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Dark GDK / white image instead of sprite.

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waka324
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Posted: 16th May 2008 10:45
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Hello.

I am having a slight issue when trying to load a sprite to the screen. It is a 640X124 image, and I had a similar issue with other images before, and I had determined that it was due to their dementions not being divisible by eight.

The odd thing with this problem is that it shows up most of the time, but every once and a while, the image will actually load perfectly! I would appreciate any help that could be given.

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jinzai
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Posted: 16th May 2008 15:38
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Its not that it needs to be divisible by eight, but it needs to be a power of 2.

By default, loading an image will load the image as a texture, and on many video cards, that has to be a power of two to prevent stretching, or blank space. I think you get it working at the times there is enough video memory to accomodate it, but then you either get stretching, or blank space.

There is a flag to the image loading. A value of 0, or no flag...loads it that way. A value of 1 will load an image of any particular size and not do anything to it. A value of 2 loads the image as a cubemap texture.

Anyway, try tacking an extra parameter on your load image function call....with the value 1.
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jason p sage
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Posted: 16th May 2008 15:42
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Quote: "A value of 2 loads the image as a cubemap texture."


If you have minute, could you post what this means? I'll google it... I think I know... but I don't quite understand as I don't understand the ramifications of this flag... and I'm sure there is one.


http://www.jasonpetersage.com/?PAGE=ironinfantry&SECTION=ironinfantry
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jinzai
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Posted: 16th May 2008 15:47 Edited at: 16th May 2008 16:00
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All I know is its "useful for shader implementation." Straight out of the DBPro help. Cubemap textures are applied differently than, say spherical ones, I assume.

I think that 0 and 2 will absolutely load it into video memory, and 1 will use system memory....maybe.

I do know that textures have mipmaps, and that is the reason for the power of 2 restriction. (Because each mipmap is half the size of the predecessor.) This is how the card can support crude LOD automatically.
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jason p sage
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Posted: 16th May 2008 16:41
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thanx
I know if you do image manipulation - you need that 1 flag, as the mip maps hose sprites and the dbMakeMemblockFromImage command.


http://www.jasonpetersage.com/?PAGE=ironinfantry&SECTION=ironinfantry
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waka324
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Posted: 17th May 2008 10:58
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ok. Well I tried modifying the texture flag with no difference, however, now that I think about it, It really should have been a power of 2. That would explain why a bitmap font I was working on only showed up about half the time, when it's sides were divisible by eight, but not a power of two. Thanks.
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waka324
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Posted: 17th May 2008 11:16
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yup. I split it into two different images and it works great now. Thanks for your help.
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