libgender/util.C

/*
 * math support
 * most of the more complicated code is taken from mesa.
 */

#include <cstdio> // ugly
#include <cmath>

#include <sys/time.h>
#include <time.h>
#include <GL/gl.h>

#include "util.h"
#include "entity.h"

#define DEG2RAD (M_PI / 180.)

void renormalize (sector &s, point &p)
{
  float i;

  p.x = modff (p.x, &i); s.x += (soffs)i;
  p.y = modff (p.y, &i); s.y += (soffs)i;
  p.z = modff (p.z, &i); s.z += (soffs)i;
}

/////////////////////////////////////////////////////////////////////////////

const vec3 normalize (const vec3 &v)
{
  GLfloat s = abs (v);

  if (!s)
    return v;

  s = 1. / s;
  return vec3 (v.x * s, v.y * s, v.z * s);
}

const vec3 cross (const vec3 &a, const vec3 &b)
{
  return vec3 (
     a.y * b.z - a.z * b.y,
     a.z * b.x - a.x * b.z,
     a.x * b.y - a.y * b.x
  );
}

/////////////////////////////////////////////////////////////////////////////

void matrix::diagonal (GLfloat v)
{
  for (int i = 4; i--; )
    for (int j = 4; j--; )
      data[i][j] = i == j ? v : 0.;
}

const matrix operator *(const matrix &a, const matrix &b)
{
  matrix r;

  // taken from mesa
  for (int i = 0; i < 4; i++)
    {
      const GLfloat ai0=a(i,0), ai1=a(i,1), ai2=a(i,2), ai3=a(i,3);

      r(i,0) = ai0 * b(0,0) + ai1 * b(1,0) + ai2 * b(2,0) + ai3 * b(3,0);
      r(i,1) = ai0 * b(0,1) + ai1 * b(1,1) + ai2 * b(2,1) + ai3 * b(3,1);
      r(i,2) = ai0 * b(0,2) + ai1 * b(1,2) + ai2 * b(2,2) + ai3 * b(3,2);
      r(i,3) = ai0 * b(0,3) + ai1 * b(1,3) + ai2 * b(2,3) + ai3 * b(3,3);
    }

  return r;
}

const matrix matrix::rotation (GLfloat angle, const vec3 &axis)
{
  GLfloat xx, yy, zz, xy, yz, zx, xs, ys, zs, one_c, s, c;

  s = (GLfloat) sinf (angle * DEG2RAD);
  c = (GLfloat) cosf (angle * DEG2RAD);

  const GLfloat mag = abs (axis);

  if (mag <= 1.0e-4)
    return matrix (1);

  matrix m;
  const vec3 n = axis * (1. / mag);

  /*
   *     Arbitrary axis rotation matrix.
   *
   *  This is composed of 5 matrices, Rz, Ry, T, Ry', Rz', multiplied
   *  like so:  Rz * Ry * T * Ry' * Rz'.  T is the final rotation
   *  (which is about the X-axis), and the two composite transforms
   *  Ry' * Rz' and Rz * Ry are (respectively) the rotations necessary
   *  from the arbitrary axis to the X-axis then back.  They are
   *  all elementary rotations.
   *
   *  Rz' is a rotation about the Z-axis, to bring the axis vector
   *  into the x-z plane.  Then Ry' is applied, rotating about the
   *  Y-axis to bring the axis vector parallel with the X-axis.  The
   *  rotation about the X-axis is then performed.  Ry and Rz are
   *  simply the respective inverse transforms to bring the arbitrary
   *  axis back to it's original orientation.  The first transforms
   *  Rz' and Ry' are considered inverses, since the data from the
   *  arbitrary axis gives you info on how to get to it, not how
   *  to get away from it, and an inverse must be applied.
   *
   *  The basic calculation used is to recognize that the arbitrary
   *  axis vector (x, y, z), since it is of unit length, actually
   *  represents the sines and cosines of the angles to rotate the
   *  X-axis to the same orientation, with theta being the angle about
   *  Z and phi the angle about Y (in the order described above)
   *  as follows:
   *
   *  cos ( theta ) = x / sqrt ( 1 - z^2 )
   *  sin ( theta ) = y / sqrt ( 1 - z^2 )
   *
   *  cos ( phi ) = sqrt ( 1 - z^2 )
   *  sin ( phi ) = z
   *
   *  Note that cos ( phi ) can further be inserted to the above
   *  formulas:
   *
   *  cos ( theta ) = x / cos ( phi )
   *  sin ( theta ) = y / sin ( phi )
   *
   *  ...etc.  Because of those relations and the standard trigonometric
   *  relations, it is pssible to reduce the transforms down to what
   *  is used below.  It may be that any primary axis chosen will give the
   *  same results (modulo a sign convention) using this method.
   *
   *  Particularly nice is to notice that all divisions that might
   *  have caused trouble when parallel to certain planes or
   *  axis go away with care paid to reducing the expressions.
   *  After checking, it does perform correctly under all cases, since
   *  in all the cases of division where the denominator would have
   *  been zero, the numerator would have been zero as well, giving
   *  the expected result.
   */

