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-rw-r--r--src/mesa/main/texcompress_rgtc.c1122
1 files changed, 1122 insertions, 0 deletions
diff --git a/src/mesa/main/texcompress_rgtc.c b/src/mesa/main/texcompress_rgtc.c
new file mode 100644
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+++ b/src/mesa/main/texcompress_rgtc.c
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+/*
+ * Copyright (C) 2011 Red Hat Inc.
+ *
+ * block compression parts are:
+ * 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 (including the next
+ * paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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.
+ *
+ * Author:
+ * Dave Airlie
+ */
+
+/**
+ * \file texcompress_rgtc.c
+ * GL_EXT_texture_compression_rgtc support.
+ */
+
+
+#include "glheader.h"
+#include "imports.h"
+#include "colormac.h"
+#include "image.h"
+#include "macros.h"
+#include "mfeatures.h"
+#include "mipmap.h"
+#include "texcompress.h"
+#include "texcompress_rgtc.h"
+#include "texstore.h"
+
+#define RGTC_DEBUG 0
+
+static void encode_rgtc_chan_u(GLubyte *blkaddr, GLubyte srccolors[4][4],
+ GLint numxpixels, GLint numypixels);
+static void encode_rgtc_chan_s(GLbyte *blkaddr, GLbyte srccolors[4][4],
+ GLint numxpixels, GLint numypixels);
+
+static void extractsrc_u( GLubyte srcpixels[4][4], const GLchan *srcaddr,
+ GLint srcRowStride, GLint numxpixels, GLint numypixels, GLint comps)
+{
+ GLubyte i, j;
+ const GLchan *curaddr;
+ for (j = 0; j < numypixels; j++) {
+ curaddr = srcaddr + j * srcRowStride * comps;
+ for (i = 0; i < numxpixels; i++) {
+ srcpixels[j][i] = *curaddr / (CHAN_MAX / 255);
+ curaddr += comps;
+ }
+ }
+}
+
+static void extractsrc_s( GLbyte srcpixels[4][4], const GLfloat *srcaddr,
+ GLint srcRowStride, GLint numxpixels, GLint numypixels, GLint comps)
+{
+ GLubyte i, j;
+ const GLfloat *curaddr;
+ for (j = 0; j < numypixels; j++) {
+ curaddr = srcaddr + j * srcRowStride * comps;
+ for (i = 0; i < numxpixels; i++) {
+ srcpixels[j][i] = FLOAT_TO_BYTE_TEX(*curaddr);
+ curaddr += comps;
+ }
+ }
+}
+
+
+GLboolean
+_mesa_texstore_red_rgtc1(TEXSTORE_PARAMS)
+{
+ GLubyte *dst;
+ const GLint texWidth = dstRowStride * 4 / 8; /* a bit of a hack */
+ const GLchan *tempImage = NULL;
+ int i, j;
+ int numxpixels, numypixels;
+ const GLchan *srcaddr;
+ GLubyte srcpixels[4][4];
+ GLubyte *blkaddr;
+ GLint dstRowDiff;
+ ASSERT(dstFormat == MESA_FORMAT_RED_RGTC1);
+ ASSERT(dstXoffset % 4 == 0);
+ ASSERT(dstYoffset % 4 == 0);
+ ASSERT(dstZoffset % 4 == 0);
+ (void) dstZoffset;
+ (void) dstImageOffsets;
+
+
+ tempImage = _mesa_make_temp_chan_image(ctx, dims,
+ baseInternalFormat,
+ _mesa_get_format_base_format(dstFormat),
+ srcWidth, srcHeight, srcDepth,
+ srcFormat, srcType, srcAddr,
+ srcPacking);
+ if (!tempImage)
+ return GL_FALSE; /* out of memory */
+
+ dst = _mesa_compressed_image_address(dstXoffset, dstYoffset, 0,
+ dstFormat,
+ texWidth, (GLubyte *) dstAddr);
+
+ blkaddr = dst;
+ dstRowDiff = dstRowStride >= (srcWidth * 4) ? dstRowStride - (((srcWidth + 3) & ~3) * 4) : 0;
+ for (j = 0; j < srcHeight; j+=4) {
+ if (srcHeight > j + 3) numypixels = 4;
+ else numypixels = srcHeight - j;
+ srcaddr = tempImage + j * srcWidth;
+ for (i = 0; i < srcWidth; i += 4) {
+ if (srcWidth > i + 3) numxpixels = 4;
+ else numxpixels = srcWidth - i;
+ extractsrc_u(srcpixels, srcaddr, srcWidth, numxpixels, numypixels, 1);
+ encode_rgtc_chan_u(blkaddr, srcpixels, numxpixels, numypixels);
