Hardware alpha & colorkey support

SDL Development
1

There are some really annoying questions(as for game development process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";
2)“What about a modern hardware graphics without support of hardware
colorkey?”.

2

sapsan wrote:

There are some really annoying questions(as for game development process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";
2)“What about a modern hardware graphics without support of hardware
colorkey?”.

Where supported.

Since SDL uses DirectX for rendering on windows, I’m guessing it gets
some speed advantages from that. This is assuming you’re working with
hardware surfaces of course…

3

Michael B. Edwin Rickert wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";
2)"What about a modern hardware graphics without support of hardware
colorkey?".

Where supported.

Since SDL uses DirectX for rendering on windows, I’m guessing it gets
some speed advantages from that. This is assuming you’re working with
hardware surfaces of course…_______________________________________________
SDL mailing list
SDL@libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

sorry for my english

videoinfo tell me, wath I have not accelerated blits with alpha
blit_hw_A = 0

without alpha (SDL_DisplayFormatAlpha) all has high speed and nontearing
(with waiting retrace)
(I am was readed article
http://www.linuxdevcenter.com/pub/a/linux/2003/08/07/sdl_anim.html about
hardware surfaces very carefully)

I am under Windows XP Pro + DirectX 9c + ATI Radeon 9600 Pro

and it is look like some question from SDL FAQ:

Q: I’m using hardware surfaces, and performance is very bad!
A: Try using software surfaces. It’s counter-intuitive, but if you’re
directly accessing the pixels on a surface or the screen, it’s actually
faster to do all your work in system memory and then send the final result
to the screen than it is to push individual pixels over the system bus to
the video card. This is especially important when doing alpha blending
because very few drivers expose 2D alpha blending in hardware. This means
that the alpha blending is performing a read operation on the destination
surface, and reading from video memory is especially slow on modern
graphics hardware.
If this is a serious problem for you, and you know your target audience
has 3D hardware, you might consider using SDL with OpenGL for 3D
acceleration.

4

sapsan wrote:

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[snip]

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http://calcrogue.jimrandomh.org/

5

repeat

Michael B. Edwin Rickert wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";
2)“What about a modern hardware graphics without support of hardware
colorkey?”.

Where supported.

Since SDL uses DirectX for rendering on windows, I’m guessing it gets
some speed advantages from that. This is assuming you’re working with
hardware surfaces of course…

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

sorry for my English

videoinfo tell me, what I have not accelerated blits with alpha
blit_hw_A = 0

without alpha (SDL_DisplayFormatAlpha) all has high speed and nontearing
(with waiting retrace)
(I am was readed article
http://www.linuxdevcenter.com/pub/a/linux/2003/08/07/sdl_anim.html about
hardware surfaces very carefully)

I am under Windows XP Pro + DirectX 9c + ATI Radeon 9600 Pro

and it is look like some question from SDL FAQ:==============================================
Q: I’m using hardware surfaces, and performance is very bad!
A: Try using software surfaces. It’s counter-intuitive, but if you’re
directly accessing the pixels on a surface or the screen, it’s actually
faster to do all your work in system memory and then send the final
result to the screen than it is to push individual pixels over the
system bus to the video card. This is especially important when doing
alpha blending because very few drivers expose 2D alpha blending in
hardware. This means that the alpha blending is performing a read
operation on the destination surface, and reading from video memory is
especially slow on modern graphics hardware.
If this is a serious problem for you, and you know your target audience
has 3D hardware, you might consider using SDL with OpenGL for 3D
acceleration.

6

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does hw
accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

2)“What about a modern hardware graphics without support of hardware
colorkey?”.

It is the responsibility of the backends to emulate colorkey with alpha.
That’s what is done in glSDL, and it’s not a big deal.

Stephane

7

Stephane Marchesin wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean about
hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does hw
accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

Sorry for my english again.

Tnx, but I got error, when try to compile SDL.dll in Borland C++ Builder 6:

[Linker Error] Unresolved external ‘_SDL_HasMMX’ referenced from
D:\PROJECTS\TOOLS\SDL\PATCH\SDL12.EXPERIMENTAL\SRC\VIDEO\SDL_BLIT_N.OBJ

What I must to do? (Because I am a pure pascal programmer :()>>

2)“What about a modern hardware graphics without support of hardware
colorkey?”.

