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
|
/*******************************************************************************************
*
* raylib [audio] example - Raw audio streaming
*
* This example has been created using raylib 1.6 (www.raylib.com)
* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
* Example created by Ramon Santamaria (@raysan5) and reviewed by James Hofmann (@triplefox)
*
* Copyright (c) 2015-2019 Ramon Santamaria (@raysan5) and James Hofmann (@triplefox)
*
********************************************************************************************/
#include "raylib.h"
#include <stdlib.h> // Required for: malloc(), free()
#include <math.h> // Required for: sinf()
#include <string.h> // Required for: memcpy()
#define MAX_SAMPLES 512
#define MAX_SAMPLES_PER_UPDATE 4096
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [audio] example - raw audio streaming");
InitAudioDevice(); // Initialize audio device
// Init raw audio stream (sample rate: 22050, sample size: 16bit-short, channels: 1-mono)
AudioStream stream = InitAudioStream(22050, 16, 1);
// Buffer for the single cycle waveform we are synthesizing
short *data = (short *)malloc(sizeof(short)*MAX_SAMPLES);
// Frame buffer, describing the waveform when repeated over the course of a frame
short *writeBuf = (short *)malloc(sizeof(short)*MAX_SAMPLES_PER_UPDATE);
PlayAudioStream(stream); // Start processing stream buffer (no data loaded currently)
// Position read in to determine next frequency
Vector2 mousePosition = { -100.0f, -100.0f };
// Cycles per second (hz)
float frequency = 440.0f;
// Previous value, used to test if sine needs to be rewritten, and to smoothly modulate frequency
float oldFrequency = 1.0f;
// Cursor to read and copy the samples of the sine wave buffer
int readCursor = 0;
// Computed size in samples of the sine wave
int waveLength = 1;
Vector2 position = { 0, 0 };
SetTargetFPS(30); // Set our game to run at 30 frames-per-second
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Update
//----------------------------------------------------------------------------------
// Sample mouse input.
mousePosition = GetMousePosition();
if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
{
float fp = (float)(mousePosition.y);
frequency = 40.0f + (float)(fp);
}
// Rewrite the sine wave.
// Compute two cycles to allow the buffer padding, simplifying any modulation, resampling, etc.
if (frequency != oldFrequency)
{
// Compute wavelength. Limit size in both directions.
int oldWavelength = waveLength;
waveLength = (int)(22050/frequency);
if (waveLength > MAX_SAMPLES/2) waveLength = MAX_SAMPLES/2;
if (waveLength < 1) waveLength = 1;
// Write sine wave.
for (int i = 0; i < waveLength*2; i++)
{
data[i] = (short)(sinf(((2*PI*(float)i/waveLength)))*32000);
}
// Scale read cursor's position to minimize transition artifacts
readCursor = (int)(readCursor * ((float)waveLength / (float)oldWavelength));
oldFrequency = frequency;
}
// Refill audio stream if required
if (IsAudioStreamProcessed(stream))
{
// Synthesize a buffer that is exactly the requested size
int writeCursor = 0;
while (writeCursor < MAX_SAMPLES_PER_UPDATE)
{
// Start by trying to write the whole chunk at once
int writeLength = MAX_SAMPLES_PER_UPDATE-writeCursor;
// Limit to the maximum readable size
int readLength = waveLength-readCursor;
if (writeLength > readLength) writeLength = readLength;
// Write the slice
memcpy(writeBuf + writeCursor, data + readCursor, writeLength*sizeof(short));
// Update cursors and loop audio
readCursor = (readCursor + writeLength) % waveLength;
writeCursor += writeLength;
}
// Copy finished frame to audio stream
UpdateAudioStream(stream, writeBuf, MAX_SAMPLES_PER_UPDATE);
}
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
DrawText(FormatText("sine frequency: %i",(int)frequency), GetScreenWidth() - 220, 10, 20, RED);
DrawText("click mouse button to change frequency", 10, 10, 20, DARKGRAY);
// Draw the current buffer state proportionate to the screen
for (int i = 0; i < screenWidth; i++)
{
position.x = i;
position.y = 250 + 50*data[i*MAX_SAMPLES/screenWidth]/32000;
DrawPixelV(position, RED);
}
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
free(data); // Unload sine wave data
free(writeBuf); // Unload write buffer
CloseAudioStream(stream); // Close raw audio stream and delete buffers from RAM
CloseAudioDevice(); // Close audio device (music streaming is automatically stopped)
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
|
