[SDL] I'm losing detail with SDL_Image

[Glenn McCord]

Thanks, David. You said the magic words "What's the OpenGL blend 
function you're using for rendering?" and after some googling found 
http://www.gamedev.net/community/forums/topic.asp?topic_id=409896&whichpage=1&#2729172

I was happy to find the following code because it took me ages to get 
transparecy to work.
glEnable(GL_ALPHA_TEST);
glAlphaFunc(GL_GREATER, 0.1f);

but I should have been using

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

And now it is all sorted

Thanks,

Glenn

David Olofson wrote:

>On Monday 04 September 2006 14:37, Glenn McCord wrote:
>  
>
>>I made these really nice looking .png images with shading and drop 
>>shadows. I'm using them to make a menu for my application.
>>
>>But when I texture map them with the help of SDL_Image I lose a lot
>>of detail. It's quite pixelated and my drop shadows have
>>disappeared. The size of the textured objects on screen are fairly
>>close to the actual size of the image.
>>
>>Is this just a limitation or is there a texturing technique that
>>I've missed? Nearest filtering and mipmapping give the same results.
>>    
>>
>
>Mipmapping could explain the pixelated part, but if you've really 
>ruled that out, I have no idea... Well, try not building the mipmaps 
>at all, just in case! Unless you're actually using mipmapping, the 
>original texture should be all you need.
>
>Are you sure the drop shadows and stuff are actually in the .png? Some 
>applications have somewhat strange default settings when exporting to 
>foreign file formats, so perhaps you're losing some layers and/or the 
>alpha channel in the export process. I also have a faint memory of 
>some version of GIMP I used screwing up when exporting multilayered 
>images, so I had to manually merge down to a single layer first.
>
>What's the OpenGL blend function you're using for rendering?
>
>
>//David Olofson - Programmer, Composer, Open Source Advocate
>
>.-------  http://olofson.net - Games, SDL examples  -------.
>|        http://zeespace.net - 2.5D rendering engine       |
>|       http://audiality.org - Music/audio engine          |
>|     http://eel.olofson.net - Real time scripting         |
>'--  http://www.reologica.se - Rheology instrumentation  --'
>
>_______________________________________________
>SDL mailing list
>SDL at libsdl.org
>http://www.libsdl.org/mailman/listinfo/sdl
>
>
>  
>