--- /dev/null
+all: s2tc
+
+CXXFLAGS = -O3 -Wall -Wextra
+
+include $(wildcard *.d)
+CXXFLAGS += -MMD
+
+s2tc: s2tc.o s2tc_compressor.o
+ $(CXX) $(LDFLAGS) -o $@ $+
+
+clean:
+ $(RM) *.o s2tc
#include <stdint.h>
#include <getopt.h>
-template <class T> inline T min(const T &a, const T &b)
-{
- if(b < a)
- return b;
- return a;
-}
-
-template <class T> inline T max(const T &a, const T &b)
-{
- if(b > a)
- return b;
- return a;
-}
+#include "s2tc_compressor.h"
+#include "s2tc_common.h"
/* START stuff that originates from image.c in DarkPlaces */
int image_width, image_height;
}
/* end of darkplaces stuff */
-
-
-
-typedef struct
-{
- signed char r, g, b;
-}
-color_t;
-inline bool operator<(const color_t &a, const color_t &b)
-{
- signed char d;
- d = a.r - b.r;
- if(d)
- return d < 0;
- d = a.g - b.g;
- if(d)
- return d < 0;
- d = a.b - b.b;
- return d < 0;
-}
-
-// 16 differences must fit in int
-// i.e. a difference must be lower than 2^27
-
-// shift right, rounded
-#define SHRR(a,n) (((a) + (1 << ((n)-1))) >> (n))
-
-inline int color_dist_avg(const color_t &a, const color_t &b)
-{
- int dr = a.r - b.r; // multiplier: 31 (-1..1)
- int dg = a.g - b.g; // multiplier: 63 (-1..1)
- int db = a.b - b.b; // multiplier: 31 (-1..1)
- return ((dr*dr) << 2) + dg*dg + ((db*db) << 2);
-}
-
-inline int color_dist_yuv(const color_t &a, const color_t &b)
-{
- int dr = a.r - b.r; // multiplier: 31 (-1..1)
- int dg = a.g - b.g; // multiplier: 63 (-1..1)
- int db = a.b - b.b; // multiplier: 31 (-1..1)
- int y = dr * 30*2 + dg * 59 + db * 11*2; // multiplier: 6259
- int u = dr * 202 - y; // * 0.5 / (1 - 0.30)
- int v = db * 202 - y; // * 0.5 / (1 - 0.11)
- return ((y*y) << 1) + SHRR(u*u, 3) + SHRR(v*v, 4);
- // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.30)) = 0.350
- // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.11)) = 0.315
-}
-
-inline int color_dist_rgb(const color_t &a, const color_t &b)
-{
- int dr = a.r - b.r; // multiplier: 31 (-1..1)
- int dg = a.g - b.g; // multiplier: 63 (-1..1)
- int db = a.b - b.b; // multiplier: 31 (-1..1)
- int y = dr * 21*2 + dg * 72 + db * 7*2; // multiplier: 6272
- int u = dr * 202 - y; // * 0.5 / (1 - 0.21)
- int v = db * 202 - y; // * 0.5 / (1 - 0.07)
- return ((y*y) << 1) + SHRR(u*u, 3) + SHRR(v*v, 4);
- // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.21)) = 0.395
- // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.07)) = 0.328
-}
-
-inline int color_dist_srgb(const color_t &a, const color_t &b)
-{
- int dr = a.r * (int) a.r - b.r * (int) b.r; // multiplier: 31*31
- int dg = a.g * (int) a.g - b.g * (int) b.g; // multiplier: 63*63
- int db = a.b * (int) a.b - b.b * (int) b.b; // multiplier: 31*31
- int y = dr * 21*2*2 + dg * 72 + db * 7*2*2; // multiplier: 393400
- int u = dr * 409 - y; // * 0.5 / (1 - 0.30)
- int v = db * 409 - y; // * 0.5 / (1 - 0.11)
- int sy = SHRR(y, 3) * SHRR(y, 4);
- int su = SHRR(u, 3) * SHRR(u, 4);
- int sv = SHRR(v, 3) * SHRR(v, 4);
- return SHRR(sy, 4) + SHRR(su, 8) + SHRR(sv, 9);
- // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.30)) = 0.350
- // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.11)) = 0.315
-}
-
-inline int srgb_get_y(const color_t &a)
-{
- // convert to linear
- int r = a.r * (int) a.r;
- int g = a.g * (int) a.g;
- int b = a.b * (int) a.b;
- // find luminance
- int y = 37 * (r * 21*2*2 + g * 72 + b * 7*2*2); // multiplier: 14555800
- // square root it (!)
- y = sqrt(y); // now in range 0 to 3815
- return y;
-}
-
-inline int color_dist_srgb_mixed(const color_t &a, const color_t &b)
-{
- // get Y
- int ay = srgb_get_y(a);
- int by = srgb_get_y(b);
- // get UV
- int au = a.r * 191 - ay;
- int av = a.b * 191 - ay;
- int bu = b.r * 191 - by;
- int bv = b.b * 191 - by;
- // get differences
- int y = ay - by;
- int u = au - bu;
- int v = av - bv;
- return ((y*y) << 3) + SHRR(u*u, 1) + SHRR(v*v, 2);
- // weight for u: ???
