/* scivi - visualization plugin for XMMS
 * Copyright (C) 2003 Vitaly V. Bursov <vitalyb@mail333.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include <math.h>
#include <errno.h>
#include <dlfcn.h>

#include "common.h"
#include "glstuff.h"

#ifndef GL_LIB_NAME
#define GL_LIB_NAME "libGL.so.1"
#endif

#define DEF_EXT(e) int scivi_gl_has_##e = 0;
DEF_EXT(GL_ARB_imaging)
DEF_EXT(GL_SGIS_generate_mipmap)
#undef DEF_EXT

int scivi_check_gl_extensions()
{
	const char *glext;

#if 0
	eprintf("Version: %s\n", sc_glGetString(GL_VERSION));
	eprintf("Vendor: %s\n", sc_glGetString(GL_VENDOR));
	eprintf("Extensions: %s\n", sc_glGetString(GL_EXTENSIONS));
#endif

	glext = sc_glGetString(GL_EXTENSIONS);
	if (glext){
#define CHECK_EXT(e) \
		(scivi_gl_has_##e) = strstr(glext, #e) != 0 && \
				(strstr(glext, #e)[strlen(#e)] == '\0' ||\
				strstr(glext, #e)[strlen(#e)] == ' ');

		CHECK_EXT(GL_ARB_imaging)
		CHECK_EXT(GL_SGIS_generate_mipmap)
#undef CHECK_EXT

		dprintf("GL_ARB_imaging: %d\n",GL_HAS(GL_ARB_imaging));
		dprintf("GL_SGIS_generate_mipmap: %d\n",GL_HAS(GL_SGIS_generate_mipmap));

	} else {
		scivi_gl_has_GL_ARB_imaging = 0;
		scivi_gl_has_GL_SGIS_generate_mipmap = 0;
	}
	return 0;
}

static void stub_func()
{
	/* stub */
	fprintf(stderr, "stub function called!\n");
	fflush(stderr);
}


static void *dlhandle = NULL;

static int load_gl_lib(const char *libname)
{
	const char *soname = libname ? libname : GL_LIB_NAME;

	if (dlhandle)
		return 0;

	dlhandle = dlopen(soname, RTLD_NOW);
	if (dlhandle == NULL){
		eprintf("Failed to load '%s' library.\n", libname);
		return 1;
	}

	sc_glXGetProcAddress = dlsym (dlhandle, "glXGetProcAddressARB");

	return 0;
}

static void unload_gl_lib()
{
	if (dlhandle){
		dlclose(dlhandle);
		dlhandle = NULL;
	}
}

static void *dl_load_gl_func(const char *name)
{
	return dlsym(dlhandle, name);
}

static int load_gl_funcs(const int dontload)
{
	int failed = 0;
	void (*(*getaddr)(const char *procname))(void);

#define GET(_fatal_, _n_)\
	if (!dontload){\
		sc_##_n_ = (void *)getaddr(#_n_); \
		if ((sc_##_n_) == NULL) { \
			sc_##_n_ = (void *)stub_func; \
			eprintf("failed to get address of '%s'\n", #_n_);\
			if ((_fatal_)) failed++;\
		}\
		/* eprintf("func %s @ %p\n", #_n_, sc_##_n_);*/ \
	} else \
		sc_##_n_ = (void *)stub_func;

	getaddr = sc_glXGetProcAddress ?
		((void*)sc_glXGetProcAddress) :
		((void*)dl_load_gl_func);

	GET(1, glMatrixMode);
	GET(1, glLoadIdentity);
	GET(1, glOrtho);
	GET(1, glPushMatrix);
	GET(1, glPopMatrix);
	GET(1, glLightModelfv);
	GET(1, glTexEnvi);
	GET(1, glBlendFunc);
	GET(1, glViewport);
	GET(1, glClearColor);
	GET(1, glTexParameteri);
	GET(1, glScalef);
	GET(1, glRotatef);
	GET(1, glTranslatef);
	GET(1, glLineWidth);
	GET(1, glPointSize);
	GET(1, glBegin);
	GET(1, glTexCoord2f);
	GET(1, glMaterialfv);
	GET(1, glVertex2f);
	GET(1, glEnd);
	GET(1, glPushAttrib);
	GET(1, glPopAttrib);
	GET(1, glNewList);
	GET(1, glCallList);
	GET(1, glEndList);
	GET(1, glBindTexture);
	GET(1, glEnable);
	GET(1, glDisable);
	GET(1, glBlendEquation);
	GET(1, glClear);
	GET(1, glCopyTexImage2D);
	GET(1, glDeleteTextures);
	GET(1, glGenTextures);
	GET(1, glGenLists);
	GET(1, glDeleteLists);
	GET(1, glFlush);
	GET(1, glGetString);
	GET(1, glGetError);

	/* GLX 1.2 functions */
	GET(1, glXSwapBuffers);
	GET(1, glXChooseVisual);
	GET(1, glXCreateContext);
	GET(1, glXMakeCurrent);
	GET(1, glXQueryExtension);
	GET(1, glXQueryVersion);
	GET(1, glXDestroyContext);
	GET(1, glXIsDirect);
	GET(1, glXCreateGLXPixmap);

	/* GLX 1.3 functions*/
	GET(0, glXGetFBConfigs);
	GET(0, glXChooseFBConfig);
	GET(0, glXGetFBConfigAttrib);
	GET(0, glXGetVisualFromFBConfig);
	GET(0, glXCreateWindow);
	GET(0, glXDestroyWindow);
	GET(0, glXCreatePixmap);
	GET(0, glXDestroyPixmap);
	GET(0, glXCreatePbuffer);
	GET(0, glXDestroyPbuffer);
	GET(0, glXQueryDrawable);
	GET(0, glXCreateNewContext);
	GET(0, glXMakeContextCurrent);
	GET(0, glXGetCurrentReadDrawable);
	GET(0, glXGetCurrentDisplay);
	GET(0, glXQueryContext);
	GET(0, glXSelectEvent);
	GET(0, glXGetSelectedEvent);

	/* GLX extensions */
	GET(0, glXGetVideoSyncSGI);
	GET(0, glXWaitVideoSyncSGI);

#undef GET
	return failed;
}

int scivi_initialize_gl_funcs(const char *libglso)
{
	if (load_gl_lib(libglso)){
		load_gl_funcs(1);
		return -1;
	}

	if (load_gl_funcs(0)){
		return 1;
	}

	return 0;
}

void scivi_finalize_gl_funcs()
{
	unload_gl_lib();
}