  xx = n.x * n.x;
  yy = n.y * n.y;
  zz = n.z * n.z;
  xy = n.x * n.y;
  yz = n.y * n.z;
  zx = n.z * n.x;
  xs = n.x * s;
  ys = n.y * s;
  zs = n.z * s;
  one_c = 1.0F - c;

  m(0,0) = (one_c * xx) + c;
  m(0,1) = (one_c * xy) - zs;
  m(0,2) = (one_c * zx) + ys;
  m(0,3) = 0;
  
  m(1,0) = (one_c * xy) + zs;
  m(1,1) = (one_c * yy) + c;
  m(1,2) = (one_c * yz) - xs;
  m(1,3) = 0;
  
  m(2,0) = (one_c * zx) - ys;
  m(2,1) = (one_c * yz) + xs;
  m(2,2) = (one_c * zz) + c;
  m(2,3) = 0;
  
  m(3,0) = 0;
  m(3,1) = 0;
  m(3,2) = 0;
  m(3,3) = 1;

  return m;
}

const vec3 operator *(const matrix &a, const vec3 &v)
{
  return vec3 (
    a(0,0) * v.x + a(0,1) * v.y + a(0,2) * v.z + a(0,3),
    a(1,0) * v.x + a(1,1) * v.y + a(1,2) * v.z + a(1,3),
    a(2,0) * v.x + a(2,1) * v.y + a(2,2) * v.z + a(2,3)
  );
}

void matrix::print ()
{
  printf ("\n");
  printf ("[ %f, %f, %f, %f ]\n", data[0][0], data[1][0], data[2][0], data[3][0]);
  printf ("[ %f, %f, %f, %f ]\n", data[0][1], data[1][1], data[2][1], data[3][1]);
  printf ("[ %f, %f, %f, %f ]\n", data[0][2], data[1][2], data[2][2], data[3][2]);
  printf ("[ %f, %f, %f, %f ]\n", data[0][3], data[1][3], data[2][3], data[3][3]);
}

const matrix matrix::translation (const vec3 &v)
{
  matrix m(1);

  m(0,3) = v.x;
  m(1,3) = v.y;
  m(2,3) = v.z;

  return m;
}

/////////////////////////////////////////////////////////////////////////////

plane::plane (GLfloat a, GLfloat b, GLfloat c, GLfloat d)
: n (vec3 (a,b,c))
{
  GLfloat s = 1. / abs (n);

  n = n * s;
  this->d = d * s;
}

/////////////////////////////////////////////////////////////////////////////

void box::add (const box &o)
{
  a.x = min (a.x, o.a.x);
  a.y = min (a.y, o.a.y);
  a.z = min (a.z, o.a.z);
  b.x = max (b.x, o.b.x);
  b.y = max (b.y, o.b.y);
  b.z = max (b.z, o.b.z);
}

void box::add (const sector &p)
{
  a.x = min (a.x, p.x);
  a.y = min (a.y, p.y);
  a.z = min (a.z, p.z);
  b.x = max (b.x, p.x);
  b.y = max (b.y, p.y);
  b.z = max (b.z, p.z);
}

void box::add (const point &p)
{
  a.x = min (a.x, (soffs)floorf (p.x));
  a.y = min (a.y, (soffs)floorf (p.y));
  a.z = min (a.z, (soffs)floorf (p.z));
  b.x = max (b.x, (soffs)ceilf  (p.x));
  b.y = max (b.y, (soffs)ceilf  (p.y));
  b.z = max (b.z, (soffs)ceilf  (p.z));
}

/////////////////////////////////////////////////////////////////////////////

struct timer timer;
static double base;
double timer::now = 0.;
double timer::diff;

void timer::frame ()
{
  struct timeval tv;
  gettimeofday (&tv, 0);

  double next = tv.tv_sec - base + tv.tv_usec / 1.e6;

  diff = next - now;
  now = next;
}

timer::timer ()
{
  struct timeval tv;
  gettimeofday (&tv, 0);
  base = tv.tv_sec + tv.tv_usec / 1.e6;
}

