patch to import Jon Smirl's work from Bitkeeper

1 files changed, 764 insertions, 0 deletions

diff --git a/src/glu/mini/mipmap.c b/src/glu/mini/mipmap.c
new file mode 100644
index 00000000000..97297729e78
--- /dev/null
+++ b/src/glu/mini/mipmap.c
@@ -0,0 +1,764 @@
+/* $Id: mipmap.c,v 1.2 2003/08/22 20:11:43 brianp Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.4
+ * Copyright (C) 1995-2000  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.
+ */
+
+
+#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,
+	      GLsizei widthin, GLsizei heightin,
+	      GLenum typein, const void *datain,
+	      GLsizei widthout, GLsizei heightout,
+	      GLenum typeout, void *dataout)
+{
+   GLint components, i, j, k;
+   GLfloat *tempin, *tempout, f;
+   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:
+   case GL_BGR:
+      components = 3;
+      break;
+   case GL_RGBA:
+   case GL_BGRA:
+#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 */
+   glGetFloatv(GL_UNPACK_ROW_LENGTH, &f); unpackrowlength = (int)f;
+   glGetFloatv(GL_UNPACK_ALIGNMENT, &f); unpackalignment = (int)f;
+   glGetFloatv(GL_UNPACK_SKIP_ROWS, &f); unpackskiprows = (int)f;
+   glGetFloatv(GL_UNPACK_SKIP_PIXELS, &f); unpackskippixels = (int)f;
+   glGetFloatv(GL_PACK_ROW_LENGTH, &f); packrowlength = (int)f;
+   glGetFloatv(GL_PACK_ALIGNMENT, &f); packalignment = (int)f;
+   glGetFloatv(GL_PACK_SKIP_ROWS, &f); packskiprows = (int)f;
+   glGetFloatv(GL_PACK_SKIP_PIXELS, &f); packskippixels = (int)f;
+
+   /* 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 data type, 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:
+   case GL_BGR:
+      n = 3;
+      break;
+   case GL_RGBA:
+   case GL_BGRA:
+#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,
+		  GLsizei width, GLenum format, GLenum type, const void *data)
+{
+   return 0;
+}
+
+
+
+GLint GLAPIENTRY
+gluBuild2DMipmaps(GLenum target, GLint components,
+		  GLsizei width, GLsizei height, GLenum format,
+		  GLenum type, const void *data)
+{
+   GLint w, h;
+   GLint maxsize;
+   void *image, *newimage;
+   GLint neww, newh, level, bpp;
+   int error;
+   GLboolean done;
+   GLint retval = 0;
+   GLint unpackrowlength, unpackalignment, unpackskiprows, unpackskippixels;
+   GLint packrowlength, packalignment, packskiprows, packskippixels;
+   GLfloat f;
+
+   if (width < 1 || height < 1)
+      return GLU_INVALID_VALUE;
+
+   glGetFloatv(GL_MAX_TEXTURE_SIZE, &f); maxsize = (int)f;
+
+   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;
+   }
+
+   /* Get current glPixelStore values */
+   glGetFloatv(GL_UNPACK_ROW_LENGTH, &f); unpackrowlength = (int)f;
+   glGetFloatv(GL_UNPACK_ALIGNMENT, &f); unpackalignment = (int)f;
+   glGetFloatv(GL_UNPACK_SKIP_ROWS, &f); unpackskiprows = (int)f;
+   glGetFloatv(GL_UNPACK_SKIP_PIXELS, &f); unpackskippixels = (int)f;
+   glGetFloatv(GL_PACK_ROW_LENGTH, &f); packrowlength = (int)f;
+   glGetFloatv(GL_PACK_ALIGNMENT, &f); packalignment = (int)f;
+   glGetFloatv(GL_PACK_SKIP_ROWS, &f); packskiprows = (int)f;
+   glGetFloatv(GL_PACK_SKIP_PIXELS, &f); packskippixels = (int)f;
+
+   /* set pixel packing */
+   glPixelStorei(GL_PACK_ROW_LENGTH, 0);
+   glPixelStorei(GL_PACK_ALIGNMENT, 1);
+   glPixelStorei(GL_PACK_SKIP_ROWS, 0);
+   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
+
+   done = GL_FALSE;
+
+   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) {
+	 retval = error;
+	 done = GL_TRUE;
+      }
+   }
+   else {
+      image = (void *) data;
+   }
+
+   level = 0;
+   while (!done) {
+      if (image != data) {
+	 /* set pixel unpacking */
+	 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+	 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+	 glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
+	 glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
+      }
+
+      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) {
+	 retval = error;
+	 done = GL_TRUE;
+      }
+
+      if (image != data) {
+	 free(image);
+      }
+      image = newimage;
+
+      w = neww;
+      h = newh;
+      level++;
+   }
+
+   if (image != data) {
+      free(image);
+   }
+
+   /* Restore original glPixelStore state */
+   glPixelStorei(GL_UNPACK_ROW_LENGTH, unpackrowlength);
+   glPixelStorei(GL_UNPACK_ALIGNMENT, unpackalignment);
+   glPixelStorei(GL_UNPACK_SKIP_ROWS, unpackskiprows);
+   glPixelStorei(GL_UNPACK_SKIP_PIXELS, unpackskippixels);
+   glPixelStorei(GL_PACK_ROW_LENGTH, packrowlength);
+   glPixelStorei(GL_PACK_ALIGNMENT, packalignment);
+   glPixelStorei(GL_PACK_SKIP_ROWS, packskiprows);
+   glPixelStorei(GL_PACK_SKIP_PIXELS, packskippixels);
+
+   return retval;
+}