+ srcaddr += numxpixels;
+ blkaddr += 8;
+ }
+ blkaddr += dstRowDiff;
+ }
+ if (tempImage)
+ free((void *) tempImage);
+
+ return GL_TRUE;
+}
+
+GLboolean
+_mesa_texstore_signed_red_rgtc1(TEXSTORE_PARAMS)
+{
+ GLbyte *dst;
+ const GLint texWidth = dstRowStride * 4 / 8; /* a bit of a hack */
+ const GLfloat *tempImage = NULL;
+ int i, j;
+ int numxpixels, numypixels;
+ const GLfloat *srcaddr;
+ GLbyte srcpixels[4][4];
+ GLbyte *blkaddr;
+ GLint dstRowDiff;
+ ASSERT(dstFormat == MESA_FORMAT_SIGNED_RED_RGTC1);
+ ASSERT(dstXoffset % 4 == 0);
+ ASSERT(dstYoffset % 4 == 0);
+ ASSERT(dstZoffset % 4 == 0);
+ (void) dstZoffset;
+ (void) dstImageOffsets;
+
+ tempImage = _mesa_make_temp_float_image(ctx, dims,
+ baseInternalFormat,
+ _mesa_get_format_base_format(dstFormat),
+ srcWidth, srcHeight, srcDepth,
+ srcFormat, srcType, srcAddr,
+ srcPacking, 0x0);
+ if (!tempImage)
+ return GL_FALSE; /* out of memory */
+
+ dst = (GLbyte *)_mesa_compressed_image_address(dstXoffset, dstYoffset, 0,
+ dstFormat,
+ texWidth, (GLubyte *) dstAddr);
+
+ blkaddr = dst;
+ dstRowDiff = dstRowStride >= (srcWidth * 4) ? dstRowStride - (((srcWidth + 3) & ~3) * 4) : 0;
+ for (j = 0; j < srcHeight; j+=4) {
+ if (srcHeight > j + 3) numypixels = 4;
+ else numypixels = srcHeight - j;
+ srcaddr = tempImage + j * srcWidth;
+ for (i = 0; i < srcWidth; i += 4) {
+ if (srcWidth > i + 3) numxpixels = 4;
+ else numxpixels = srcWidth - i;
+ extractsrc_s(srcpixels, srcaddr, srcWidth, numxpixels, numypixels, 1);
+ encode_rgtc_chan_s(blkaddr, srcpixels, numxpixels, numypixels);
+ srcaddr += numxpixels;
+ blkaddr += 8;
+ }
+ blkaddr += dstRowDiff;
+ }
+ if (tempImage)
+ free((void *) tempImage);
+
+ return GL_TRUE;
+}
+
+GLboolean
+_mesa_texstore_rg_rgtc2(TEXSTORE_PARAMS)
+{
+ GLubyte *dst;
+ const GLint texWidth = dstRowStride * 4 / 16; /* a bit of a hack */
+ const GLchan *tempImage = NULL;
+ int i, j;
+ int numxpixels, numypixels;
+ const GLchan *srcaddr;
+ GLubyte srcpixels[4][4];
+ GLubyte *blkaddr;
+ GLint dstRowDiff;
+
+ ASSERT(dstFormat == MESA_FORMAT_RG_RGTC2);
+ ASSERT(dstXoffset % 4 == 0);
+ ASSERT(dstYoffset % 4 == 0);
+ ASSERT(dstZoffset % 4 == 0);
+ (void) dstZoffset;
+ (void) dstImageOffsets;
+
+ tempImage = _mesa_make_temp_chan_image(ctx, dims,
+ baseInternalFormat,
+ _mesa_get_format_base_format(dstFormat),
+ srcWidth, srcHeight, srcDepth,
+ srcFormat, srcType, srcAddr,
+ srcPacking);
+ if (!tempImage)
+ return GL_FALSE; /* out of memory */
+
+ dst = _mesa_compressed_image_address(dstXoffset, dstYoffset, 0,
+ dstFormat,
+ texWidth, (GLubyte *) dstAddr);
+
+ blkaddr = dst;
+ dstRowDiff = dstRowStride >= (srcWidth * 8) ? dstRowStride - (((srcWidth + 7) & ~7) * 8) : 0;
+ for (j = 0; j < srcHeight; j+=4) {
+ if (srcHeight > j + 3) numypixels = 4;
+ else numypixels = srcHeight - j;
+ srcaddr = tempImage + j * srcWidth * 2;
+ for (i = 0; i < srcWidth; i += 4) {
+ if (srcWidth > i + 3) numxpixels = 4;
+ else numxpixels = srcWidth - i;
+ extractsrc_u(srcpixels, srcaddr, srcWidth, numxpixels, numypixels, 2);
+ encode_rgtc_chan_u(blkaddr, srcpixels, numxpixels, numypixels);
+
+ blkaddr += 8;
+ extractsrc_u(srcpixels, (GLchan *)srcaddr + 1, srcWidth, numxpixels, numypixels, 2);
+ encode_rgtc_chan_u(blkaddr, srcpixels, numxpixels, numypixels);
+
+ blkaddr += 8;
+
+ srcaddr += numxpixels * 2;
+ }
+ blkaddr += dstRowDiff;
+ }
+ if (tempImage)
+ free((void *) tempImage);
+
+ return GL_TRUE;
