| 1 | /* |
| 2 | * Small SDL example to demonstrate dynamically loading |
| 3 | * OpenGL lib and functions |
| 4 | * |
| 5 | * (FYI it was supposed to look like snow in the wind or something...) |
| 6 | * |
| 7 | * Compile with : |
| 8 | * gcc testdyngl.c `sdl-config --libs --cflags` -o testdyngl -DHAVE_OPENGL |
| 9 | * |
| 10 | * You can specify a different OpenGL lib on the command line, i.e. : |
| 11 | * ./testdyngl /usr/X11R6/lib/libGL.so.1.2 |
| 12 | * or |
| 13 | * ./testdyngl /usr/lib/libGL.so.1.0.4496 |
| 14 | * |
| 15 | */ |
| 16 | |
| 17 | #include <stdio.h> |
| 18 | #include <stdlib.h> |
| 19 | |
| 20 | #include "SDL.h" |
| 21 | |
| 22 | #ifdef __MACOS__ |
| 23 | #define HAVE_OPENGL |
| 24 | #endif |
| 25 | |
| 26 | #ifdef HAVE_OPENGL |
| 27 | |
| 28 | #include "SDL_opengl.h" |
| 29 | |
| 30 | /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ |
| 31 | static void quit(int rc) |
| 32 | { |
| 33 | SDL_Quit(); |
| 34 | exit(rc); |
| 35 | } |
| 36 | |
| 37 | void* get_funcaddr(const char* p) |
| 38 | { |
| 39 | void* f=SDL_GL_GetProcAddress(p); |
| 40 | if (f) |
| 41 | { |
| 42 | return f; |
| 43 | } |
| 44 | else |
| 45 | { |
| 46 | printf("Unable to get function pointer for %s\n",p); |
| 47 | quit(1); |
| 48 | } |
| 49 | return NULL; |
| 50 | } |
| 51 | |
| 52 | typedef struct |
| 53 | { |
| 54 | void(APIENTRY*glBegin)(GLenum); |
| 55 | void(APIENTRY*glEnd)(); |
| 56 | void(APIENTRY*glVertex3f)(GLfloat, GLfloat, GLfloat); |
| 57 | void(APIENTRY*glClearColor)(GLfloat, GLfloat, GLfloat, GLfloat); |
| 58 | void(APIENTRY*glClear)(GLbitfield); |
| 59 | void(APIENTRY*glDisable)(GLenum); |
| 60 | void(APIENTRY*glEnable)(GLenum); |
| 61 | void(APIENTRY*glColor4ub)(GLubyte,GLubyte,GLubyte,GLubyte); |
| 62 | void(APIENTRY*glPointSize)(GLfloat); |
| 63 | void(APIENTRY*glHint)(GLenum,GLenum); |
| 64 | void(APIENTRY*glBlendFunc)(GLenum,GLenum); |
| 65 | void(APIENTRY*glMatrixMode)(GLenum); |
| 66 | void(APIENTRY*glLoadIdentity)(); |
| 67 | void(APIENTRY*glOrtho)(GLdouble,GLdouble,GLdouble,GLdouble,GLdouble,GLdouble); |
| 68 | void(APIENTRY*glRotatef)(GLfloat,GLfloat,GLfloat,GLfloat); |
| 69 | void(APIENTRY*glViewport)(GLint,GLint,GLsizei,GLsizei); |
| 70 | void(APIENTRY*glFogf)(GLenum,GLfloat); |
| 71 | } |
| 72 | glfuncs; |
| 73 | |
| 74 | void init_glfuncs(glfuncs* f) |
| 75 | { |
| 76 | f->glBegin=get_funcaddr("glBegin"); |
| 77 | f->glEnd=get_funcaddr("glEnd"); |
| 78 | f->glVertex3f=get_funcaddr("glVertex3f"); |
| 79 | f->glClearColor=get_funcaddr("glClearColor"); |
| 80 | f->glClear=get_funcaddr("glClear"); |
| 81 | f->glDisable=get_funcaddr("glDisable"); |
| 82 | f->glEnable=get_funcaddr("glEnable"); |
| 83 | f->glColor4ub=get_funcaddr("glColor4ub"); |
| 84 | f->glPointSize=get_funcaddr("glPointSize"); |
| 85 | f->glHint=get_funcaddr("glHint"); |
| 86 | f->glBlendFunc=get_funcaddr("glBlendFunc"); |
| 87 | f->glMatrixMode=get_funcaddr("glMatrixMode"); |
| 88 | f->glLoadIdentity=get_funcaddr("glLoadIdentity"); |
| 89 | f->glOrtho=get_funcaddr("glOrtho"); |
| 90 | f->glRotatef=get_funcaddr("glRotatef"); |
| 91 | f->glViewport=get_funcaddr("glViewport"); |
| 92 | f->glFogf=get_funcaddr("glFogf"); |
| 93 | } |
| 94 | |
| 95 | #define NB_PIXELS 1000 |