GLuint SDL_GL_LoadTexture (SDL_Surface * surface, GLfloat * texcoord)
{
  GLuint texture;
  int w, h;
  SDL_Surface *image;
  SDL_Rect area;
  Uint32 saved_flags;
  Uint8 saved_alpha;

  /* Use the surface width and height expanded to powers of 2 */
  //w = power_of_two (surface->w);
  //h = power_of_two (surface->h);
  w = power_of_two (surface->w);
  h = power_of_two (surface->h);
  texcoord[0] = 0.0f;           /* Min X */
  texcoord[1] = 0.0f;           /* Min Y */
  texcoord[2] = (GLfloat) surface->w / w;       /* Max X */
  texcoord[3] = (GLfloat) surface->h / h;       /* Max Y */

  image = SDL_CreateRGBSurface (SDL_SWSURFACE, w, h, 32,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN     /* OpenGL RGBA masks */
                                0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000
#else
                                0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF
#endif
    );
  if (image == NULL)
    {
      return 0;
    }

  /* Save the alpha blending attributes */
  saved_flags = surface->flags & (SDL_SRCALPHA | SDL_RLEACCELOK);
  saved_alpha = surface->format->alpha;
  if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
    {
      SDL_SetAlpha (surface, 0, 0);
    }

  /* Copy the surface into the GL texture image */
  area.x = 0;
  area.y = 0;
  area.w = surface->w;
  area.h = surface->h;
  SDL_BlitSurface (surface, &area, image, &area);

  /* Restore the alpha blending attributes */
  if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
    {
      SDL_SetAlpha (surface, saved_flags, saved_alpha);
    }

  /* Create an OpenGL texture for the image */
  glGenTextures (1, &texture);
  glBindTexture (GL_TEXTURE_2D, texture);
  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexImage2D (GL_TEXTURE_2D,
                0,
                GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->pixels);
  SDL_FreeSurface (image);      /* No longer needed */

  return texture;
}

void draw_some_random_funky_floor_dance_music (int size, int dx, int dy, int dz)
{
  int x, z, ry;

  for (x = 0; x < 100; x++)
    {
      for (z = 0; z < 100; z++)
        {
          vector<vertex2d> pts;
          pts.push_back (vertex2d (point (dx + (x * size),       dy, dz + (z * size)),       vec3  (0, 1, 0), texc (0, 0)));
          pts.push_back (vertex2d (point (dx + (x * size),       dy, dz + ((z + 1) * size)), vec3  (0, 1, 0), texc (0, 1)));
          pts.push_back (vertex2d (point (dx + ((x + 1) * size), dy, dz + ((z + 1) * size)), vec3  (0, 1, 0), texc (1, 1)));
          pts.push_back (vertex2d (point (dx + ((x + 1) * size), dy, dz + (z * size)),       vec3  (0, 1, 0), texc (1, 0)));

          entity_quads *q = new entity_quads;
          q->set (pts);
          q->show ();
        }
    }
}

//skedjuhlar main_scheduler;

