Getting Eye direction vector

Hello, I’m trying to draw some water in modern OpenGL (greather than 3.x).
I’ve got model matrix, view matrix and projection matrix uniforms and my positions’ attribute. The problem is: how can I get the eye direction vector?
Thanks in advance.

The eye position is 0,0,0 in eye space, which is what the model-view matrix transforms to. So after you’ve transformed the vertex position by the model-view matrix, the eye direction is simply the negation of the transformed vertex position (ignoring the w coordinate, which should be 1; the model-view matrix shouldn’t contain any projective transformations).

Thanks. The error was that I’ve negated the entire output vertex including w coord.