+}
+
+GLboolean
+_mesa_texstore_signed_rg_rgtc2(TEXSTORE_PARAMS)
+{
+ GLbyte *dst;
+ const GLint texWidth = dstRowStride * 4 / 16; /* a bit of a hack */
+ const GLfloat *tempImage = NULL;
+ int i, j;
+ int numxpixels, numypixels;
+ const GLfloat *srcaddr;
+ GLbyte srcpixels[4][4];
+ GLbyte *blkaddr;
+ GLint dstRowDiff;
+
+ ASSERT(dstFormat == MESA_FORMAT_SIGNED_RG_RGTC2);
+ ASSERT(dstXoffset % 4 == 0);
+ ASSERT(dstYoffset % 4 == 0);
+ ASSERT(dstZoffset % 4 == 0);
+ (void) dstZoffset;
+ (void) dstImageOffsets;
+
+ tempImage = _mesa_make_temp_float_image(ctx, dims,
+ baseInternalFormat,
+ _mesa_get_format_base_format(dstFormat),
+ srcWidth, srcHeight, srcDepth,
+ srcFormat, srcType, srcAddr,
+ srcPacking, 0x0);
+ if (!tempImage)
+ return GL_FALSE; /* out of memory */
+
+ dst = (GLbyte *)_mesa_compressed_image_address(dstXoffset, dstYoffset, 0,
+ dstFormat,
+ texWidth, (GLubyte *) dstAddr);
+
+ blkaddr = dst;
+ dstRowDiff = dstRowStride >= (srcWidth * 8) ? dstRowStride - (((srcWidth + 7) & ~7) * 8) : 0;
+ for (j = 0; j < srcHeight; j += 4) {
+ if (srcHeight > j + 3) numypixels = 4;
+ else numypixels = srcHeight - j;
+ srcaddr = tempImage + j * srcWidth * 2;
+ for (i = 0; i < srcWidth; i += 4) {
+ if (srcWidth > i + 3) numxpixels = 4;
+ else numxpixels = srcWidth - i;
+
+ extractsrc_s(srcpixels, srcaddr, srcWidth, numxpixels, numypixels, 2);
+ encode_rgtc_chan_s(blkaddr, srcpixels, numxpixels, numypixels);
+ blkaddr += 8;
+
+ extractsrc_s(srcpixels, srcaddr + 1, srcWidth, numxpixels, numypixels, 2);
+ encode_rgtc_chan_s(blkaddr, srcpixels, numxpixels, numypixels);
+ blkaddr += 8;
+
+ srcaddr += numxpixels * 2;
+
+ }
+ blkaddr += dstRowDiff;
+ }
+ if (tempImage)
+ free((void *) tempImage);
+
+ return GL_TRUE;
+}
+
+static void _fetch_texel_rgtc_u(GLint srcRowStride, const GLubyte *pixdata,
+ GLint i, GLint j, GLchan *value, int comps)
+{
+ GLchan decode;
+ const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8 * comps);
+ const GLubyte alpha0 = blksrc[0];
+ const GLubyte alpha1 = blksrc[1];
+ 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;
+
+ if (code == 0)
+ decode = UBYTE_TO_CHAN( alpha0 );
+ else if (code == 1)
+ decode = UBYTE_TO_CHAN( alpha1 );
+ else if (alpha0 > alpha1)
+ decode = UBYTE_TO_CHAN( ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7) );
+ else if (code < 6)
+ decode = UBYTE_TO_CHAN( ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5) );
+ else if (code == 6)
+ decode = 0;
+ else
+ decode = CHAN_MAX;
+
+ *value = decode;
+}
+
+
+static void _fetch_texel_rgtc_s(GLint srcRowStride, const GLbyte *pixdata,
+ GLint i, GLint j, GLbyte *value, int comps)
+{
+ GLbyte decode;
+ const GLbyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8 * comps);
+ const GLbyte alpha0 = blksrc[0];
+ const GLbyte alpha1 = blksrc[1];
+ const GLbyte bit_pos = ((j&3) * 4 + (i&3)) * 3;
+ const GLbyte acodelow = blksrc[2 + bit_pos / 8];
+ const GLbyte acodehigh = blksrc[3 + bit_pos / 8];
+ const GLbyte code = (acodelow >> (bit_pos & 0x7) |
+ (acodehigh << (8 - (bit_pos & 0x7)))) & 0x7;
+
+ if (code == 0)
+ decode = alpha0;
+ else if (code == 1)
+ decode = alpha1;
+ else if (alpha0 > alpha1)
+ decode = ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7);
+ else if (code < 6)
+ decode = ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5);
+ else if (code == 6)
+ decode = -128;
+ else
+ decode = 127;
+
+ *value = decode;
+}
+
+void