- // weight for v: ???
-}
-
-// FIXME this is likely broken
-inline int color_dist_lab_srgb(const color_t &a, const color_t &b)
-{
- // undo sRGB
- float ar = powf(a.r / 31.0f, 2.4f);
- float ag = powf(a.g / 63.0f, 2.4f);
- float ab = powf(a.b / 31.0f, 2.4f);
- float br = powf(b.r / 31.0f, 2.4f);
- float bg = powf(b.g / 63.0f, 2.4f);
- float bb = powf(b.b / 31.0f, 2.4f);
- // convert to CIE XYZ
- float aX = 0.4124f * ar + 0.3576f * ag + 0.1805f * ab;
- float aY = 0.2126f * ar + 0.7152f * ag + 0.0722f * ab;
- float aZ = 0.0193f * ar + 0.1192f * ag + 0.9505f * ab;
- float bX = 0.4124f * br + 0.3576f * bg + 0.1805f * bb;
- float bY = 0.2126f * br + 0.7152f * bg + 0.0722f * bb;
- float bZ = 0.0193f * br + 0.1192f * bg + 0.9505f * bb;
- // convert to CIE Lab
- float Xn = 0.3127f;
- float Yn = 0.3290f;
- float Zn = 0.3583f;
- float aL = 116 * cbrtf(aY / Yn) - 16;
- float aA = 500 * (cbrtf(aX / Xn) - cbrtf(aY / Yn));
- float aB = 200 * (cbrtf(aY / Yn) - cbrtf(aZ / Zn));
- float bL = 116 * cbrtf(bY / Yn) - 16;
- float bA = 500 * (cbrtf(bX / Xn) - cbrtf(bY / Yn));
- float bB = 200 * (cbrtf(bY / Yn) - cbrtf(bZ / Zn));
- // euclidean distance, but moving weight away from A and B
- return 1000 * ((aL - bL) * (aL - bL) + (aA - bA) * (aA - bA) + (aB - bB) * (aB - bB));
-}
-
-inline int color_dist_normalmap(const color_t &a, const color_t &b)
-{
- float ca[3], cb[3];
- ca[0] = a.r / 31.0 * 2 - 1;
- ca[1] = a.g / 63.0 * 2 - 1;
- ca[2] = a.b / 31.0 * 2 - 1;
- cb[0] = b.r / 31.0 * 2 - 1;
- cb[1] = b.g / 63.0 * 2 - 1;
- cb[2] = b.b / 31.0 * 2 - 1;
-
- return
- 500 *
- (
- (cb[0] - ca[0]) * (cb[0] - ca[0])
- +
- (cb[1] - ca[1]) * (cb[1] - ca[1])
- +
- (cb[2] - ca[2]) * (cb[2] - ca[2])
- )
- ;
- // max value: 500 * (4 + 4 + 4) = 6000
-}
-
-typedef int ColorDistFunc(const color_t &a, const color_t &b);
-
-inline int alpha_dist(unsigned char a, unsigned char b)
-{
- return (a - (int) b) * (a - (int) b);
-}
-
-template <class T, class F>
-// n: input count
-// m: total color count (including non-counted inputs)
-// m >= n
-void reduce_colors_inplace(T *c, int n, int m, F dist)
-{
- int i, j, k;
- int bestsum = -1;
- int besti = 0;
- int bestj = 1;
- int dists[m][n];
- // first the square
- for(i = 0; i < n; ++i)
- {
- dists[i][i] = 0;
- for(j = i+1; j < n; ++j)
- {
- int d = dist(c[i], c[j]);
- dists[i][j] = dists[j][i] = d;
- }
- }
- // then the box
- for(; i < m; ++i)
- {
- for(j = 0; j < n; ++j)
- {
- int d = dist(c[i], c[j]);
- dists[i][j] = d;
- }
- }
- for(i = 0; i < m; ++i)
- for(j = i+1; j < m; ++j)
- {
- int sum = 0;
- for(k = 0; k < n; ++k)
- {
- int di = dists[i][k];
- int dj = dists[j][k];
- int m = min(di, dj);
- sum += m;
- }
- if(bestsum < 0 || sum < bestsum)
- {
- bestsum = sum;
- besti = i;
- bestj = j;
- }
- }
- if(besti != 0)
- c[0] = c[besti];
- if(bestj != 1)
- c[1] = c[bestj];
-}
-template <class T, class F>
-void reduce_colors_inplace_2fixpoints(T *c, int n, int m, F dist, const T &fix0, const T &fix1)
-{
- int i, j, k;
- int bestsum = -1;
- int besti = 0;
- int bestj = 1;
- int dists[m+2][n];
- // first the square
- for(i = 0; i < n; ++i)
- {
- dists[i][i] = 0;
- for(j = i+1; j < n; ++j)
- {
- int d = dist(c[i], c[j]);
- dists[i][j] = dists[j][i] = d;
- }
- }
- // then the box
- for(; i < m; ++i)
- {
- for(j = 0; j < n; ++j)
- {
- int d = dist(c[i], c[j]);
- dists[i][j] = d;
- }
- }
- // then the two extra rows
- for(j = 0; j < n; ++j)
- {
- int d = dist(fix0, c[j]);
