOfView (fovy, width / height, zNear, zFar);

My view matrix:

View = Matrix4.LookAt (position, position + Direction, up);

My Model matrix:

Matrix4 modelMatrix = Matrix4.CreateTranslation(new Vector3(chunkPos.X * 32, chunkPos.Y * 32, chunkPos.Z * 32));

Here's how I form the MVP matrix:

ViewProjection = View * Projection;
ModelViewProjection = Model * ViewProjection;

And finally the vertex shader:

gl_Position = mMVP * vertex;

Screenshots displaying the problem:

Squeezed Y-axis in screen-space Squeezed Y-axis in screen-space

I tried to fix the problem by adding a y-axis scale of 1.5 to my View matrix, and it seems it helped a bit with the problem. The result:

enter image description here

The question

I want to understand why I have to scale it this way. I thought the aspect ratio I give to the CreatePerspectiveFieldOfView would do this correction for me.


1 Answer 1


And literally 1min after I post the question I found out the answer. The problem was that on my projection matrix creation the width and height are integers, and thus the aspect ratio would be always 1. I changed the width and height to floats, and it started working.

  • 1
    \$\begingroup\$ Glad you found your answer. Asking the question by itself usually leads to more clarity into the problem at hand. This story comes to mind. \$\endgroup\$ Commented Apr 21, 2014 at 7:12

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