This is my perspective projection matrix code

inline m4
Projection(float WidthOverHeight, float FOV)
{
    float Near = 1.0f;
    float Far = 100.0f;

    float f = 1.0f/(float)tan(DegToRad(FOV / 2.0f));
    float fn = 1.0f / (Near - Far);


    float a = f / WidthOverHeight;
    float b = f;
    float c = Far * fn;
    float d = Near * Far * fn;

    m4 Result = 
    {
        {{a, 0, 0, 0},
         {0, b, 0, 0},
         {0, 0, c, -1},
         {0, 0, d, 0}}
    };
    return Result;
}

And here is the main code

    m4 Project = Projection(ar, 90);
    m4 Move = {};
    CreateMat4(&Move,
        1, 0, 0, 0,
        0, 1, 0, 0,
        0, 0, 1, -2,
        0, 0, 0, 1);
    m4 Rotate = Rotation(Scale);
    Scale  = 0.01f;

    m4 FinalTransformation = Project * Move * Rotate;
    SetShaderUniformMat4("Project", FinalTransformation, ShaderProgram);

Here are some pictures of the cube rotating. In the shader code I just multiply the transformation by the position (with the transformation being on the left).

I am not sure if it's helpful but here is the rotation code:

float c = cos(Angle);
float s = sin(Angle);
m4 R =
{
    {{ c, 0, s, 0},
     { 0, 1, 0, 0},
     {-s, 0, c, 0},
     { 0, 0, 0, 1}}
};
return R;

I tried multiplying the matricies in the shader code instead of on the c side but then everything disappeared.

CodePudding user response：

OpenGL matrixes are stored with column major order. You have to read the columns from left to right. For example the 1st column of the matrix R is { c, 0, s, 0}, the 2nd one is { 0, 1, 0, 0} the 3rd is {-s, 0, c, 0} and the 4th is { 0, 0, 0, 1}. The lines in your code are actually columns (not rows).
Therefore you need to to transpose you projection matrix (Project) and translation matrix (Move).