It is the responsibility of the backends to emulate colorkey with alpha.
That’s what is done in glSDL, and it’s not a big deal.

Stephane

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

8

sapsan wrote:

Stephane Marchesin wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean
about hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does
hw accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

Sorry for my english again.

Hehe :slight_smile: no problem, I don’t think mine is perfect either.

Tnx, but I got error, when try to compile SDL.dll in Borland C++
Builder 6:

[Linker Error] Unresolved external ‘_SDL_HasMMX’ referenced from
D:\PROJECTS\TOOLS\SDL\PATCH\SDL12.EXPERIMENTAL\SRC\VIDEO\SDL_BLIT_N.OBJ

What I must to do? (Because I am a pure pascal programmer :()

You need to add the SDL12/src/cpuinfo/SDL_cpuinfo.c to the borland C
project.
If you do so, please send the modified project files here (or to me by
mail if they are too big and you have nowhere to put them). That problem
affects other people so it would be nice.

Stephane

9

Stephane Marchesin wrote:

sapsan wrote:

Stephane Marchesin wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean
about hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does
hw accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

Sorry for my english again.

Hehe :slight_smile: no problem, I don’t think mine is perfect either.

Tnx, but I got error, when try to compile SDL.dll in Borland C++
Builder 6:

[Linker Error] Unresolved external ‘_SDL_HasMMX’ referenced from
D:\PROJECTS\TOOLS\SDL\PATCH\SDL12.EXPERIMENTAL\SRC\VIDEO\SDL_BLIT_N.OBJ

What I must to do? (Because I am a pure pascal programmer :()

You need to add the SDL12/src/cpuinfo/SDL_cpuinfo.c to the borland C
project.
If you do so, please send the modified project files here (or to me
by mail if they are too big and you have nowhere to put them). That
problem affects other people so it would be nice.

OK.

10

Stephane Marchesin wrote:

sapsan wrote:

Stephane Marchesin wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean
about hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does
hw accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

Sorry for my english again.

Hehe :slight_smile: no problem, I don’t think mine is perfect either.

Tnx, but I got error, when try to compile SDL.dll in Borland C++
Builder 6:

[Linker Error] Unresolved external ‘_SDL_HasMMX’ referenced from
D:\PROJECTS\TOOLS\SDL\PATCH\SDL12.EXPERIMENTAL\SRC\VIDEO\SDL_BLIT_N.OBJ

What I must to do? (Because I am a pure pascal programmer :()

You need to add the SDL12/src/cpuinfo/SDL_cpuinfo.c to the borland C
project.
If you do so, please send the modified project files here (or to me
by mail if they are too big and you have nowhere to put them). That
problem affects other people so it would be nice.

Stephane

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

I am was build SDL.dll, but got the error: "The procedure entry point
SDL_Error could not be located in the dynamic link library SDL.dll"
What I must to do?
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11

sapsan wrote:

Stephane Marchesin wrote:

sapsan wrote:

Stephane Marchesin wrote:

sapsan wrote:

There are some really annoying questions(as for game development
process):
1)" Does current SDL version has hardware alpha blitting(i mean
about hardware per pixel alpha support)?";

No, because of a bug in SDL.

No backend currently has support for hardware accelerated alpha.
However, there is a fix for the bug and a backend (glSDL) that does
hw accelerated alpha in this tarball :
http://icps.u-strasbg.fr/~marchesin/sdl/SDL12-experimental.tgz

Sorry for my english again.

Hehe :slight_smile: no problem, I don’t think mine is perfect either.

Tnx, but I got error, when try to compile SDL.dll in Borland C++
Builder 6:

[Linker Error] Unresolved external ‘_SDL_HasMMX’ referenced from
D:\PROJECTS\TOOLS\SDL\PATCH\SDL12.EXPERIMENTAL\SRC\VIDEO\SDL_BLIT_N.OBJ

What I must to do? (Because I am a pure pascal programmer :()

You need to add the SDL12/src/cpuinfo/SDL_cpuinfo.c to the borland C
project.
If you do so, please send the modified project files here (or to me
by mail if they are too big and you have nowhere to put them). That
problem affects other people so it would be nice.

Stephane

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

I am was build SDL.dll, but got the error: "The procedure entry point
SDL_Error could not be located in the dynamic link library SDL.dll"
What I must to do?

sorry - not fully discription -, I am got this error, then try to launch
some application with new SDL.dll
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