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Added a test program for dynamically loading OpenGL
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/* | ||
* Small SDL example to demonstrate dynamically loading | ||
* OpenGL lib and functions | ||
* | ||
* (FYI it was supposed to look like snow in the wind or something...) | ||
* | ||
* Compile with : | ||
* gcc testdyngl.c `sdl-config --libs --cflags` -o testdyngl | ||
* | ||
* You can specify a different OpenGL lib on the command line, i.e. : | ||
* ./testdyngl /usr/X11R6/lib/libGL.so.1.2 | ||
* or | ||
* ./testdyngl /usr/lib/libGL.so.1.0.4496 | ||
* | ||
*/ | ||
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#include <stdio.h> | ||
#include <stdlib.h> | ||
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#include "SDL.h" | ||
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#ifdef HAVE_OPENGL | ||
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#include "SDL_opengl.h" | ||
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void* get_funcaddr(const char* p) | ||
{ | ||
void* f=SDL_GL_GetProcAddress(p); | ||
if (f) | ||
{ | ||
return f; | ||
} | ||
else | ||
{ | ||
printf("Unable to get function pointer for %s\n",p); | ||
exit(1); | ||
} | ||
} | ||
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typedef struct | ||
{ | ||
void(*glBegin)(GLenum); | ||
void(*glEnd)(); | ||
void(*glVertex3f)(GLfloat, GLfloat, GLfloat); | ||
void(*glClearColor)(GLfloat, GLfloat, GLfloat, GLfloat); | ||
void(*glClear)(GLbitfield); | ||
void(*glDisable)(GLenum); | ||
void(*glEnable)(GLenum); | ||
void(*glColor4ub)(GLubyte,GLubyte,GLubyte,GLubyte); | ||
void(*glPointSize)(GLfloat); | ||
void(*glHint)(GLenum,GLenum); | ||
void(*glBlendFunc)(GLenum,GLenum); | ||
void(*glMatrixMode)(GLenum); | ||
void(*glLoadIdentity)(); | ||
void(*glOrtho)(GLdouble,GLdouble,GLdouble,GLdouble,GLdouble,GLdouble); | ||
void(*glRotatef)(GLfloat,GLfloat,GLfloat,GLfloat); | ||
void(*glViewport)(GLint,GLint,GLsizei,GLsizei); | ||
void(*glFogf)(GLenum,GLfloat); | ||
} | ||
glfuncs; | ||
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void init_glfuncs(glfuncs* f) | ||
{ | ||
f->glBegin=get_funcaddr("glBegin"); | ||
f->glEnd=get_funcaddr("glEnd"); | ||
f->glVertex3f=get_funcaddr("glVertex3f"); | ||
f->glClearColor=get_funcaddr("glClearColor"); | ||
f->glClear=get_funcaddr("glClear"); | ||
f->glDisable=get_funcaddr("glDisable"); | ||
f->glEnable=get_funcaddr("glEnable"); | ||
f->glColor4ub=get_funcaddr("glColor4ub"); | ||
f->glPointSize=get_funcaddr("glPointSize"); | ||
f->glHint=get_funcaddr("glHint"); | ||
f->glBlendFunc=get_funcaddr("glBlendFunc"); | ||
f->glMatrixMode=get_funcaddr("glMatrixMode"); | ||
f->glLoadIdentity=get_funcaddr("glLoadIdentity"); | ||
f->glOrtho=get_funcaddr("glOrtho"); | ||
f->glRotatef=get_funcaddr("glRotatef"); | ||
f->glViewport=get_funcaddr("glViewport"); | ||
f->glFogf=get_funcaddr("glFogf"); | ||
} | ||
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#define NB_PIXELS 1000 | ||
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int main(int argc,char *argv[]) | ||
{ | ||
glfuncs f; | ||
int i; | ||
SDL_Event event; | ||
int done=0; | ||
GLfloat pixels[NB_PIXELS*3]; | ||
char default_gl_lib[]="/usr/lib/libGL.so"; | ||
char* current_gl_lib=default_gl_lib; | ||
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if (argc==2) | ||
{ | ||
current_gl_lib=argv[1]; | ||
} | ||
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if (SDL_Init(SDL_INIT_EVERYTHING)<0) | ||
{ | ||
printf("Unable to init SDL : %s\n",SDL_GetError()); | ||
exit(1); | ||
} | ||
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if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1)<0) | ||
{ | ||
printf("Unable to set GL attribute : %s\n",SDL_GetError()); | ||
exit(1); | ||
} | ||
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if (SDL_GL_LoadLibrary(current_gl_lib)<0) | ||
{ | ||
printf("Unable to dynamically open GL lib : %s\n",SDL_GetError()); | ||
exit(1); | ||
} | ||
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if (SDL_SetVideoMode(640,480,0,SDL_OPENGL)==NULL) | ||
{ | ||
printf("Unable to open video mode : %s\n",SDL_GetError()); | ||
exit(1); | ||
} | ||
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init_glfuncs(&f); | ||
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for(i=0;i<NB_PIXELS;i++) | ||
{ | ||
pixels[3*i]=rand()%250-125; | ||
pixels[3*i+1]=rand()%250-125; | ||
pixels[3*i+2]=rand()%250-125; | ||
} | ||
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f.glViewport(0,0,640,480); | ||
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f.glMatrixMode(GL_PROJECTION); | ||
f.glLoadIdentity(); | ||
f.glOrtho(-100,100,-100,100,-500,500); | ||
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f.glMatrixMode(GL_MODELVIEW); | ||
f.glLoadIdentity(); | ||
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f.glEnable(GL_DEPTH_TEST); | ||
f.glDisable(GL_TEXTURE_2D); | ||
f.glEnable(GL_BLEND); | ||
f.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); | ||
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f.glClearColor(0.0f,0.0f,0.0f,0.0f); | ||
f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); | ||
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f.glEnable(GL_POINT_SMOOTH); | ||
f.glHint(GL_POINT_SMOOTH_HINT,GL_NICEST); | ||
f.glPointSize(5.0f); | ||
f.glEnable(GL_FOG); | ||
f.glFogf(GL_FOG_START,-500); | ||
f.glFogf(GL_FOG_END,500); | ||
f.glFogf(GL_FOG_DENSITY,0.005); | ||
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do | ||
{ | ||
f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); | ||
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f.glRotatef(2.0,1.0,1.0,1.0); | ||
f.glRotatef(1.0,0.0,1.0,1.0); | ||
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f.glColor4ub(255,255,255,255); | ||
f.glBegin(GL_POINTS); | ||
for(i=0;i<NB_PIXELS;i++) | ||
{ | ||
f.glVertex3f(pixels[3*i],pixels[3*i+1],pixels[3*i+2]); | ||
} | ||
f.glEnd(); | ||
SDL_GL_SwapBuffers(); | ||
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while(SDL_PollEvent(&event)) | ||
{ | ||
if(event.type & SDL_KEYDOWN) | ||
done=1; | ||
} | ||
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SDL_Delay(20); | ||
} | ||
while(!done); | ||
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SDL_Quit(); | ||
return 0; | ||
} | ||
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#else /* HAVE_OPENGL */ | ||
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int main(int argc, char *argv[]) | ||
{ | ||
printf("No OpenGL support on this system\n"); | ||
return 1; | ||
} | ||
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#endif /* HAVE_OPENGL */ |