Form drawings flickering

[ExcludeReality]

I have a problem with form drawings "flickering" on the screen.
I attached a small example of a 3D cube being drawn on the forelayer.
Use the arrow-keys to move the cube around. Every time the cube is redrawn it turns completely white and then appears.
I can understand this behavior because the cube is being redrawn very often and the forelayer is being erased just before drawing.
But I was hoping there is a better way to do this, or perhaps cover it up, so that it doesn't appear far too much.

Thanks.

 

[derez]

The way around this problem is to draw the cube somewhere else (another form or a bitmap object) and when drawing is complete - to copy the bitmap to the form.
In your code there is only one drawing action (fpoligon) each cycle so it will not change anything.
The erasing will better be done only on the cube area - you have its points from the last render action, instead of the whole form.

Running the code - I see only the existing image and not the drawing of the cube, and it fails on the second pressing of arrow. ????

 

[ExcludeReality]

Running the code - I see only the existing image and not the drawing of the cube, and it fails on the second pressing of arrow. ????

I removed the existing image, so the whole cube is drawn on the forelayer. I also erase only the cube area of the screen.
But I haven't noticed any improvements. Please look at the new attached file.

 

[derez]

I had this problem before and ignored it - the poligon doesn't work with the old type parameters (xlist ,ylist) but only with the new method using one array of points.

I think this is a bug in 6.90.

The drawing takes time and this is the flicker you see.

I changed your program to work with array of points and I see the flickering, but the only solution for it is to draw on another form or bitmap and copy the new image to the form. This way the drawing is done while the image is still on the main form.

Check this http://www.b4x.com/forum/share-your-creations/3908-exercise-3d-rotation.html#post22546

 

[derez]

Here is a modified program without flickering. The picture is used to clear the form from previous drawing.

 

[ExcludeReality]

Here is a modified program without flickering. The picture is used to clear the form from previous drawing.

I get an error message while running the code. It has a problem with this line:

Form1.Polygon (List(),0,4,cGreen,f)

The message says that the value can't be null.

But anyway, I don't think drawing the polygon on one form then moving it to another will make any difference, since I only have one drawing action.
In addition, wouldn't it be more efficient to set the form color to gray than to load a gray picture?

 

[derez]

I get an error message while running the code. It has a problem with this line:

I guess that you are not running 6.90 because this works only in 6.90.

Use your program but draw on another form after "clearing" it with the picture. this is necessary because changing the background color does not affect the image of the form.
Copying the image by MainForm.image = Form1.image is immediate and does not cause flicker at all.

Edit: I attach the mod prog. Maybe you need to modify in the polygon line listx() to listx and listy() to listy

Edit: cube3 is doing it with imagelibEx instead of another form.

 

[ExcludeReality]

Use your program but draw on another form after "clearing" it with the picture. this is necessary because changing the background color does not affect the image of the form.
Copying the image by MainForm.image = Form1.image is immediate and does not cause flicker at all.

You're right, the flickering doesn't appear now. Thanks for your help.
And yes, I'm still running version 6.80.