- dists[m][j] = d;
- }
- for(j = 0; j < n; ++j)
- {
- int d = dist(fix1, c[j]);
- dists[m+1][j] = d;
- }
- for(i = 0; i < m; ++i)
- for(j = i+1; j < m; ++j)
- {
- int sum = 0;
- for(k = 0; k < n; ++k)
- {
- int di = dists[i][k];
- int dj = dists[j][k];
- int d0 = dists[m][k];
- int d1 = dists[m+1][k];
- int m = min(min(di, dj), min(d0, d1));
- sum += m;
- }
- if(bestsum < 0 || sum < bestsum)
- {
- bestsum = sum;
- besti = i;
- bestj = j;
- }
- }
- if(besti != 0)
- c[0] = c[besti];
- if(bestj != 1)
- c[1] = c[bestj];
-}
-
-inline int diffuse(float *diff, float src)
-{
- int ret;
- src += *diff;
- ret = src;
- *diff = (src - ret);
- return ret;
-}
-
-void rgb565_image(unsigned char *out, const unsigned char *rgba, int w, int h, int alpharange)
-{
- int x, y;
- float diffuse_r = 0;
- float diffuse_g = 0;
- float diffuse_b = 0;
- float diffuse_a = 0;
- for(y = 0; y < h; ++y)
- for(x = 0; x < w; ++x)
- {
- out[(x + y * w) * 4 + 2] = diffuse(&diffuse_r, rgba[(x + y * w) * 4 + 2] * 31.0 / 255.0);
- out[(x + y * w) * 4 + 1] = diffuse(&diffuse_g, rgba[(x + y * w) * 4 + 1] * 63.0 / 255.0);
- out[(x + y * w) * 4 + 0] = diffuse(&diffuse_b, rgba[(x + y * w) * 4 + 0] * 31.0 / 255.0);
- out[(x + y * w) * 4 + 3] = diffuse(&diffuse_a, rgba[(x + y * w) * 4 + 3] * (alpharange / 255.0));
- }
-}
-
-enum DxtMode
-{
- DXT1,
- DXT3,
- DXT5
-};
-enum ColorDistMode
-{
- RGB,
- YUV,
- SRGB,
- SRGB_MIXED,
- LAB,
- AVG,
- NORMALMAP
-};
-
-template<DxtMode dxt, ColorDistFunc ColorDist, bool userandom>
-void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, int nrandom)
-{
- color_t c[16 + (userandom ? nrandom : 0)];
-
- unsigned char ca[16];
- int n = 0, m = 0;
- int x, y;
-
- for(x = 0; x < w; ++x)
- for(y = 0; y < h; ++y)
- {
- c[n].r = rgba[(x + y * iw) * 4 + 2];
- c[n].g = rgba[(x + y * iw) * 4 + 1];
- c[n].b = rgba[(x + y * iw) * 4 + 0];
- if(dxt == DXT5)
- ca[n] = rgba[(x + y * iw) * 4 + 3];
- ++n;
- }
-
- m = n;
-
- if(userandom)
- {
- color_t mins = c[0];
- color_t maxs = c[0];
- for(x = 1; x < n; ++x)
- {
- mins.r = min(mins.r, c[x].r);
- mins.g = min(mins.g, c[x].g);
- mins.b = min(mins.b, c[x].b);
- maxs.r = max(maxs.r, c[x].r);
- maxs.g = max(maxs.g, c[x].g);
- maxs.b = max(maxs.b, c[x].b);
- }
- color_t len = { maxs.r - mins.r + 1, maxs.g - mins.g + 1, maxs.b - mins.b + 1 };
- for(x = 0; x < nrandom; ++x)
- {
- c[m].r = mins.r + rand() % len.r;
- c[m].g = mins.g + rand() % len.g;
- c[m].b = mins.b + rand() % len.b;
- ++m;
- }
- }
-
- reduce_colors_inplace(c, n, m, ColorDist);
- if(dxt == DXT5)
- {
- reduce_colors_inplace_2fixpoints(ca, n, n, alpha_dist, (unsigned char) 0, (unsigned char) 255);
- if(ca[1] < ca[0])
- {
- ca[2] = ca[0];
- ca[0] = ca[1];
- ca[1] = ca[2];
- }
- }
- if(c[1] < c[0])
- {
- c[2] = c[0];
- c[0] = c[1];
- c[1] = c[2];
- }
-
- memset(out, 0, 16);
- switch(dxt)
- {
- case DXT5:
- out[0] = ca[0];
- out[1] = ca[1];
- case DXT3:
- out[8] = ((c[0].g & 0x07) << 5) | c[0].b;
- out[9] = (c[0].r << 3) | (c[0].g >> 3);
- out[10] = ((c[1].g & 0x07) << 5) | c[1].b;
- out[11] = (c[1].r << 3) | (c[1].g >> 3);
- break;
- case DXT1:
- out[0] = ((c[0].g & 0x07) << 5) | c[0].b;
- out[1] = (c[0].r << 3) | (c[0].g >> 3);
- out[2] = ((c[1].g & 0x07) << 5) | c[1].b;
- out[3] = (c[1].r << 3) | (c[1].g >> 3);
- break;
- }
- for(x = 0; x < w; ++x)
- for(y = 0; y < h; ++y)
- {
- int pindex = (x+y*4);
- c[2].r = rgba[(x + y * iw) * 4 + 2];
- c[2].g = rgba[(x + y * iw) * 4 + 1];
