mipmap.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 *
 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/**
 * \file mipmap.c  mipmap generation and teximage resizing functions.
 */

#include "imports.h"
#include "mipmap.h"
#include "texcompress.h"
#include "texformat.h"
#include "teximage.h"
#include "image.h"



/**
 * Average together two rows of a source image to produce a single new
 * row in the dest image.  It's legal for the two source rows to point
 * to the same data.  The source width must be equal to either the
 * dest width or two times the dest width.
 */
static void
do_row(const struct gl_texture_format *format, GLint srcWidth,
       const GLvoid *srcRowA, const GLvoid *srcRowB,
       GLint dstWidth, GLvoid *dstRow)
{
   const GLuint k0 = (srcWidth == dstWidth) ? 0 : 1;
   const GLuint colStride = (srcWidth == dstWidth) ? 1 : 2;

   /* This assertion is no longer valid with non-power-of-2 textures
   assert(srcWidth == dstWidth || srcWidth == 2 * dstWidth);
   */

   switch (format->MesaFormat) {
   case MESA_FORMAT_RGBA:
      {
         GLuint i, j, k;
         const GLchan (*rowA)[4] = (const GLchan (*)[4]) srcRowA;
         const GLchan (*rowB)[4] = (const GLchan (*)[4]) srcRowB;
         GLchan (*dst)[4] = (GLchan (*)[4]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) / 4;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) / 4;
            dst[i][2] = (rowA[j][2] + rowA[k][2] +
                         rowB[j][2] + rowB[k][2]) / 4;
            dst[i][3] = (rowA[j][3] + rowA[k][3] +
                         rowB[j][3] + rowB[k][3]) / 4;
         }
      }
      return;
   case MESA_FORMAT_RGB:
      {
         GLuint i, j, k;
         const GLchan (*rowA)[3] = (const GLchan (*)[3]) srcRowA;
         const GLchan (*rowB)[3] = (const GLchan (*)[3]) srcRowB;
         GLchan (*dst)[3] = (GLchan (*)[3]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) / 4;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) / 4;
            dst[i][2] = (rowA[j][2] + rowA[k][2] +
                         rowB[j][2] + rowB[k][2]) / 4;
         }
      }
      return;
   case MESA_FORMAT_ALPHA:
   case MESA_FORMAT_LUMINANCE:
   case MESA_FORMAT_INTENSITY:
      {
         GLuint i, j, k;
         const GLchan *rowA = (const GLchan *) srcRowA;
         const GLchan *rowB = (const GLchan *) srcRowB;
         GLchan *dst = (GLchan *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) / 4;
         }
      }
      return;
   case MESA_FORMAT_LUMINANCE_ALPHA:
      {
         GLuint i, j, k;
         const GLchan (*rowA)[2] = (const GLchan (*)[2]) srcRowA;
         const GLchan (*rowB)[2] = (const GLchan (*)[2]) srcRowB;
         GLchan (*dst)[2] = (GLchan (*)[2]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) / 4;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) / 4;
         }
      }
      return;
   case MESA_FORMAT_Z32:
      {
         GLuint i, j, k;
         const GLuint *rowA = (const GLuint *) srcRowA;
         const GLuint *rowB = (const GLuint *) srcRowB;
         GLfloat *dst = (GLfloat *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i] = rowA[j] / 4 + rowA[k] / 4 + rowB[j] / 4 + rowB[k] / 4;
         }
      }
      return;
   case MESA_FORMAT_Z16:
      {
         GLuint i, j, k;
         const GLushort *rowA = (const GLushort *) srcRowA;
         const GLushort *rowB = (const GLushort *) srcRowB;
         GLushort *dst = (GLushort *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) / 4;
         }
      }
      return;
   /* Begin hardware formats */
   case MESA_FORMAT_RGBA8888:
   case MESA_FORMAT_RGBA8888_REV:
