view test/testdyngl.c @ 855:aa4ac9e65d92

I noticed MacOSX SDL sets up working directory to parent of executable. On BeOS is should setup it the same way, but it only does when Tracker wasn't restarted. I checked code and it looks like a hack to me :( It looks for env variable and than comapres it to default when OpenTracker was started after boot, and wasn't restarted. That's probably ok, for that exact case. Unfortunetly that variable isn't always like that. For example, after Tracker crashes and is restarted, env variable most probably is different (depends on how Tracker was restarted, by what application, etc... for example: i have launcher application from which i can restart Tracker, and after that nev variable points to that application's directory, not Tracker's).
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Feb 2004 18:58:40 +0000 (2004-02-24)
parents 0afe0e38e02c
children 9f6ad2286011
line wrap: on
line source
/*
 * 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 HAVE_OPENGL

#include "SDL_opengl.h"

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);
	}
}

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;

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];
#ifdef _WIN32
	char *gl_library = "OpenGL32.DLL";
#else
	char *gl_library = "libGL.so.1";
#endif
	
	if (argv[1]) {
		gl_library = argv[1];
	}
	
	if (SDL_Init(SDL_INIT_VIDEO)<0)
	{
		printf("Unable to init SDL : %s\n",SDL_GetError());
		exit(1);
	}
	
	if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1)<0)
	{
		printf("Unable to set GL attribute : %s\n",SDL_GetError());
		exit(1);
	}
	
	if (SDL_GL_LoadLibrary(gl_library)<0)
	{
		printf("Unable to dynamically open GL lib : %s\n",SDL_GetError());
		exit(1);
	}

	if (SDL_SetVideoMode(640,480,0,SDL_OPENGL)==NULL)
	{
		printf("Unable to open video mode : %s\n",SDL_GetError());
		exit(1);
	}

	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 */