- c[2].b = rgba[(x + y * iw) * 4 + 0];
- ca[2] = rgba[(x + y * iw) * 4 + 3];
- switch(dxt)
- {
- case DXT5:
- {
- int da[4];
- int bitindex = pindex * 3;
- da[0] = alpha_dist(ca[0], ca[2]);
- da[1] = alpha_dist(ca[1], ca[2]);
- da[2] = alpha_dist(0, ca[2]);
- da[3] = alpha_dist(255, ca[2]);
- if(da[2] <= da[0] && da[2] <= da[1] && da[2] <= da[3])
- {
- // 6
- ++bitindex;
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- ++bitindex;
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- }
- else if(da[3] <= da[0] && da[3] <= da[1])
- {
- // 7
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- ++bitindex;
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- ++bitindex;
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- }
- else if(da[0] <= da[1])
- {
- // 0
- }
- else
- {
- // 1
- out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
- }
- }
- if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
- {
- int bitindex = pindex * 2;
- out[bitindex / 8 + 12] |= (1 << (bitindex % 8));
- }
- break;
- case DXT3:
- {
- int bitindex = pindex * 4;
- out[bitindex / 8 + 0] |= (ca[2] << (bitindex % 8));
- }
- if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
- {
- int bitindex = pindex * 2;
- out[bitindex / 8 + 12] |= (1 << (bitindex % 8));
- }
- break;
- case DXT1:
- {
- int bitindex = pindex * 2;
- if(!ca[2])
- out[bitindex / 8 + 4] |= (3 << (bitindex % 8));
- else if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
- out[bitindex / 8 + 4] |= (1 << (bitindex % 8));
- }
- break;
- }
- }
-}
-
-// compile time dispatch magic
-template<DxtMode dxt, ColorDistFunc ColorDist>
-void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, int nrandom)
-{
- if(nrandom)
- s2tc_encode_block<dxt, ColorDist, true>(out, rgba, iw, w, h, nrandom);
- else
- s2tc_encode_block<dxt, ColorDist, false>(out, rgba, iw, w, h, nrandom);
-}
-
-template<ColorDistFunc ColorDist>
-void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, DxtMode dxt, int nrandom)
-{
- switch(dxt)
- {
- case DXT1:
- s2tc_encode_block<DXT1, ColorDist>(out, rgba, iw, w, h, nrandom);
- break;
- case DXT3:
- s2tc_encode_block<DXT3, ColorDist>(out, rgba, iw, w, h, nrandom);
- break;
- default:
- case DXT5:
- s2tc_encode_block<DXT5, ColorDist>(out, rgba, iw, w, h, nrandom);
- break;
- }
-}
-
-void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, DxtMode dxt, ColorDistMode cd, int nrandom)
-{
- switch(cd)
- {
- case RGB:
- s2tc_encode_block<color_dist_rgb>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case YUV:
- s2tc_encode_block<color_dist_yuv>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case SRGB:
- s2tc_encode_block<color_dist_srgb>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case SRGB_MIXED:
- s2tc_encode_block<color_dist_srgb_mixed>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case LAB:
- s2tc_encode_block<color_dist_lab_srgb>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case AVG:
- s2tc_encode_block<color_dist_avg>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- case NORMALMAP:
- s2tc_encode_block<color_dist_normalmap>(out, rgba, iw, w, h, dxt, nrandom);
- break;
- }
-}
-
uint32_t LittleLong(uint32_t w)
{
union
--- /dev/null
+#ifndef S2TC_COMMON_H
+#define S2TC_COMMON_H
+
+template <class T> inline T min(const T &a, const T &b)
+{
+ if(b < a)
+ return b;
+ return a;
+}
+
+template <class T> inline T max(const T &a, const T &b)
+{
+ if(b > a)
