Can glm::lookAt() Be Used to Set the Model Matrix?

Transform the modelMatrix

In a typical rendering pipeline, transformations are applied to objects in a scene using a sequence of matrices:

Object Coordinates (Model Space):

• The local space of a single object. Vertex positions are defined in this space.

World Coordinates:

• The global coordinate system of the scene, where all objects are positioned.

Model Matrix:

• Transforms an object from model space to world space. Defines its location, orientation, and scaling.

View Space (Eye Coordinates):

• The coordinate system based on the viewer's position, direction, and up vector.

View Matrix:

• Transforms from world space to view space, providing the "camera" perspective.

Clip Coordinates:

• Homogeneous coordinates used for clipping against the view frustum.

Projection Matrix:

• Transforms from view space to clip space, mapping 3D points to 2D points on the viewport.

Normalized Device Coordinates (NDC):

• Clip space coordinates divided by the w component, used for perspective division.

Window Coordinates (Screen Coordinates):

• Coordinates of the viewport rectangle, where the final image is drawn.

Transforming the Model Matrix with glm

While glm::lookAt() is primarily designed to set the view matrix, certain modifications can be applied to use it for the model matrix:

Transformations to Address Position:

• Negating the third column elements of the resulting matrix: m_Orientation[3][0] = -m_Orientation[3][0]; ...

Vertex Shader Transformation:

• Multiplying the camera matrix, model matrix, and vertex position: gl_Position = CameraMatrix * ModelMatrix * Pos

Note: While this approach can achieve the desired result, it is not optimal for setting the model matrix. It is generally recommended to use specific functions provided by libraries or create your own function to handle model matrix transformations.

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