+_mesa_fetch_texel_2d_f_red_rgtc1(const struct gl_texture_image *texImage,
+ GLint i, GLint j, GLint k, GLfloat *texel)
+{
+ GLchan red;
+ _fetch_texel_rgtc_u(texImage->RowStride, (GLubyte *)(texImage->Data),
+ i, j, &red, 1);
+ texel[RCOMP] = CHAN_TO_FLOAT(red);
+ texel[GCOMP] = 0.0;
+ texel[BCOMP] = 0.0;
+ texel[ACOMP] = 1.0;
+}
+
+void
+_mesa_fetch_texel_2d_f_signed_red_rgtc1(const struct gl_texture_image *texImage,
+ GLint i, GLint j, GLint k, GLfloat *texel)
+{
+ GLbyte red;
+ _fetch_texel_rgtc_s(texImage->RowStride, (GLbyte *)(texImage->Data),
+ i, j, &red, 1);
+ texel[RCOMP] = BYTE_TO_FLOAT_TEX(red);
+ texel[GCOMP] = 0.0;
+ texel[BCOMP] = 0.0;
+ texel[ACOMP] = 1.0;
+}
+
+void
+_mesa_fetch_texel_2d_f_rg_rgtc2(const struct gl_texture_image *texImage,
+ GLint i, GLint j, GLint k, GLfloat *texel)
+{
+ GLchan red, green;
+ _fetch_texel_rgtc_u(texImage->RowStride, (GLubyte *)(texImage->Data),
+ i, j, &red, 2);
+ _fetch_texel_rgtc_u(texImage->RowStride, (GLubyte *)(texImage->Data) + 8,
+ i, j, &green, 2);
+ texel[RCOMP] = CHAN_TO_FLOAT(red);
+ texel[GCOMP] = CHAN_TO_FLOAT(green);
+ texel[BCOMP] = 0.0;
+ texel[ACOMP] = 1.0;
+}
+
+void
+_mesa_fetch_texel_2d_f_signed_rg_rgtc2(const struct gl_texture_image *texImage,
+ GLint i, GLint j, GLint k, GLfloat *texel)
+{
+ GLbyte red, green;
+ _fetch_texel_rgtc_s(texImage->RowStride, (GLbyte *)(texImage->Data),
+ i, j, &red, 2);
+ _fetch_texel_rgtc_s(texImage->RowStride, (GLbyte *)(texImage->Data) + 8,
+ i, j, &green, 2);
+ texel[RCOMP] = BYTE_TO_FLOAT_TEX(red);
+ texel[GCOMP] = BYTE_TO_FLOAT_TEX(green);
+ texel[BCOMP] = 0.0;
+ texel[ACOMP] = 1.0;
+}
+
+static void write_rgtc_encoded_channel(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 encode_rgtc_chan_u(GLubyte *blkaddr, GLubyte srccolors[4][4],
+ GLint numxpixels, GLint numypixels)
+{
+ GLubyte alphabase[2], alphause[2];
+ GLshort alphatest[2] = { 0 };
+ 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] == 0)
+ alphaabsmin = GL_TRUE;
+ else if (srccolors[j][i] == 255)
+ alphaabsmax = GL_TRUE;
+ else {
+ if (srccolors[j][i] > alphabase[1])
+ alphabase[1] = srccolors[j][i];
+ if (srccolors[j][i] < alphabase[0])
+ alphabase[0] = srccolors[j][i];
+ }
+ }
+ }
+
+
+ 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];
+ blkaddr++;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+#if RGTC_DEBUG
+ fprintf(stderr, "enc0 used\n");
+#endif
+ 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] > acutValues[0]) {
+ alphaenc1[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphause[1];
+ }
+ else if (srccolors[j][i] > acutValues[1]) {
+ alphaenc1[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphause[1] * 6 + alphause[0] * 1) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[2]) {
+ alphaenc1[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphause[1] * 5 + alphause[0] * 2) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[3]) {
+ alphaenc1[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphause[1] * 4 + alphause[0] * 3) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[4]) {
+ alphaenc1[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphause[1] * 3 + alphause[0] * 4) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[5]) {
+ alphaenc1[4*j + i] = 6;
+ alphadist = srccolors[j][i] - (alphause[1] * 2 + alphause[0] * 5) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[6]) {
+ alphaenc1[4*j + i] = 7;
+ alphadist = srccolors[j][i] - (alphause[1] * 1 + alphause[0] * 6) / 7;