+ return b;
+ return a;
+}
+
+#endif
--- /dev/null
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "s2tc_compressor.h"
+#include "s2tc_common.h"
+
+typedef struct
+{
+ signed char r, g, b;
+}
+color_t;
+
+inline bool operator<(const color_t &a, const color_t &b)
+{
+ signed char d;
+ d = a.r - b.r;
+ if(d)
+ return d < 0;
+ d = a.g - b.g;
+ if(d)
+ return d < 0;
+ d = a.b - b.b;
+ return d < 0;
+}
+// 16 differences must fit in int
+// i.e. a difference must be lower than 2^27
+
+// shift right, rounded
+#define SHRR(a,n) (((a) + (1 << ((n)-1))) >> (n))
+
+inline int color_dist_avg(const color_t &a, const color_t &b)
+{
+ int dr = a.r - b.r; // multiplier: 31 (-1..1)
+ int dg = a.g - b.g; // multiplier: 63 (-1..1)
+ int db = a.b - b.b; // multiplier: 31 (-1..1)
+ return ((dr*dr) << 2) + dg*dg + ((db*db) << 2);
+}
+
+inline int color_dist_yuv(const color_t &a, const color_t &b)
+{
+ int dr = a.r - b.r; // multiplier: 31 (-1..1)
+ int dg = a.g - b.g; // multiplier: 63 (-1..1)
+ int db = a.b - b.b; // multiplier: 31 (-1..1)
+ int y = dr * 30*2 + dg * 59 + db * 11*2; // multiplier: 6259
+ int u = dr * 202 - y; // * 0.5 / (1 - 0.30)
+ int v = db * 202 - y; // * 0.5 / (1 - 0.11)
+ return ((y*y) << 1) + SHRR(u*u, 3) + SHRR(v*v, 4);
+ // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.30)) = 0.350
+ // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.11)) = 0.315
+}
+
+inline int color_dist_rgb(const color_t &a, const color_t &b)
+{
+ int dr = a.r - b.r; // multiplier: 31 (-1..1)
+ int dg = a.g - b.g; // multiplier: 63 (-1..1)
+ int db = a.b - b.b; // multiplier: 31 (-1..1)
+ int y = dr * 21*2 + dg * 72 + db * 7*2; // multiplier: 6272
+ int u = dr * 202 - y; // * 0.5 / (1 - 0.21)
+ int v = db * 202 - y; // * 0.5 / (1 - 0.07)
+ return ((y*y) << 1) + SHRR(u*u, 3) + SHRR(v*v, 4);
+ // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.21)) = 0.395
+ // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.07)) = 0.328
+}
+
+inline int color_dist_srgb(const color_t &a, const color_t &b)
+{
+ int dr = a.r * (int) a.r - b.r * (int) b.r; // multiplier: 31*31
+ int dg = a.g * (int) a.g - b.g * (int) b.g; // multiplier: 63*63
+ int db = a.b * (int) a.b - b.b * (int) b.b; // multiplier: 31*31
+ int y = dr * 21*2*2 + dg * 72 + db * 7*2*2; // multiplier: 393400
+ int u = dr * 409 - y; // * 0.5 / (1 - 0.30)
+ int v = db * 409 - y; // * 0.5 / (1 - 0.11)
+ int sy = SHRR(y, 3) * SHRR(y, 4);
+ int su = SHRR(u, 3) * SHRR(u, 4);
+ int sv = SHRR(v, 3) * SHRR(v, 4);
+ return SHRR(sy, 4) + SHRR(su, 8) + SHRR(sv, 9);
+ // weight for u: sqrt(2^-4) / (0.5 / (1 - 0.30)) = 0.350
+ // weight for v: sqrt(2^-5) / (0.5 / (1 - 0.11)) = 0.315
+}
+
+inline int srgb_get_y(const color_t &a)
+{
+ // convert to linear
+ int r = a.r * (int) a.r;
+ int g = a.g * (int) a.g;
+ int b = a.b * (int) a.b;
+ // find luminance
+ int y = 37 * (r * 21*2*2 + g * 72 + b * 7*2*2); // multiplier: 14555800
+ // square root it (!)
+ y = sqrt(y); // now in range 0 to 3815
+ return y;
+}
+
+inline int color_dist_srgb_mixed(const color_t &a, const color_t &b)
+{
+ // get Y
+ int ay = srgb_get_y(a);
+ int by = srgb_get_y(b);
+ // get UV
+ int au = a.r * 191 - ay;
+ int av = a.b * 191 - ay;
+ int bu = b.r * 191 - by;
+ int bv = b.b * 191 - by;
+ // get differences
+ int y = ay - by;
+ int u = au - bu;
+ int v = av - bv;
+ return ((y*y) << 3) + SHRR(u*u, 1) + SHRR(v*v, 2);
+ // weight for u: ???
+ // weight for v: ???
