Camera zoom. Am I an idiot?

[PierreGordo]

Hello,

I am trying to figure out how to zoom the camera in and out. After failing to do this multiple times I am at a loss for words. I have no idea why such a simple concept in other game engines is so confusing in bevy. Does anyone have a working solution? I have the following, very basic, camera setup:
commands.spawn((Camera2d::default(), Camera));

I tried some stuff with the OrthographicProjection but it all just seems so needlessly confusing to do such a simple stuff as zooming in plus it did not even work.

If somebody has a working solution, please help me with this as I am new to both bevy and rust. :)

[NiklasEi]

You can mutate the camera's projection to zoom in and out.

Take a look at https://bevy-cheatbook.github.io/graphics/camera.html#zooming-the-camera

[PierreGordo]

Hi, thank you for your reply.

Unfortunately the bevy cheat book is quite outdated and the syntax has changed, but your answer put me on the right track and I managed to put together some well-enough working code. Now there is still some goofiness happening (if you zoom in too much, you start zooming out instead of in), but overall I am happy with the results. For anyone searching how to zoom in bevy 0.16 here is my amateurish attempt.

// The "Single" in the query says that there is only one element that matches these parameters so I don't have to for loop later
fn zoom_camera(mouse_wheel: Res<AccumulatedMouseScroll>, camera_query: Single<&mut Projection, With<Camera>>){

    //Since projection is an enum of Perspective, orthographic and custom this match gets out only the orthographic element that i want to modify
    match *camera_query.into_inner() {
        Projection::Orthographic(ref mut orthographic) => {
            //Adding to scale zooms out (the -= is there since it is reversed -> adding to scale zooms out)
            orthographic.scale -= mouse_wheel.delta.y;
        }
        _ => (),
    }
}

[akimakinai]

You might want to multiply scale instead of adding, to make it closer to zero for zooming.

bevy/examples/2d/2d_viewport_to_world.rs

Lines 88 to 97 in cd67bac

	// Camera zoom controls
	if let Projection::Orthographic(projection2d) = &mut *projection {
	if input.pressed(KeyCode::Comma) {
	projection2d.scale *= powf(4.0f32, time.delta_secs());
	}
	if input.pressed(KeyCode::Period) {
	projection2d.scale *= powf(0.25f32, time.delta_secs());
	}
	}

[PierreGordo]

@akimakinai That is a great idea! Also that would fix the goofiness that occurs when scale goes below 0. Thank you for this most excellent suggestion :).