1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
////////////////////////////////
// NOTE(allen): Quick Mutex
// TODO(allen): intrinsics wrappers
#include <intrin.h>
function u32
AtomicAddU32AndReturnOriginal(u32 volatile *Value, u32 Addend)
{
// NOTE(casey): Returns the original value _prior_ to adding
u32 Result = _InterlockedExchangeAdd((long volatile*)Value, (long)Addend);
return(Result);
}
global volatile u32 win32_audio_ticket = 0;
global volatile u32 win32_audio_serving = 0;
function void
win32_audio_begin_ticket_mutex(void)
{
u32 Ticket = AtomicAddU32AndReturnOriginal(&win32_audio_ticket, 1);
while(Ticket != win32_audio_serving) {_mm_pause();}
}
function void
win32_audio_end_ticket_mutex(void)
{
AtomicAddU32AndReturnOriginal(&win32_audio_serving, 1);
}
////////////////////////////////
// NOTE(allen): Fallback Mixers
function void
win32_default_mix_sources(void *ctx, f32 *mix_buffer, u32 sample_count){
}
function void
win32_default_mix_destination(i16 *dst, f32 *src, u32 sample_count){
u32 opl = sample_count*2;
for(u32 i = 0; i < sample_count; i += 1){
dst[i] = (i16)src[i];
}
}
////////////////////////////////
// NOTE(allen): Win32 Audio System API
internal
system_set_source_mixer_sig(){
win32_audio_begin_ticket_mutex();
win32vars.audio_mix_ctx = ctx;
win32vars.audio_mix_sources = mix_func;
win32_audio_end_ticket_mutex();
}
internal
system_set_destination_mixer_sig(){
win32_audio_begin_ticket_mutex();
win32vars.audio_mix_destination = mix_func;
win32_audio_end_ticket_mutex();
}
////////////////////////////////
// NOTE(allen): Win32 Audio Loop
function b32
win32_submit_audio(HWAVEOUT WaveOut, WAVEHDR *Header, u32 SampleCount, f32 *mix_buffer){
b32 Result = false;
// NOTE(allen): prep buffers
u32 mix_buffer_size = SampleCount*2*sizeof(f32);
memset(mix_buffer, 0, mix_buffer_size);
i16 *Samples = (i16 *)Header->lpData;
// NOTE(allen): prep mixer pointers
win32_audio_begin_ticket_mutex();
void *audio_mix_ctx = win32vars.audio_mix_ctx;
Audio_Mix_Sources_Function *audio_mix_sources = win32vars.audio_mix_sources;
Audio_Mix_Destination_Function *audio_mix_destination = win32vars.audio_mix_destination;
win32_audio_end_ticket_mutex();
if (audio_mix_sources == 0){
audio_mix_sources = win32_default_mix_sources;
}
if (audio_mix_destination == 0){
audio_mix_destination = win32_default_mix_destination;
}
// NOTE(allen): mix
audio_mix_sources(audio_mix_ctx, mix_buffer, SampleCount);
audio_mix_destination(Samples, mix_buffer, SampleCount);
// NOTE(allen): send final samples to win32
DWORD Error = waveOutPrepareHeader(WaveOut, Header, sizeof(*Header));
if(Error == MMSYSERR_NOERROR)
{
Error = waveOutWrite(WaveOut, Header, sizeof(*Header));
if(Error == MMSYSERR_NOERROR)
{
// NOTE(casey): Success
Result = true;
}
}
return(Result);
}
function DWORD WINAPI
win32_audio_loop(void *Passthrough){
//
// NOTE(casey): Set up our audio output buffer
//
u32 SamplesPerSecond = 48000;
u32 SamplesPerBuffer = 16*SamplesPerSecond/1000;
u32 ChannelCount = 2;
u32 BytesPerChannelValue = 2;
u32 BytesPerSample = ChannelCount*BytesPerChannelValue;
u32 BufferCount = 3;
u32 BufferSize = SamplesPerBuffer*BytesPerSample;
u32 HeaderSize = sizeof(WAVEHDR);
u32 TotalBufferSize = (BufferSize+HeaderSize);
u32 MixBufferSize = (SamplesPerBuffer*ChannelCount*sizeof(f32));
u32 TotalAudioMemorySize = BufferCount*TotalBufferSize + MixBufferSize;
//
// NOTE(casey): Initialize audio out
//
HWAVEOUT WaveOut = {};
WAVEFORMATEX Format = {};
Format.wFormatTag = WAVE_FORMAT_PCM;
Format.nChannels = (WORD)ChannelCount;
Format.wBitsPerSample = (WORD)(8*BytesPerChannelValue);
Format.nSamplesPerSec = SamplesPerSecond;
Format.nBlockAlign = (Format.nChannels*Format.wBitsPerSample)/8;
Format.nAvgBytesPerSec = Format.nBlockAlign * Format.nSamplesPerSec;
b32 quit = false;
void *MixBuffer = 0;
void *AudioBufferMemory = 0;
if(waveOutOpen(&WaveOut, WAVE_MAPPER, &Format, GetCurrentThreadId(), 0, CALLBACK_THREAD) == MMSYSERR_NOERROR)
{
AudioBufferMemory = VirtualAlloc(0, TotalAudioMemorySize, MEM_COMMIT, PAGE_READWRITE);
if(AudioBufferMemory)
{
u8 *At = (u8 *)AudioBufferMemory;
MixBuffer = At;
At += MixBufferSize;
for(u32 BufferIndex = 0;
BufferIndex < BufferCount;
++BufferIndex)
{
WAVEHDR *Header = (WAVEHDR *)At;
Header->lpData = (char *)(Header + 1);
Header->dwBufferLength = BufferSize;
At += TotalBufferSize;
win32_submit_audio(WaveOut, Header, SamplesPerBuffer, (f32*)MixBuffer);
}
}
else
{
// TODO(allen): audio error
quit = true;
}
}
else
{
// TODO(allen): audio error
quit = true;
}
//
// NOTE(casey): Serve audio forever (until we are told to stop)
//
SetTimer(0, 0, 100, 0);
for (;!quit;)
{
MSG Message = {};
GetMessage(&Message, 0, 0, 0);
if(Message.message == MM_WOM_DONE)
{
WAVEHDR *Header = (WAVEHDR *)Message.lParam;
if(Header->dwFlags & WHDR_DONE)
{
Header->dwFlags &= ~WHDR_DONE;
}
waveOutUnprepareHeader(WaveOut, Header, sizeof(*Header));
win32_submit_audio(WaveOut, Header, SamplesPerBuffer, (f32*)MixBuffer);
}
}
if(WaveOut)
{
waveOutClose(WaveOut);
}
if(AudioBufferMemory)
{
VirtualFree(AudioBufferMemory, 0, MEM_RELEASE);
}
return(0);
}
function DWORD
win32_audio_init(void){
DWORD thread_id = 0;
HANDLE handle = CreateThread(0, 0, win32_audio_loop, 0, 0, &thread_id);
CloseHandle(handle);
return(thread_id);
}
|
