Scaling with hardware acceleration but without blending

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broadblues
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Re: Scaling with hardware acceleration but without blending

Post by broadblues »

@mritter

That doesn't work as it multiplies the src colour by the src alpha (you may not notice this for images with a very on / off alpha as the 0.0 areas wouldn't show when you alpha blitted this into a window but it would notice for a 0.5 (0x80) transparency ).
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Re: Scaling with hardware acceleration but without blending

Post by softwarefailure »

broadblues wrote: Have you experimented with triangle mode in the CompositeTags function ? Not sure if that blends in the same way ot not ( it may do).
Yes, I have and it shows the same behaviour. It would have been my next question how to get transformation without the blending ;)
I'm not sure about the old ScaleBitmap API it certainly still works, but whether it's hardware accelerated I'm not sure. It might even depend on which hardware.
So who is qualified to give a definitive answer here?
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broadblues
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Re: Scaling with hardware acceleration but without blending

Post by broadblues »

So who is qualified to give a definitive answer here?
An OS dev with their fingers in graphic.library Hans de Reuter, SSolie, Rene O or some such....
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Re: Scaling with hardware acceleration but without blending

Post by softwarefailure »

An OS dev with their fingers in graphic.library Hans de Reuter, SSolie, Rene O or some such....
*bump*
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Re: Scaling with hardware acceleration but without blending

Post by ssolie »

softwarefailure wrote:
An OS dev with their fingers in graphic.library Hans de Reuter, SSolie, Rene O or some such....
*bump*
What was the question exactly?
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Re: Scaling with hardware acceleration but without blending

Post by softwarefailure »

When used with 32-bit ARGB bitmaps, does graphics/BitMapScale() always operate in software or will it use the GPU for scaling if the bitmap is in video memory?
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Re: Scaling with hardware acceleration but without blending

Post by ssolie »

softwarefailure wrote:When used with 32-bit ARGB bitmaps, does graphics/BitMapScale() always operate in software or will it use the GPU for scaling if the bitmap is in video memory?
The answer is that it depends. There are all sorts of optimizations depending on the circumstances and whether the underlying hardware driver can do the scaling or not.

It seems to me that the API could use some work. Otherwise, you are left to guess whether the underlying operation will be done with hardware assist or not as hinted in the autodoc.
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