I am trying to rotate a sprite so it is always facing a 3D camera.

Object

GLfloat vertexData[] = {
    //  X     Y     Z       U     V
    0.0f, 0.8f, 0.0f,   0.5f, 1.0f,
    -0.8f,-0.8f, 0.0f,   0.0f, 0.0f,
     0.8f,-0.8f, 0.0f,   1.0f, 0.0f,
};

Per frame transform

glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), gCamera.up());
shaders->setUniform("camera", gCamera.matrix());
shaders->setUniform("model", newTransform);

In the vertex shader:

gl_Position = camera * model * vec4(vert, 1);

The object will track the camera if I move the camera up or down, but if I move the camera left/right (spin the camera around the object's y axis), it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360.

If I use -gCamera.up() instead, it would track the camera side to side, but spin the opposite direction when I move the camera up/down.

What am I doing wrong?