   case MESA_FORMAT_ARGB8888:
   case MESA_FORMAT_ARGB8888_REV:
#if FEATURE_EXT_texture_sRGB
   case MESA_FORMAT_SRGBA8:
#endif
      {
         GLuint i, j, k;
         const GLubyte (*rowA)[4] = (const GLubyte (*)[4]) srcRowA;
         const GLubyte (*rowB)[4] = (const GLubyte (*)[4]) srcRowB;
         GLubyte (*dst)[4] = (GLubyte (*)[4]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) / 4;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) / 4;
            dst[i][2] = (rowA[j][2] + rowA[k][2] +
                         rowB[j][2] + rowB[k][2]) / 4;
            dst[i][3] = (rowA[j][3] + rowA[k][3] +
                         rowB[j][3] + rowB[k][3]) / 4;
         }
      }
      return;
   case MESA_FORMAT_RGB888:
   case MESA_FORMAT_BGR888:
#if FEATURE_EXT_texture_sRGB
   case MESA_FORMAT_SRGB8:
#endif
      {
         GLuint i, j, k;
         const GLubyte (*rowA)[3] = (const GLubyte (*)[3]) srcRowA;
         const GLubyte (*rowB)[3] = (const GLubyte (*)[3]) srcRowB;
         GLubyte (*dst)[3] = (GLubyte (*)[3]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) / 4;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) / 4;
            dst[i][2] = (rowA[j][2] + rowA[k][2] +
                         rowB[j][2] + rowB[k][2]) / 4;
         }
      }
      return;
   case MESA_FORMAT_RGB565:
   case MESA_FORMAT_RGB565_REV:
      {
         GLuint i, j, k;
         const GLushort *rowA = (const GLushort *) srcRowA;
         const GLushort *rowB = (const GLushort *) srcRowB;
         GLushort *dst = (GLushort *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            const GLint rowAr0 = rowA[j] & 0x1f;
            const GLint rowAr1 = rowA[k] & 0x1f;
            const GLint rowBr0 = rowB[j] & 0x1f;
            const GLint rowBr1 = rowB[k] & 0x1f;
            const GLint rowAg0 = (rowA[j] >> 5) & 0x3f;
            const GLint rowAg1 = (rowA[k] >> 5) & 0x3f;
            const GLint rowBg0 = (rowB[j] >> 5) & 0x3f;
            const GLint rowBg1 = (rowB[k] >> 5) & 0x3f;
            const GLint rowAb0 = (rowA[j] >> 11) & 0x1f;
            const GLint rowAb1 = (rowA[k] >> 11) & 0x1f;
            const GLint rowBb0 = (rowB[j] >> 11) & 0x1f;
            const GLint rowBb1 = (rowB[k] >> 11) & 0x1f;
            const GLint red   = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
            const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
            const GLint blue  = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
            dst[i] = (blue << 11) | (green << 5) | red;
         }
      }
      return;
   case MESA_FORMAT_ARGB4444:
   case MESA_FORMAT_ARGB4444_REV:
      {
         GLuint i, j, k;
         const GLushort *rowA = (const GLushort *) srcRowA;
         const GLushort *rowB = (const GLushort *) srcRowB;
         GLushort *dst = (GLushort *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            const GLint rowAr0 = rowA[j] & 0xf;
            const GLint rowAr1 = rowA[k] & 0xf;
            const GLint rowBr0 = rowB[j] & 0xf;
            const GLint rowBr1 = rowB[k] & 0xf;
            const GLint rowAg0 = (rowA[j] >> 4) & 0xf;
            const GLint rowAg1 = (rowA[k] >> 4) & 0xf;
            const GLint rowBg0 = (rowB[j] >> 4) & 0xf;
            const GLint rowBg1 = (rowB[k] >> 4) & 0xf;
            const GLint rowAb0 = (rowA[j] >> 8) & 0xf;
            const GLint rowAb1 = (rowA[k] >> 8) & 0xf;
            const GLint rowBb0 = (rowB[j] >> 8) & 0xf;
            const GLint rowBb1 = (rowB[k] >> 8) & 0xf;
            const GLint rowAa0 = (rowA[j] >> 12) & 0xf;
            const GLint rowAa1 = (rowA[k] >> 12) & 0xf;
            const GLint rowBa0 = (rowB[j] >> 12) & 0xf;