+}
+
+// FIXME this is likely broken
+inline int color_dist_lab_srgb(const color_t &a, const color_t &b)
+{
+ // undo sRGB
+ float ar = powf(a.r / 31.0f, 2.4f);
+ float ag = powf(a.g / 63.0f, 2.4f);
+ float ab = powf(a.b / 31.0f, 2.4f);
+ float br = powf(b.r / 31.0f, 2.4f);
+ float bg = powf(b.g / 63.0f, 2.4f);
+ float bb = powf(b.b / 31.0f, 2.4f);
+ // convert to CIE XYZ
+ float aX = 0.4124f * ar + 0.3576f * ag + 0.1805f * ab;
+ float aY = 0.2126f * ar + 0.7152f * ag + 0.0722f * ab;
+ float aZ = 0.0193f * ar + 0.1192f * ag + 0.9505f * ab;
+ float bX = 0.4124f * br + 0.3576f * bg + 0.1805f * bb;
+ float bY = 0.2126f * br + 0.7152f * bg + 0.0722f * bb;
+ float bZ = 0.0193f * br + 0.1192f * bg + 0.9505f * bb;
+ // convert to CIE Lab
+ float Xn = 0.3127f;
+ float Yn = 0.3290f;
+ float Zn = 0.3583f;
+ float aL = 116 * cbrtf(aY / Yn) - 16;
+ float aA = 500 * (cbrtf(aX / Xn) - cbrtf(aY / Yn));
+ float aB = 200 * (cbrtf(aY / Yn) - cbrtf(aZ / Zn));
+ float bL = 116 * cbrtf(bY / Yn) - 16;
+ float bA = 500 * (cbrtf(bX / Xn) - cbrtf(bY / Yn));
+ float bB = 200 * (cbrtf(bY / Yn) - cbrtf(bZ / Zn));
+ // euclidean distance, but moving weight away from A and B
+ return 1000 * ((aL - bL) * (aL - bL) + (aA - bA) * (aA - bA) + (aB - bB) * (aB - bB));
+}
+
+inline int color_dist_normalmap(const color_t &a, const color_t &b)
+{
+ float ca[3], cb[3];
+ ca[0] = a.r / 31.0 * 2 - 1;
+ ca[1] = a.g / 63.0 * 2 - 1;
+ ca[2] = a.b / 31.0 * 2 - 1;
+ cb[0] = b.r / 31.0 * 2 - 1;
+ cb[1] = b.g / 63.0 * 2 - 1;
+ cb[2] = b.b / 31.0 * 2 - 1;
+
+ return
+ 500 *
+ (
+ (cb[0] - ca[0]) * (cb[0] - ca[0])
+ +
+ (cb[1] - ca[1]) * (cb[1] - ca[1])
+ +
+ (cb[2] - ca[2]) * (cb[2] - ca[2])
+ )
+ ;
+ // max value: 500 * (4 + 4 + 4) = 6000
+}
+
+typedef int ColorDistFunc(const color_t &a, const color_t &b);
+
+inline int alpha_dist(unsigned char a, unsigned char b)
+{
+ return (a - (int) b) * (a - (int) b);
+}
+
+template <class T, class F>
+// n: input count
+// m: total color count (including non-counted inputs)
+// m >= n
+void reduce_colors_inplace(T *c, int n, int m, F dist)
+{
+ int i, j, k;
+ int bestsum = -1;
+ int besti = 0;
+ int bestj = 1;
+ int dists[m][n];
+ // first the square
+ for(i = 0; i < n; ++i)
+ {
+ dists[i][i] = 0;
+ for(j = i+1; j < n; ++j)
+ {
+ int d = dist(c[i], c[j]);
+ dists[i][j] = dists[j][i] = d;
+ }
+ }
+ // then the box
+ for(; i < m; ++i)
+ {
+ for(j = 0; j < n; ++j)
+ {
+ int d = dist(c[i], c[j]);
+ dists[i][j] = d;
+ }
+ }
+ for(i = 0; i < m; ++i)
+ for(j = i+1; j < m; ++j)
+ {
+ int sum = 0;
+ for(k = 0; k < n; ++k)
+ {
+ int di = dists[i][k];
+ int dj = dists[j][k];
+ int m = min(di, dj);
+ sum += m;
+ }
+ if(bestsum < 0 || sum < bestsum)
+ {
+ bestsum = sum;
+ besti = i;
+ bestj = j;
+ }
+ }
+ if(besti != 0)
+ c[0] = c[besti];
+ if(bestj != 1)
+ c[1] = c[bestj];
+}
+template <class T, class F>
+void reduce_colors_inplace_2fixpoints(T *c, int n, int m, F dist, const T &fix0, const T &fix1)
+{
+ int i, j, k;
+ int bestsum = -1;
+ int besti = 0;
+ int bestj = 1;
+ int dists[m+2][n];
+ // first the square
+ for(i = 0; i < n; ++i)
+ {
+ dists[i][i] = 0;
+ for(j = i+1; j < n; ++j)
+ {
+ int d = dist(c[i], c[j]);
+ dists[i][j] = dists[j][i] = d;
+ }
+ }
+ // then the box
+ for(; i < m; ++i)
+ {
+ for(j = 0; j < n; ++j)
+ {
+ int d = dist(c[i], c[j]);
+ dists[i][j] = d;
+ }
+ }
+ // then the two extra rows
+ for(j = 0; j < n; ++j)
+ {
+ int d = dist(fix0, c[j]);
+ dists[m][j] = d;
+ }
+ for(j = 0; j < n; ++j)
+ {
+ int d = dist(fix1, c[j]);
