DirectX 11 D3DXMatrixTranslation continues to run?

Question

I want to bind moving an object to a button press. When I press the button, the object vanishes quickly and appears as if the first Translation was always running. Then when I let go of the button, it quickly vanishes and ends up where it would've been without touching the button. 'Bouncing' between the two when I press/release the button.

D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix;
bool result;


// Generate the view matrix based on the camera's position.
m_Camera->Render();

// Get the world, view, and projection matrices from the camera and d3d objects.
m_Camera->GetViewMatrix(viewMatrix);
m_Direct3D->GetWorldMatrix(worldMatrix);
m_Direct3D->GetProjectionMatrix(projectionMatrix);

// Move the world matrix by the rotation value so that the object will move.
if(m_Input->IsAPressed() == true) {
D3DXMatrixTranslation(&worldMatrix, 1.0f*rotation, 0.0f, 0.0f);
}
else {
    D3DXMatrixTranslation(&worldMatrix, 0.1f*rotation, 0.0f, 0.0f);
}

// Put the model vertex and index buffers on the graphics pipeline to prepare them for drawing.
m_Model->Render(m_Direct3D->GetDeviceContext());

// Render the model using the light shader.
result = m_LightShader->Render(m_Direct3D->GetDeviceContext(), m_Model->GetIndexCount(), worldMatrix, viewMatrix, projectionMatrix, 
                               m_Model->GetTexture(), m_Light->GetDirection(), m_Light->GetDiffuseColor());


if(!result)
{
    return false;
}

// Present the rendered scene to the screen.
m_Direct3D->EndScene();

I'm still really new to DX11 and I've had a good look around. I'm pulling my hair out here trying to work out whats going on.

Answer 1

That's what your code does. If a button is pressed you set one world matrix, if not - another. What you need to do is multiply the world matrix by a newly generated translation matrix. Notice that this multiplication will happen ~60 times every second, so you need to move only a very tiny distance with each one.

Your code should be like this

if (m_Input->IsAPressed() == true) {
   D3DXMATRIX translation;
   D3DXMatrixTranslation(&translation, 0.05f, 0.0f, 0.0f);
   worldMatrix *= translation;
}

You may need to do

m_Direct3D->SetWorldMatrix(worldMatrix);

Or something similar. I don't think I'm familiar with the classes you're using for m_Camera and m_Direct3D.