Initial revision

1 files changed, 790 insertions, 0 deletions

diff --git a/src/glu/mesa/mipmap.c b/src/glu/mesa/mipmap.c
new file mode 100644
index 00000000000..24af0ba33c0
--- /dev/null
+++ b/src/glu/mesa/mipmap.c
@@ -0,0 +1,790 @@
+/* $Id: mipmap.c,v 1.1 1999/08/19 00:55:42 jtg Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.1
+ * Copyright (C) 1995-1999  Brian Paul
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+/*
+ * $Log: mipmap.c,v $
+ * Revision 1.1  1999/08/19 00:55:42  jtg
+ * Initial revision
+ *
+ * Revision 1.13  1999/03/05 17:49:06  brianp
+ * added support for GL_EXT_abgr ([email protected])
+ *
+ * Revision 1.12  1999/01/03 03:23:15  brianp
+ * now using GLAPIENTRY and GLCALLBACK keywords (Ted Jump)
+ *
+ * Revision 1.11  1998/09/18 02:44:03  brianp
+ * further changes to gluScaleImage() per Randy Frank
+ *
+ * Revision 1.10  1998/09/17 03:20:26  brianp
+ * fixed another bug in gluScaleImage() per Sven Panne
+ *
+ * Revision 1.9  1998/07/31 03:06:20  brianp
+ * tweaked the gluScaleImage() function per Randy Frank
+ *
+ * Revision 1.8  1998/07/08 01:02:53  brianp
+ * if gluBuildxDMipmaps() width or height <= 0 return GLU_INVALID_VALUE
+ *
+ * Revision 1.7  1998/07/01 00:18:02  brianp
+ * if gluBuildxDMipmaps() width or height <= 0 just return 0
+ *
+ * Revision 1.6  1998/06/01 01:06:41  brianp
+ * small update for Next/OpenStep from Alexander Mai
+ *
+ * Revision 1.5  1997/07/24 01:28:44  brianp
+ * changed precompiled header symbol from PCH to PC_HEADER
+ *
+ * Revision 1.4  1997/06/23 00:22:56  brianp
+ * added dummy() call to work around an MSVC 4.1 bug
+ *
+ * Revision 1.3  1997/05/28 02:29:38  brianp
+ * added support for precompiled headers (PCH), inserted APIENTRY keyword
+ *
+ * Revision 1.2  1997/05/24 13:32:25  brianp
+ * undef EPSILON in case it's already defined
+ *
+ * Revision 1.1  1996/09/27 01:19:39  brianp
+ * Initial revision
+ *
+ */
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "gluP.h"
+#endif
+
+
+/*
+ * Compute ceiling of integer quotient of A divided by B:
+ */
+#define CEILING( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )
+
+
+
+#ifdef EPSILON
+#undef EPSILON
+#endif
+#define EPSILON 0.001
+
+
+/* To work around optimizer bug in MSVC4.1 */
+#if defined(__WIN32__) && !defined(OPENSTEP)
+void dummy(GLuint j, GLuint k){
+}
+#else
+#define dummy(J, K)
+#endif
+
+
+GLint GLAPIENTRY gluScaleImage( GLenum format,
+                              GLint widthin, GLint heightin,
+                              GLenum typein, const void *datain,
+                              GLint widthout, GLint heightout,
+                              GLenum typeout, void *dataout )
+{
+   GLint components, i, j, k;
+   GLfloat *tempin, *tempout;
+   GLfloat sx, sy;
+   GLint unpackrowlength, unpackalignment, unpackskiprows, unpackskippixels;
+   GLint packrowlength, packalignment, packskiprows, packskippixels;
+   GLint sizein, sizeout;
+   GLint rowstride, rowlen;
+
+
+   /* Determine number of components per pixel */
+   switch (format) {
+      case GL_COLOR_INDEX:
+      case GL_STENCIL_INDEX:
+      case GL_DEPTH_COMPONENT:
+      case GL_RED:
+      case GL_GREEN:
+      case GL_BLUE:
+      case GL_ALPHA:
+      case GL_LUMINANCE:
+         components = 1;
+	 break;
+      case GL_LUMINANCE_ALPHA:
+	 components = 2;
+	 break;
+      case GL_RGB:
+	 components = 3;
+	 break;
+      case GL_RGBA:
+#ifdef GL_EXT_abgr
+      case GL_ABGR_EXT:
+#endif
+	 components = 4;
+	 break;
+      default:
+	 return GLU_INVALID_ENUM;
+   }
+
+   /* Determine bytes per input datum */
+   switch (typein) {
+      case GL_UNSIGNED_BYTE:	sizein = sizeof(GLubyte);	break;
+      case GL_BYTE:		sizein = sizeof(GLbyte);	break;
+      case GL_UNSIGNED_SHORT:	sizein = sizeof(GLushort);	break;
+      case GL_SHORT:		sizein = sizeof(GLshort);	break;
+      case GL_UNSIGNED_INT:	sizein = sizeof(GLuint);	break;
+      case GL_INT:		sizein = sizeof(GLint);		break;
+      case GL_FLOAT:		sizein = sizeof(GLfloat);	break;
+      case GL_BITMAP:
+	 /* not implemented yet */
