view docs/html/sdlgetrgba.html @ 1524:38a12fd1a2c1

Fixed bug #46 Date: Fri, 13 Jan 2006 18:09:45 -0500 From: mhall4400 vipmail kvcc edu Subject: Possible SDL bug Greetings I believe Ive come across a bug in your SDL product (1.2.9), in the CD-ROM control portion of the library. When calling the SDL_CDPlay() function to play the last track of a CD using the offset and length from an SDL_CD structure generated by SDL_CDOpen(), I get the following error from a call to SDL_Error(): mciSendCommand() error: The specified parameter is out of range for the specified command. The code returning the error is: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, g_playingDriveSDLCD->track[trackNumberInt].length) Subtracting one from the length of the provided length seems to repair the problem: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, (g_playingDriveSDLCD->track[trackNumberInt].length) - 1) Ive replicated this problem on Windows 98 SE (several months since last patch), fully-patched Window ME, seldom-patched Windows XP SP1, and fully-patched Windows XP SP2. While investigating the issue, I came across a line in your librarys win32 source code in file \src\cdrom\win32\SDL_syscdrom.c (source code zip archive from your download page), function: SDL_SYS_CDGetTOC(), line 226 where you add 1 to the value for length to fix MCI last track length bug. This may be the source of the issue (because subtracting 1 from the length seems to resolve the issue). Microsoft may have patched the referenced bug since you wrote that line. Mike Hall
author Sam Lantinga <slouken@libsdl.org>
date Tue, 14 Mar 2006 05:34:39 +0000
parents 355632dca928
children
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>SDL_GetRGBA</H1
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>Name</H2
>SDL_GetRGBA&nbsp;--&nbsp;Get RGBA values from a pixel in the specified pixel format.</DIV
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>#include "SDL.h"</PRE
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><CODE
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>void <B
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>SDL_GetRGBA</B
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>(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);</CODE
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>Description</H2
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>Get RGBA component values from a pixel stored in the specified pixel format.</P
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>This function uses the entire 8-bit [0..255] range when converting color
components from pixel formats with less than 8-bits per RGB component
(e.g., a completely white pixel in 16-bit RGB565 format would return
[0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8]).</P
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>If the surface has no alpha component, the alpha will be returned as 0xff
(100% opaque).</P
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>SDL_GetRGB</A
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>SDL_MapRGB</A
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>SDL_MapRGBA</A
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>SDL_PixelFormat</A
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