--- /dev/null
+/*
+ * libtxc_dxtn
+ * Version: 1.0
+ *
+ * Copyright (C) 2004 Roland Scheidegger 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.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "txc_dxtn.h"
+
+/* weights used for error function, basically weights (unsquared 2/4/1) according to rgb->luminance conversion
+ not sure if this really reflects visual perception */
+#define REDWEIGHT 4
+#define GREENWEIGHT 16
+#define BLUEWEIGHT 1
+
+#define ALPHACUT 127
+
+static void fancybasecolorsearch( GLubyte *blkaddr, GLubyte srccolors[4][4][4], GLubyte *bestcolor[2],
+ GLint numxpixels, GLint numypixels, GLint type, GLboolean haveAlpha)
+{
+ /* use same luminance-weighted distance metric to determine encoding as for finding the base colors */
+
+ /* TODO could also try to find a better encoding for the 3-color-encoding type, this really should be done
+ if it's rgba_dxt1 and we have alpha in the block, currently even values which will be mapped to black
+ due to their alpha value will influence the result */
+ GLint i, j, colors, z;
+ GLuint pixerror, pixerrorred, pixerrorgreen, pixerrorblue, pixerrorbest;
+ GLint colordist, blockerrlin[2][3];
+ GLubyte nrcolor[2];
+ GLint pixerrorcolorbest[3];
+ GLubyte enc = 0;
+ GLubyte cv[4][4];
+ GLubyte testcolor[2][3];
+
+/* fprintf(stderr, "color begin 0 r/g/b %d/%d/%d, 1 r/g/b %d/%d/%d\n",
+ bestcolor[0][0], bestcolor[0][1], bestcolor[0][2], bestcolor[1][0], bestcolor[1][1], bestcolor[1][2]);*/
+ if (((bestcolor[0][0] & 0xf8) << 8 | (bestcolor[0][1] & 0xfc) << 3 | bestcolor[0][2] >> 3) <
+ ((bestcolor[1][0] & 0xf8) << 8 | (bestcolor[1][1] & 0xfc) << 3 | bestcolor[1][2] >> 3)) {
+ testcolor[0][0] = bestcolor[0][0];
+ testcolor[0][1] = bestcolor[0][1];
+ testcolor[0][2] = bestcolor[0][2];
+ testcolor[1][0] = bestcolor[1][0];
+ testcolor[1][1] = bestcolor[1][1];
+ testcolor[1][2] = bestcolor[1][2];
+ }
+ else {
+ testcolor[1][0] = bestcolor[0][0];
+ testcolor[1][1] = bestcolor[0][1];
+ testcolor[1][2] = bestcolor[0][2];
+ testcolor[0][0] = bestcolor[1][0];
+ testcolor[0][1] = bestcolor[1][1];
+ testcolor[0][2] = bestcolor[1][2];
+ }
+
+ for (i = 0; i < 3; i ++) {
+ cv[0][i] = testcolor[0][i];
+ cv[1][i] = testcolor[1][i];
+ cv[2][i] = (testcolor[0][i] * 2 + testcolor[1][i]) / 3;
+ cv[3][i] = (testcolor[0][i] + testcolor[1][i] * 2) / 3;
+ }
+
+ blockerrlin[0][0] = 0;
+ blockerrlin[0][1] = 0;
+ blockerrlin[0][2] = 0;
+ blockerrlin[1][0] = 0;
+ blockerrlin[1][1] = 0;
+ blockerrlin[1][2] = 0;
+
+ nrcolor[0] = 0;
+ nrcolor[1] = 0;
+
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ pixerrorbest = 0xffffffff;
+ for (colors = 0; colors < 4; colors++) {
+ colordist = srccolors[j][i][0] - (cv[colors][0]);
+ pixerror = colordist * colordist * REDWEIGHT;
+ pixerrorred = colordist;
+ colordist = srccolors[j][i][1] - (cv[colors][1]);
+ pixerror += colordist * colordist * GREENWEIGHT;
+ pixerrorgreen = colordist;
+ colordist = srccolors[j][i][2] - (cv[colors][2]);
+ pixerror += colordist * colordist * BLUEWEIGHT;
+ pixerrorblue = colordist;
+ if (pixerror < pixerrorbest) {
+ enc = colors;
+ pixerrorbest = pixerror;
+ pixerrorcolorbest[0] = pixerrorred;
+ pixerrorcolorbest[1] = pixerrorgreen;
+ pixerrorcolorbest[2] = pixerrorblue;
+ }
+ }
+ if (enc == 0) {
+ for (z = 0; z < 3; z++) {
+ blockerrlin[0][z] += 3 * pixerrorcolorbest[z];
+ }
+ nrcolor[0] += 3;
+ }
+ else if (enc == 2) {
+ for (z = 0; z < 3; z++) {
+ blockerrlin[0][z] += 2 * pixerrorcolorbest[z];
+ }
+ nrcolor[0] += 2;
+ for (z = 0; z < 3; z++) {
+ blockerrlin[1][z] += 1 * pixerrorcolorbest[z];
+ }
+ nrcolor[1] += 1;
+ }
+ else if (enc == 3) {
+ for (z = 0; z < 3; z++) {
+ blockerrlin[0][z] += 1 * pixerrorcolorbest[z];
+ }
+ nrcolor[0] += 1;
+ for (z = 0; z < 3; z++) {
+ blockerrlin[1][z] += 2 * pixerrorcolorbest[z];
