Drawing to the second render target created on the same frame results in a white texture

[JaniM]

Full reproduction below. If you remove the marked line, the code works as expected.

use macroquad::prelude::*;

const VIRTUAL_WIDTH: f32 = 1280.0;
const VIRTUAL_HEIGHT: f32 = 720.0;

#[macroquad::main("Letterbox")]
async fn main() {

    // remove the following line and it works
    render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32); // <--

    let render_target = render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32);

    let mut render_target_cam =
        Camera2D::from_display_rect(Rect::new(0., 0., VIRTUAL_WIDTH, VIRTUAL_HEIGHT));
    render_target_cam.render_target = Some(render_target.clone());

    loop {
        set_camera(&render_target_cam);
        clear_background(BLUE);
        draw_circle(VIRTUAL_WIDTH / 2.0 - 65.0, VIRTUAL_HEIGHT / 2.0, 35.0, RED);

        set_default_camera();
        clear_background(BLACK);
        draw_texture_ex(
            &render_target.texture,
            0.,
            0.,
            WHITE,
            DrawTextureParams {
                ..Default::default()
            },
        );

        next_frame().await;
    }
}

[JaniM]

Triage:

• This is related to the drop handler of textures. The following code does not exhibit the error.

let _foo = render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32);
let render_target = render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32);

• If I delete these three lines, the bug is not exhibited.

  macroquad/src/texture.rs

  Lines 56 to 58 in 2f7f3c8

  	if let Some(texture) = self.textures.get(texture) {
  	ctx.delete_texture(texture);
  	}

• If I delete this line in miniquad, the issue doesn't happen. https://github.com/not-fl3/miniquad/blob/ca8d6341690085aa01924db6c8e03989d9c262f7/src/graphics/gl.rs#L857

• The issue does not exist on the current master version of macroquad.

[not-fl3]

I believe it was fixed already but it did not yet made to crates.io

[historydev]

I believe it was fixed already but it did not yet made to crates.io

let rt1 = render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32); // <-- works
let _ = render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32); // <-- white screen /* == */ 
render_target(VIRTUAL_WIDTH as u32, VIRTUAL_HEIGHT as u32); // <-- white screen

It seems that if the return value is not used, what the author sees is what you get.

[JaniM]

It is fixed on master.