CODEWITHSUNDEEP
c++qtopengl
Mercury
Mercury

Reputation: 1965

using perspective in openGL

I would like to get the ray out of my current view.

I generate the following projection matrix:

QMatrix4x4 m_proj;
...
m_proj.perspective(camFOV, ar, camZnear, camZfar);

when I apply a point in 3d I get the normalized coordinates (range of [-1 1]).

If I get a click event, I normalize the coordinates to [-1 1] and multiply it by when m_proj.inverted(), but I get weird results (a number greater than 1).

In other words, how do I transform a click in the screen (x,y) coordinates to a ray in the camera coordinate system?

EDIT:

This is similar question to Qt OpenGL- How to get the object based on the mouse click But how do I do it with modern opengl?

Upvotes: 1

Views: 716

Answers (1)

Mercury
Mercury

Reputation: 1965

For future users:

QVector4D uv(xy.x() / m_w * 2 - 1, -(xy.y() / m_h * 2 - 1),1,1);
QVector3D sv = m_proj.inverted() * uv;

where sv is a point on the camera screen

Upvotes: 1

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