JOGL setPerspective wrong?

问题

I've decided to use JOGL for my project. But here is the problem with setting perspective. Simple code:

System.out.println("BEFORE:");
projectionMatrix.identity();
projectionMatrix.setPerspective(fovy, aspect, zNear, zFar);
System.out.println(projectionMatrix);

System.out.println("AFTER:");
projectionMatrix.identity();        
projectionMatrix.m00 =
    (float)(1.0 / (aspect*Math.tan(viewAngle)));
projectionMatrix.m11 =
    (float)(1.0 / Math.tan(viewAngle));
projectionMatrix.m22 =
    (float)((-zNear-zFar) / (zNear-zFar));
projectionMatrix.m33 = 0.0f;

projectionMatrix.m23 =
        (float)((2*zFar*zNear) / (zNear-zFar));
projectionMatrix.m32 = 1.0f;
System.out.println(projectionMatrix);

Output:

BEFORE:
2.414E+0  0.000E+0  0.000E+0  0.000E+0
0.000E+0  2.414E+0  0.000E+0  0.000E+0
0.000E+0  0.000E+0 -1.000E+0 -2.000E-2
0.000E+0  0.000E+0 -1.000E+0  0.000E+0

AFTER:
1.000E+0  0.000E+0  0.000E+0  0.000E+0
0.000E+0  1.000E+0  0.000E+0  0.000E+0
0.000E+0  0.000E+0  1.000E+0  1.000E+0
0.000E+0  0.000E+0 -2.000E-2  0.000E+0

As you can see, matrices are different. Their (jogl) code:

public Matrix4f setPerspective(float fovy, float aspect, float zNear, float zFar) {
    float h = (float) Math.tan(fovy * 0.5f) * zNear;
    float w = h * aspect;
    m00 = zNear / w;
    m01 = 0.0f;
    m02 = 0.0f;
    m03 = 0.0f;
    m10 = 0.0f;
    m11 = zNear / h;
    m12 = 0.0f;
    m13 = 0.0f;
    m20 = 0.0f;
    m21 = 0.0f;
    m22 = -(zFar + zNear) / (zFar - zNear);
    m23 = -1.0f;
    m30 = 0.0f;
    m31 = 0.0f;
    m32 = -2.0f * zFar * zNear / (zFar - zNear);
    m33 = 0.0f;
    return this;
}

Gives different from mine. Program works fine with my version of code. How do I use their library?

Another problem: simple by switching from javax.vecmath.Matrix4f to org.joml.Matrix4f rotation becomes broken (rotate around wrong axis and around a point that is slightly off camera).

回答1:

First, update jogl, second use FloatUtil.makePerspective(final float[] m, final int m_off, final boolean initM, final float fovy_rad, final float aspect, final float zNear, final float zFar)

float[] m is the matrix you need to submit. This offers you flexibility, that means if you want use pools, you can. Otherwise just pass new float[16] and catch the return result

来源：https://stackoverflow.com/questions/33398712/jogl-setperspective-wrong

标签

opengl

matrix

camera

rotation

jogl