+      default:
+	 return GL_INVALID_ENUM;
+   }
+
+   /* Determine bytes per output datum */
+   switch (typeout) {
+      case GL_UNSIGNED_BYTE:	sizeout = sizeof(GLubyte);	break;
+      case GL_BYTE:		sizeout = sizeof(GLbyte);	break;
+      case GL_UNSIGNED_SHORT:	sizeout = sizeof(GLushort);	break;
+      case GL_SHORT:		sizeout = sizeof(GLshort);	break;
+      case GL_UNSIGNED_INT:	sizeout = sizeof(GLuint);	break;
+      case GL_INT:		sizeout = sizeof(GLint);	break;
+      case GL_FLOAT:		sizeout = sizeof(GLfloat);	break;
+      case GL_BITMAP:
+	 /* not implemented yet */
+      default:
+	 return GL_INVALID_ENUM;
+   }
+
+   /* Get glPixelStore state */
+   glGetIntegerv( GL_UNPACK_ROW_LENGTH, &unpackrowlength );
+   glGetIntegerv( GL_UNPACK_ALIGNMENT, &unpackalignment );
+   glGetIntegerv( GL_UNPACK_SKIP_ROWS, &unpackskiprows );
+   glGetIntegerv( GL_UNPACK_SKIP_PIXELS, &unpackskippixels );
+   glGetIntegerv( GL_PACK_ROW_LENGTH, &packrowlength );
+   glGetIntegerv( GL_PACK_ALIGNMENT, &packalignment );
+   glGetIntegerv( GL_PACK_SKIP_ROWS, &packskiprows );
+   glGetIntegerv( GL_PACK_SKIP_PIXELS, &packskippixels );
+
+   /* Allocate storage for intermediate images */
+   tempin = (GLfloat *) malloc( widthin * heightin
+			        * components * sizeof(GLfloat) );
+   if (!tempin) {
+      return GLU_OUT_OF_MEMORY;
+   }
+   tempout = (GLfloat *) malloc( widthout * heightout
+		 	         * components * sizeof(GLfloat) );
+   if (!tempout) {
+      free( tempin );
+      return GLU_OUT_OF_MEMORY;
+   }
+
+
+   /*
+    * Unpack the pixel data and convert to floating point
+    */
+
+   if (unpackrowlength>0) {
+      rowlen = unpackrowlength;
+   }
+   else {
+      rowlen = widthin;
+   }
+   if (sizein >= unpackalignment) {
+      rowstride = components * rowlen;
+   }
+   else {
+      rowstride = unpackalignment/sizein
+	        * CEILING( components * rowlen * sizein, unpackalignment );
+   }
+
+   switch (typein) {
+      case GL_UNSIGNED_BYTE:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLubyte *ubptr = (GLubyte *) datain
+	                   + i * rowstride
+			   + unpackskiprows * rowstride
+			   + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *ubptr++;
+	    }
+	 }
+	 break;
+      case GL_BYTE:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLbyte *bptr = (GLbyte *) datain
+	                 + i * rowstride
+			 + unpackskiprows * rowstride
+			 + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *bptr++;
+	    }
+	 }
+	 break;
+      case GL_UNSIGNED_SHORT:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLushort *usptr = (GLushort *) datain
+	                    + i * rowstride
+			    + unpackskiprows * rowstride
+			    + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *usptr++;
+	    }
+	 }
+	 break;
+      case GL_SHORT:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLshort *sptr = (GLshort *) datain
+	                  + i * rowstride
+			  + unpackskiprows * rowstride
+			  + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *sptr++;
+	    }
+	 }
+	 break;
+      case GL_UNSIGNED_INT:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLuint *uiptr = (GLuint *) datain
+	                  + i * rowstride
+			  + unpackskiprows * rowstride
+			  + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *uiptr++;
+	    }
+	 }
+	 break;
+      case GL_INT:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLint *iptr = (GLint *) datain
+	                + i * rowstride
+			+ unpackskiprows * rowstride
+			+ unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = (GLfloat) *iptr++;
+	    }
+	 }
+	 break;
+      case GL_FLOAT:
+	 k = 0;
+	 for (i=0;i<heightin;i++) {
+	    GLfloat *fptr = (GLfloat *) datain
+	                  + i * rowstride
+			  + unpackskiprows * rowstride
+			  + unpackskippixels * components;
+	    for (j=0;j<widthin*components;j++) {
+               dummy(j, k);
+	       tempin[k++] = *fptr++;
+	    }
+	 }
+	 break;
+      default:
+	 return GLU_INVALID_ENUM;
+   }
+
+
+   /*
+    * Scale the image!