Revision:	1.17
Committed:	Wed Oct 6 17:04:06 2004 UTC (21 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.16:	+18 -15 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.3	/*
2			* math support
3			* most of the more complicated code is taken from mesa.
4			*/
5
6	root	1.2	#include <cstdio> // ugly
7	root	1.1	#include <cmath>
8
9	root	1.4	#include <sys/time.h>
10			#include <time.h>
11	root	1.15	#include <GL/gl.h>
12	root	1.2
13	root	1.1	#include "util.h"
14	root	1.15	#include "entity.h"
15	root	1.1
16	root	1.3	#define DEG2RAD (M_PI / 180.)
17
18	root	1.6	void renormalize (sector &s, point &p)
19			{
20			float i;
21
22	root	1.11	p.x = modff (p.x, &i); s.x += (soffs)i;
23			p.y = modff (p.y, &i); s.y += (soffs)i;
24			p.z = modff (p.z, &i); s.z += (soffs)i;
25	root	1.6	}
26
27	root	1.7	/////////////////////////////////////////////////////////////////////////////
28
29	root	1.1	const vec3 normalize (const vec3 &v)
30			{
31	root	1.3	GLfloat s = abs (v);
32
33			if (!s)
34			return v;
35	root	1.1
36	root	1.3	s = 1. / s;
37	root	1.1	return vec3 (v.x * s, v.y * s, v.z * s);
38			}
39
40			const vec3 cross (const vec3 &a, const vec3 &b)
41			{
42			return vec3 (
43	root	1.3	a.y * b.z - a.z * b.y,
44			a.z * b.x - a.x * b.z,
45			a.x * b.y - a.y * b.x
46			);
47	root	1.2	}
48
49	root	1.7	/////////////////////////////////////////////////////////////////////////////
50
51	root	1.12	void matrix::diagonal (GLfloat v)
52	root	1.2	{
53			for (int i = 4; i--; )
54			for (int j = 4; j--; )
55			data[i][j] = i == j ? v : 0.;
56			}
57
58	root	1.12	const matrix operator *(const matrix &a, const matrix &b)
59	root	1.2	{
60	root	1.12	matrix r;
61	root	1.2
62	root	1.3	// taken from mesa
63			for (int i = 0; i < 4; i++)
64			{
65			const GLfloat ai0=a(i,0), ai1=a(i,1), ai2=a(i,2), ai3=a(i,3);
66
67			r(i,0) = ai0 * b(0,0) + ai1 * b(1,0) + ai2 * b(2,0) + ai3 * b(3,0);
68			r(i,1) = ai0 * b(0,1) + ai1 * b(1,1) + ai2 * b(2,1) + ai3 * b(3,1);
69			r(i,2) = ai0 * b(0,2) + ai1 * b(1,2) + ai2 * b(2,2) + ai3 * b(3,2);
70			r(i,3) = ai0 * b(0,3) + ai1 * b(1,3) + ai2 * b(2,3) + ai3 * b(3,3);
71			}
72	root	1.2
73	root	1.3	return r;
74			}
75	root	1.2
76	root	1.12	const matrix matrix::rotation (GLfloat angle, const vec3 &axis)
77	root	1.3	{
78			GLfloat xx, yy, zz, xy, yz, zx, xs, ys, zs, one_c, s, c;
79	root	1.2
80	root	1.3	s = (GLfloat) sinf (angle * DEG2RAD);
81			c = (GLfloat) cosf (angle * DEG2RAD);
82
83			const GLfloat mag = abs (axis);
84
85			if (mag <= 1.0e-4)
86	root	1.12	return matrix (1);
87	root	1.3
88	root	1.12	matrix m;
89	root	1.3	const vec3 n = axis * (1. / mag);
90
91			/*
92			* Arbitrary axis rotation matrix.
93			*
94			* This is composed of 5 matrices, Rz, Ry, T, Ry', Rz', multiplied
95			* like so: Rz * Ry * T * Ry' * Rz'. T is the final rotation
96			* (which is about the X-axis), and the two composite transforms
97			* Ry' * Rz' and Rz * Ry are (respectively) the rotations necessary
98			* from the arbitrary axis to the X-axis then back. They are
99			* all elementary rotations.
100			*
101			* Rz' is a rotation about the Z-axis, to bring the axis vector
102			* into the x-z plane. Then Ry' is applied, rotating about the
103			* Y-axis to bring the axis vector parallel with the X-axis. The
104			* rotation about the X-axis is then performed. Ry and Rz are
105			* simply the respective inverse transforms to bring the arbitrary
106			* axis back to it's original orientation. The first transforms
107			* Rz' and Ry' are considered inverses, since the data from the
108			* arbitrary axis gives you info on how to get to it, not how
109			* to get away from it, and an inverse must be applied.
110			*
111			* The basic calculation used is to recognize that the arbitrary
112			* axis vector (x, y, z), since it is of unit length, actually
113			* represents the sines and cosines of the angles to rotate the
