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dquakeplus/source/psp/video_hardware_dxtn.cpp

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2022-02-08 21:49:56 +00:00
/*
* libtxc_dxtn
* Version: 0.1b
*
* Fixed some bugs with dxt1 compression
*
* Copyright (C) 2004 Roland Scheidegger
* All Rights Reserved.
* Copyright (C) 2006-2008 Franck Charlet
* 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
* THE AUTHOR 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 <pspgu.h>
#include "video_hardware_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
// ----------------------------------------------------
// Convert the DXTx buffers for the PSP
static void Convert_DXT5(unsigned char *data, unsigned int size)
{
unsigned short *src = (unsigned short *) data;
int i;
int j;
unsigned short converted[8];
for(j = 0; size >= 16; size -= 16, j++) {
converted[4] = src[1];
converted[5] = src[2];
converted[6] = src[3];
converted[7] = src[0];
converted[0] = src[6];
converted[1] = src[7];
converted[2] = src[4];
converted[3] = src[5];
for(i = 0; i < 8; i++) src[i] = converted[i];
src += 8;
}
}
static void Convert_DXT3(unsigned char *data, unsigned int size)
{
unsigned short *src = (unsigned short *) data;
int i;
int j;
unsigned short converted[8];
for(j = 0; size >= 16; size -= 16, j++) {
converted[4] = src[0];
converted[5] = src[1];
converted[6] = src[2];
converted[7] = src[3];
converted[0] = src[6];
converted[1] = src[7];
converted[2] = src[4];
converted[3] = src[5];
for(i = 0; i < 8; i++) src[i] = converted[i];
src += 8;
}
}
static void Convert_DXT1(unsigned char *data, unsigned int size)
{
unsigned short *src = (unsigned short *) data;
int i;
int j;
unsigned short converted[4];
for(j = 0; size >= 8; size -= 8, j++) {
converted[0] = src[2];
converted[1] = src[3];
converted[2] = src[0];
converted[3] = src[1];
for(i = 0; i < 4; i++) src[i] = converted[i];
src += 4;
}
}
// ----------------------------------------------------
static void fancybasecolorsearch( unsigned char *blkaddr, unsigned char srccolors[4][4][4], unsigned char *bestcolor[2], int numxpixels, int numypixels, int type, int haveAlpha) {
/* use same luminance-weighted distance metric to determine encoding as for finding the base colors */
int i, j, colors, z;
unsigned int pixerror, pixerrorred, pixerrorgreen, pixerrorblue, pixerrorbest;
int colordist, blockerrlin[2][3];
unsigned char nrcolor[2];
int pixerrorcolorbest[3];
unsigned char enc = 0;
unsigned char cv[4][4];
unsigned char testcolor[2][3];
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++) {
int 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 */
unsigned char 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];
}
}
}
static void storedxtencodedblock( unsigned char *blkaddr, unsigned char srccolors[4][4][4], unsigned char *bestcolor[2], int numxpixels, int numypixels, int type, int haveAlpha) {
/* use same luminance-weighted distance metric to determine encoding as for finding the base colors */
int i, j, colors;
unsigned int testerror, testerror2, pixerror, pixerrorbest;
int colordist;
unsigned short color0, color1, tempcolor;
unsigned int bits = 0, bits2 = 0;
unsigned char *colorptr;
unsigned char enc = 0;
unsigned char 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));
}
}
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 == GU_PSM_DXT1) && (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));
}
}
/* 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++ = (unsigned char) (bits2 & 0xff);
*blkaddr++ = (unsigned char) (( bits2 >> 8) & 0xff);
*blkaddr++ = (unsigned char) (( bits2 >> 16) & 0xff);
*blkaddr = (unsigned char) (bits2 >> 24);
} else {
*blkaddr++ = color0 & 0xff;
*blkaddr++ = color0 >> 8;
*blkaddr++ = color1 & 0xff;
*blkaddr++ = color1 >> 8;
*blkaddr++ = (unsigned char) (bits & 0xff);
*blkaddr++ = (unsigned char) (( bits >> 8) & 0xff);
*blkaddr++ = (unsigned char) (( bits >> 16) & 0xff);
*blkaddr = (unsigned char) (bits >> 24);
}
}
static void encodedxtcolorblockfaster( unsigned char *blkaddr, unsigned char srccolors[4][4][4], int numxpixels, int numypixels, unsigned int 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 */
unsigned char *bestcolor[2];
unsigned char basecolors[2][3];
unsigned char i, j;
unsigned int lowcv, highcv, testcv;
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 */
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];
}
}
}
/* 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, TRUE);
/* find the best encoding for these colors, and store the result */
storedxtencodedblock(blkaddr, srccolors, bestcolor, numxpixels, numypixels, type, TRUE);
}
static void writedxt5encodedalphablock( unsigned char *blkaddr, unsigned char alphabase1, unsigned char alphabase2, unsigned char 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(unsigned char *blkaddr, unsigned char srccolors[4][4][4], int numxpixels, int numypixels) {
unsigned char alphabase[2], alphause[2];
short alphatest[2];
unsigned int alphablockerror1, alphablockerror2, alphablockerror3;
unsigned char i, j, aindex, acutValues[7];
unsigned char alphaenc1[16], alphaenc2[16], alphaenc3[16];
int alphaabsmin = FALSE;
int alphaabsmax = FALSE;
short alphadist;
alphatest[0] = 0;
alphatest[1] = 0;
/* 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 = TRUE;
else if(srccolors[j][i][3] == 255)
alphaabsmax = 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 += 1;
*blkaddr++ = 0;
*blkaddr++ = 0;
*blkaddr++ = 0;
*blkaddr++ = 0;
*blkaddr++ = 0;
*blkaddr++ = 0;
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;
}
}
/* 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)) {
short blockerrlin1 = 0;
short blockerrlin2 = 0;
unsigned char nralphainrangelow = 0;
unsigned char 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;
}
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);
/* again shouldn't really happen often... */
if(alphatest[0] < 0) alphatest[0] = 0;
alphatest[1] = alphatest[1] + (blockerrlin2 / nralphainrangehigh);
if(alphatest[1] > 255) alphatest[1] = 255;
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)) {
writedxt5encodedalphablock( blkaddr, alphause[1], alphause[0], alphaenc1 );
} else if(alphablockerror2 <= alphablockerror3) {
writedxt5encodedalphablock( blkaddr, alphabase[0], alphabase[1], alphaenc2 );
} else {
writedxt5encodedalphablock( blkaddr, (unsigned char) alphatest[0], (unsigned char) alphatest[1], alphaenc3 );
}
}
static void extractsrccolors( unsigned char srcpixels[4][4][4], const GLchan *srcaddr, int srcRowStride, int numxpixels, int numypixels, int comps) {
unsigned char 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);
}
}
}
}
int tx_compress_dxtn(int srccomps, int width, int height, const unsigned char *srcPixData, unsigned int destFormat, unsigned char *dest)
{
unsigned char *blkaddr = dest;
unsigned char srcpixels[4][4][4];
const GLchan *srcaddr = srcPixData;
int numxpixels, numypixels;//blubswillrule: hehe, "nummy pixels"
int i, j;
switch (destFormat)
{
case GU_PSM_DXT1:
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;
}
}
Convert_DXT1((unsigned char *) dest, blkaddr - dest);
break;
case GU_PSM_DXT3:
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;
}
}
Convert_DXT3((unsigned char *) dest, blkaddr - dest);
break;
case GU_PSM_DXT5:
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;
}
}
Convert_DXT5((unsigned char *) dest, blkaddr - dest);
break;
default:
return(0);
}
return(blkaddr - dest);
}
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