| /* |
| * 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 -DHAVE_OPENGL |
| * |
| * 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 |
| * |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| |
| #include "SDL.h" |
| |
| #ifdef __MACOS__ |
| #define HAVE_OPENGL |
| #endif |
| |
| #ifdef HAVE_OPENGL |
| |
| #include "SDL_opengl.h" |
| |
| /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ |
| static void |
| quit(int rc) |
| { |
| SDL_Quit(); |
| exit(rc); |
| } |
| |
| 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); |
| quit(1); |
| } |
| return NULL; |
| } |
| |
| typedef struct |
| { |
| void (APIENTRY * glBegin) (GLenum); |
| void (APIENTRY * glEnd) (); |
| void (APIENTRY * glVertex3f) (GLfloat, GLfloat, GLfloat); |
| void (APIENTRY * glClearColor) (GLfloat, GLfloat, GLfloat, GLfloat); |
| void (APIENTRY * glClear) (GLbitfield); |
| void (APIENTRY * glDisable) (GLenum); |
| void (APIENTRY * glEnable) (GLenum); |
| void (APIENTRY * glColor4ub) (GLubyte, GLubyte, GLubyte, GLubyte); |
| void (APIENTRY * glPointSize) (GLfloat); |
| void (APIENTRY * glHint) (GLenum, GLenum); |
| void (APIENTRY * glBlendFunc) (GLenum, GLenum); |
| void (APIENTRY * glMatrixMode) (GLenum); |
| void (APIENTRY * glLoadIdentity) (); |
| void (APIENTRY * glOrtho) (GLdouble, GLdouble, GLdouble, GLdouble, |
| GLdouble, GLdouble); |
| void (APIENTRY * glRotatef) (GLfloat, GLfloat, GLfloat, GLfloat); |
| void (APIENTRY * glViewport) (GLint, GLint, GLsizei, GLsizei); |
| void (APIENTRY * glFogf) (GLenum, GLfloat); |
| } |
| glfuncs; |
| |
| 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"); |
| } |
| |
| #define NB_PIXELS 1000 |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| glfuncs f; |
| int i; |
| SDL_Event event; |
| int done = 0; |
| GLfloat pixels[NB_PIXELS * 3]; |
| const char *gl_library = NULL; /* Use the default GL library */ |
| |
| if (argv[1]) { |
| gl_library = argv[1]; |
| } |
| |
| if (SDL_Init(SDL_INIT_VIDEO) < 0) { |
| printf("Unable to init SDL : %s\n", SDL_GetError()); |
| return (1); |
| } |
| |
| if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1) < 0) { |
| printf("Unable to set GL attribute : %s\n", SDL_GetError()); |
| quit(1); |
| } |
| |
| if (SDL_GL_LoadLibrary(gl_library) < 0) { |
| printf("Unable to dynamically open GL lib : %s\n", SDL_GetError()); |
| quit(1); |
| } |
| |
| if (SDL_SetVideoMode(640, 480, 0, SDL_OPENGL) == NULL) { |
| printf("Unable to open video mode : %s\n", SDL_GetError()); |
| quit(1); |
| } |
| |
| /* Set the window manager title bar */ |
| SDL_WM_SetCaption("SDL Dynamic OpenGL Loading Test", "testdyngl"); |
| |
| init_glfuncs(&f); |
| |
| 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; |
| } |
| |
| f.glViewport(0, 0, 640, 480); |
| |
| f.glMatrixMode(GL_PROJECTION); |
| f.glLoadIdentity(); |
| f.glOrtho(-100, 100, -100, 100, -500, 500); |
| |
| f.glMatrixMode(GL_MODELVIEW); |
| f.glLoadIdentity(); |
| |
| f.glEnable(GL_DEPTH_TEST); |
| f.glDisable(GL_TEXTURE_2D); |
| f.glEnable(GL_BLEND); |
| f.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); |
| |
| f.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); |
| f.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); |
| |
| 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); |
| |
| do { |
| f.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); |
| |
| f.glRotatef(2.0, 1.0, 1.0, 1.0); |
| f.glRotatef(1.0, 0.0, 1.0, 1.0); |
| |
| 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(); |
| |
| while (SDL_PollEvent(&event)) { |
| if (event.type & SDL_KEYDOWN) |
| done = 1; |
| } |
| |
| SDL_Delay(20); |
| } |
| while (!done); |
| |
| SDL_Quit(); |
| return 0; |
| } |
| |
| #else /* HAVE_OPENGL */ |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| printf("No OpenGL support on this system\n"); |
| return 1; |
| } |
| |
| #endif /* HAVE_OPENGL */ |