114			* X-axis to the same orientation, with theta being the angle about
115			* Z and phi the angle about Y (in the order described above)
116			* as follows:
117			*
118			* cos ( theta ) = x / sqrt ( 1 - z^2 )
119			* sin ( theta ) = y / sqrt ( 1 - z^2 )
120			*
121			* cos ( phi ) = sqrt ( 1 - z^2 )
122			* sin ( phi ) = z
123			*
124			* Note that cos ( phi ) can further be inserted to the above
125			* formulas:
126			*
127			* cos ( theta ) = x / cos ( phi )
128			* sin ( theta ) = y / sin ( phi )
129			*
130			* ...etc. Because of those relations and the standard trigonometric
131			* relations, it is pssible to reduce the transforms down to what
132			* is used below. It may be that any primary axis chosen will give the
133			* same results (modulo a sign convention) using this method.
134			*
135			* Particularly nice is to notice that all divisions that might
136			* have caused trouble when parallel to certain planes or
137			* axis go away with care paid to reducing the expressions.
138			* After checking, it does perform correctly under all cases, since
139			* in all the cases of division where the denominator would have
140			* been zero, the numerator would have been zero as well, giving
141			* the expected result.
142			*/
143
144			xx = n.x * n.x;
145			yy = n.y * n.y;
146			zz = n.z * n.z;
147			xy = n.x * n.y;
148			yz = n.y * n.z;
149			zx = n.z * n.x;
150			xs = n.x * s;
151			ys = n.y * s;
152			zs = n.z * s;
153			one_c = 1.0F - c;
154
155			m(0,0) = (one_c * xx) + c;
156			m(0,1) = (one_c * xy) - zs;
157			m(0,2) = (one_c * zx) + ys;
158			m(0,3) = 0;
159
160			m(1,0) = (one_c * xy) + zs;
161			m(1,1) = (one_c * yy) + c;
162			m(1,2) = (one_c * yz) - xs;
163			m(1,3) = 0;
164
165			m(2,0) = (one_c * zx) - ys;
166			m(2,1) = (one_c * yz) + xs;
167			m(2,2) = (one_c * zz) + c;
168			m(2,3) = 0;
169
170			m(3,0) = 0;
171			m(3,1) = 0;
172			m(3,2) = 0;
173			m(3,3) = 1;
174
175	root	1.9	return m;
176	root	1.3	}
177
178	root	1.12	const vec3 operator *(const matrix &a, const vec3 &v)
179	root	1.3	{
180			return vec3 (
181	root	1.9	a(0,0) * v.x + a(0,1) * v.y + a(0,2) * v.z + a(0,3),
182			a(1,0) * v.x + a(1,1) * v.y + a(1,2) * v.z + a(1,3),
183			a(2,0) * v.x + a(2,1) * v.y + a(2,2) * v.z + a(2,3)
184	root	1.3	);
185	root	1.2	}
186
187	root	1.12	void matrix::print ()
188	root	1.2	{
189			printf ("\n");
190			printf ("[ %f, %f, %f, %f ]\n", data[0][0], data[1][0], data[2][0], data[3][0]);
191			printf ("[ %f, %f, %f, %f ]\n", data[0][1], data[1][1], data[2][1], data[3][1]);
192			printf ("[ %f, %f, %f, %f ]\n", data[0][2], data[1][2], data[2][2], data[3][2]);
193			printf ("[ %f, %f, %f, %f ]\n", data[0][3], data[1][3], data[2][3], data[3][3]);
194			}
195
196	root	1.12	const matrix matrix::translation (const vec3 &v)
197	root	1.2	{
198	root	1.12	matrix m(1);
199	root	1.2
200	root	1.9	m(0,3) = v.x;
201			m(1,3) = v.y;
202			m(2,3) = v.z;
203	root	1.2
204	root	1.9	return m;
205	root	1.1	}
206
207	root	1.7	/////////////////////////////////////////////////////////////////////////////
208
209			plane::plane (GLfloat a, GLfloat b, GLfloat c, GLfloat d)
210	root	1.9	: n (vec3 (a,b,c))
211	root	1.7	{
212			GLfloat s = 1. / abs (n);
213
214			n = n * s;
215	root	1.9	this->d = d * s;
216	root	1.7	}
217
218			/////////////////////////////////////////////////////////////////////////////
219
220	root	1.1	void box::add (const box &o)
221			{
222			a.x = min (a.x, o.a.x);
223			a.y = min (a.y, o.a.y);
224			a.z = min (a.z, o.a.z);
225			b.x = max (b.x, o.b.x);
226			b.y = max (b.y, o.b.y);
227			b.z = max (b.z, o.b.z);
228			}
229
230	root	1.5	void box::add (const sector &p)
231	root	1.1	{
232			a.x = min (a.x, p.x);
233			a.y = min (a.y, p.y);
234			a.z = min (a.z, p.z);
235			b.x = max (b.x, p.x);
236			b.y = max (b.y, p.y);
237			b.z = max (b.z, p.z);
238	root	1.5	}
239
240			void box::add (const point &p)
241			{
