在这段代码中音频是如何播放的(C/SDL)

I think this is meant to be a 4k style of visualization program but written in C.

我认为这是一种4k格式的可视化程序，但用C语言编写。

So it draws some spheres and plays some music, I am not trying to understand the graphics, that is generally maths. It also uses SDL. I am trying to understand where the music is coming from, there isn't any apparent function for the audio.

所以它画了一些球，播放了一些音乐，我并不是想要理解图形，这通常是数学。它还使用SDL。我试着去理解音乐是从哪里来的，音频没有任何明显的功能。

The music is initialized SDL_AudioSpec as, oa; and some parameters are set but where does the tune actually come from, is this a build in sample from SDL.

音乐初始化SDL_AudioSpec as, oa;有些参数是设置的，但是这首曲子来自哪里，这是SDL的一个样本。

/* "Shadow Sun" */
/* tonic - http://jet.ro */
#include "SDL.h"
#include "SDL_opengl.h"
#include <math.h>
#include <stdlib.h>
#define    S1(a,b,c) #a".."#b".."#c"."
#define   X2(a)                      a a
#define   X4(a)                    a a a a
#define  S14(a,b,c)           X4(S1(a,b,c))
#define  S2(a)               #a"."#a"....."
#define S24(a)             X4  ( S2 ( a ) )
#define S4(a)             #a   #a   #a   #a
#define S3(a,b,        c) S1(a,b,c)S4(..)
#define SE         X4(  X4(  S4  (..)))
#define P(x)    glDisable(GL_##x);
#define EF_(x) F[C][1638##x+M
#define B     float

char l[]=SE SE X2(S3(J,H,M)S3(J,H,E)S3(F,E,A)S3(F,E,J)S3(H,E
,O)S3( H,E,C)S3 (H,F,x) S3(H,F,L)) ;
char b[] = SE X2(S4(j.jv.j.v)S4
(f.fr.f.r)S4(e.eq.e.q)S4(h.ht.h.t))SE;
char*r [3] ={S14(v,v,q)S14(r,r,m)
S14(q,q,l)S14(t,t,o),S24(J)S24(F)S24(E)S24(H),S24(M)S24(J)S24(H)S24(L) };
Uint32 S;GLUquadric*Q;
int D,R,U,L,p=0;B T,F[5][0100000]={{0},{0}};void G(
void*u,Uint8*_,int L){while(L>0){int M=p&037777,s=p>>12,H=(s%R)[l],J=(s
#define EF(C,l,s,ms)    ((s*ms+EF_(4)-l]*(1-ms))*0.5f+EF_(3)]*0.5f)
%U)[b],C=0,a=0,n;
B      v,q,m,E=(0x2000-(p&017777))/8192e0f;
#define FQ(s) (B)sin((0.12*pow(2,n/12.0))*p*s)
#define IZ(v,c) if(v c)v*=v;else v=0;
#define BF F[C][M]=F[C][M+16384]=q;v+=q;++C
#define IP(n,x,y,z,c) if(n!='.'){x}q=EF(C,y,q,z);c;BF;
#define IS(s,c)   if(q c s 0.75f)q=s 0.75f;
#define NQ(N,a,m) n=N-(N>='a'?'a'+24:'A')+a;q=FQ(m);
v=q=0;IP(H,NQ(H,12,1)m=FQ(1.01f);IZ(q,>
0.6)IZ(m,>0.6)q+=m;q*=E*0.5f+0.5f;,
12288,0.2f,;)for(;a<3;++a){char
sn=(s%D)[a[r]];q=0;IP (sn,NQ(
sn,12,0.25f)IZ(q,<0.3),12288,
0.2f,;)}q=0;IP(J,NQ(J,0,0.125f)
X4(q*=q;)q=(B)fmod(q*20,4)*4;
,6144,0.25f,IS(-,<)IS(+,>)q*=
E)v*=0.6f;*(Sint16*)_=(Sint16
)(v*32767);_+=2;++p;L-=2;}}
#define N(x) glEnable(GL_##x);
void I(int a){B b[]={a?0.f:1,a?0:4.f,-2.f,0},c[]={0,
-2,0,0},d[]={.2f,0.f,0.f    ,1},e[]={a?.5f:.8f,a?.75f
:.3f,a?1:.2f,1},f[]={0,.2f,.3f,1},g[]={0,0,0,1,1,1,1},*h=&g[3];
#define GF(l,x,v) glLightfv(GL_LIGHT##l,GL_##x,v);
GF(0,POSITION,b)GF(0,AMBIENT,d)GF(0,DIFFUSE,e)GF(0,SPECULAR,h)if(a)P(LIGHT1
)else N(LIGHT1)GF(1,POSITION,c)GF(1,AMBIENT,f)GF(1,DIFFUSE,f)GF(1,SPECULAR,g)
#define GM(t,x,v) glMaterial##t(GL_FRONT,GL_##x,v);
GM(fv,AMBIENT,g)GM(fv,DIFFUSE,h)GM(fv,SPECULAR,h)GM(
fv,EMISSION,g) GM (f,SHININESS,60) glColorMaterial (
GL_FRONT,GL_DIFFUSE);N(COLOR_MATERIAL)}
void K(int b,
B c,int d){ int a; B  e=c*c,g=1e0f/e;glColor3f(1,1,1);
#define BC(v,f,p,q) B v=(B)f(ta*(sin(T*p*g)*5e-2+q*c)*g)*c
for(a=0;a<b;++a){B ta=T*1e-4f+a*c;BC(x,cos,2.3e-4,0.0867);
BC(y,sin,2e-4,0.2735);
BC(z,cos,1.5e-4,0.1243);
glPushMatrix();
glTranslatef(x,y,z); 
glRotatef(50,1,0,0); 
glRotatef (T*5e-2f+a*20,0,1,0);
glCallList(d);

