Ishotihadus
105 lines
3.6 KiB
C
105 lines
3.6 KiB
C
#include <stdint.h>
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#include <string.h>
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#include "dxtc.h"
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static inline uint_fast32_t color(uint_fast32_t r, uint_fast32_t g, uint_fast32_t b, uint_fast32_t a) {
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return r | g << 8 | b << 16 | a << 24;
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}
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static inline void rgb565(const uint_fast16_t c, int *r, int *g, int *b) {
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*r = (c & 0xf800) >> 8;
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*g = (c & 0x07e0) >> 3;
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*b = (c & 0x001f) << 3;
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*r |= *r >> 5;
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*g |= *g >> 6;
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*b |= *b >> 5;
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}
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static inline void decode_dxt1_block(const uint64_t *data, uint32_t *outbuf) {
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int r0, g0, b0, r1, g1, b1;
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int q0 = ((uint16_t*)data)[0];
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int q1 = ((uint16_t*)data)[1];
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rgb565(q0, &r0, &g0, &b0);
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rgb565(q1, &r1, &g1, &b1);
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uint_fast32_t c[4] = { color(r0, g0, b0, 255), color(r1, g1, b1, 255) };
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if (q0 > q1) {
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c[2] = color((r0 * 2 + r1) / 3, (g0 * 2 + g1) / 3, (b0 * 2 + b1) / 3, 255);
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c[3] = color((r0 + r1 * 2) / 3, (g0 + g1 * 2) / 3, (b0 + b1 * 2) / 3, 255);
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} else {
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c[2] = color((r0 + r1) / 2, (g0 + g1) / 2, (b0 + b1) / 2, 255);
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}
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uint_fast32_t d = *data >> 32;
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for (int i = 0; i < 16; i++, d >>= 2)
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outbuf[i] = c[d & 3];
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}
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void decode_dxt1(const uint64_t *data, const int w, const int h, uint32_t *image) {
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int bcw = (w + 3) / 4;
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int bch = (h + 3) / 4;
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int clen_last = (w + 3) % 4 + 1;
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uint32_t buf[16];
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const uint64_t *d = data;
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for (int t = 0; t < bch; t++) {
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for (int s = 0; s < bcw; s++, d++) {
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decode_dxt1_block(d, buf);
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int clen = (s < bcw - 1 ? 4 : clen_last) * 4;
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for (int i = 0, y = h - t * 4 - 1; i < 4 && y >= 0; i++, y--)
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memcpy(image + y * w + s * 4, buf + i * 4, clen);
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}
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}
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}
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static inline void decode_dxt5_block(const uint64_t *data, uint32_t *outbuf) {
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uint_fast32_t a[8] = { ((uint8_t*)data)[0], ((uint8_t*)data)[1] };
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if (a[0] > a[1]) {
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a[2] = (a[0] * 6 + a[1] ) / 7;
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a[3] = (a[0] * 5 + a[1] * 2) / 7;
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a[4] = (a[0] * 4 + a[1] * 3) / 7;
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a[5] = (a[0] * 3 + a[1] * 4) / 7;
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a[6] = (a[0] * 2 + a[1] * 5) / 7;
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a[7] = (a[0] + a[1] * 6) / 7;
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} else {
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a[2] = (a[0] * 4 + a[1] ) / 5;
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a[3] = (a[0] * 3 + a[1] * 2) / 5;
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a[4] = (a[0] * 2 + a[1] * 3) / 5;
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a[5] = (a[0] + a[1] * 4) / 5;
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a[7] = 255;
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}
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for (int i = 0; i < 8; i++)
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a[i] <<= 24;
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int r0, g0, b0, r1, g1, b1;
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int q0 = ((uint16_t*)(data + 1))[0];
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int q1 = ((uint16_t*)(data + 1))[1];
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rgb565(q0, &r0, &g0, &b0);
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rgb565(q1, &r1, &g1, &b1);
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uint_fast32_t c[4] = { color(r0, g0, b0, 0), color(r1, g1, b1, 0) };
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if (q0 > q1) {
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c[2] = color((r0 * 2 + r1) / 3, (g0 * 2 + g1) / 3, (b0 * 2 + b1) / 3, 0);
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c[3] = color((r0 + r1 * 2) / 3, (g0 + g1 * 2) / 3, (b0 + b1 * 2) / 3, 0);
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} else {
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c[2] = color((r0 + r1) / 2, (g0 + g1) / 2, (b0 + b1) / 2, 0);
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}
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uint_fast64_t da = *data >> 16;
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uint_fast32_t dc = *(data + 1) >> 32;
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for (int i = 0; i < 16; i++, da >>= 3, dc >>= 2)
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outbuf[i] = a[da & 7] | c[dc & 3];
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}
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void decode_dxt5(const uint64_t *data, const int w, const int h, uint32_t *image) {
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int bcw = (w + 3) / 4;
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int bch = (h + 3) / 4;
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int clen_last = (w + 3) % 4 + 1;
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uint32_t buf[16];
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const uint64_t *d = data;
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for (int t = 0; t < bch; t++) {
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for (int s = 0; s < bcw; s++, d += 2) {
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decode_dxt5_block(d, buf);
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int clen = (s < bcw - 1 ? 4 : clen_last) * 4;
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for (int i = 0, y = h - t * 4 - 1; i < 4 && y >= 0; i++, y--)
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memcpy(image + y * w + s * 4, buf + i * 4, clen);
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}
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}
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}
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