diff options
| author | Carl Hetherington <cth@carlh.net> | 2012-10-08 15:41:39 +0100 |
|---|---|---|
| committer | Carl Hetherington <cth@carlh.net> | 2012-10-08 15:41:39 +0100 |
| commit | e9c88f5652a79b25adafc65fce6282a1d824ed16 (patch) | |
| tree | 60d6b3a214bb42d88b02b21c5d09ef7d98f92bd5 /src/lib/ffmpeg_decoder.cc | |
| parent | 5f02ea34590cd6b796a6eaa55211abf5b36fd329 (diff) | |
Do alpha blending maybe right.
Diffstat (limited to 'src/lib/ffmpeg_decoder.cc')
| -rw-r--r-- | src/lib/ffmpeg_decoder.cc | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc index 5167ce488..8feb36623 100644 --- a/src/lib/ffmpeg_decoder.cc +++ b/src/lib/ffmpeg_decoder.cc @@ -275,26 +275,24 @@ FFmpegDecoder::do_pass () for (int sub_x = 0; sub_x < rect->w; ++sub_x) { uint32_t const val = palette[*sub_line_p++]; - int const red = (val & 0xff); - int const green = (val & 0xff00) >> 8; - int const blue = (val & 0xff0000) >> 16; - int const alpha = (val & 0xff000000) >> 24; + + int const red = (val & 0xff); + int const green = (val & 0xff00) >> 8; + int const blue = (val & 0xff0000) >> 16; + float const alpha = ((val & 0xff000000) >> 24) / 255.0; - if (alpha) { - *frame_line_y_p = RGB_TO_Y_CCIR (red, green, blue); - } - frame_line_y_p++; + int const cy = *frame_line_y_p; + + *frame_line_y_p++ = int (cy * (1 - alpha)) + int (RGB_TO_Y_CCIR (red, green, blue) * alpha); current_u |= ((RGB_TO_U_CCIR (red, green, blue, 0) & 0xf0) >> 4) << (4 * subsample_step); current_v |= ((RGB_TO_V_CCIR (red, green, blue, 0) & 0xf0) >> 4) << (4 * subsample_step); if (subsample_step == 1 && (sub_y % 2) == 0) { - if (alpha) { - *frame_line_u_p = current_u; - *frame_line_v_p = current_v; - } - frame_line_u_p++; - frame_line_v_p++; + int const cu = *frame_line_u_p; + int const cv = *frame_line_v_p; + *frame_line_u_p++ = int (cu * (1 - alpha)) + int (current_u * alpha); + *frame_line_v_p++ = int (cv * (1 - alpha)) + int (current_v * alpha); current_u = current_v = 0; } |