+ }
+ else {
+ alphaenc1[4*j + i] = 1;
+ alphadist = srccolors[j][i] - alphause[0];
+ }
+ alphablockerror1 += alphadist * alphadist;
+ }
+ }
+
+#if RGTC_DEBUG
+ 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]);
+ }
+ }
+ fprintf(stderr, "\n");
+#endif
+
+ /* 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] == 0) {
+ alphaenc2[4*j + i] = 6;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i] == 255) {
+ alphaenc2[4*j + i] = 7;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ alphaenc2[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphabase[0];
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ alphaenc2[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphabase[0] * 4 + alphabase[1] * 1) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ alphaenc2[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphabase[0] * 3 + alphabase[1] * 2) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ alphaenc2[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphabase[0] * 2 + alphabase[1] * 3) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ alphaenc2[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphabase[0] * 1 + alphabase[1] * 4) / 5;
+ }
+ else {
+ alphaenc2[4*j + i] = 1;
+ alphadist = srccolors[j][i] - 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] > alphatest[1]) && (srccolors[j][i] < (255 -(alphabase[1] - alphabase[0]) / 28)))
+ alphatest[1] = srccolors[j][i];
+ if ((srccolors[j][i] < alphatest[0]) && (srccolors[j][i] > (alphabase[1] - alphabase[0]) / 28))
+ alphatest[0] = srccolors[j][i];
+ }
+ }
+ /* 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] <= alphatest[0] / 2) {
+ }
+ else if (srccolors[j][i] > ((255 + alphatest[1]) / 2)) {
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ blockerrlin1 += (srccolors[j][i] - alphatest[0]);
+ nralphainrangelow += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else {
+ blockerrlin2 += (srccolors[j][i] - 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);
+#if RGTC_DEBUG
+ fprintf(stderr, "block err lin low %d, nr %d\n", blockerrlin1, nralphainrangelow);
+ fprintf(stderr, "block err lin high %d, nr %d\n", blockerrlin2, nralphainrangehigh);
+#endif
+ /* 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] <= alphatest[0] / 2) {
+ alphaenc3[4*j + i] = 6;
+ alphadist = srccolors[j][i];
+ }
+ else if (srccolors[j][i] > ((255 + alphatest[1]) / 2)) {
+ alphaenc3[4*j + i] = 7;
+ alphadist = 255 - srccolors[j][i];
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ alphaenc3[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphatest[0];
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ alphaenc3[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ alphaenc3[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ alphaenc3[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ alphaenc3[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5;
+ }
+ else {
+ alphaenc3[4*j + i] = 1;
+ alphadist = srccolors[j][i] - alphatest[1];
+ }
+ alphablockerror3 += alphadist * alphadist;
+ }
+ }
+ }
+ }
+ /* write the alpha values and encoding back. */
+ if ((alphablockerror1 <= alphablockerror2) && (alphablockerror1 <= alphablockerror3)) {
+#if RGTC_DEBUG
+ if (alphablockerror1 > 96) fprintf(stderr, "enc1 used, error %d\n", alphablockerror1);
+#endif
+ write_rgtc_encoded_channel( blkaddr, alphause[1], alphause[0], alphaenc1 );
+ }
+ else if (alphablockerror2 <= alphablockerror3) {