+ }
+ nrcolor[1] += 2;
+ }
+ else if (enc == 1) {
+ for (z = 0; z < 3; z++) {
+ blockerrlin[1][z] += 3 * pixerrorcolorbest[z];
+ }
+ nrcolor[1] += 3;
+ }
+ }
+ }
+ if (nrcolor[0] == 0) nrcolor[0] = 1;
+ if (nrcolor[1] == 0) nrcolor[1] = 1;
+ for (j = 0; j < 2; j++) {
+ for (i = 0; i < 3; i++) {
+ GLint newvalue = testcolor[j][i] + blockerrlin[j][i] / nrcolor[j];
+ if (newvalue <= 0)
+ testcolor[j][i] = 0;
+ else if (newvalue >= 255)
+ testcolor[j][i] = 255;
+ else testcolor[j][i] = newvalue;
+ }
+ }
+
+ if ((abs(testcolor[0][0] - testcolor[1][0]) < 8) &&
+ (abs(testcolor[0][1] - testcolor[1][1]) < 4) &&
+ (abs(testcolor[0][2] - testcolor[1][2]) < 8)) {
+ /* both colors are so close they might get encoded as the same 16bit values */
+ GLubyte coldiffred, coldiffgreen, coldiffblue, coldiffmax, factor, ind0, ind1;
+
+ coldiffred = abs(testcolor[0][0] - testcolor[1][0]);
+ coldiffgreen = 2 * abs(testcolor[0][1] - testcolor[1][1]);
+ coldiffblue = abs(testcolor[0][2] - testcolor[1][2]);
+ coldiffmax = coldiffred;
+ if (coldiffmax < coldiffgreen) coldiffmax = coldiffgreen;
+ if (coldiffmax < coldiffblue) coldiffmax = coldiffblue;
+ if (coldiffmax > 0) {
+ if (coldiffmax > 4) factor = 2;
+ else if (coldiffmax > 2) factor = 3;
+ else factor = 4;
+ /* Won't do much if the color value is near 255... */
+ /* argh so many ifs */
+ if (testcolor[1][1] >= testcolor[0][1]) {
+ ind1 = 1; ind0 = 0;
+ }
+ else {
+ ind1 = 0; ind0 = 1;
+ }
+ if ((testcolor[ind1][1] + factor * coldiffgreen) <= 255)
+ testcolor[ind1][1] += factor * coldiffgreen;
+ else testcolor[ind1][1] = 255;
+ if ((testcolor[ind1][0] - testcolor[ind0][1]) > 0) {
+ if ((testcolor[ind1][0] + factor * coldiffred) <= 255)
+ testcolor[ind1][0] += factor * coldiffred;
+ else testcolor[ind1][0] = 255;
+ }
+ else {
+ if ((testcolor[ind0][0] + factor * coldiffred) <= 255)
+ testcolor[ind0][0] += factor * coldiffred;
+ else testcolor[ind0][0] = 255;
+ }
+ if ((testcolor[ind1][2] - testcolor[ind0][2]) > 0) {
+ if ((testcolor[ind1][2] + factor * coldiffblue) <= 255)
+ testcolor[ind1][2] += factor * coldiffblue;
+ else testcolor[ind1][2] = 255;
+ }
+ else {
+ if ((testcolor[ind0][2] + factor * coldiffblue) <= 255)
+ testcolor[ind0][2] += factor * coldiffblue;
+ else testcolor[ind0][2] = 255;
+ }
+ }
+ }
+
+ if (((testcolor[0][0] & 0xf8) << 8 | (testcolor[0][1] & 0xfc) << 3 | testcolor[0][2] >> 3) <
+ ((testcolor[1][0] & 0xf8) << 8 | (testcolor[1][1] & 0xfc) << 3 | testcolor[1][2]) >> 3) {
+ for (i = 0; i < 3; i++) {
+ bestcolor[0][i] = testcolor[0][i];
+ bestcolor[1][i] = testcolor[1][i];
+ }
+ }
+ else {
+ for (i = 0; i < 3; i++) {
+ bestcolor[0][i] = testcolor[1][i];
+ bestcolor[1][i] = testcolor[0][i];
+ }
+ }
+
+/* fprintf(stderr, "color end 0 r/g/b %d/%d/%d, 1 r/g/b %d/%d/%d\n",
+ bestcolor[0][0], bestcolor[0][1], bestcolor[0][2], bestcolor[1][0], bestcolor[1][1], bestcolor[1][2]);*/
+}
+
+
+
+static void storedxtencodedblock( GLubyte *blkaddr, GLubyte srccolors[4][4][4], GLubyte *bestcolor[2],
+ GLint numxpixels, GLint numypixels, GLuint type, GLboolean haveAlpha)
+{
+ /* use same luminance-weighted distance metric to determine encoding as for finding the base colors */
+
+ GLint i, j, colors;
+ GLuint testerror, testerror2, pixerror, pixerrorbest;
+ GLint colordist;
+ GLushort color0, color1, tempcolor;
+ GLuint bits = 0, bits2 = 0;
+ GLubyte *colorptr;
+ GLubyte enc = 0;
+ GLubyte cv[4][4];
+
+ bestcolor[0][0] = bestcolor[0][0] & 0xf8;
+ bestcolor[0][1] = bestcolor[0][1] & 0xfc;
+ bestcolor[0][2] = bestcolor[0][2] & 0xf8;
+ bestcolor[1][0] = bestcolor[1][0] & 0xf8;
+ bestcolor[1][1] = bestcolor[1][1] & 0xfc;
+ bestcolor[1][2] = bestcolor[1][2] & 0xf8;
+
+ color0 = bestcolor[0][0] << 8 | bestcolor[0][1] << 3 | bestcolor[0][2] >> 3;