glPopMatrix();}}
int _tmain(int c,char **a) 
{ SDL_Event e;
SDL_AudioSpec as, oa;if (
SDL_Init(48)<0)
exit(1);
atexit(SDL_Quit);
SDL_SetVideoMode(640,480,32,2);
as.freq=053042;
as.format=AUDIO_S16;
as.channels=1;
as.samples=4096;
as.callback=G;
D=strlen(r[0]);
R=strlen(l);
U=strlen(b);
if(
SDL_OpenAudio(&as,&oa) <0)
exit(2);
SDL_PauseAudio(0);
Q=gluNewQuadric();
L=glGenLists(2);
#define NL_ GL_COMPILE);gluSphere(Q,0.1,40
#define NL(a,d) glNewList(L+a,NL_/d,20/d);
glEndList();
NL(0,1)NL(1,5)N(LIGHTING)N(LIGHT0)N(CULL_FACE)
glShadeModel(GL_SMOOTH);
N(BLEND)glBlendFunc(
GL_ONE,GL_ONE);
S=SDL_GetTicks();
T=0;
while(!SDL_PollEvent(&e)||((e.type!=2||e.key.keysym.sym!=27)&& e.type!=12))
{
B d,f;
Uint32 g;
f=T;
g=SDL_GetTicks()-S;T=T*0.75f+g*2.5e-1f;glClearColor(0,0,0,1);
glClear(16640);
glViewport(0,0,640,480);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45,4./3,0.5,100);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
d=T*1e-4f;
gluLookAt(cos(d)*3,0,sin(d)*3,0, 0, 0, 0,1, 0);
I(0);
K(0144, 1, L); 
P(COLOR_MATERIAL)I(1);K(100+0144+0x64+0620+0454,15,L+1);
P(COLOR_MATERIAL)
    SDL_GL_SwapBuffers();
/* $Revision: 1.1 $*/
SDL_Delay(~0&1);
}
SDL_CloseAudio(); 
return 0;
}

1 个解决方案

#1

This code is not meant to be instructive! :)

这段代码不应该具有指导意义!:)

Look at the macros and you see that there are several tokenizing macros. These macros combine tokens into new tokens before the compiler sees them and are a simple and effective method for code obfuscation in C and can make the source smaller too. You will have to sift deeply through those macro expansions until you find what is happening.

看一下宏，你会发现有几个标记宏。这些宏在编译器看到它们之前将令牌组合到新标记中，这是一种简单而有效的方法，可以在C中进行代码混淆，也可以使源代码更小。你将不得不深入地筛选那些宏观的扩张，直到你发现正在发生的事情。

The code will either call SDL_MixAudio() or directly modify the audio stream buffer in a callback. The callback pointer is stored in the SDL_AudioSpec struct passed to SDL_OpenAudio() or SDL_OpenAudioDevice(). The second parameter of the callback is the writable audio stream.

代码要么调用SDL_MixAudio()，要么直接在回调中修改音频流缓冲区。回调指针存储在SDL_AudioSpec struct中，传递给SDL_OpenAudio()或SDL_OpenAudioDevice()。回调的第二个参数是可写音频流。

Good luck!

好运！

#1

This code is not meant to be instructive! :)

这段代码不应该具有指导意义!:)

Good luck!

好运！

秒客网

在这段代码中音频是如何播放的(C/SDL)

1 个解决方案

#1

#1

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