0
\$\begingroup\$

I'm implementing my own game engine in C++ and I need help here,

I have a game object, its orientation property is a quaternion and I want to rotate it A degrees in the Y axis.

So, I have:

currentAngle += 0.01; // currentAngle is a member variable, so yes i initialized it
quat q(currentAngle, vec3(0, 1, 0));
myGameObject->SetOrientation(q);

GameObject::SetOrientation(quat q)
{
 myOrientation  = q;
}

but as the game object rotates, it also gets scaled (deformed). So I checked how I am applying the transformation matrices

myModelMatrix = Math::CreateTransformationMatrix(
    transformation->GetPosition(),
    transformation->GetOrientation(), 
    transformation->GetScale()); 


mat4& Math::CreateTransformationMatrix(vec3&    translation, quat& orientation, vec3& scaleSize)
{

     mat4 translate = glm::translate(glm::mat4(), translation);
     mat4 rotate = glm::toMat4(orientation);
     mat4 scale = glm::scale(glm::mat4(), scaleSize);

    return  translate * rotate * scale;
}

but it looks ok (at least to me), I removed the scale matrix form the multiplication to check if somehow I was doing something with it. However, it didnt fix anything.

I also tried:

  quat q(currentAngle, vec3(0, 1, 0));
   quat orientation = myGameObject->GetOrientation();
   orientation  = orientation  *q;
   myGameObject->SetOrientation(orientation);

But it didnt work either. I also checked the code in my shaders and I am positive is not the problem.

This is how I send the matrices to the shader:

glUseProgram(progarmId);1
    glUniformMatrix4fv(uniforms[name], 1, GL_FALSE, glm::value_ptr(matrix));

I tried modifying the 3rd parameter to True and swapping the order of the projection view matrix multiplication and it didnt work either :/

So, guys ... any ideas what could I be doing wrong ? I'm out of ideas :/

\$\endgroup\$
1
\$\begingroup\$

I'm not sure if it is what's causing the problem but the CreateTransformationMatrix method should not return a reference type because the result is allocated on the stack in the scope of the method. So the resulting matrix is in an undefined state.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.