+#if RGTC_DEBUG
+ if (alphablockerror2 > 96) fprintf(stderr, "enc2 used, error %d\n", alphablockerror2);
+#endif
+ write_rgtc_encoded_channel( blkaddr, alphabase[0], alphabase[1], alphaenc2 );
+ }
+ else {
+#if RGTC_DEBUG
+ fprintf(stderr, "enc3 used, error %d\n", alphablockerror3);
+#endif
+ write_rgtc_encoded_channel( blkaddr, (GLubyte)alphatest[0], (GLubyte)alphatest[1], alphaenc3 );
+ }
+}
+
+
+static void write_rgtc_encoded_channel_s(GLbyte *blkaddr,
+ GLbyte alphabase1,
+ GLbyte alphabase2,
+ GLbyte 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 encode_rgtc_chan_s(GLbyte *blkaddr, GLbyte srccolors[4][4],
+ GLint numxpixels, GLint numypixels)
+{
+ GLbyte alphabase[2], alphause[2];
+ GLshort alphatest[2] = { 0 };
+ GLuint alphablockerror1, alphablockerror2, alphablockerror3;
+ GLbyte i, j, aindex, acutValues[7];
+ GLbyte 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] == 0)
+ alphaabsmin = GL_TRUE;
+ else if (srccolors[j][i] == 255)
+ alphaabsmax = GL_TRUE;
+ else {
+ if (srccolors[j][i] > alphabase[1])
+ alphabase[1] = srccolors[j][i];
+ if (srccolors[j][i] < alphabase[0])
+ alphabase[0] = srccolors[j][i];
+ }
+ }
+ }
+
+
+ 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];
+ blkaddr++;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+ *blkaddr++ = 0;
+#if RGTC_DEBUG
+ fprintf(stderr, "enc0 used\n");
+#endif
+ 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] > acutValues[0]) {
+ alphaenc1[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphause[1];
+ }
+ else if (srccolors[j][i] > acutValues[1]) {
+ alphaenc1[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphause[1] * 6 + alphause[0] * 1) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[2]) {
+ alphaenc1[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphause[1] * 5 + alphause[0] * 2) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[3]) {
+ alphaenc1[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphause[1] * 4 + alphause[0] * 3) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[4]) {
+ alphaenc1[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphause[1] * 3 + alphause[0] * 4) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[5]) {
+ alphaenc1[4*j + i] = 6;
+ alphadist = srccolors[j][i] - (alphause[1] * 2 + alphause[0] * 5) / 7;
+ }
+ else if (srccolors[j][i] > acutValues[6]) {
+ alphaenc1[4*j + i] = 7;
+ alphadist = srccolors[j][i] - (alphause[1] * 1 + alphause[0] * 6) / 7;
+ }
+ else {
+ alphaenc1[4*j + i] = 1;
+ alphadist = srccolors[j][i] - alphause[0];
+ }
+ alphablockerror1 += alphadist * alphadist;
+ }
+ }
+#if RGTC_DEBUG
+ 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]);
+ }
+
+ fprintf(stderr, "\n");
+#endif
+
+ /* 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] == 0) {
+ alphaenc2[4*j + i] = 6;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i] == 255) {
+ alphaenc2[4*j + i] = 7;
+ alphadist = 0;
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ alphaenc2[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphabase[0];
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ alphaenc2[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphabase[0] * 4 + alphabase[1] * 1) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ alphaenc2[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphabase[0] * 3 + alphabase[1] * 2) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ alphaenc2[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphabase[0] * 2 + alphabase[1] * 3) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ alphaenc2[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphabase[0] * 1 + alphabase[1] * 4) / 5;
