float speed = 3.0f;
float deadZone = 0.10f;
glm::vec2 direction(0.0f);

while (!glfwWindowShouldClose(window))
{
    currentTime = glfwGetTime();
    deltaTime = (currentTime - lastUpdate) * 1000.0f;

    //Update logic
    inputHandler->tick(deltaTime);

    float inputX, inputY;
    inputX = inputHandler->getGamepad(0)->getAxes(AXIS::HORIZONTAL);
    inputY = inputHandler->getGamepad(0)->getAxes(AXIS::VERTICAL);

    float magnitude = sqrtf((inputX * inputX) + (inputY * inputY));
    if (magnitude > deadZone) //Radial dead zone detection
    {
        //Could the stutter be caused by type casting?
        direction.x += inputX * float((speed * deltaTime) / 1000.0f);
        direction.y += inputY * float((speed * deltaTime) / 1000.0f);
    }

    ... //Set vertex values and UV coord

    //Set the matrix values according to the joystick input
    glm::mat4 MVP(1.0f);
    MVP = glm::translate(MVP, glm::vec3(direction, 0.0f));
    glUniformMatrix4fv(mvpID, 1, GL_FALSE, glm::value_ptr(MVP));

    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    ...
}

#version 150

in vec2 vertexPosition_modelspace;
in vec2 UV;

uniform mat4 MVP;

out vec2 vUV;

void main() {
    vUV = UV;
    gl_Position = MVP * vec4(vertexPosition_modelspace, 0, 1);
}