Correctly Calculating Model and View Matrices for OpenGL Use?

Question

I'm having a bit of trouble with matrices in GL 3.2. How, preferably in matrix notation, do I go about generating a model and view matrix? How do I setup my model/view matrix? I already have a projection matrix; it's defined as:

float right = 800.0f, left = 0.0f;
float top = 0.0f, bottom = 600.0f;
float far = 1.0f, near = -1.0f;

float ortho_mat[16] = {(2.0f / (right - left)), 0.0f, 0.0f, 0.0f,
                     0.0f, (2.0f / (top - bottom)), 0.0f, 0.0f,
                     0.0f, 0.0f, (-2.0f / (far - near)), 0.0f,
                     (-((right + left) / (right - left))),
                     (-((top + bottom) / (top - bottom))),
                     (-((far + near) / (far - near))), 1.0f};

I understand that this orthographic matrix has to be multiplied by the model and view matrices, and those have to be multiplied by the point. How do I setup those matrices?

Edit: I don't mind if they're concatenated into one (modelview).

OpenGL man pages contain formulas for translate, rotate, scale, lookAt, etc. — Tim

Mortennobel Mortennobel · Accepted Answer · 2012-10-04T19:08:30

I suggest that you use the library OpenGL Mathematics instead of implementing everything yourself. OpenGL Mathematics contains all the math you need for OpenGL - and the syntax is inspired from GLSL. The library is found here:

http://glm.g-truc.net/

Alternative you could implement your own math library. In that case I suggest you take a look at the Angels math library (from the book "Interactive Computer Graphics: A Top-Down Approach with Shader-Based OpenGL, 6/E"). This library is very simple to understand:

http://www.cs.unm.edu/~angel/BOOK/INTERACTIVE_COMPUTER_GRAPHICS/SIXTH_EDITION/CODE/include/

(look in the mat.h and vec.h)

Correctly Calculating Model and View Matrices for OpenGL Use?

2 Answers