Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetAlpha.3 @ 4324:1496aa09e41e SDL-1.2
Steven Noonan to sdl
While trying to build the SDLMain.m included with SDL 1.2.14, with
#define SDL_USE_NIB_FILE 1:
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:
In function '-[SDLMain fixMenu:withAppName:]':
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:122:
warning: 'sizeToFit' is deprecated (declared at
/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/AppKit.framework/Headers/NSMenu.h:281)
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:
In function 'main':
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:376:
warning: 'poseAsClass:' is deprecated (declared at
/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSObject.h:127)
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:376:
error: 'poseAsClass:' is unavailable (declared at
/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSObject.h:127)
/Users/steven/Development/darwinia/targets/macosx/Darwinia/SDLMain.m:377:
warning: passing argument 2 of 'NSApplicationMain' from incompatible
pointer type
Eric Wing to Sam
I don't have time today to look at this in detail, but the problem is definitely the poseAsClass: method.
This was deprecated in Obj-C 2.0 and not retained in 64-bit.
I've never used this method and it has always been limited to esoteric uses. I think this is why Apple wanted to dump it (among complicating some other things they do). I have read about others getting bit by this when migrating. Long story short, there really isn't a migration path for this method. The question that then must be asked is why are we using it (what does it accomplish), and then figure out the 'proper' way of accomplishing that.
Glancing at SDLMain.m, it's not obvious to me why it is there or what it is really accomplishing. My only speculation is that NSApplicationMain hardcodes something to look for NSApplication and a subclass (SDLApplication) fails for some reason (assuming that the original coder did this for good reason).
Three thoughts come to mind.
1) The Info.plist has properties to control things related to the startup class and nib.
NSPrincipalClass, NSMainNibFile
Maybe principle class needs to be SDLApplication and we can delete the poseAs
2) I was told that 10.6 introduced new APIs to make programatic NIB wrangling and avoidance easier. Unfortunately, I don't know the specifics.
3) Instead of subclassing NSApplication in SDLMain.m, maybe we can just add a category. It looks like the following is the only thing that is done (quick glance):
@interface SDLApplication : NSApplication
@end
@implementation SDLApplication
/* Invoked from the Quit menu item */
- (void)terminate:(id)sender
{
/* Post a SDL_QUIT event */
SDL_Event event;
event.type = SDL_QUIT;
SDL_PushEvent(&event);
}
@end
So instead, we change this to: (warning written in mail and untested)
@interface NSApplication (SDLApplication)
- (void) terminate:(id)sender;
@end
@implementation NSApplication (SDLApplication)
/* Invoked from the Quit menu item */
- (void)terminate:(id)sender
{
/* Post a SDL_QUIT event */
SDL_Event event;
event.type = SDL_QUIT;
SDL_PushEvent(&event);
}
@end
Then everywhere SDLApplication is used, we change it to NSApplication (and remove the poseAsClass line).
Perhaps you could ask the bug reporter to try this solution (#3).
And if that fails, maybe try #1.
-Eric
Steven Noonan to Sam
The suggested change (diff below) seems to work fine.
- Steven
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Mon, 12 Oct 2009 21:07:12 +0000 |
| parents | 1238da4a7112 |
| children |
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.TH "SDL_SetAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetAlpha \- Adjust the alpha properties of a surface .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetAlpha\fP\fR(\fBSDL_Surface *surface, Uint32 flag, Uint8 alpha\fR); .SH "DESCRIPTION" .PP .RS \fBNote: .PP This function and the semantics of SDL alpha blending have changed since version 1\&.1\&.4\&. Up until version 1\&.1\&.5, an alpha value of 0 was considered opaque and a value of 255 was considered transparent\&. This has now been inverted: 0 (\fBSDL_ALPHA_TRANSPARENT\fP) is now considered transparent and 255 (\fBSDL_ALPHA_OPAQUE\fP) is now considered opaque\&. .RE .PP \fBSDL_SetAlpha\fP is used for setting the per-surface alpha value and/or enabling and disabling alpha blending\&. .PP The\fBsurface\fR parameter specifies which surface whose alpha attributes you wish to adjust\&. \fBflags\fR is used to specify whether alpha blending should be used (\fBSDL_SRCALPHA\fP) and whether the surface should use RLE acceleration for blitting (\fBSDL_RLEACCEL\fP)\&. \fBflags\fR can be an OR\&'d combination of these two options, one of these options or 0\&. If \fBSDL_SRCALPHA\fP is not passed as a flag then all alpha information is ignored when blitting the surface\&. The \fBalpha\fR parameter is the per-surface alpha value; a surface need not have an alpha channel to use per-surface alpha and blitting can still be accelerated with \fBSDL_RLEACCEL\fP\&. .PP .RS \fBNote: .PP The per-surface alpha value of 128 is considered a special case and is optimised, so it\&'s much faster than other per-surface values\&. .RE .PP Alpha effects surface blitting in the following ways: .TP 20 RGBA->RGB with \fBSDL_SRCALPHA\fP The source is alpha-blended with the destination, using the alpha channel\&. \fBSDL_SRCCOLORKEY\fP and the per-surface alpha are ignored\&. .TP 20 RGBA->RGB without \fBSDL_SRCALPHA\fP The RGB data is copied from the source\&. The source alpha channel and the per-surface alpha value are ignored\&. .TP 20 RGB->RGBA with \fBSDL_SRCALPHA\fP The source is alpha-blended with the destination using the per-surface alpha value\&. If \fBSDL_SRCCOLORKEY\fP is set, only the pixels not matching the colorkey value are copied\&. The alpha channel of the copied pixels is set to opaque\&. .TP 20 RGB->RGBA without \fBSDL_SRCALPHA\fP The RGB data is copied from the source and the alpha value of the copied pixels is set to opaque\&. If \fBSDL_SRCCOLORKEY\fP is set, only the pixels not matching the colorkey value are copied\&. .TP 20 RGBA->RGBA with \fBSDL_SRCALPHA\fP The source is alpha-blended with the destination using the source alpha channel\&. The alpha channel in the destination surface is left untouched\&. \fBSDL_SRCCOLORKEY\fP is ignored\&. .TP 20 RGBA->RGBA without \fBSDL_SRCALPHA\fP The RGBA data is copied to the destination surface\&. If \fBSDL_SRCCOLORKEY\fP is set, only the pixels not matching the colorkey value are copied\&. .TP 20 RGB->RGB with \fBSDL_SRCALPHA\fP The source is alpha-blended with the destination using the per-surface alpha value\&. If \fBSDL_SRCCOLORKEY\fP is set, only the pixels not matching the colorkey value are copied\&. .TP 20 RGB->RGB without \fBSDL_SRCALPHA\fP The RGB data is copied from the source\&. If \fBSDL_SRCCOLORKEY\fP is set, only the pixels not matching the colorkey value are copied\&. .PP .RS \fBNote: .PP Note that RGBA->RGBA blits (with SDL_SRCALPHA set) keep the alpha of the destination surface\&. This means that you cannot compose two arbitrary RGBA surfaces this way and get the result you would expect from "overlaying" them; the destination alpha will work as a mask\&. .PP Also note that per-pixel and per-surface alpha cannot be combined; the per-pixel alpha is always used if available .RE .SH "RETURN VALUE" .PP This function returns \fB0\fR, or \fB-1\fR if there was an error\&. .SH "SEE ALSO" .PP \fI\fBSDL_MapRGBA\fP\fR, \fI\fBSDL_GetRGBA\fP\fR, \fI\fBSDL_DisplayFormatAlpha\fP\fR, \fI\fBSDL_BlitSurface\fP\fR .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01