/*
 * Copyright (c) 2011 David Airlie
 *
 * Based on tri.c which is:
 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the name of
 * Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Silicon Graphics.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
 * ANY KIND,
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "glad/gl.h"
#include "glut_wrap.h"

GLenum doubleBuffer = 1;
int win;

static void Init(void)
{
   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
   fflush(stderr);

#ifndef GL_ARB_vertex_type_2_10_10_10_rev
   fprintf(stderr,"built without ARB_vertex_type_2_10_10_10_rev\n");
   exit(1);
#endif

   if (!glutExtensionSupported("GL_ARB_vertex_type_2_10_10_10_rev")){
     fprintf(stderr,"requires ARB_vertex_type_2_10_10_10_rev\n");
     exit(1);
   }

   glClearColor(0.3, 0.1, 0.3, 0.0);
}

static void Reshape(int width, int height)
{

   glViewport(0, 0, (GLint)width, (GLint)height);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-100.0, 100.0, -100.0, 100.0, -50.0, 1000.0);
   glMatrixMode(GL_MODELVIEW);
}

static void Key(unsigned char key, int x, int y)
{
   switch (key) {
      case 27:
         glutDestroyWindow(win);
         exit(0);
      default:
         glutPostRedisplay();
         return;
   }
}

#define i32to10(x) ((x) >= 0 ? (x & 0x1ff) : 1024-(abs((x))& 0x1ff))
#define i32to2(x) ((x) >= 0 ? (x & 0x1) : 1-abs((x)))

static unsigned iconv(int x, int y, int z, int w)
{
	unsigned val;

	val = i32to10(x);
	val |= i32to10(y) << 10;
	val |= i32to10(z) << 20;
	val |= i32to2(w) << 30;
	return val;
}
#define conv(x,y,z,w) (((x) & 0x3ff) | ((y) & 0x3ff) << 10 | ((z) & 0x3ff)<< 20 | ((w) & 0x3) << 30)

static void Draw(void)
{
   glClear(GL_COLOR_BUFFER_BIT); 

#ifdef GL_ARB_vertex_type_2_10_10_10_rev
   glBegin(GL_TRIANGLES);
   glColorP3ui(GL_UNSIGNED_INT_2_10_10_10_REV, conv(820, 0, 0, 0));
   glVertexP3ui(GL_INT_2_10_10_10_REV, iconv(-90, -90, -30, 0));
   glColorP3ui(GL_UNSIGNED_INT_2_10_10_10_REV, conv(0, 921, 0, 0));
   glVertexP3ui(GL_INT_2_10_10_10_REV, iconv(90, -90, -30, 0));
   glColorP3ui(GL_UNSIGNED_INT_2_10_10_10_REV, conv(0, 0, 716, 0));
   glVertexP3ui(GL_INT_2_10_10_10_REV, iconv(0, 90, -30, 0));
   glEnd();
#endif /* GL_ARB_vertex_type_2_10_10_10_rev */

   glFlush();

   if (doubleBuffer) {
      glutSwapBuffers();
   }
}

static GLenum Args(int argc, char **argv)
{
   GLint i;

   for (i = 1; i < argc; i++) {
      if (strcmp(argv[i], "-sb") == 0) {
         doubleBuffer = GL_FALSE;
      } else if (strcmp(argv[i], "-db") == 0) {
         doubleBuffer = GL_TRUE;
      } else {
         fprintf(stderr, "%s (Bad option).\n", argv[i]);
         return GL_FALSE;
      }
   }
   return GL_TRUE;
}

int main(int argc, char **argv)
{
   GLenum type;

   glutInit(&argc, argv);

   if (Args(argc, argv) == GL_FALSE) {
      exit(1);
   }

   glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);

   type = GLUT_RGB | GLUT_ALPHA;
   type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
   glutInitDisplayMode(type);

   win = glutCreateWindow(*argv);
   if (!win) {
      exit(1);
   }

   gladLoaderLoadGL();
   Init();

   glutReshapeFunc(Reshape);
   glutKeyboardFunc(Key);
   glutDisplayFunc(Draw);
   glutMainLoop();
   gladLoaderUnloadGL();
   return 0;
}