+ color1 = bestcolor[1][0] << 8 | bestcolor[1][1] << 3 | bestcolor[1][2] >> 3;
+ if (color0 < color1) {
+ tempcolor = color0; color0 = color1; color1 = tempcolor;
+ colorptr = bestcolor[0]; bestcolor[0] = bestcolor[1]; bestcolor[1] = colorptr;
+ }
+
+
+ for (i = 0; i < 3; i++) {
+ cv[0][i] = bestcolor[0][i];
+ cv[1][i] = bestcolor[1][i];
+ cv[2][i] = (bestcolor[0][i] * 2 + bestcolor[1][i]) / 3;
+ cv[3][i] = (bestcolor[0][i] + bestcolor[1][i] * 2) / 3;
+ }
+
+ testerror = 0;
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ pixerrorbest = 0xffffffff;
+ for (colors = 0; colors < 4; colors++) {
+ colordist = srccolors[j][i][0] - cv[colors][0];
+ pixerror = colordist * colordist * REDWEIGHT;
+ colordist = srccolors[j][i][1] - cv[colors][1];
+ pixerror += colordist * colordist * GREENWEIGHT;
+ colordist = srccolors[j][i][2] - cv[colors][2];
+ pixerror += colordist * colordist * BLUEWEIGHT;
+ if (pixerror < pixerrorbest) {
+ pixerrorbest = pixerror;
+ enc = colors;
+ }
+ }
+ testerror += pixerrorbest;
+ bits |= enc << (2 * (j * 4 + i));
+ }
+ }
+ /* some hw might disagree but actually decoding should always use 4-color encoding
+ for non-dxt1 formats */
+ if (type == GL_COMPRESSED_RGB_S3TC_DXT1_EXT || type == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) {
+ for (i = 0; i < 3; i++) {
+ cv[2][i] = (bestcolor[0][i] + bestcolor[1][i]) / 2;
+ /* this isn't used. Looks like the black color constant can only be used
+ with RGB_DXT1 if I read the spec correctly (note though that the radeon gpu disagrees,
+ it will decode 3 to black even with DXT3/5), and due to how the color searching works
+ it won't get used even then */
+ cv[3][i] = 0;
+ }
+ testerror2 = 0;
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ pixerrorbest = 0xffffffff;
+ if ((type == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) && (srccolors[j][i][3] <= ALPHACUT)) {
+ enc = 3;
+ pixerrorbest = 0; /* don't calculate error */
+ }
+ else {
+ /* we're calculating the same what we have done already for colors 0-1 above... */
+ for (colors = 0; colors < 3; colors++) {
+ colordist = srccolors[j][i][0] - cv[colors][0];
+ pixerror = colordist * colordist * REDWEIGHT;
+ colordist = srccolors[j][i][1] - cv[colors][1];
+ pixerror += colordist * colordist * GREENWEIGHT;
+ colordist = srccolors[j][i][2] - cv[colors][2];
+ pixerror += colordist * colordist * BLUEWEIGHT;
+ if (pixerror < pixerrorbest) {
+ pixerrorbest = pixerror;
+ /* need to exchange colors later */
+ if (colors > 1) enc = colors;
+ else enc = colors ^ 1;
+ }
+ }
+ }
+ testerror2 += pixerrorbest;
+ bits2 |= enc << (2 * (j * 4 + i));
+ }
+ }
+ } else {
+ testerror2 = 0xffffffff;
+ }
+
+ /* finally we're finished, write back colors and bits */
+ if ((testerror > testerror2) || (haveAlpha)) {
+ *blkaddr++ = color1 & 0xff;
+ *blkaddr++ = color1 >> 8;
+ *blkaddr++ = color0 & 0xff;
+ *blkaddr++ = color0 >> 8;
+ *blkaddr++ = bits2 & 0xff;
+ *blkaddr++ = ( bits2 >> 8) & 0xff;
+ *blkaddr++ = ( bits2 >> 16) & 0xff;
+ *blkaddr = bits2 >> 24;
+ }
+ else {
+ *blkaddr++ = color0 & 0xff;
+ *blkaddr++ = color0 >> 8;
+ *blkaddr++ = color1 & 0xff;
+ *blkaddr++ = color1 >> 8;
+ *blkaddr++ = bits & 0xff;
+ *blkaddr++ = ( bits >> 8) & 0xff;
+ *blkaddr++ = ( bits >> 16) & 0xff;
+ *blkaddr = bits >> 24;
+ }
+}
+
+static void encodedxtcolorblockfaster( GLubyte *blkaddr, GLubyte srccolors[4][4][4],
+ GLint numxpixels, GLint numypixels, GLuint type )
+{
+/* simplistic approach. We need two base colors, simply use the "highest" and the "lowest" color
+ present in the picture as base colors */
+
+ /* define lowest and highest color as shortest and longest vector to 0/0/0, though the
+ vectors are weighted similar to their importance in rgb-luminance conversion
+ doesn't work too well though...
