Half Speed on 32 Bit Desktops

I have a problem. My game runs 1/2 speed on 32 bit
windows desktops. I don’t know what I do wrong, I
redraw each frame and use SDL_DisplayFormat on
surfaces.
It also does this when I draw nothing and clear the
screen each frame. Is this to be expected?
Anyone know what causes this?
Thanks in advance.__________________________________
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Half speed compared to what?

If you’re comparing to 16 bit modes, it’s quite obvious: Going to 32
bits with the same resolution means twice as much data to move around

  • and blitting to the screen (VRAM access with the CPU) is usually
    the major bottleneck, and takes the full impact of such changes.

//David Olofson - Programmer, Composer, Open Source Advocate

.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,… |
`-----------------------------------> http://audiality.org -’
http://olofson.nethttp://www.reologica.se —On Tuesday 11 January 2005 00.39, Jason Robertson wrote:

I have a problem. My game runs 1/2 speed on 32 bit
windows desktops.

David Olofson wrote:

Half speed compared to what?

Sorry I should’ve been more specific. I assumed we
assumed there are only 2 bit depths to compare :slight_smile:
I see thats the reason, but what are the options to
speed things up? 16 bit textures? Dirty rects?
It seems to be slow just to clear the screen each
frame.__________________________________
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David Olofson wrote:

Half speed compared to what?

Sorry I should’ve been more specific. I assumed we
assumed there are only 2 bit depths to compare :slight_smile:
I see thats the reason, but what are the options to
speed things up? 16 bit textures? Dirty rects?
It seems to be slow just to clear the screen each
frame.

If you are updating small areas of the window then dirty rectangles is a
good approach. The smaller the amount of data that has to be copied the
faster it will go.

OTOH, it is almost always the case that using OpenGL is the right way to
go, even for purely 2D applications.

	Bob PendletonOn Tue, 2005-01-11 at 06:52 -0800, Jason Robertson wrote:

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Bob Pendleton wrote:

it is almost always the case that using OpenGL is
the right way to go

Ok, I was hoping not to hear that. It means I may need
a DirectX layer since OpenGL support on windows isn’t
always guaranteed, and an OpenGL layer for
portability.
Thanks everyone.__________________________________
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OpenGL support on windows isnt garaunteed?

thats odd, never heard that before

you know OpenGL is like THE standard for 3d computer graphics and computer
graphic cards?

not starting a flame war, just thats how i perceived OpenGL but i could be
wrong :P> ----- Original Message -----

From: dead_alive2002@yahoo.com (Jason Robertson)
To:
Sent: Tuesday, January 11, 2005 2:00 PM
Subject: [SDL] RE: Half Speed on 32 Bit Desktops

Bob Pendleton wrote:

it is almost always the case that using OpenGL is
the right way to go

Ok, I was hoping not to hear that. It means I may need
a DirectX layer since OpenGL support on windows isn’t
always guaranteed, and an OpenGL layer for
portability.
Thanks everyone.


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OpenGL is THE standard - but you know Microsoft and standards. :wink:

Some versions of Windows have had (deliberately) broken OpenGL
support, forcing users to install proper OpenGL drivers on their own
to play OpenGL games. One would suspect that the idea was to have the
average user believe that “Direct3D is superior and the real
standard, since it works out of the box and is much faster.”

It almost worked, but fortunately, a few stubborn and very skilled
developers just refuse to give up on OpenGL - and a major part of the
industry is using their engines…

//David Olofson - Programmer, Composer, Open Source Advocate

.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,… |
`-----------------------------------> http://audiality.org -’
http://olofson.nethttp://www.reologica.se —On Tuesday 11 January 2005 23.10, Alan Wolfe wrote:

OpenGL support on windows isnt garaunteed?

thats odd, never heard that before

you know OpenGL is like THE standard for 3d computer graphics and
computer graphic cards?

Alan Wolfe wrote:
“you know OpenGL is like THE standard for 3d computer
graphics and computer graphic cards?”

Ehem. Let me restate my observation. Yes OpenGL is THE
standard graphics rendering API, no doubt. However,
OpenGL drivers being installed and OpenGL hardware
acceleration is still unfortunately not guaranteed on
each windows machine. Trust me I’d love it if everyone
had decent cards and updated drivers, but I’m making a
smallish 2D game so that may be asking too much. If it
were a full 3D game I’d have no reservations about
requiring OpenGL.__________________________________
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ok i dig that, sorry for off topic conversation (:> ----- Original Message -----

From: dead_alive2002@yahoo.com (Jason Robertson)
To:
Sent: Tuesday, January 11, 2005 8:28 PM
Subject: [SDL] RE: Half Speed on 32 Bit Desktops

Alan Wolfe wrote:
“you know OpenGL is like THE standard for 3d computer
graphics and computer graphic cards?”

Ehem. Let me restate my observation. Yes OpenGL is THE
standard graphics rendering API, no doubt. However,
OpenGL drivers being installed and OpenGL hardware
acceleration is still unfortunately not guaranteed on
each windows machine. Trust me I’d love it if everyone
had decent cards and updated drivers, but I’m making a
smallish 2D game so that may be asking too much. If it
were a full 3D game I’d have no reservations about
requiring OpenGL.


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