glmlookAt

glmlookAt refers to the GLM library’s lookAt function, a utility that generates a view matrix for a camera in 3D OpenGL applications. It is the GLM equivalent of the legacy gluLookAt, returning a 4x4 matrix that transforms world coordinates into camera space. The function is commonly used to establish the camera’s position and orientation before rendering.

The function signature in typical usage is glm::mat4 lookAt(glm::vec3 eye, glm::vec3 center, glm::vec3 up). It takes the eye position (the camera location), center (the point the camera looks at), and up (the world up vector). Internally, it computes an orthonormal basis: f = normalize(center - eye) represents the forward direction, s = normalize(cross(f, up)) is the right vector, and u = cross(s, f) is the true up vector. The resulting view matrix has the orientation columns (s, u, -f) and a translation component that accounts for the camera position: translation entries are (-dot(s, eye), -dot(u, eye), dot(f, eye)) in the matrix’s last column. This configuration creates a matrix that, when applied to world coordinates, moves and rotates the scene so that the camera is at eye looking toward center with the given up direction.

Common caveats include: eye equals center yields an undefined view matrix; up must not be parallel to forward (f), and up should be a nonzero vector. The resulting matrix is used in combination with projection and model matrices to form the complete MVP transform for rendering.