+ This seems to be a rather difficult problem */
+
+ GLubyte *bestcolor[2];
+ GLubyte basecolors[2][3];
+ GLubyte i, j;
+ GLuint lowcv, highcv, testcv;
+ GLboolean haveAlpha = GL_FALSE;
+
+ lowcv = highcv = srccolors[0][0][0] * srccolors[0][0][0] * REDWEIGHT +
+ srccolors[0][0][1] * srccolors[0][0][1] * GREENWEIGHT +
+ srccolors[0][0][2] * srccolors[0][0][2] * BLUEWEIGHT;
+ bestcolor[0] = bestcolor[1] = srccolors[0][0];
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ /* don't use this as a base color if the pixel will get black/transparent anyway */
+ if ((type != GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) || (srccolors[j][i][3] > ALPHACUT)) {
+ testcv = srccolors[j][i][0] * srccolors[j][i][0] * REDWEIGHT +
+ srccolors[j][i][1] * srccolors[j][i][1] * GREENWEIGHT +
+ srccolors[j][i][2] * srccolors[j][i][2] * BLUEWEIGHT;
+ if (testcv > highcv) {
+ highcv = testcv;
+ bestcolor[1] = srccolors[j][i];
+ }
+ else if (testcv < lowcv) {
+ lowcv = testcv;
+ bestcolor[0] = srccolors[j][i];
+ }
+ }
+ else haveAlpha = GL_TRUE;
+ }
+ }
+ /* make sure the original color values won't get touched... */
+ for (j = 0; j < 2; j++) {
+ for (i = 0; i < 3; i++) {
+ basecolors[j][i] = bestcolor[j][i];
+ }
+ }
+ bestcolor[0] = basecolors[0];
+ bestcolor[1] = basecolors[1];
+
+ /* try to find better base colors */
+ fancybasecolorsearch(blkaddr, srccolors, bestcolor, numxpixels, numypixels, type, haveAlpha);
+ /* find the best encoding for these colors, and store the result */
+ storedxtencodedblock(blkaddr, srccolors, bestcolor, numxpixels, numypixels, type, haveAlpha);
+}
+
+static void writedxt5encodedalphablock( GLubyte *blkaddr, GLubyte alphabase1, GLubyte alphabase2,
+ GLubyte alphaenc[16])
+{
+ *blkaddr++ = alphabase1;
+ *blkaddr++ = alphabase2;
+ *blkaddr++ = alphaenc[0] | (alphaenc[1] << 3) | ((alphaenc[2] & 3) << 6);
+ *blkaddr++ = (alphaenc[2] >> 2) | (alphaenc[3] << 1) | (alphaenc[4] << 4) | ((alphaenc[5] & 1) << 7);
+ *blkaddr++ = (alphaenc[5] >> 1) | (alphaenc[6] << 2) | (alphaenc[7] << 5);
+ *blkaddr++ = alphaenc[8] | (alphaenc[9] << 3) | ((alphaenc[10] & 3) << 6);
+ *blkaddr++ = (alphaenc[10] >> 2) | (alphaenc[11] << 1) | (alphaenc[12] << 4) | ((alphaenc[13] & 1) << 7);
+ *blkaddr++ = (alphaenc[13] >> 1) | (alphaenc[14] << 2) | (alphaenc[15] << 5);
+}
+
+static void encodedxt5alpha(GLubyte *blkaddr, GLubyte srccolors[4][4][4],
+ GLint numxpixels, GLint numypixels)
+{
+ GLubyte alphabase[2], alphause[2];
+ GLshort alphatest[2];
+ GLuint alphablockerror1, alphablockerror2, alphablockerror3;
+ GLubyte i, j, aindex, acutValues[7];
+ GLubyte alphaenc1[16], alphaenc2[16], alphaenc3[16];
+ GLboolean alphaabsmin = GL_FALSE;
+ GLboolean alphaabsmax = GL_FALSE;
+ GLshort alphadist;
+
+ /* find lowest and highest alpha value in block, alphabase[0] lowest, alphabase[1] highest */
+ alphabase[0] = 0xff; alphabase[1] = 0x0;
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ if (srccolors[j][i][3] == 0)
+ alphaabsmin = GL_TRUE;
+ else if (srccolors[j][i][3] == 255)
+ alphaabsmax = GL_TRUE;
+ else {
+ if (srccolors[j][i][3] > alphabase[1])
+ alphabase[1] = srccolors[j][i][3];
+ if (srccolors[j][i][3] < alphabase[0])
+ alphabase[0] = srccolors[j][i][3];
+ }
+ }
+ }
+
+
+ if ((alphabase[0] > alphabase[1]) && !(alphaabsmin && alphaabsmax)) { /* one color, either max or min */
+ /* shortcut here since it is a very common case (and also avoids later problems) */
+ /* || (alphabase[0] == alphabase[1] && !alphaabsmin && !alphaabsmax) */
+ /* could also thest for alpha0 == alpha1 (and not min/max), but probably not common, so don't bother */
+
+ *blkaddr++ = srccolors[0][0][3];
+ blkaddr++;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+/* fprintf(stderr, "enc0 used\n");*/
+ return;
+ }
+
+ /* find best encoding for alpha0 > alpha1 */
+ /* it's possible this encoding is better even if both alphaabsmin and alphaabsmax are true */
+ alphablockerror1 = 0x0;
+ alphablockerror2 = 0xffffffff;
+ alphablockerror3 = 0xffffffff;
+ if (alphaabsmin) alphause[0] = 0;
+ else alphause[0] = alphabase[0];
+ if (alphaabsmax) alphause[1] = 255;
+ else alphause[1] = alphabase[1];
+ /* calculate the 7 cut values, just the middle between 2 of the computed alpha values */
+ for (aindex = 0; aindex < 7; aindex++) {
+ /* don't forget here is always rounded down */
+ acutValues[aindex] = (alphause[0] * (2*aindex + 1) + alphause[1] * (14 - (2*aindex + 1))) / 14;
+ }
+
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ /* maybe it's overkill to have the most complicated calculation just for the error
+ calculation which we only need to figure out if encoding1 or encoding2 is better... */
+ if (srccolors[j][i][3] > acutValues[0]) {
+ alphaenc1[4*j + i] = 0;
+ alphadist = srccolors[j][i][3] - alphause[1];
+ }
+ else if (srccolors[j][i][3] > acutValues[1]) {
+ alphaenc1[4*j + i] = 2;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 6 + alphause[0] * 1) / 7;