242			a.x = min (a.x, (soffs)floorf (p.x));
243			a.y = min (a.y, (soffs)floorf (p.y));
244			a.z = min (a.z, (soffs)floorf (p.z));
245	root	1.6	b.x = max (b.x, (soffs)ceilf (p.x));
246			b.y = max (b.y, (soffs)ceilf (p.y));
247			b.z = max (b.z, (soffs)ceilf (p.z));
248	root	1.1	}
249	root	1.7
250			/////////////////////////////////////////////////////////////////////////////
251	root	1.4
252			struct timer timer;
253			static double base;
254			double timer::now = 0.;
255			double timer::diff;
256
257			void timer::frame ()
258			{
259			struct timeval tv;
260			gettimeofday (&tv, 0);
261
262			double next = tv.tv_sec - base + tv.tv_usec / 1.e6;
263
264			diff = next - now;
265			now = next;
266			}
267
268			timer::timer ()
269			{
270			struct timeval tv;
271			gettimeofday (&tv, 0);
272			base = tv.tv_sec + tv.tv_usec / 1.e6;
273			}
274
275	root	1.13	GLuint SDL_GL_LoadTexture (SDL_Surface * surface, GLfloat * texcoord)
276			{
277			GLuint texture;
278			int w, h;
279			SDL_Surface *image;
280			SDL_Rect area;
281			Uint32 saved_flags;
282			Uint8 saved_alpha;
283
284			/* Use the surface width and height expanded to powers of 2 */
285	root	1.14	//w = power_of_two (surface->w);
286			//h = power_of_two (surface->h);
287	root	1.13	w = power_of_two (surface->w);
288			h = power_of_two (surface->h);
289			texcoord[0] = 0.0f; /* Min X */
290			texcoord[1] = 0.0f; /* Min Y */
291			texcoord[2] = (GLfloat) surface->w / w; /* Max X */
292			texcoord[3] = (GLfloat) surface->h / h; /* Max Y */
293
294			image = SDL_CreateRGBSurface (SDL_SWSURFACE, w, h, 32,
295			#if SDL_BYTEORDER == SDL_LIL_ENDIAN /* OpenGL RGBA masks */
296			0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000
297			#else
298			0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF
299			#endif
300			);
301			if (image == NULL)
302			{
303			return 0;
304			}
305
306			/* Save the alpha blending attributes */
307			saved_flags = surface->flags & (SDL_SRCALPHA \| SDL_RLEACCELOK);
308			saved_alpha = surface->format->alpha;
309			if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
310			{
311			SDL_SetAlpha (surface, 0, 0);
312			}
313
314			/* Copy the surface into the GL texture image */
315			area.x = 0;
316			area.y = 0;
317			area.w = surface->w;
318			area.h = surface->h;
319			SDL_BlitSurface (surface, &area, image, &area);
320
321			/* Restore the alpha blending attributes */
322			if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
323			{
324			SDL_SetAlpha (surface, saved_flags, saved_alpha);
325			}
326
327			/* Create an OpenGL texture for the image */
328			glGenTextures (1, &texture);
329			glBindTexture (GL_TEXTURE_2D, texture);
330			glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
331			glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
332			glTexImage2D (GL_TEXTURE_2D,
333			0,
334			GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->pixels);
335			SDL_FreeSurface (image); /* No longer needed */
336
337			return texture;
338			}
339
340	root	1.17	void draw_some_random_funky_floor_dance_music (int size, int dx, int dy, int dz)
341			{
342			int x, z, ry;
343	root	1.15
344	root	1.17	for (x = 0; x < 100; x++)
345			{
346			for (z = 0; z < 100; z++)
347			{
348			vector<vertex2d> pts;
349			pts.push_back (vertex2d (point (dx + (x * size), dy, dz + (z * size)), vec3 (0, 1, 0), texc (0, 0)));
350			pts.push_back (vertex2d (point (dx + (x * size), dy, dz + ((z + 1) * size)), vec3 (0, 1, 0), texc (0, 1)));
351			pts.push_back (vertex2d (point (dx + ((x + 1) * size), dy, dz + ((z + 1) * size)), vec3 (0, 1, 0), texc (1, 1)));
352			pts.push_back (vertex2d (point (dx + ((x + 1) * size), dy, dz + (z * size)), vec3 (0, 1, 0), texc (1, 0)));
353	root	1.15
354	root	1.17	entity_quads *q = new entity_quads;
355			q->set (pts);
356			q->show ();
357			}
358			}
359	root	1.15	}
360	root	1.13
361	root	1.10	//skedjuhlar main_scheduler;
362	root	1.17