I'm trying to load an image for my game. Each robot is a structure and I store the image in it. What happen when the image is drawn is sometimes it draw some artefact over the image and sometimes it doesn't and it's completely random. In the first image attached, only the blue robot doesn't have artefact and in the second one, the pink one doesn't have it either. Those 2 frame are from different run of the program and the 4 robots are the same.

I was just wondering if storing an ALLEGRO_BITMAP into a structure is a good idea or this could be the source of my problem?

PS: I don't know how to link image directly in the post so I attached it.

It's hard to help you without having the code that produces this output.

So if I had to guess from the screenshots, I'd say it looks like you're trying to draw bitmaps that weren't properly initialized. These pink-ish garbage sprites above the robots look like you were trying to draw bitmaps with random data in them.

Or, actually, looking at the garbage sprites... it also looks like it could be actual sprites that for some reason have the wrong dimensions, so that the pixels are at the wrong locations.

In any case, as I said, without any code it's really hard to help here.

You could be drawing destroyed copies of bitmaps depending on your code. What do you do with your stored ALLEGRO_BITMAP*? Remember it's just a pointer but if you're destroying it in your destructor and you make copies of your struct then the original will be destroyed and you will be left with a dangling pointer.

Here's the code (it's scattered around my program) :

How I create the Robot:

void BENDERBOT(ROBOTCOLORS color) {
  RegisterRobot("Bender", color, &BenderActions, &PimpOutBender,
      "resources\\images\\basic_robot.bmp", -1, -1, -1);
}

The image is stored in newRobot.graphic at the 112-115th line. Also note that if, when I call the RegistewrRobot and customImage = NULL the program gives it the default image and it work fine but if I give it the path to the default image it gives me artefact.

Then this is when I draw the robot :

And this is when I destroy the bitmap :

The bitmap is destroyed at line 21-22th line.

Those are the only action I take on the robot.graphic.

Finally here is the action order of my game loop :

@Edgar Reynaldo
I don't know because all the robot are managed the same way and the artefact are random. They don't appear on random frame they just show up randomly on a robot graphic . Plus I don't destroy the robot.graphic until the end of the game.

The fact that if I load the bitmap using a path in the RegisterRobot or using NULL to load the same bitmap doesn't give me the same result feel strange to me.

I see this is where you create "shield", but where do you fill its contents? If you just create a bitmap without filling it, it will only contain garbage.
Also is there a special reason to set the bitmap flags to "memory bitmaps" after creating these bitmaps? First of all, memory bitmaps should be avoided if possible, because they're slow. Secondly, if you were intending "shield" or "image" to be memory bitmaps, you should have called al_set_new_bitmap_flags before creating the bitmaps.

Is there a reason for creating and destroying the bitmap in every draw call? Creating bitmaps can be slow and shouldn't be done every frame unless absolutely necessary. Since you're using constant sizes here, recreating the bitmap every frame isn't necessary. Just create the image onces with the robot and destroy it once the robot is destroyed.

Yeah I found out that the shield was doing the artefact and I will simply remove the pre-rendered shield. I did that because I had a FPS problem which had nothing to do with it.

The memory thing was because I wanted to draw my particles (which use al_put_pixel) on it but Edgar told me to lock/unlock my bitmap instead.

Yes I will fix this creating/destroying bitmap thing.

Thank you for your help!