+ }
+ else if (srccolors[j][i][3] > acutValues[2]) {
+ alphaenc1[4*j + i] = 3;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 5 + alphause[0] * 2) / 7;
+ }
+ else if (srccolors[j][i][3] > acutValues[3]) {
+ alphaenc1[4*j + i] = 4;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 4 + alphause[0] * 3) / 7;
+ }
+ else if (srccolors[j][i][3] > acutValues[4]) {
+ alphaenc1[4*j + i] = 5;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 3 + alphause[0] * 4) / 7;
+ }
+ else if (srccolors[j][i][3] > acutValues[5]) {
+ alphaenc1[4*j + i] = 6;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 2 + alphause[0] * 5) / 7;
+ }
+ else if (srccolors[j][i][3] > acutValues[6]) {
+ alphaenc1[4*j + i] = 7;
+ alphadist = srccolors[j][i][3] - (alphause[1] * 1 + alphause[0] * 6) / 7;
+ }
+ else {
+ alphaenc1[4*j + i] = 1;
+ alphadist = srccolors[j][i][3] - alphause[0];
+ }
+ alphablockerror1 += alphadist * alphadist;
+ }
+ }
+/* for (i = 0; i < 16; i++) {
+ fprintf(stderr, "%d ", alphaenc1[i]);
+ }
+ fprintf(stderr, "cutVals ");
+ for (i = 0; i < 8; i++) {
+ fprintf(stderr, "%d ", acutValues[i]);
+ }
+ fprintf(stderr, "srcVals ");
+ for (j = 0; j < numypixels; j++)
+ for (i = 0; i < numxpixels; i++) {
+ fprintf(stderr, "%d ", srccolors[j][i][3]);
+ }
+
+ fprintf(stderr, "\n");
+ }*/
+ /* it's not very likely this encoding is better if both alphaabsmin and alphaabsmax
+ are false but try it anyway */
+ if (alphablockerror1 >= 32) {
+
+ /* don't bother if encoding is already very good, this condition should also imply
+ we have valid alphabase colors which we absolutely need (alphabase[0] <= alphabase[1]) */
+ alphablockerror2 = 0;
+ for (aindex = 0; aindex < 5; aindex++) {
+ /* don't forget here is always rounded down */
+ acutValues[aindex] = (alphabase[0] * (10 - (2*aindex + 1)) + alphabase[1] * (2*aindex + 1)) / 10;
+ }
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ /* maybe it's overkill to have the most complicated calculation just for the error
+ calculation which we only need to figure out if encoding1 or encoding2 is better... */
+ if (srccolors[j][i][3] == 0) {
+ alphaenc2[4*j + i] = 6;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i][3] == 255) {
+ alphaenc2[4*j + i] = 7;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i][3] <= acutValues[0]) {
+ alphaenc2[4*j + i] = 0;
+ alphadist = srccolors[j][i][3] - alphabase[0];
+ }
+ else if (srccolors[j][i][3] <= acutValues[1]) {
+ alphaenc2[4*j + i] = 2;
+ alphadist = srccolors[j][i][3] - (alphabase[0] * 4 + alphabase[1] * 1) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[2]) {
+ alphaenc2[4*j + i] = 3;
+ alphadist = srccolors[j][i][3] - (alphabase[0] * 3 + alphabase[1] * 2) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[3]) {
+ alphaenc2[4*j + i] = 4;
+ alphadist = srccolors[j][i][3] - (alphabase[0] * 2 + alphabase[1] * 3) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[4]) {
+ alphaenc2[4*j + i] = 5;
+ alphadist = srccolors[j][i][3] - (alphabase[0] * 1 + alphabase[1] * 4) / 5;
+ }
+ else {
+ alphaenc2[4*j + i] = 1;
+ alphadist = srccolors[j][i][3] - alphabase[1];
+ }
+ alphablockerror2 += alphadist * alphadist;
+ }
+ }
+
+
+ /* skip this if the error is already very small
+ this encoding is MUCH better on average than #2 though, but expensive! */
+ if ((alphablockerror2 > 96) && (alphablockerror1 > 96)) {
+ GLshort blockerrlin1 = 0;
+ GLshort blockerrlin2 = 0;
+ GLubyte nralphainrangelow = 0;
+ GLubyte nralphainrangehigh = 0;
+ alphatest[0] = 0xff;
+ alphatest[1] = 0x0;
+ /* if we have large range it's likely there are values close to 0/255, try to map them to 0/255 */
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ if ((srccolors[j][i][3] > alphatest[1]) && (srccolors[j][i][3] < (255 -(alphabase[1] - alphabase[0]) / 28)))
+ alphatest[1] = srccolors[j][i][3];
+ if ((srccolors[j][i][3] < alphatest[0]) && (srccolors[j][i][3] > (alphabase[1] - alphabase[0]) / 28))
+ alphatest[0] = srccolors[j][i][3];
+ }
+ }
+ /* shouldn't happen too often, don't really care about those degenerated cases */
+ if (alphatest[1] <= alphatest[0]) {
+ alphatest[0] = 1;
+ alphatest[1] = 254;
+/* fprintf(stderr, "only 1 or 0 colors for encoding!\n");*/
+ }
+ for (aindex = 0; aindex < 5; aindex++) {
+ /* don't forget here is always rounded down */
+ acutValues[aindex] = (alphatest[0] * (10 - (2*aindex + 1)) + alphatest[1] * (2*aindex + 1)) / 10;
+ }
+
+ /* find the "average" difference between the alpha values and the next encoded value.
+ This is then used to calculate new base values.
+ Should there be some weighting, i.e. those values closer to alphatest[x] have more weight,
+ since they will see more improvement, and also because the values in the middle are somewhat
+ likely to get no improvement at all (because the base values might move in different directions)?