+    */
+
+   if (widthout > 1)
+      sx = (GLfloat) (widthin-1) / (GLfloat) (widthout-1);
+   else
+      sx = (GLfloat) (widthin-1);
+   if (heightout > 1)
+      sy = (GLfloat) (heightin-1) / (GLfloat) (heightout-1);
+   else
+      sy = (GLfloat) (heightin-1);
+
+/*#define POINT_SAMPLE*/
+#ifdef POINT_SAMPLE
+   for (i=0;i<heightout;i++) {
+      GLint ii = i * sy;
+      for (j=0;j<widthout;j++) {
+	 GLint jj = j * sx;
+
+	 GLfloat *src = tempin + (ii * widthin + jj) * components;
+	 GLfloat *dst = tempout + (i * widthout + j) * components;
+
+	 for (k=0;k<components;k++) {
+	    *dst++ = *src++;
+	 }
+      }
+   }
+#else
+   if (sx<1.0 && sy<1.0) {
+      /* magnify both width and height:  use weighted sample of 4 pixels */
+      GLint i0, i1, j0, j1;
+      GLfloat alpha, beta;
+      GLfloat *src00, *src01, *src10, *src11;
+      GLfloat s1, s2;
+      GLfloat *dst;
+
+      for (i=0;i<heightout;i++) {
+	 i0 = i * sy;
+	 i1 = i0 + 1;
+	 if (i1 >= heightin) i1 = heightin-1;
+/*	 i1 = (i+1) * sy - EPSILON;*/
+	 alpha = i*sy - i0;
+	 for (j=0;j<widthout;j++) {
+	    j0 = j * sx;
+	    j1 = j0 + 1;
+	    if (j1 >= widthin) j1 = widthin-1;
+/*	    j1 = (j+1) * sx - EPSILON; */
+	    beta = j*sx - j0;
+
+	    /* compute weighted average of pixels in rect (i0,j0)-(i1,j1) */
+	    src00 = tempin + (i0 * widthin + j0) * components;
+	    src01 = tempin + (i0 * widthin + j1) * components;
+	    src10 = tempin + (i1 * widthin + j0) * components;
+	    src11 = tempin + (i1 * widthin + j1) * components;
+
+	    dst = tempout + (i * widthout + j) * components;
+
+	    for (k=0;k<components;k++) {
+	       s1 = *src00++ * (1.0-beta) + *src01++ * beta;
+	       s2 = *src10++ * (1.0-beta) + *src11++ * beta;
+	       *dst++ = s1 * (1.0-alpha) + s2 * alpha;
+	    }
+	 }
+      }
+   }
+   else {
+      /* shrink width and/or height:  use an unweighted box filter */
+      GLint i0, i1;
+      GLint j0, j1;
+      GLint ii, jj;
+      GLfloat sum, *dst;
+
+      for (i=0;i<heightout;i++) {
+	 i0 = i * sy;
+	 i1 = i0 + 1;
+	 if (i1 >= heightin) i1 = heightin-1; 
+/*	 i1 = (i+1) * sy - EPSILON; */
+	 for (j=0;j<widthout;j++) {
+	    j0 = j * sx;
+	    j1 = j0 + 1;
+	    if (j1 >= widthin) j1 = widthin-1;
+/*	    j1 = (j+1) * sx - EPSILON; */
+
+	    dst = tempout + (i * widthout + j) * components;
+
+	    /* compute average of pixels in the rectangle (i0,j0)-(i1,j1) */
+	    for (k=0;k<components;k++) {
+	       sum = 0.0;
+	       for (ii=i0;ii<=i1;ii++) {
+		  for (jj=j0;jj<=j1;jj++) {
+		     sum += *(tempin + (ii * widthin + jj) * components + k);
+		  }
+	       }
+	       sum /= (j1-j0+1) * (i1-i0+1);
+	       *dst++ = sum;
+	    }
+	 }
+      }
+   }
+#endif
+
+
+   /*
+    * Return output image
+    */
+
+   if (packrowlength>0) {
+      rowlen = packrowlength;
+   }
+   else {
+      rowlen = widthout;
+   }
+   if (sizeout >= packalignment) {
+      rowstride = components * rowlen;
+   }
+   else {
+      rowstride = packalignment/sizeout
+	        * CEILING( components * rowlen * sizeout, packalignment );
+   }
+
+   switch (typeout) {
+      case GL_UNSIGNED_BYTE:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLubyte *ubptr = (GLubyte *) dataout
+	                   + i * rowstride
+			   + packskiprows * rowstride
+			   + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *ubptr++ = (GLubyte) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_BYTE:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLbyte *bptr = (GLbyte *) dataout
