ANIM (File Format): Difference between revisions
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→Rotation Vector Bitstream Format
imported>Jackoalan |
imported>Jackoalan |
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In addition to the bitstream quantization, the format includes a bitmap specifying which frames of the animation have | In addition to the bitstream quantization, the format includes a bitmap specifying which frames of the animation have | ||
keys added. Consequently, the runtime generates missing keys via interpolation (reducing animation size further). | keys added. Consequently, the runtime generates missing keys via interpolation (reducing animation size further). | ||
=== Key Values === | |||
When decoding the animation, each bone's rotation (and possibly translation) values are initialized to the ''initial_*'' | |||
values in the ''bone channel descriptors''. For every frame of every bone channel, the key value in the bitstream is ''added'' | |||
with the previous key value (to resolve the delta encoding). | |||
Once resolved, rotation components are divided by ''rotation_divisor'', resulting in an axis-angle | |||
[[wikipedia:Axis–angle_representation#Rotation_vector|rotation vector]]. The magnitude of this vector | |||
is the ''angle'' part and is multiplied by 𝛑 and combined with the ''angle sign-bit'' to get the rotation in radians. | |||
Translation components are multiplied by ''translation_multiplier'', yielding world coordinates. | |||
{| class="wikitable" | {| class="wikitable" | ||
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|<remainder of file> | |<remainder of file> | ||
|key_bitstream | |key_bitstream | ||
|Word-packed bitstream laid out as described by the descriptor table. The bitstream is unpacked just like ''key_bitmap'' | |Word-packed bitstream laid out as described by the descriptor table. The bitstream is unpacked just like ''key_bitmap''. | ||
Key values are tightly-packed, quantized integers whose bit-depth is specified by the ''q_*'' values in the descriptor table. | |||
Each bone-channel key-set starts with a single bit providing the ''angle sign-bit'' (1 for negative, 0 for positive). | |||
The key integers are signed using [[wikipedia:Two's complement|Two's complement]] representation. | |||
|} | |} | ||