+ OTOH it would mean the values in the middle are even less likely to get an improvement
+ */
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ if (srccolors[j][i][3] <= alphatest[0] / 2) {
+ }
+ else if (srccolors[j][i][3] > ((255 + alphatest[1]) / 2)) {
+ }
+ else if (srccolors[j][i][3] <= acutValues[0]) {
+ blockerrlin1 += (srccolors[j][i][3] - alphatest[0]);
+ nralphainrangelow += 1;
+ }
+ else if (srccolors[j][i][3] <= acutValues[1]) {
+ blockerrlin1 += (srccolors[j][i][3] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ blockerrlin2 += (srccolors[j][i][3] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i][3] <= acutValues[2]) {
+ blockerrlin1 += (srccolors[j][i][3] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ blockerrlin2 += (srccolors[j][i][3] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i][3] <= acutValues[3]) {
+ blockerrlin1 += (srccolors[j][i][3] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ blockerrlin2 += (srccolors[j][i][3] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i][3] <= acutValues[4]) {
+ blockerrlin1 += (srccolors[j][i][3] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ blockerrlin2 += (srccolors[j][i][3] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else {
+ blockerrlin2 += (srccolors[j][i][3] - alphatest[1]);
+ nralphainrangehigh += 1;
+ }
+ }
+ }
+ /* shouldn't happen often, needed to avoid div by zero */
+ if (nralphainrangelow == 0) nralphainrangelow = 1;
+ if (nralphainrangehigh == 0) nralphainrangehigh = 1;
+ alphatest[0] = alphatest[0] + (blockerrlin1 / nralphainrangelow);
+/* fprintf(stderr, "block err lin low %d, nr %d\n", blockerrlin1, nralphainrangelow);
+ fprintf(stderr, "block err lin high %d, nr %d\n", blockerrlin2, nralphainrangehigh);*/
+ /* again shouldn't really happen often... */
+ if (alphatest[0] < 0) {
+ alphatest[0] = 0;
+/* fprintf(stderr, "adj alpha base val to 0\n");*/
+ }
+ alphatest[1] = alphatest[1] + (blockerrlin2 / nralphainrangehigh);
+ if (alphatest[1] > 255) {
+ alphatest[1] = 255;
+/* fprintf(stderr, "adj alpha base val to 255\n");*/
+ }
+
+ alphablockerror3 = 0;
+ for (aindex = 0; aindex < 5; aindex++) {
+ /* don't forget here is always rounded down */
+ acutValues[aindex] = (alphatest[0] * (10 - (2*aindex + 1)) + alphatest[1] * (2*aindex + 1)) / 10;
+ }
+ for (j = 0; j < numypixels; j++) {
+ for (i = 0; i < numxpixels; i++) {
+ /* maybe it's overkill to have the most complicated calculation just for the error
+ calculation which we only need to figure out if encoding1 or encoding2 is better... */
+ if (srccolors[j][i][3] <= alphatest[0] / 2) {
+ alphaenc3[4*j + i] = 6;
+ alphadist = srccolors[j][i][3];
+ }
+ else if (srccolors[j][i][3] > ((255 + alphatest[1]) / 2)) {
+ alphaenc3[4*j + i] = 7;
+ alphadist = 255 - srccolors[j][i][3];
+ }
+ else if (srccolors[j][i][3] <= acutValues[0]) {
+ alphaenc3[4*j + i] = 0;
+ alphadist = srccolors[j][i][3] - alphatest[0];
+ }
+ else if (srccolors[j][i][3] <= acutValues[1]) {
+ alphaenc3[4*j + i] = 2;
+ alphadist = srccolors[j][i][3] - (alphatest[0] * 4 + alphatest[1] * 1) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[2]) {
+ alphaenc3[4*j + i] = 3;
+ alphadist = srccolors[j][i][3] - (alphatest[0] * 3 + alphatest[1] * 2) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[3]) {
+ alphaenc3[4*j + i] = 4;
+ alphadist = srccolors[j][i][3] - (alphatest[0] * 2 + alphatest[1] * 3) / 5;
+ }
+ else if (srccolors[j][i][3] <= acutValues[4]) {
+ alphaenc3[4*j + i] = 5;
+ alphadist = srccolors[j][i][3] - (alphatest[0] * 1 + alphatest[1] * 4) / 5;
+ }
+ else {
+ alphaenc3[4*j + i] = 1;
+ alphadist = srccolors[j][i][3] - alphatest[1];
+ }
+ alphablockerror3 += alphadist * alphadist;
+ }
+ }
+ }
+ }
+ /* write the alpha values and encoding back. */
+ if ((alphablockerror1 <= alphablockerror2) && (alphablockerror1 <= alphablockerror3)) {
+/* if (alphablockerror1 > 96) fprintf(stderr, "enc1 used, error %d\n", alphablockerror1);*/
+ writedxt5encodedalphablock( blkaddr, alphause[1], alphause[0], alphaenc1 );
+ }
+ else if (alphablockerror2 <= alphablockerror3) {
+/* if (alphablockerror2 > 96) fprintf(stderr, "enc2 used, error %d\n", alphablockerror2);*/
+ writedxt5encodedalphablock( blkaddr, alphabase[0], alphabase[1], alphaenc2 );
+ }
+ else {
+/* fprintf(stderr, "enc3 used, error %d\n", alphablockerror3);*/
+ writedxt5encodedalphablock( blkaddr, (GLubyte)alphatest[0], (GLubyte)alphatest[1], alphaenc3 );
+ }
+}
+
+static void extractsrccolors( GLubyte srcpixels[4][4][4], const GLchan *srcaddr,
+ GLint srcRowStride, GLint numxpixels, GLint numypixels, GLint comps)
+{
+ GLubyte i, j, c;
+ const GLchan *curaddr;
+ for (j = 0; j < numypixels; j++) {
+ curaddr = srcaddr + j * srcRowStride * comps;
+ for (i = 0; i < numxpixels; i++) {
+ for (c = 0; c < comps; c++) {
+ srcpixels[j][i][c] = *curaddr++ / (CHAN_MAX / 255);
+ }
+ }
+ }
+}
+
+
+void tx_compress_dxtn(GLint srccomps, GLint width, GLint height, const GLubyte *srcPixData,
+ GLenum destFormat, GLubyte *dest, GLint dstRowStride)
+{
+ GLubyte *blkaddr = dest;
+ GLubyte srcpixels[4][4][4];
+ const GLchan *srcaddr = srcPixData;
+ GLint numxpixels, numypixels;
+ GLint i, j;