+	                 + i * rowstride
+			 + packskiprows * rowstride
+			 + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *bptr++ = (GLbyte) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_UNSIGNED_SHORT:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLushort *usptr = (GLushort *) dataout
+	                    + i * rowstride
+			    + packskiprows * rowstride
+			    + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *usptr++ = (GLushort) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_SHORT:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLshort *sptr = (GLshort *) dataout
+	                  + i * rowstride
+			  + packskiprows * rowstride
+			  + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *sptr++ = (GLshort) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_UNSIGNED_INT:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLuint *uiptr = (GLuint *) dataout
+	                  + i * rowstride
+			  + packskiprows * rowstride
+			  + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *uiptr++ = (GLuint) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_INT:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLint *iptr = (GLint *) dataout
+	                + i * rowstride
+			+ packskiprows * rowstride
+			+ packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *iptr++ = (GLint) tempout[k++];
+	    }
+	 }
+	 break;
+      case GL_FLOAT:
+	 k = 0;
+	 for (i=0;i<heightout;i++) {
+	    GLfloat *fptr = (GLfloat *) dataout
+	                  + i * rowstride
+			  + packskiprows * rowstride
+			  + packskippixels * components;
+	    for (j=0;j<widthout*components;j++) {
+               dummy(j, k+i);
+	       *fptr++ = tempout[k++];
+	    }
+	 }
+	 break;
+      default:
+	 return GLU_INVALID_ENUM;
+   }
+
+
+   /* free temporary image storage */
+   free( tempin );
+   free( tempout );
+
+   return 0;
+}
+
+
+
+/*
+ * Return the largest k such that 2^k <= n.
+ */
+static GLint ilog2( GLint n )
+{
+   GLint k;
+
+   if (n<=0) return 0;
+   for (k=0; n>>=1; k++) ;
+   return k;
+}
+
+
+
+/*
+ * Find the value nearest to n which is also a power of two.
+ */
+static GLint round2( GLint n )
+{
+   GLint m;
+
+   for (m=1; m<n; m*=2)
+     ;
+
+   /* m>=n */
+   if (m-n <= n-m/2) {
+      return m;
+   }
+   else {
+      return m/2;
+   }
+}
+
+
+/*
+ * Given an pixel format and datatype, return the number of bytes to
+ * store one pixel.
+ */
+static GLint bytes_per_pixel( GLenum format, GLenum type )
+{
+   GLint n, m;
+
+   switch (format) {
+      case GL_COLOR_INDEX:
+      case GL_STENCIL_INDEX:
+      case GL_DEPTH_COMPONENT:
+      case GL_RED:
+      case GL_GREEN:
+      case GL_BLUE:
+      case GL_ALPHA:
+      case GL_LUMINANCE:
+	 n = 1;
+	 break;
+      case GL_LUMINANCE_ALPHA:
+	 n = 2;
+	 break;
+      case GL_RGB:
+	 n = 3;
+	 break;
+      case GL_RGBA:
+#ifdef GL_EXT_abgr
+      case GL_ABGR_EXT:
+#endif
+	 n = 4;
+	 break;
+      default:
+	 n = 0;
+   }
+
+   switch (type) {
+      case GL_UNSIGNED_BYTE:	m = sizeof(GLubyte);	break;
+      case GL_BYTE:		m = sizeof(GLbyte);	break;
+      case GL_BITMAP:		m = 1;			break;
+      case GL_UNSIGNED_SHORT:	m = sizeof(GLushort);	break;
+      case GL_SHORT:		m = sizeof(GLshort);	break;
+      case GL_UNSIGNED_INT:	m = sizeof(GLuint);	break;
+      case GL_INT:		m = sizeof(GLint);	break;
+      case GL_FLOAT:		m = sizeof(GLfloat);	break;
+      default:			m = 0;
+   }
+
+   return n * m;
+}
+
+
+
+/*
+ * WARNING: This function isn't finished and has never been tested!!!!
