As the title says, you are able to compose the ViewMatrix and the ProjectionMatrix into one instead of multiplying a vector by the individual matrices.

Instead of doing this at run time for each item: Vector * ViewMatrix -> Vector ProjectionMatrix

Do this at the start: ViewMatrix * ProjectionMatrix -> ComposedMatrix

Then when drawing vectors: Vector * ComposedMatrix

This would minimize the number of necessary matrix multiplications. Is there any reason not to do this?

  • 2
    $\begingroup$ Yes, that's what people do. Matrix multiplication is (theoretically) associative, so $((vA)B)C = v(ABC)$. $\endgroup$
    – lightxbulb
    Jul 3, 2020 at 15:22
  • $\begingroup$ Thanks for the information $\endgroup$
    – Nixcc
    Jul 3, 2020 at 19:56
  • 1
    $\begingroup$ But usually it is projectionmatrix * viewmatrix * positionvector $\endgroup$
    – Thomas
    Jul 5, 2020 at 18:44


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