Make Square Fill Entire Window
How do I determine what transforms I need to make a square fill an entire window in modern OpenGL? Say for example I have an 800 x 600 window and the coordinates with the vertices of two triangles extending from -1 and 1. Without any type of transformation, these coordinates would fill an 800 x 600 window because OpenGL's coordinates extend from -1 to 1. What if I want to use a standard MVP transformation, though? How do I determine what needs to be done in order to fill an entire window. Consider this code:
glm::mat4 projectionMatrix = glm::perspective(60.0f, 4.f/3.f, 0.1f, 100.0f); // gluPerspective equivalent for those who may not know about glm
glm::mat4 viewMatrix = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -5.0f));
glm::mat4 modelMatrix = glm::mat4(1.0f);
with the same coordinates. I would now get a square somewhere in the middle of the window. Assuming I do not change the projection matrix, what changes would need to be made to the View and Model matrices? I understand the matrix math, but not how it relates to window coordinates themselves.
Could someone please help me understand this?