+ }
+ else {
+ alphaenc2[4*j + i] = 1;
+ alphadist = srccolors[j][i] - 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] > alphatest[1]) && (srccolors[j][i] < (255 -(alphabase[1] - alphabase[0]) / 28)))
+ alphatest[1] = srccolors[j][i];
+ if ((srccolors[j][i] < alphatest[0]) && (srccolors[j][i] > (alphabase[1] - alphabase[0]) / 28))
+ alphatest[0] = srccolors[j][i];
+ }
+ }
+ /* 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] <= alphatest[0] / 2) {
+ }
+ else if (srccolors[j][i] > ((255 + alphatest[1]) / 2)) {
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ blockerrlin1 += (srccolors[j][i] - alphatest[0]);
+ nralphainrangelow += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ blockerrlin1 += (srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ blockerrlin2 += (srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5);
+ nralphainrangelow += 1;
+ nralphainrangehigh += 1;
+ }
+ else {
+ blockerrlin2 += (srccolors[j][i] - 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);
+#if RGTC_DEBUG
+ fprintf(stderr, "block err lin low %d, nr %d\n", blockerrlin1, nralphainrangelow);
+ fprintf(stderr, "block err lin high %d, nr %d\n", blockerrlin2, nralphainrangehigh);
+#endif
+ /* 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] <= alphatest[0] / 2) {
+ alphaenc3[4*j + i] = 6;
+ alphadist = srccolors[j][i];
+ }
+ else if (srccolors[j][i] > ((255 + alphatest[1]) / 2)) {
+ alphaenc3[4*j + i] = 7;
+ alphadist = 255 - srccolors[j][i];
+ }
+ else if (srccolors[j][i] <= acutValues[0]) {
+ alphaenc3[4*j + i] = 0;
+ alphadist = srccolors[j][i] - alphatest[0];
+ }
+ else if (srccolors[j][i] <= acutValues[1]) {
+ alphaenc3[4*j + i] = 2;
+ alphadist = srccolors[j][i] - (alphatest[0] * 4 + alphatest[1] * 1) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[2]) {
+ alphaenc3[4*j + i] = 3;
+ alphadist = srccolors[j][i] - (alphatest[0] * 3 + alphatest[1] * 2) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[3]) {
+ alphaenc3[4*j + i] = 4;
+ alphadist = srccolors[j][i] - (alphatest[0] * 2 + alphatest[1] * 3) / 5;
+ }
+ else if (srccolors[j][i] <= acutValues[4]) {
+ alphaenc3[4*j + i] = 5;
+ alphadist = srccolors[j][i] - (alphatest[0] * 1 + alphatest[1] * 4) / 5;
+ }
+ else {
+ alphaenc3[4*j + i] = 1;
+ alphadist = srccolors[j][i] - alphatest[1];
+ }
+ alphablockerror3 += alphadist * alphadist;
+ }
+ }
+ }
+ }
+ /* write the alpha values and encoding back. */
+ if ((alphablockerror1 <= alphablockerror2) && (alphablockerror1 <= alphablockerror3)) {
+#if RGTC_DEBUG
+ if (alphablockerror1 > 96) fprintf(stderr, "enc1 used, error %d\n", alphablockerror1);
+#endif
+ write_rgtc_encoded_channel_s( blkaddr, alphause[1], alphause[0], alphaenc1 );
+ }
+ else if (alphablockerror2 <= alphablockerror3) {
+#if RGTC_DEBUG
+ if (alphablockerror2 > 96) fprintf(stderr, "enc2 used, error %d\n", alphablockerror2);
+#endif
+ write_rgtc_encoded_channel_s( blkaddr, alphabase[0], alphabase[1], alphaenc2 );
+ }
+ else {
+#if RGTC_DEBUG
+ fprintf(stderr, "enc3 used, error %d\n", alphablockerror3);
+#endif
+ write_rgtc_encoded_channel_s( blkaddr, (GLubyte)alphatest[0], (GLubyte)alphatest[1], alphaenc3 );
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 13:26:22 +0000