+ dists[m+1][j] = d;
+ }
+ for(i = 0; i < m; ++i)
+ for(j = i+1; j < m; ++j)
+ {
+ int sum = 0;
+ for(k = 0; k < n; ++k)
+ {
+ int di = dists[i][k];
+ int dj = dists[j][k];
+ int d0 = dists[m][k];
+ int d1 = dists[m+1][k];
+ int m = min(min(di, dj), min(d0, d1));
+ sum += m;
+ }
+ if(bestsum < 0 || sum < bestsum)
+ {
+ bestsum = sum;
+ besti = i;
+ bestj = j;
+ }
+ }
+ if(besti != 0)
+ c[0] = c[besti];
+ if(bestj != 1)
+ c[1] = c[bestj];
+}
+
+inline int diffuse(float *diff, float src)
+{
+ int ret;
+ src += *diff;
+ ret = src;
+ *diff = (src - ret);
+ return ret;
+}
+
+void rgb565_image(unsigned char *out, const unsigned char *rgba, int w, int h, int alpharange)
+{
+ int x, y;
+ float diffuse_r = 0;
+ float diffuse_g = 0;
+ float diffuse_b = 0;
+ float diffuse_a = 0;
+ for(y = 0; y < h; ++y)
+ for(x = 0; x < w; ++x)
+ {
+ out[(x + y * w) * 4 + 2] = diffuse(&diffuse_r, rgba[(x + y * w) * 4 + 2] * 31.0 / 255.0);
+ out[(x + y * w) * 4 + 1] = diffuse(&diffuse_g, rgba[(x + y * w) * 4 + 1] * 63.0 / 255.0);
+ out[(x + y * w) * 4 + 0] = diffuse(&diffuse_b, rgba[(x + y * w) * 4 + 0] * 31.0 / 255.0);
+ out[(x + y * w) * 4 + 3] = diffuse(&diffuse_a, rgba[(x + y * w) * 4 + 3] * (alpharange / 255.0));
+ }
+}
+
+template<DxtMode dxt, ColorDistFunc ColorDist, bool userandom>
+void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, int nrandom)
+{
+ color_t c[16 + (userandom ? nrandom : 0)];
+
+ unsigned char ca[16];
+ int n = 0, m = 0;
+ int x, y;
+
+ for(x = 0; x < w; ++x)
+ for(y = 0; y < h; ++y)
+ {
+ c[n].r = rgba[(x + y * iw) * 4 + 2];
+ c[n].g = rgba[(x + y * iw) * 4 + 1];
+ c[n].b = rgba[(x + y * iw) * 4 + 0];
+ if(dxt == DXT5)
+ ca[n] = rgba[(x + y * iw) * 4 + 3];
+ ++n;
+ }
+
+ m = n;
+
+ if(userandom)
+ {
+ color_t mins = c[0];
+ color_t maxs = c[0];
+ for(x = 1; x < n; ++x)
+ {
+ mins.r = min(mins.r, c[x].r);
+ mins.g = min(mins.g, c[x].g);
+ mins.b = min(mins.b, c[x].b);
+ maxs.r = max(maxs.r, c[x].r);
+ maxs.g = max(maxs.g, c[x].g);
+ maxs.b = max(maxs.b, c[x].b);
+ }
+ color_t len = { maxs.r - mins.r + 1, maxs.g - mins.g + 1, maxs.b - mins.b + 1 };
+ for(x = 0; x < nrandom; ++x)
+ {
+ c[m].r = mins.r + rand() % len.r;
+ c[m].g = mins.g + rand() % len.g;
+ c[m].b = mins.b + rand() % len.b;
+ ++m;
+ }
+ }
+
+ reduce_colors_inplace(c, n, m, ColorDist);
+ if(dxt == DXT5)
+ {
+ reduce_colors_inplace_2fixpoints(ca, n, n, alpha_dist, (unsigned char) 0, (unsigned char) 255);
+ if(ca[1] < ca[0])
+ {
+ ca[2] = ca[0];
+ ca[0] = ca[1];
+ ca[1] = ca[2];
+ }
+ }
+ if(c[1] < c[0])
+ {
+ c[2] = c[0];
+ c[0] = c[1];
+ c[1] = c[2];
+ }
+
+ memset(out, 0, 16);
+ switch(dxt)
+ {
+ case DXT5:
+ out[0] = ca[0];
+ out[1] = ca[1];
+ case DXT3:
+ out[8] = ((c[0].g & 0x07) << 5) | c[0].b;
+ out[9] = (c[0].r << 3) | (c[0].g >> 3);
+ out[10] = ((c[1].g & 0x07) << 5) | c[1].b;
+ out[11] = (c[1].r << 3) | (c[1].g >> 3);
+ break;
+ case DXT1:
+ out[0] = ((c[0].g & 0x07) << 5) | c[0].b;
+ out[1] = (c[0].r << 3) | (c[0].g >> 3);
+ out[2] = ((c[1].g & 0x07) << 5) | c[1].b;
+ out[3] = (c[1].r << 3) | (c[1].g >> 3);
+ break;
+ }
+ for(x = 0; x < w; ++x)
+ for(y = 0; y < h; ++y)
+ {
+ int pindex = (x+y*4);
+ c[2].r = rgba[(x + y * iw) * 4 + 2];
+ c[2].g = rgba[(x + y * iw) * 4 + 1];
+ c[2].b = rgba[(x + y * iw) * 4 + 0];
+ ca[2] = rgba[(x + y * iw) * 4 + 3];
+ switch(dxt)
+ {
+ case DXT5:
+ {
+ int da[4];
+ int bitindex = pindex * 3;
+ da[0] = alpha_dist(ca[0], ca[2]);
+ da[1] = alpha_dist(ca[1], ca[2]);
+ da[2] = alpha_dist(0, ca[2]);