| 96 | |
| 97 | int main(int argc,char *argv[]) |
| 98 | { |
| 99 | glfuncs f; |
| 100 | int i; |
| 101 | SDL_Event event; |
| 102 | int done=0; |
| 103 | GLfloat pixels[NB_PIXELS*3]; |
| 104 | const char *gl_library = NULL; /* Use the default GL library */ |
| 105 | |
| 106 | if (argv[1]) { |
| 107 | gl_library = argv[1]; |
| 108 | } |
| 109 | |
| 110 | if (SDL_Init(SDL_INIT_VIDEO)<0) |
| 111 | { |
| 112 | printf("Unable to init SDL : %s\n",SDL_GetError()); |
| 113 | return(1); |
| 114 | } |
| 115 | |
| 116 | if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1)<0) |
| 117 | { |
| 118 | printf("Unable to set GL attribute : %s\n",SDL_GetError()); |
| 119 | quit(1); |
| 120 | } |
| 121 | |
| 122 | if (SDL_GL_LoadLibrary(gl_library)<0) |
| 123 | { |
| 124 | printf("Unable to dynamically open GL lib : %s\n",SDL_GetError()); |
| 125 | quit(1); |
| 126 | } |
| 127 | |
| 128 | if (SDL_SetVideoMode(640,480,0,SDL_OPENGL)==NULL) |
| 129 | { |
| 130 | printf("Unable to open video mode : %s\n",SDL_GetError()); |
| 131 | quit(1); |
| 132 | } |
| 133 | |
| 134 | /* Set the window manager title bar */ |
| 135 | SDL_WM_SetCaption( "SDL Dynamic OpenGL Loading Test", "testdyngl" ); |
| 136 | |
| 137 | init_glfuncs(&f); |
| 138 | |
| 139 | for(i=0;i<NB_PIXELS;i++) |
| 140 | { |
| 141 | pixels[3*i]=rand()%250-125; |
| 142 | pixels[3*i+1]=rand()%250-125; |
| 143 | pixels[3*i+2]=rand()%250-125; |
| 144 | } |
| 145 | |
| 146 | f.glViewport(0,0,640,480); |
| 147 | |
| 148 | f.glMatrixMode(GL_PROJECTION); |
| 149 | f.glLoadIdentity(); |
| 150 | f.glOrtho(-100,100,-100,100,-500,500); |
| 151 | |
| 152 | f.glMatrixMode(GL_MODELVIEW); |
| 153 | f.glLoadIdentity(); |
| 154 | |
| 155 | f.glEnable(GL_DEPTH_TEST); |
| 156 | f.glDisable(GL_TEXTURE_2D); |
| 157 | f.glEnable(GL_BLEND); |
| 158 | f.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); |
| 159 | |
| 160 | f.glClearColor(0.0f,0.0f,0.0f,0.0f); |
| 161 | f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); |
| 162 | |
| 163 | f.glEnable(GL_POINT_SMOOTH); |
| 164 | f.glHint(GL_POINT_SMOOTH_HINT,GL_NICEST); |
| 165 | f.glPointSize(5.0f); |
| 166 | f.glEnable(GL_FOG); |
| 167 | f.glFogf(GL_FOG_START,-500); |
| 168 | f.glFogf(GL_FOG_END,500); |
| 169 | f.glFogf(GL_FOG_DENSITY,0.005); |
| 170 | |
| 171 | do |
| 172 | { |
| 173 | f.glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); |
| 174 | |
| 175 | f.glRotatef(2.0,1.0,1.0,1.0); |
| 176 | f.glRotatef(1.0,0.0,1.0,1.0); |
| 177 | |
| 178 | f.glColor4ub(255,255,255,255); |
| 179 | f.glBegin(GL_POINTS); |
| 180 | for(i=0;i<NB_PIXELS;i++) |
| 181 | { |
| 182 | f.glVertex3f(pixels[3*i],pixels[3*i+1],pixels[3*i+2]); |
| 183 | } |
| 184 | f.glEnd(); |
| 185 | SDL_GL_SwapBuffers(); |
| 186 | |
| 187 | while(SDL_PollEvent(&event)) |
| 188 | { |
| 189 | if(event.type & SDL_KEYDOWN) |
| 190 | done=1; |
| 191 | } |
| 192 | |
| 193 | SDL_Delay(20); |
| 194 | } |
| 195 | while(!done); |
| 196 | |
| 197 | SDL_Quit(); |
| 198 | return 0; |
| 199 | } |
| 200 | |
| 201 | #else /* HAVE_OPENGL */ |
| 202 | |
| 203 | int main(int argc, char *argv[]) |
| 204 | { |
| 205 | printf("No OpenGL support on this system\n"); |
| 206 | return 1; |
| 207 | } |
| 208 | |
| 209 | #endif /* HAVE_OPENGL */ |