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In Java I create a frustum projection matrix via

Matrix.frustumM(projMatrix, 0, left, right, bottom top, near, far);

and a view matrix via

Matrix.setLookAtM(viewMatrix, 0,
                               0, 0, -2.5,  // eye position
                               0, 0, 0      // look position
                               0, -1, 0);   // up direction

My question is:

Which part of the frustum originates at the eye position? Is it the tip of the pyramid, or the centre of the near plane?

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The eye position is at the tip of the pyramid though the actual projection will end up on the near plane i.e the near plane will be your "screen"

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  • \$\begingroup\$ So if I had a world coordinate point at (0, 0, 0) and the camera was at (0, 0, 1) looking directly at (0, 0, 0), with a near distance of 1, then that (0, 0, 0) point should appear in the centre of the screen? \$\endgroup\$ – Antinous Dec 6 '18 at 20:56
  • \$\begingroup\$ Not sure because it would be in the near plane \$\endgroup\$ – Hampus Dec 6 '18 at 21:21

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