+ GLint dstRowDiff;
+
+ switch (destFormat) {
+ case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+ case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+ /* hmm we used to get called without dstRowStride... */
+ dstRowDiff = dstRowStride >= (width * 2) ? dstRowStride - (((width + 3) & ~3) * 2) : 0;
+/* fprintf(stderr, "dxt1 tex width %d tex height %d dstRowStride %d\n",
+ width, height, dstRowStride); */
+ for (j = 0; j < height; j += 4) {
+ if (height > j + 3) numypixels = 4;
+ else numypixels = height - j;
+ srcaddr = srcPixData + j * width * srccomps;
+ for (i = 0; i < width; i += 4) {
+ if (width > i + 3) numxpixels = 4;
+ else numxpixels = width - i;
+ extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
+ encodedxtcolorblockfaster(blkaddr, srcpixels, numxpixels, numypixels, destFormat);
+ srcaddr += srccomps * numxpixels;
+ blkaddr += 8;
+ }
+ blkaddr += dstRowDiff;
+ }
+ break;
+ case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+ dstRowDiff = dstRowStride >= (width * 4) ? dstRowStride - (((width + 3) & ~3) * 4) : 0;
+/* fprintf(stderr, "dxt3 tex width %d tex height %d dstRowStride %d\n",
+ width, height, dstRowStride); */
+ for (j = 0; j < height; j += 4) {
+ if (height > j + 3) numypixels = 4;
+ else numypixels = height - j;
+ srcaddr = srcPixData + j * width * srccomps;
+ for (i = 0; i < width; i += 4) {
+ if (width > i + 3) numxpixels = 4;
+ else numxpixels = width - i;
+ extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
+ *blkaddr++ = (srcpixels[0][0][3] >> 4) | (srcpixels[0][1][3] & 0xf0);
+ *blkaddr++ = (srcpixels[0][2][3] >> 4) | (srcpixels[0][3][3] & 0xf0);
+ *blkaddr++ = (srcpixels[1][0][3] >> 4) | (srcpixels[1][1][3] & 0xf0);
+ *blkaddr++ = (srcpixels[1][2][3] >> 4) | (srcpixels[1][3][3] & 0xf0);
+ *blkaddr++ = (srcpixels[2][0][3] >> 4) | (srcpixels[2][1][3] & 0xf0);
+ *blkaddr++ = (srcpixels[2][2][3] >> 4) | (srcpixels[2][3][3] & 0xf0);
+ *blkaddr++ = (srcpixels[3][0][3] >> 4) | (srcpixels[3][1][3] & 0xf0);
+ *blkaddr++ = (srcpixels[3][2][3] >> 4) | (srcpixels[3][3][3] & 0xf0);
+ encodedxtcolorblockfaster(blkaddr, srcpixels, numxpixels, numypixels, destFormat);
+ srcaddr += srccomps * numxpixels;
+ blkaddr += 8;
+ }
+ blkaddr += dstRowDiff;
+ }
+ break;
+ case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+ dstRowDiff = dstRowStride >= (width * 4) ? dstRowStride - (((width + 3) & ~3) * 4) : 0;
+/* fprintf(stderr, "dxt5 tex width %d tex height %d dstRowStride %d\n",
+ width, height, dstRowStride); */
+ for (j = 0; j < height; j += 4) {
+ if (height > j + 3) numypixels = 4;
+ else numypixels = height - j;
+ srcaddr = srcPixData + j * width * srccomps;
+ for (i = 0; i < width; i += 4) {
+ if (width > i + 3) numxpixels = 4;
+ else numxpixels = width - i;
+ extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
+ encodedxt5alpha(blkaddr, srcpixels, numxpixels, numypixels);
+ encodedxtcolorblockfaster(blkaddr + 8, srcpixels, numxpixels, numypixels, destFormat);
+ srcaddr += srccomps * numxpixels;
+ blkaddr += 16;
+ }
+ blkaddr += dstRowDiff;
+ }
+ break;
+ default:
+ fprintf(stderr, "libdxtn: Bad dstFormat %d in tx_compress_dxtn\n", destFormat);
+ return;
+ }
+}
+
+
--- /dev/null
+/*
+ * libtxc_dxtn
+ * Version: 1.0
+ *
+ * Copyright (C) 2004 Roland Scheidegger 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.
+ */
+
+#include <stdio.h>
+#include "txc_dxtn.h"
+
+#define EXP5TO8R(packedcol) \
+ ((((packedcol) >> 8) & 0xf8) | (((packedcol) >> 13) & 0x7))
+
+#define EXP6TO8G(packedcol) \
+ ((((packedcol) >> 3) & 0xfc) | (((packedcol) >> 9) & 0x3))
+
+#define EXP5TO8B(packedcol) \
+ ((((packedcol) << 3) & 0xf8) | (((packedcol) >> 2) & 0x7))
+
+#define EXP4TO8(col) \
+ ((col) | ((col) << 4))
+
+/* inefficient. To be efficient, it would be necessary to decode 16 pixels at once */
+
+static void dxt135_decode_imageblock ( const GLubyte *img_block_src,
+ GLint i, GLint j, GLuint dxt_type, GLvoid *texel ) {
+ GLchan *rgba = (GLchan *) texel;
+ const GLushort color0 = img_block_src[0] | (img_block_src[1] << 8);
+ const GLushort color1 = img_block_src[2] | (img_block_src[3] << 8);
+ const GLuint bits = img_block_src[4] | (img_block_src[5] << 8) |
+ (img_block_src[6] << 16) | (img_block_src[7] << 24);
+ /* What about big/little endian? */
+ GLubyte bit_pos = 2 * (j * 4 + i) ;
+ GLubyte code = (GLubyte) ((bits >> bit_pos) & 3);
+
+ rgba[ACOMP] = CHAN_MAX;
+ switch (code) {
+ case 0:
+ rgba[RCOMP] = UBYTE_TO_CHAN( EXP5TO8R(color0) );
+ rgba[GCOMP] = UBYTE_TO_CHAN( EXP6TO8G(color0) );
+ rgba[BCOMP] = UBYTE_TO_CHAN( EXP5TO8B(color0) );
+ break;
+ case 1:
+ rgba[RCOMP] = UBYTE_TO_CHAN( EXP5TO8R(color1) );
+ rgba[GCOMP] = UBYTE_TO_CHAN( EXP6TO8G(color1) );
+ rgba[BCOMP] = UBYTE_TO_CHAN( EXP5TO8B(color1) );
+ break;
+ case 2:
+ if ((dxt_type > 1) || (color0 > color1)) {
+ rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) * 2 + EXP5TO8R(color1)) / 3) );
+ rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) * 2 + EXP6TO8G(color1)) / 3) );
+ rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) * 2 + EXP5TO8B(color1)) / 3) );
+ }
+ else {
+ rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) + EXP5TO8R(color1)) / 2) );
+ rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) + EXP6TO8G(color1)) / 2) );
+ rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) + EXP5TO8B(color1)) / 2) );
+ }
+ break;
+ case 3:
+ if ((dxt_type > 1) || (color0 > color1)) {
+ rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) + EXP5TO8R(color1) * 2) / 3) );
+ rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) + EXP6TO8G(color1) * 2) / 3) );
+ rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) + EXP5TO8B(color1) * 2) / 3) );
+ }
+ else {
+ rgba[RCOMP] = 0;
+ rgba[GCOMP] = 0;
+ rgba[BCOMP] = 0;
+ if (dxt_type == 1) rgba[ACOMP] = UBYTE_TO_CHAN(0);
+ }
+ break;
+ default:
+ /* CANNOT happen (I hope) */
+ break;
+ }
+}
+
+
+void fetch_2d_texel_rgb_dxt1(GLint srcRowStride, const GLubyte *pixdata,
+ GLint i, GLint j, GLvoid *texel)
+{
+ /* Extract the (i,j) pixel from pixdata and return it
+ * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
+ */
+
+ const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8);
+ dxt135_decode_imageblock(blksrc, (i&3), (j&3), 0, texel);
+}
+
+
+void fetch_2d_texel_rgba_dxt1(GLint srcRowStride, const GLubyte *pixdata,
+ GLint i, GLint j, GLvoid *texel)
+{
+ /* Extract the (i,j) pixel from pixdata and return it
+ * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
+ */
+
+ const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8);
+ dxt135_decode_imageblock(blksrc, (i&3), (j&3), 1, texel);
+}
+
+void fetch_2d_texel_rgba_dxt3(GLint srcRowStride, const GLubyte *pixdata,
+ GLint i, GLint j, GLvoid *texel) {
+
+ /* Extract the (i,j) pixel from pixdata and return it
+ * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
+ */
+
+ GLchan *rgba = (GLchan *) texel;
+ const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 16);
+#if 0
+ /* Simple 32bit version. */
+/* that's pretty brain-dead for a single pixel, isn't it? */
+ const GLubyte bit_pos = 4 * ((j&3) * 4 + (i&3));
+ const GLuint alpha_low = blksrc[0] | (blksrc[1] << 8) | (blksrc[2] << 16) | (blksrc[3] << 24);
+ const GLuint alpha_high = blksrc[4] | (blksrc[5] << 8) | (blksrc[6] << 16) | (blksrc[7] << 24);
+
+ dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
+ if (bit_pos < 32)
+ rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8((alpha_low >> bit_pos) & 15)) );
+ else
+ rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8((alpha_high >> (bit_pos - 32)) & 15)) );
+#endif
+#if 1
+/* TODO test this! */
+ const GLubyte anibble = (blksrc[((j&3) * 4 + (i&3)) / 2] >> (4 * (i&1))) & 0xf;
+ dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
+ rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8(anibble)) );
+#endif
+
+}
+
+void fetch_2d_texel_rgba_dxt5(GLint srcRowStride, const GLubyte *pixdata,
+ GLint i, GLint j, GLvoid *texel) {
+
+ /* Extract the (i,j) pixel from pixdata and return it
+ * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
+ */
+
+ GLchan *rgba = (GLchan *) texel;
+ const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 16);
+ const GLubyte alpha0 = blksrc[0];
+ const GLubyte alpha1 = blksrc[1];
+#if 0
+ const GLubyte bit_pos = 3 * ((j&3) * 4 + (i&3));
+ /* simple 32bit version */
+ const GLuint bits_low = blksrc[2] | (blksrc[3] << 8) | (blksrc[4] << 16) | (blksrc[5] << 24);
+ const GLuint bits_high = blksrc[6] | (blksrc[7] << 8);
+ GLubyte code;
+
+ if (bit_pos < 30)
+ code = (GLubyte) ((bits_low >> bit_pos) & 7);
+ else if (bit_pos == 30)
+ code = (GLubyte) ((bits_low >> 30) & 3) | ((bits_high << 2) & 4);
+ else
+ code = (GLubyte) ((bits_high >> (bit_pos - 32)) & 7);
+#endif
+#if 1
+/* TODO test this! */
+ const GLubyte bit_pos = ((j&3) * 4 + (i&3)) * 3;
+ const GLubyte acodelow = blksrc[2 + bit_pos / 8];
+ const GLubyte acodehigh = blksrc[3 + bit_pos / 8];
+ const GLubyte code = (acodelow >> (bit_pos & 0x7) |
+ (acodehigh << (8 - (bit_pos & 0x7)))) & 0x7;
+#endif
+ dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
+#if 0
+ if (alpha0 > alpha1) {
+ switch (code) {
+ case 0:
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
+ break;
+ case 1:
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
+ break;
+ case 2:
+ case 3:
+ case 4:
+ case 5:
+ case 6:
+ case 7:
+ rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7) );
+ break;
+ }
+ }
+ else {
+ switch (code) {
+ case 0:
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
+ break;
+ case 1:
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
+ break;
+ case 2:
+ case 3:
+ case 4:
+ case 5:
+ rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5) );
+ break;
+ case 6:
+ rgba[ACOMP] = 0;
+ break;
+ case 7:
+ rgba[ACOMP] = CHAN_MAX;
+ break;
+ }
+ }
+#endif
+/* not sure. Which version is faster? */
+#if 1
+/* TODO test this */
+ if (code == 0)
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
+ else if (code == 1)
+ rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
+ else if (alpha0 > alpha1)
+ rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7) );
+ else if (code < 6)
+ rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5) );
+ else if (code == 6)
+ rgba[ACOMP] = 0;
+ else
+ rgba[ACOMP] = CHAN_MAX;
+#endif
+}
projects / mesa.git / commitdiff