SDL_CreateRGBSurfaceFrom
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SDL_Surface *SDL_CreateRGBSurfaceFrom(void *pixels, int width, int height, int depth, int pitch, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);
Can anyone explain to me what the parameter "pitch" is? PLEASE don''t use advanced terms...
thanks in advance
Quote from the above linked documentation: "pitch is the length of each scanline in bytes."
So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3.
EDIT: That would be a line in the source image. I.e. the one "pixels" is pointing to.
[edited by - TomasH on May 27, 2004 6:53:13 AM]
So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3.
EDIT: That would be a line in the source image. I.e. the one "pixels" is pointing to.
[edited by - TomasH on May 27, 2004 6:53:13 AM]
Author
thanls for the help!
you said:
"So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3."
1)"line" refers to "void *pixels"?
2) If we are going to create a surface initialized by the bytes pointed by "void *pixels", then why do we need the RGB and A masks? Those data ( for the color 0 should be included in the bytes of "pixels", shouldn''t they? So??
thanks...
you said:
"So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3."
1)"line" refers to "void *pixels"?
2) If we are going to create a surface initialized by the bytes pointed by "void *pixels", then why do we need the RGB and A masks? Those data ( for the color 0 should be included in the bytes of "pixels", shouldn''t they? So??
thanks...
quote:Original post by sdlprorammer
1)"line" refers to "void *pixels"?
Yes
quote:Original post by sdlprorammer
2) If we are going to create a surface initialized by the bytes pointed by "void *pixels", then why do we need the RGB and A masks? Those data ( for the color 0 should be included in the bytes of "pixels", shouldn''t they? So??
Because "pixels" just points to raw data - i.e. there is no information on how the data is ordered...
Author
thatnks but...:
>Because "pixels" just points to raw data - i.e. there is no information on how the data is ordered...
Eeeer.. what do u mean? What kind of data are these that can not be ( basiccally ) used?
>Because "pixels" just points to raw data - i.e. there is no information on how the data is ordered...
Eeeer.. what do u mean? What kind of data are these that can not be ( basiccally ) used?
quote:Original post by TomasH
So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3.
No, the pitch is the number of bytes from the start of one line to the next. This may or may not be width * bytesperpixel.
quote:
Eeeer.. what do u mean? What kind of data are these that can not be ( basiccally ) used?
Because you know the pixelformat, so you know how the data is stored.
Author
>Because you know the pixelformat, so you know how the data is stored.
Then i don''t need to know RGBA in advance. ... ??.. but the function requires themm..?
Then i don''t need to know RGBA in advance. ... ??.. but the function requires themm..?
quote:Original post by DBXquote:Original post by TomasH
So if the line is 640 pixels wide, and each pixel is three bytes, then pitch is 640*3.
No, the pitch is the number of bytes from the start of one line to the next. This may or may not be width * bytesperpixel.
Oh, yes, of course you''re right. Sorry...
quote:Original post by sdlprorammer
>Because you know the pixelformat, so you know how the data is stored.
Then i don''t need to know RGBA in advance. ... ??.. but the function requires themm..?
Yes, you should have this information.
SDL_CreateRGBSurfaceFrom is used to take pixel data that you have loaded from a file or created in some other way and use it (or part of it) to create a SDL surface. So if you managed to load the data or create it, you really should know how the data is stored. Right?
Author
>No, the pitch is the number of bytes from the start of one line to the next. This may or may not be width * bytesperpixel.
Then how can i determine what value to pass to the function?????????
>SDL_CreateRGBSurfaceFrom is used to take pixel data that you have loaded from a file or created in some other way and use it (or part of it) to create a SDL surface.
Ok, so far we are OK.
>So if you managed to load the data or create it, you really should know how the data is stored. Right?
But RGBA is what the data contains! ???
Then how can i determine what value to pass to the function?????????
>SDL_CreateRGBSurfaceFrom is used to take pixel data that you have loaded from a file or created in some other way and use it (or part of it) to create a SDL surface.
Ok, so far we are OK.
>So if you managed to load the data or create it, you really should know how the data is stored. Right?
But RGBA is what the data contains! ???
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