Load Surfaces To Video/System Memory Based on GFX Card

Load Surfaces To Video/System Memory Based on GFX Card - Printable Version

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Load Surfaces To Video/System Memory Based on GFX Card - JokeofWeek - 29-08-2008

Alright, so every now and then I'll go through posts and see a post that says something along the lines of : "The best option would be to get the specs of the graphic card, and load surfaces based on that, since video memory is faster." So one day, I finally decided to look into and, and found out that this is actually really easy to accomplish xD. What this does is, depending on a few values, decides on a certain amount of video memory the client can use for surfaces.

This won't be full on Copy & Paste, you're going to have to work a little!

This is all client side, no worries Smile

Add this variable to modGlobals as a Public Variable. This is the variable that will hold the video memory left for the program to use.

Code:
' Video Memory

Public VRAM As Integer

And add these constants. These constants are set by you, and are the constants which will be used as the maximum amount of memory for the program to use and the minimum required for the surfaces to be set for video memory :

Code:
' Video Memory Modifier

Public Const MAX_USAGE As Byte = 64

Public Const MIN_USAGE As Byte = 16

I personally find these good values for the following reason : a ) 64MB is plenty of memory for all your surfaces. b ) If the users card has 64mb or less, it's probably (by today's standards) a low end computer, so only use 16MB of video memory for this program. c ) If the user has a 16mb video card, the program should definitely not be using video memory xD

Now in sub InitDirectDraw, add this at the top :

Code:
Dim DDSCaps As DDSCAPS2             'DirectDraw capabilities structure

DDSCAPS2 is a special structure provided with the DX7 .dll which holds the graphic card's capabilities. This is the key to finding the video memory Smile

Now, in between where you Set the Cooperative Level of DD (challenging :wink: ) and where you initialize the DDSD_Primary flags ( hint : With DDSD_Primary), add the following code :

Code:
' Set Video Memory Allowed To Be Used

    VRAM = Val(DD.GetFreeMem(DDSCaps)) / 1024 / 1024

    If VRAM < MAX_USAGE And VRAM > MIN_USAGE Then VRAM = MIN_USAGE     ' IF IN BETWEEN MAX AND MIN, MID LEVEL GFX CARD, SET TO MIN USAGE

    If VRAM > MAX_USAGE Then VRAM = MAX_USAGE                        ' IF HIGH LEVEL GFX CARD, SET TO MAX USAGE

    If VRAM < MIN_USAGE Then VRAM = 0                                ' IF LOW LEVEL GFX CARD, SET TO NO USAGE

[/code]

Now first, this gets the free video memory and converts it to megabytes, and then based on the value it got, checks with the MAX_USAGE and the MIN_USAGE constants to see how much video memory it should use.

Now that the video memory variable is set, we have to use it someplace don't we! This is how we'll load a surface using it. First, in your sub InitDDSurf, add the variable :

Code:
Dim FileSize As Integer

and add the following line after the check to see if the file exists :

Code:
FileSize = FileLen(tempFileName) / 1024 / 1024

FileLen is a built-in vb6 function which gives the length of a file in bytes. So we convert it to megabytes for simplification Smile

. Now we have to check how much the file size is compared to the Video Memory we have left to allocate. So , where you are setting the surface description, replace it with the lines :

Code:
If VRAM >= FileSize Then

        SurfDesc.lFlags = DDSD_CAPS

        SurfDesc.DDSCaps.lCaps = DDSCAPS_OFFSCREENPLAIN Or DDSCAPS_VIDEOMEMORY

        VRAM = VRAM - FileSize

    Else

        SurfDesc.lFlags = DDSD_CAPS

        SurfDesc.DDSCaps.lCaps = DDSCAPS_OFFSCREENPLAIN Or DDSCAPS_SYSTEMMEMORY

    End If

Now what this does is checks to make sure there is enough video memory left to allocate to the file, and then if there is, sets it to use video memory (DDSCAPS_VIDEOMEMORY) instead of system memory (DDSCAPS_SYSTEMMEMORY) and if so, it takes away the amount of megabytes used by the file from the variable VRAM for the next surface.

And there you go Big Grin

Pretty simple don't you think? Smile

Re: Load Surfaces To Video/System Memory Based on GFX Card - GIAKEN - 29-08-2008

Little typo:

Code:
FileSize = FileLen(FilePath) / 1024 / 1204

Re: Load Surfaces To Video/System Memory Based on GFX Card - JokeofWeek - 29-08-2008

GIAKEN Wrote:Little typo:

Code:
FileSize = FileLen(FilePath) / 1024 / 1204

Ah, thanks for that Smile

Fixed in the main post Smile

Re: Load Surfaces To Video/System Memory Based on GFX Card - JokeofWeek - 06-09-2008

Edited tutorial on September 6th 2008 :
-Modified it to work with MSE 3.50 (current version)
-Fixed a typo which would cause a RTE