iphone游戏开发实践指南 源代码

/* File: MyOpenALSupport.c Abstract: OpenAL-related support functions Version: 1.4 Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in consideration of your agreement to the following terms, and your use, installation, modification or redistribution of this Apple software constitutes acceptance of these terms. If you do not agree with these terms, please do not use, install, modify or redistribute this Apple software. In consideration of your agreement to abide by the following terms, and subject to these terms, Apple grants you a personal, non-exclusive license, under Apple's copyrights in this original Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the Apple Software, with or without modifications, in source and/or binary forms; provided that if you redistribute the Apple Software in its entirety and without modifications, you must retain this notice and the following text and disclaimers in all such redistributions of the Apple Software. Neither the name, trademarks, service marks or logos of Apple Inc. may be used to endorse or promote products derived from the Apple Software without specific prior written permission from Apple. Except as expressly stated in this notice, no other rights or licenses, express or implied, are granted by Apple herein, including but not limited to any patent rights that may be infringed by your derivative works or by other works in which the Apple Software may be incorporated. The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Copyright (C) 2009 Apple Inc. All Rights Reserved. */ #include "MyOpenALSupport.h" ALvoid alBufferDataStaticProc(const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq) { static alBufferDataStaticProcPtr proc = NULL; if (proc == NULL) { proc = (alBufferDataStaticProcPtr) alcGetProcAddress(NULL, (const ALCchar*) "alBufferDataStatic"); } if (proc) proc(bid, format, data, size, freq); return; } void* MyGetOpenALAudioData(CFURLRef inFileURL, ALsizei *outDataSize, ALenum *outDataFormat, ALsizei* outSampleRate) { OSStatus err = noErr; SInt64 theFileLengthInFrames = 0; AudioStreamBasicDescription theFileFormat; UInt32 thePropertySize = sizeof(theFileFormat); ExtAudioFileRef extRef = NULL; void* theData = NULL; AudioStreamBasicDescription theOutputFormat; // Open a file with ExtAudioFileOpen() err = ExtAudioFileOpenURL(inFileURL, &extRef); if(err) { printf("MyGetOpenALAudioData: ExtAudioFileOpenURL FAILED, Error = %ld\n", err); goto Exit; } // Get the audio data format err = ExtAudioFileGetProperty(extRef, kExtAudioFileProperty_FileDataFormat, &thePropertySize, &theFileFormat); if(err) { printf("MyGetOpenALAudioData: ExtAudioFileGetProperty(kExtAudioFileProperty_FileDataFormat) FAILED, Error = %ld\n", err); goto Exit; } if (theFileFormat.mChannelsPerFrame > 2) { printf("MyGetOpenALAudioData - Unsupported Format, channel count is greater than stereo\n"); goto Exit;} // Set the client format to 16 bit signed integer (native-endian) data // Maintain the channel count and sample rate of the original source format theOutputFormat.mSampleRate = theFileFormat.mSampleRate; theOutputFormat.mChannelsPerFrame = theFileFormat.mChannelsPerFrame; theOutputFormat.mFormatID = kAudioFormatLinearPCM; theOutputFormat.mBytesPerPacket = 2 * theOutputFormat.mChannelsPerFrame; theOutputFormat.mFramesPerPacket = 1; theOutputFormat.mBytesPerFrame = 2 * theOutputFormat.mChannelsPerFrame; theOutputFormat.mBitsPerChannel = 16; theOutputFormat.mFormatFlags = kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked | kAudioFormatFlagIsSignedInteger; // Set the desired client (output) data format err = ExtAudioFileSetProperty(extRef, kExtAudioFileProperty_ClientDataFormat, sizeof(theOutputFormat), &theOutputFormat); if(err) { printf("MyGetOpenALAudioData: ExtAudioFileSetProperty(kExtAudioFileProperty_ClientDataFormat) FAILED, Error = %ld\n", err); goto Exit; } // Get the total frame count thePropertySize = sizeof(theFileLengthInFrames); err = ExtAudioFileGetProperty(extRef, kExtAudioFileProperty_FileLengthFrames, &thePropertySize, &theFileLengthInFrames); if(err) { printf("MyGetOpenALAudioData: ExtAudioFileGetProperty(kExtAudioFileProperty_FileLengthFrames) FAILED, Error = %ld\n", err); goto Exit; } // Read all the data into memory UInt32 dataSize = theFileLengthInFrames * theOutputFormat.mBytesPerFrame;; theData = malloc(dataSize); if (theData) { AudioBufferList theDataBuffer; theDataBuffer.mNumberBuffers = 1; theDataBuffer.mBuffers[0].mDataByteSize = dataSize; theDataBuffer.mBuffers[0].mNumberChannels = theOutputFormat.mChannelsPerFrame; theDataBuffer.mBuffers[0].mData = theData; // Read the data into an AudioBufferList err = ExtAudioFileRead(extRef, (UInt32*)&theFileLengthInFrames, &theDataBuffer); if(err == noErr) { // success *outDataSize = (ALsizei)dataSize; *outDataFormat = (theOutputFormat.mChannelsPerFrame > 1) ? AL_FORMAT_STEREO16 : AL_FORMAT_MONO16; *outSampleRate = (ALsizei)theOutputFormat.mSampleRate; } else { // failure free (theData); theData = NULL; // make sure to return NULL printf("MyGetOpenALAudioData: ExtAudioFileRead FAILED, Error = %ld\n", err); goto Exit; } } Exit: // Dispose the ExtAudioFileRef, it is no longer needed if (extRef) ExtAudioFileDispose(extRef); return theData; }