+ */
+GLint GLAPIENTRY gluBuild1DMipmaps( GLenum target, GLint components,
+                                  GLint width, GLenum format,
+                                  GLenum type, const void *data )
+{
+   GLubyte *texture;
+   GLint levels, max_levels;
+   GLint new_width, max_width;
+   GLint i, j, k, l;
+
+   if (width < 1)
+      return GLU_INVALID_VALUE;
+
+   glGetIntegerv( GL_MAX_TEXTURE_SIZE, &max_width );
+   max_levels = ilog2( max_width ) + 1;
+
+   /* Compute how many mipmap images to make */
+   levels = ilog2( width ) + 1;
+   if (levels>max_levels) {
+      levels = max_levels;
+   }
+
+   new_width = 1 << (levels-1);
+
+   texture = (GLubyte *) malloc( new_width * components );
+   if (!texture) {
+      return GLU_OUT_OF_MEMORY;
+   }
+
+   if (width != new_width) {
+      /* initial rescaling */
+      switch (type) {
+	 case GL_UNSIGNED_BYTE:
+	    {
+	       GLubyte *ub_data = (GLubyte *) data;
+	       for (i=0;i<new_width;i++) {
+		  j = i * width / new_width;
+		  for (k=0;k<components;k++) {
+		     texture[i*components+k] = ub_data[j*components+k];
+		  }
+	       }
+	    }
+	    break;
+	 default:
+	    /* Not implemented */
+	    return GLU_ERROR;
+      }
+   }
+
+   /* generate and load mipmap images */
+   for (l=0;l<levels;l++) {
+      glTexImage1D( GL_TEXTURE_1D, l, components, new_width, 0,
+		    format, GL_UNSIGNED_BYTE, texture );
+
+      /* Scale image down to 1/2 size */
+      new_width = new_width / 2;
+      for (i=0;i<new_width;i++) {
+	 for (k=0;k<components;k++) {
+	    GLint sample1, sample2;
+	    sample1 = (GLint) texture[i*2*components+k];
+	    sample2 = (GLint) texture[(i*2+1)*components+k];
+	    texture[i*components+k] = (GLubyte) ((sample1 + sample2) / 2);
+	 }
+      }
+   }
+
+   free( texture );
+
+   /* make sure remaining mipmap levels are removed */
+   for (l=levels;l<max_levels;l++) {
+      glTexImage1D( GL_TEXTURE_1D, l, components, 0, 0,
+		    format, GL_UNSIGNED_BYTE, NULL );
+   }
+
+   return 0;
+}
+
+
+
+GLint GLAPIENTRY gluBuild2DMipmaps( GLenum target, GLint components,
+                                  GLint width, GLint height, GLenum format,
+                                  GLenum type, const void *data )
+{
+   GLint w, h, maxsize;
+   void *image, *newimage;
+   GLint neww, newh, level, bpp;
+   int error;
+
+   if (width < 1 || height < 1)
+      return GLU_INVALID_VALUE;
+
+   glGetIntegerv( GL_MAX_TEXTURE_SIZE, &maxsize );
+
+   w = round2( width );
+   if (w>maxsize) {
+      w = maxsize;
+   }
+   h = round2( height );
+   if (h>maxsize) {
+      h = maxsize;
+   }
+
+   bpp = bytes_per_pixel( format, type );
+   if (bpp==0) {
+      /* probably a bad format or type enum */
+      return GLU_INVALID_ENUM;
+   }
+
+   if (w!=width || h!=height) {
+      /* must rescale image to get "top" mipmap texture image */
+      image = malloc( (w+4) * h * bpp );
+      if (!image) {
+	 return GLU_OUT_OF_MEMORY;
+      }
+      error = gluScaleImage( format, width, height, type, data,
+			     w, h, type, image );
+      if (error) {
+	 return error;
+      }
+   }
+   else {
+      image = (void *) data;
+   }
+
+   level = 0;
+   while (1) {
+      glTexImage2D( target, level, components, w, h, 0, format, type, image );
+
+      if (w==1 && h==1)  break;
+
+      neww = (w<2) ? 1 : w/2;
+      newh = (h<2) ? 1 : h/2;
+      newimage = malloc( (neww+4) * newh * bpp );
+      if (!newimage) {
+	 return GLU_OUT_OF_MEMORY;
+      }
+
+      error =  gluScaleImage( format, w, h, type, image,
+			      neww, newh, type, newimage );
+      if (error) {
+	 return error;
+      }
+
+      if (image!=data) {
+	 free( image );
+      }
+      image = newimage;
+
+      w = neww;
+      h = newh;
+      level++;
+   }
+
+   if (image!=data) {
+      free( image );
+   }
+
+   return 0;
+}
+