            const GLint rowBa1 = (rowB[k] >> 12) & 0xf;
            const GLint red   = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
            const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
            const GLint blue  = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
            const GLint alpha = (rowAa0 + rowAa1 + rowBa0 + rowBa1) >> 2;
            dst[i] = (alpha << 12) | (blue << 8) | (green << 4) | red;
         }
      }
      return;
   case MESA_FORMAT_ARGB1555:
   case MESA_FORMAT_ARGB1555_REV: /* XXX broken? */
      {
         GLuint i, j, k;
         const GLushort *rowA = (const GLushort *) srcRowA;
         const GLushort *rowB = (const GLushort *) srcRowB;
         GLushort *dst = (GLushort *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            const GLint rowAr0 = rowA[j] & 0x1f;
            const GLint rowAr1 = rowA[k] & 0x1f;
            const GLint rowBr0 = rowB[j] & 0x1f;
            const GLint rowBr1 = rowB[k] & 0xf;
            const GLint rowAg0 = (rowA[j] >> 5) & 0x1f;
            const GLint rowAg1 = (rowA[k] >> 5) & 0x1f;
            const GLint rowBg0 = (rowB[j] >> 5) & 0x1f;
            const GLint rowBg1 = (rowB[k] >> 5) & 0x1f;
            const GLint rowAb0 = (rowA[j] >> 10) & 0x1f;
            const GLint rowAb1 = (rowA[k] >> 10) & 0x1f;
            const GLint rowBb0 = (rowB[j] >> 10) & 0x1f;
            const GLint rowBb1 = (rowB[k] >> 10) & 0x1f;
            const GLint rowAa0 = (rowA[j] >> 15) & 0x1;
            const GLint rowAa1 = (rowA[k] >> 15) & 0x1;
            const GLint rowBa0 = (rowB[j] >> 15) & 0x1;
            const GLint rowBa1 = (rowB[k] >> 15) & 0x1;
            const GLint red   = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
            const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
            const GLint blue  = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
            const GLint alpha = (rowAa0 + rowAa1 + rowBa0 + rowBa1) >> 2;
            dst[i] = (alpha << 15) | (blue << 10) | (green << 5) | red;
         }
      }
      return;
   case MESA_FORMAT_AL88:
   case MESA_FORMAT_AL88_REV:
#if FEATURE_EXT_texture_sRGB
   case MESA_FORMAT_SLA8:
#endif
      {
         GLuint i, j, k;
         const GLubyte (*rowA)[2] = (const GLubyte (*)[2]) srcRowA;
         const GLubyte (*rowB)[2] = (const GLubyte (*)[2]) srcRowB;
         GLubyte (*dst)[2] = (GLubyte (*)[2]) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            dst[i][0] = (rowA[j][0] + rowA[k][0] +
                         rowB[j][0] + rowB[k][0]) >> 2;
            dst[i][1] = (rowA[j][1] + rowA[k][1] +
                         rowB[j][1] + rowB[k][1]) >> 2;
         }
      }
      return;
   case MESA_FORMAT_RGB332:
      {
         GLuint i, j, k;
         const GLubyte *rowA = (const GLubyte *) srcRowA;
         const GLubyte *rowB = (const GLubyte *) srcRowB;
         GLubyte *dst = (GLubyte *) dstRow;
         for (i = j = 0, k = k0; i < (GLuint) dstWidth;
              i++, j += colStride, k += colStride) {
            const GLint rowAr0 = rowA[j] & 0x3;
            const GLint rowAr1 = rowA[k] & 0x3;
            const GLint rowBr0 = rowB[j] & 0x3;
            const GLint rowBr1 = rowB[k] & 0x3;
            const GLint rowAg0 = (rowA[j] >> 2) & 0x7;
            const GLint rowAg1 = (rowA[k] >> 2) & 0x7;
            const GLint rowBg0 = (rowB[j] >> 2) & 0x7;
            const GLint rowBg1 = (rowB[k] >> 2) & 0x7;
            const GLint rowAb0 = (rowA[j] >> 5) & 0x7;
            const GLint rowAb1 = (rowA[k] >> 5) & 0x7;
            const GLint rowBb0 = (rowB[j] >> 5) & 0x7;