Increasing framerate

I have created a "Solar Simulator" which very accurately calculates orbits and gravitational forces. I use the PictureBox.Circle command to draw the "planets" on the backbuffer and then I set the output picturebox's picture equal to the backbuffer's image.

The reason I am doing it this way is to eliminate screen flicker, but I am running into some serious framerate issues. Doing the calculations with double precision variables takes almost no time at all. 3/4's of the time is spent drawing the spheres and flipping the screen buffer.

I am almost positive that there is a faster way to do this. Any suggestions?

Use the API instead of using VB's built in functions, they are notoriously slow. You can use bitblt to copy from 2 different places and the elipse api punction to draw circles.

If you want to use DC's and such to store you gfx in memory just go look around or ask on the forums for a bitblt demo using DC's. You're bound to get one :D

Hope this helps.


Drewski

hy, could you post your prog .. seems to be interesting ..:cool:

cya

If you really go an think about it, Circle, Line, etc, are just wrappers on API functions already. Use circle for your circles, and then use PaintPicture to flip. It's BitBlt for Picture boxes. It that doesnt speed things up, then go to API (they take almost the same parameters anyway).

Z.

ya it sounds cool...

Here's a tutorial on Bitblt for those who are bitblock-challenged =)

http://vbden.tripod.com/articles/invmask.htm

I implemented your suggestions, but it didn't speed up noticibly... Considering that on average I do 100 iterations of the gravitational formula per frame and most frames don't even have much movement, I guess I'm not all that surprised.

About posting it, I most definitely will... Right now it is horribly coded and there are a couple bugs... Maybe in a few hours?

Keep in mind that I am very new to VB. There are a couple mistakes in how I apply some of the mathmatical formulas, but this should simulate orbits of planets around a sun many many many times more accurately than anything I have seen.

I plan on completely rewriting most of the code, but I would still love to hear your comments.

Just D/L - not bad!

Speed issues:

Remember to clear just the graphics that have moved -
(rather than object.cls)

Drawing directly onto the form and not bothering with pictureboxes may help to. You can still control refreshes
for smooth graphics using just a form.

stuff like object.fillcolor / .circle is slow to - use the api equivalent.

HTH

Cheers

J.

Thanks for the suggestions :D I will implement them as soon as I get to work.

Use one picturebox.
AutoRedraw = True, Visible = True.
Draw your graphics, and then use PictureBox.Refresh to update it.

VB has built in double-buffering, ain't it nifty? Picture-swapping and picture manipulation always result in bad framerates.

Also for your gravity formula you may want to implement a look-up table, if it is very slow.

and actually...
Object.FillColor/FillStyle/Circle/Line/etc. Simply call the API methods with the correct properties, saving you a LOT of work. Use 'em if they are simpler, they're not THAT much slower.