Bug on asteroids

[Cyshots]

Hey i see long lines and its goes very slow at times which i cant control my jet

[karlellis]

Hi, I have the same issue as described by @Cyshots .
When the Asteroids goes out of screen, vertical/horizontal lines appears and then system lag, became very slow and unstable, I have to reset flipper to exit game.
I attach some screenshots.

Asteroids latest version (https://github.com/xMasterX/all-the-plugins/tree/dev/apps_source_code/flipper-asteroids)
Tested in Flipper Zero with Firmware:

• Official 1.2.0
• Unleashed
• Momentum

Any idea on how to solve this?
Thanks.

[karlellis]

Hi,
I'm not so skilled so I used copilot.
To avoid drawing segments across the screen when a polygon crosses the boundary, you can split the line segments into smaller segments that stay within screen bounds.
Changing the function "draw_poly" at line 276 of "flipper-asteroids/app.c"

void draw_poly(Canvas* const canvas, Poly* poly, uint8_t x, uint8_t y, float a) {
    Poly rot;
    rotate_poly(&rot, poly, a);
    canvas_set_color(canvas, ColorBlack);
    for(uint32_t j = 0; j < rot.points; j++) {
        uint32_t a = j;
        uint32_t b = j + 1;
        if(b == rot.points) b = 0;
        canvas_draw_line(canvas, x + rot.x[a], y + rot.y[a], x + rot.x[b], y + rot.y[b]);
    }
}

with this one:

void draw_poly(Canvas* const canvas, Poly* poly, uint8_t x, uint8_t y, float angle) {
    Poly rotated;
    rotate_poly(&rotated, poly, angle);
    canvas_set_color(canvas, ColorBlack);

    for(uint32_t i = 0; i < rotated.points; i++) {
        uint32_t next = (i + 1) % rotated.points;

        int x1 = (int)(x + rotated.x[i]) % SCREEN_XRES;
        int y1 = (int)(y + rotated.y[i]) % SCREEN_YRES;
        int x2 = (int)(x + rotated.x[next]) % SCREEN_XRES;
        int y2 = (int)(y + rotated.y[next]) % SCREEN_YRES;

        if (x1 < 0) x1 += SCREEN_XRES;
        if (y1 < 0) y1 += SCREEN_YRES;
        if (x2 < 0) x2 += SCREEN_XRES;
        if (y2 < 0) y2 += SCREEN_YRES;

        // If the line crosses the screen boundary
        if (abs(x1 - x2) > SCREEN_XRES / 2) {
            if (x1 > x2) {
                canvas_draw_line(canvas, x1, y1, SCREEN_XRES, y1);
                canvas_draw_line(canvas, 0, y2, x2, y2);
            } else {
                canvas_draw_line(canvas, x2, y2, SCREEN_XRES, y2);
                canvas_draw_line(canvas, 0, y1, x1, y1);
            }
        } else if (abs(y1 - y2) > SCREEN_YRES / 2) {
            if (y1 > y2) {
                canvas_draw_line(canvas, x1, y1, x1, SCREEN_YRES);
                canvas_draw_line(canvas, x2, 0, x2, y2);
            } else {
                canvas_draw_line(canvas, x2, y2, x2, SCREEN_YRES);
                canvas_draw_line(canvas, x1, 0, x1, y1);
            }
        } else {
            canvas_draw_line(canvas, x1, y1, x2, y2);
        }
    }
}

...fixes the issue.

Have a good day!

[onepointfive-REAL]

Will the developer fix it?

[mishamyte]

Hi @Cyshots, @karlellis, @onepointfive-REAL - this is fixed in #242.

What was going on

@karlellis had the right instinct: the trouble starts the moment part of a ship or asteroid crosses the edge of the screen. canvas_draw_line() takes signed coordinates, but the display library underneath stores them as unsigned 16-bit numbers, so a point one pixel off the left edge doesn't become -1, it becomes 65535. The game then draws a line all the way out to that point, one pixel at a time, straight across the display. Those are the stray lines in your photos. Drawing that many pixels every frame, on the same thread that reads the buttons, is also why the Flipper stopped responding and needed a reset.

A later update tried to stop this by pinning every corner back inside the screen. That killed the freeze but not the lines - a shape hanging over an edge just got flattened against it, which is the straight line along the border you still see on the current version.

This is fixed in Asteroids 1.3; once #242 is merged it will reach the app through the normal catalog update in your firmware.

Thanks for the clear reports and the screenshots - they made this easy to track down.