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avcodec/s3tc: fix decoding when dimensions are not a multiple of 4 

Image dimensions were rounded down causing rows to wrap early if dimensions were not a multiple of 4.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Tom Butterworth 2015-05-07 16:17:10 +01:00 committed by Michael Niedermayer
parent 584cc1ade1
commit 873d7e0e63
1 changed files with 13 additions and 10 deletions
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23
libavcodec/s3tc.c
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@ -26,6 +26,7 @@
#include "s3tc.h"
static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d,
unsigned int w, unsigned int h,
unsigned int qstride, unsigned int flag,
uint64_t alpha) {
unsigned int x, y, c0, c1, a = (!flag * 255u) << 24;
@ -62,14 +63,16 @@ static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d,
colors[2] = rb2 + g2 + a;
pixels = bytestream2_get_le32(gb);
for (y=0; y<4; y++) {
for (x=0; x<4; x++) {
for (y=0; y<h; y++) {
for (x=0; x<w; x++) {
a = (alpha & 0x0f) << 28;
a += a >> 4;
d[x] = a + colors[pixels&3];
pixels >>= 2;
alpha >>= 4;
}
for (; x<4; x++)
pixels >>= 2;
d += qstride;
}
}
@ -77,21 +80,21 @@ static inline void dxt1_decode_pixels(GetByteContext *gb, uint32_t *d,
void ff_decode_dxt1(GetByteContext *gb, uint8_t *dst,
const unsigned int w, const unsigned int h,
const unsigned int stride) {
unsigned int bx, by, qstride = stride/4;
unsigned int x, y, qstride = stride/4;
uint32_t *d = (uint32_t *) dst;
for (by=0; by < h/4; by++, d += stride-w)
for (bx = 0; bx < w / 4; bx++, d += 4)
dxt1_decode_pixels(gb, d, qstride, 0, 0LL);
for (y=0; y < h; y += 4, d += stride-w)
for (x = 0; x < w; d += FFMIN(4, w-x), x += 4)
dxt1_decode_pixels(gb, d, FFMIN(4, w-x), FFMIN(4, h-y), qstride, 0, 0LL);
}
void ff_decode_dxt3(GetByteContext *gb, uint8_t *dst,
const unsigned int w, const unsigned int h,
const unsigned int stride) {
unsigned int bx, by, qstride = stride/4;
unsigned int x, y, qstride = stride/4;
uint32_t *d = (uint32_t *) dst;
for (by=0; by < h/4; by++, d += stride-w)
for (bx = 0; bx < w / 4; bx++, d += 4)
dxt1_decode_pixels(gb, d, qstride, 1, bytestream2_get_le64(gb));
for (y=0; y < h; y += 4, d += stride-w)
for (x = 0; x < w; d += FFMIN(4, w-x), x += 4)
dxt1_decode_pixels(gb, d, FFMIN(4, w-x), FFMIN(4, h-y), qstride, 1, bytestream2_get_le64(gb));
}