Why doesnt my orthogonal projection matrix work?

Question

I am trying to render some quads that are located in the plane (z=0) with an orthogonal projection. I did set up a projection matrix after reading Formula for a orthogonal projection matrix? but I think I did something wrong.

My first attempt was the following matrix. W, and H are the width and height of my desired viewport which is 640x640 in the following examples :

 ˹ 2/w 0   0  0 ˺
 | 0   2/h 0  0 |
 | 0   0   0  0 |
 ˻ 0   0   0  1 ˼

Here is what I obtained when I rendered a quad whose topleft corner was in (0,0,0) :

Since it was flipped vertically I changed my matrix to :

 ˹ 2/w  0   0  0 ˺
 | 0   -2/h 0  0 |
 | 0    0   0  0 |
 ˻ 0    0   0  1 ˼

I obtained :

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Then I tried to move my quad around and the results were unexpected. I wanted the X and Y of the 3D space to match those of the viewport. However here is what happened when I moved the quad along the X axis :

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Moving along the Y axis gave equally unexpected results :

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How can I fix my matrix so that the X and Y axis of the 3D space match those of the viewport ? Many thanks in advance.

Answer 1

You missing the far near clipping. Try this

2/viewWidth    0              0             0
0             -2/viewHeight   0             0
0              0              1/(far-near)  -near/(far-near)
0              0              0             1

Answer 2

This projection matrix is actually correct. The problem was in the quad translation code, sorry for messing up.