camera viewport DOES affect camera space

[PSteinhaus]

This is on master at 4e27d18
Slightly related to #171

expected behavior

The docs state that

Viewport do not affect camera space, just the render position on the screen.

observed behavior

I modified the rustaceanmark example minimally to try out the macroquad camera. During this I stumbled upon the fact that specifying a viewport does alter your cameras space. As you can see here specifying a viewport has the effect of zooming in:

native (Ubuntu 23.10, Nvidia GTX 1060):

wasm (Firefox and Chromium):

Code:

use macroquad::prelude::*;

struct Rustaceane {
    pos: Vec2,
    speed: Vec2,
    color: Color,
}

#[macroquad::main("Rustaceanmark")]
async fn main() {
    let mut rustaceanes: Vec<Rustaceane> = Vec::new();
    let rustacean_tex = load_texture("examples/rustacean_happy.png").await.unwrap();
    rustacean_tex.set_filter(FilterMode::Nearest);

    let mut cam = Camera2D::default();
    cam.viewport = Some((0, 0, 200, 200));

    loop {
        clear_background(Color::default());
        set_camera(&cam);

        if macroquad::input::is_mouse_button_down(MouseButton::Left) {
            for _i in 0..100 {
                rustaceanes.push(Rustaceane {
                    pos: Vec2::from(macroquad::input::mouse_position()),
                    speed: Vec2::new(
                        rand::gen_range(-250., 250.) / 60.,
                        rand::gen_range(-250., 250.) / 60.,
                    ),
                    color: Color::from_rgba(
                        rand::gen_range(50, 240),
                        rand::gen_range(80, 240),
                        rand::gen_range(100, 240),
                        255,
                    ),
                })
            }
        }

        for rustaceane in &mut rustaceanes {
            rustaceane.pos += rustaceane.speed;

            if ((rustaceane.pos.x + rustacean_tex.width() / 2.) > screen_width())
                || ((rustaceane.pos.x + rustacean_tex.width() / 2.) < 0.)
            {
                rustaceane.speed.x *= -1.;
            }
            if ((rustaceane.pos.y + rustacean_tex.height() / 2.) > screen_height())
                || ((rustaceane.pos.y + rustacean_tex.height() / 2.) < 0.)
            {
                rustaceane.speed.y *= -1.;
            }

            draw_texture(
                &rustacean_tex,
                rustaceane.pos.x,
                rustaceane.pos.y,
                rustaceane.color,
            );
        }

        draw_text(format!("FPS: {}", get_fps()).as_str(), 0., 16., 32., WHITE);
        draw_text(
            format!("Rustaceanes: {}", rustaceanes.len()).as_str(),
            0.,
            32.,
            32.,
            WHITE,
        );

        next_frame().await
    }
}

experiment with from_display_rect camera configuration

I can get the right space back though, if I also set the zoom and target accordingly by using from_display_rect with the same dimensions as the viewport:

native (and wasm looks the same):

Code:

use macroquad::prelude::*;

struct Rustaceane {
    pos: Vec2,
    speed: Vec2,
    color: Color,
}

#[macroquad::main("Rustaceanmark")]
async fn main() {
    let mut rustaceanes: Vec<Rustaceane> = Vec::new();
    let rustacean_tex = load_texture("examples/rustacean_happy.png").await.unwrap();
    rustacean_tex.set_filter(FilterMode::Nearest);

    const WORLD_WIDTH: f32 = 200.;
    const WORLD_HEIGHT: f32 = 200.;

    let mut cam = Camera2D::from_display_rect(Rect::new(0., 0., WORLD_WIDTH, WORLD_HEIGHT));
    cam.zoom = Vec2::new(cam.zoom.x, -cam.zoom.y); // workaround for https://github.com/not-fl3/macroquad/issues/171
    cam.viewport = Some((0, 0, WORLD_WIDTH as i32, WORLD_HEIGHT as i32));

    loop {
        clear_background(Color::default());
        set_camera(&cam);

        if macroquad::input::is_mouse_button_down(MouseButton::Left) {
            for _i in 0..100 {
                rustaceanes.push(Rustaceane {
                    pos: Vec2::from(macroquad::input::mouse_position()),
                    speed: Vec2::new(
                        rand::gen_range(-250., 250.) / 60.,
                        rand::gen_range(-250., 250.) / 60.,
                    ),
                    color: Color::from_rgba(
                        rand::gen_range(50, 240),
                        rand::gen_range(80, 240),
                        rand::gen_range(100, 240),
                        255,
                    ),
                })
            }
        }

        for rustaceane in &mut rustaceanes {
            rustaceane.pos += rustaceane.speed;

            if ((rustaceane.pos.x + rustacean_tex.width() / 2.) > screen_width())
                || ((rustaceane.pos.x + rustacean_tex.width() / 2.) < 0.)
            {
                rustaceane.speed.x *= -1.;
            }
            if ((rustaceane.pos.y + rustacean_tex.height() / 2.) > screen_height())
                || ((rustaceane.pos.y + rustacean_tex.height() / 2.) < 0.)
            {
                rustaceane.speed.y *= -1.;
            }

            draw_texture(
                &rustacean_tex,
                rustaceane.pos.x,
                rustaceane.pos.y,
                rustaceane.color,
            );
        }

        draw_text(format!("FPS: {}", get_fps()).as_str(), 0., 16., 32., WHITE);
        draw_text(
            format!("Rustaceanes: {}", rustaceanes.len()).as_str(),
            0.,
            32.,
            32.,
            WHITE,
        );

        next_frame().await
    }
}

experiments with multiple cameras

If we try to go one step further and restore the default camera (using set_default_camera) after drawing the sprites but before drawing the text we get this:

As you can see, now the text is being scaled down.

If we do something like this instead:

let mut def_cam = Camera2D::default();
def_cam.viewport = Some((0, 0, screen_width() as i32, screen_height() as i32));
set_camera(&def_cam);

we get no text drawn at all (or probably somewhere we can't see):

[PSteinhaus]

What does work though to get something like a functioning viewport is using the clipping functionality in macroquad:

const WORLD_WIDTH: f32 = 200.;
const WORLD_HEIGHT: f32 = 200.;

let mut cam = Camera2D::from_display_rect(Rect::new(0., 0., WORLD_WIDTH, WORLD_HEIGHT));
cam.zoom = Vec2::new(cam.zoom.x, -cam.zoom.y); // workaround for https://github.com/not-fl3/macroquad/issues/171
set_camera(&cam);
unsafe {
    window::get_internal_gl().quad_gl.scissor(Some((0, 0, WORLD_WIDTH as i32, WORLD_HEIGHT as i32)));
}

// ... draw sprites

unsafe {
    window::get_internal_gl().quad_gl.scissor(None);
}
set_default_camera();

Now I even get the camera space that I asked for! :D