Game Loops

[jmiller]

I'm new at actually making a full game, so I'm hoping someone can help me.
When you write a game loop, graphically speaking, you want it to run at or above around 30 fps, right? That means the game goes through all your items in the loop and draws all the images 30 times a second, right? Well, I've tried something like that where I have a ball and I animate it whenever the loop is called. The ball has an animation delay on it so it will only change frames so many times per second, say 10 or so. The problem is, if you let the loop run as fast as possible, without any time delay, it draws the the ball about 3000 times per second, and causes some serious lag with the mouse and such, even with DoEvents called in the loop. Should I put a time delay on the entire game loop?

[Amithran]

What you need to do, is add some sort of variable for the ball object called

dim m_timeDelay as Long

(i make all "member" variables of "objects" or "classes" prefixed with m_)

and use the GetTickCount() api function to find out how much time has passed sense the last animation. ie.

if GetTickCount >= m_timeDelay + 10000 Then '10000 millaseconds is 10 seconds
 Call doAnimation 'do what ever animation stuff here
 m_timeDelay = GetTickCount()
End if

m_timeDelay + someINT is how long you want to wait before you do an action. (1000 = 1 second)

This wont effect game loop times so you can have a game loop 1/60 of a second (60 fps/60 loops per second) and only be animating or doing something a certain amount of time..


I hope that wasn't too ambigous.

EDIT: I use 10000 as the time delay becuase I misread your post and thought you wanted once per 10 seconds, instead of 10 times per second. use 10 for the latter.

[Zaei]

Screw delays =).

Here is what a professional game would use:

Dim tDelta As Single
Dim s As Long
Dim e As Long
...
While True  'Your game loop
   s = GetTickCount()
   'Do Stuff
   DoEvents
   e = GetTickCount()
   tDelta = CSng(e - s) / 1000.0
Wend

tDelta holds the fraction of a second that has passed while the loop has run once. Simply hold a vector for the length you want your ball to move in one second, and multiply it by tDelta each time you add it to the currept position.

Z.

[Gaming_World]

That wouldn't fix the problem with the cpu lag from the loop. Only a delay can fix the cpu lag. That code would allow for super smooth animation, but it would still lag up other processes (like the mouse).

[Amithran]

Originally posted by Zaei
Screw delays =).

Here is what a professional game would use:

Dim tDelta As Single
Dim s As Long
Dim e As Long
...
While True  'Your game loop
   s = GetTickCount()
   'Do Stuff
   DoEvents
   e = GetTickCount()
   tDelta = CSng(e - s) / 1000.0
Wend

tDelta holds the fraction of a second that has passed while the loop has run once. Simply hold a vector for the length you want your ball to move in one second, and multiply it by tDelta each time you add it to the currept position.

Z.

While your "PROFESSIONAL" code would be standard for movement, it doesn't work for what (his wording at least) implied. Which as I read it was, "how can I animate a ball 10 times every second?"

So THERE!! My answer is better then yours (sure context is a technicality, but if its good enough in court...)

But I will admit that as far as movement calculations, your method would be the way to go.
I had read his question to be concerning more "Sprite Animation" then "Movement Animation" (again based on context). In which my answer would be the victor.

[Zaei]

Actually, the first sentence of his post implies that he wants to make a full game, so why post code that would not be as useful to that end?

Z.

[Amithran]

It useful.
Especially for sprite animation, where graphics are based on a bitmap of several renderings of an animation. While you may think running through those animations at hyperspeed isnt it a problem, it is. Sprite animations are ment to happen at specific intervals.

My Code specificly has purpose for sprite animation (which As I stated was what I thought he wanted).



Infact I would say my code is twice as useful as yours. Becuase not only can it do its purpose, but it CAN (maybe not super smooth) do movement animation as well.

!

[Zaei]

This is not worth arguing over. You do it your way, Ill do it mine. jmiller can choose which method he prefers.

Z.

[Machaira]

Originally posted by Zaei
Here is what a professional game would use:

Hate to tell you, but a professional game wouldn't use that as professional games are written in C/C++.

[Zaei]

Concepts are language independent =).

Z.

[Sastraxi]

Fight Fight Fight

[Zaei]

Originally posted by Sastraxi
Fight Fight Fight

Yeah, im really getting hammered on this one =).

Z.

[CornedBee]

And to make you feel even more bad, a professional game would probably query the performance counter, if available. Just look at the D3D framework that comes with the C++ DX8 SDK.


Don't take me to seriously...

[Zaei]

Hey, im already doing ALL of this (including the QPC() and QPF() calls, and in C++), so I dont feel bad at all =).

And besides, When you are using VB, there isnt THAT much point in using QueryPERFORMANCECounter() =).

Z.

[CornedBee]

[Sastraxi]

But there is a little