When loading the texture into the OpenGL application, we make sure to set the wrap mode for the s and t directions to GL_CLAMP_TO_BORDER. We do this because if the texture coordinates are outside of the range of zero to one, we do not want any contribution from the projected texture. With this mode, using the default border color, the texture will return (0,0,0,0) when the texture coordinates are outside of the range between 0 and 1 inclusive.
The transformation matrix for the slide projector is set up in the OpenGL application. We start by using the GLM function glm::lookAt to produce a view matrix for the projector. In this example, we locate the projector at (5, 5, 5), looking toward the point (-2, -4,0), with an up vector ...