+ da[3] = alpha_dist(255, ca[2]);
+ if(da[2] <= da[0] && da[2] <= da[1] && da[2] <= da[3])
+ {
+ // 6
+ ++bitindex;
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ ++bitindex;
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ }
+ else if(da[3] <= da[0] && da[3] <= da[1])
+ {
+ // 7
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ ++bitindex;
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ ++bitindex;
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ }
+ else if(da[0] <= da[1])
+ {
+ // 0
+ }
+ else
+ {
+ // 1
+ out[bitindex / 8 + 2] |= (1 << (bitindex % 8));
+ }
+ }
+ if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
+ {
+ int bitindex = pindex * 2;
+ out[bitindex / 8 + 12] |= (1 << (bitindex % 8));
+ }
+ break;
+ case DXT3:
+ {
+ int bitindex = pindex * 4;
+ out[bitindex / 8 + 0] |= (ca[2] << (bitindex % 8));
+ }
+ if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
+ {
+ int bitindex = pindex * 2;
+ out[bitindex / 8 + 12] |= (1 << (bitindex % 8));
+ }
+ break;
+ case DXT1:
+ {
+ int bitindex = pindex * 2;
+ if(!ca[2])
+ out[bitindex / 8 + 4] |= (3 << (bitindex % 8));
+ else if(ColorDist(c[0], c[2]) > ColorDist(c[1], c[2]))
+ out[bitindex / 8 + 4] |= (1 << (bitindex % 8));
+ }
+ break;
+ }
+ }
+}
+
+// compile time dispatch magic
+template<DxtMode dxt, ColorDistFunc ColorDist>
+void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, int nrandom)
+{
+ if(nrandom)
+ s2tc_encode_block<dxt, ColorDist, true>(out, rgba, iw, w, h, nrandom);
+ else
+ s2tc_encode_block<dxt, ColorDist, false>(out, rgba, iw, w, h, nrandom);
+}
+
+template<ColorDistFunc ColorDist>
+void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, DxtMode dxt, int nrandom)
+{
+ switch(dxt)
+ {
+ case DXT1:
+ s2tc_encode_block<DXT1, ColorDist>(out, rgba, iw, w, h, nrandom);
+ break;
+ case DXT3:
+ s2tc_encode_block<DXT3, ColorDist>(out, rgba, iw, w, h, nrandom);
+ break;
+ default:
+ case DXT5:
+ s2tc_encode_block<DXT5, ColorDist>(out, rgba, iw, w, h, nrandom);
+ break;
+ }
+}
+
+void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, DxtMode dxt, ColorDistMode cd, int nrandom)
+{
+ switch(cd)
+ {
+ case RGB:
+ s2tc_encode_block<color_dist_rgb>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case YUV:
+ s2tc_encode_block<color_dist_yuv>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case SRGB:
+ s2tc_encode_block<color_dist_srgb>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case SRGB_MIXED:
+ s2tc_encode_block<color_dist_srgb_mixed>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case LAB:
+ s2tc_encode_block<color_dist_lab_srgb>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case AVG:
+ s2tc_encode_block<color_dist_avg>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ case NORMALMAP:
+ s2tc_encode_block<color_dist_normalmap>(out, rgba, iw, w, h, dxt, nrandom);
+ break;
+ }
+}
--- /dev/null
+#ifndef S2TC_COMPRESSOR_H
+#define S2TC_COMPRESSOR_H
+
+void rgb565_image(unsigned char *out, const unsigned char *rgba, int w, int h, int alpharange);
+
+enum DxtMode
+{
+ DXT1,
+ DXT3,
+ DXT5
+};
+enum ColorDistMode
+{
+ RGB,
+ YUV,
+ SRGB,
+ SRGB_MIXED,
+ LAB,
+ AVG,
+ NORMALMAP
+};
+
+void s2tc_encode_block(unsigned char *out, const unsigned char *rgba, int iw, int w, int h, DxtMode dxt, ColorDistMode cd, int nrandom);
+
+#endif
set -ex
CXX="g++ -Wall -Wextra -O3"
-$CXX s2tc.cpp -o s2tc
+make clean all
mkdir -p html
exec 3>html/index.html
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