Ist dies eine korrekte perspektivische FOV-Matrix?

Question

Ich habe eine perspektivische FOV, aber wenn Sie sich drehen, ist es nicht "aussehen" nicht korrekt, sondern weitere Objekte, die schneller sind als nähere Objekte, was sie in der Mitte des Bildschirms passiert.

Also: Ist das richtig?Verwenden Sie Rechtshänder-Koordinaten, wenn dies wichtig ist? generasacodicetagpre.

danke.

Answer 1

I see a couple of problems. First, the argument to tan() should be converted from degrees to radians.

Second, the formula for perspective projection in OpenGL is a little different from yours. As specified here, it uses 'near - far' in the denominator instead of your 'far - near'. The numerator terms are also different. Modifying your function slightly and converting from Java to C, I produced a projection matrix identical to the one given by gluPerspective() with the following:

static void my_PerspectiveFOV(double fov, double aspect, double near, double far, double* mret) {
    double D2R = M_PI / 180.0;
    double yScale = 1.0 / tan(D2R * fov / 2);
    double xScale = yScale / aspect;
    double nearmfar = near - far;
    double m[] = {
        xScale, 0, 0, 0,
        0, yScale, 0, 0,
        0, 0, (far + near) / nearmfar, -1,
        0, 0, 2*far*near / nearmfar, 0 
    };
    geom_matrix4_copy(m, mret);
}

Answer 2

For questions such as this one I would suggest an excellent resources: https://www.scratchapixel.com/lessons/3d-basic-rendering/perspective-and-orthographic-projection-matrix It really goes in the detail of the projection matrix. They are more lessons on the topic of camera, constructing camera rays, etc. You will need to do some digging.