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Increase quaternion compressed precision

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After dropping the largest value, the rest 3 are guaranteed not
larger than 1 / sqrtf(2), given normalized quaternion
This commit is contained in:
Benau 2018-07-16 12:13:31 +08:00
parent fc563cc678
commit 5c6de6d0fa
1 changed files with 17 additions and 12 deletions
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29
src/utils/mini_glm.hpp
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@ -360,6 +360,10 @@ namespace MiniGLM
}
if (calculate_w)
{
float inv_sqrt_2 = 1.0f / sqrtf(2.0f);
ret[0] *= inv_sqrt_2;
ret[1] *= inv_sqrt_2;
ret[2] *= inv_sqrt_2;
float largest_val = sqrtf(fmaxf(0.0f, 1.0f -
(ret[0] * ret[0]) - (ret[1] * ret[1]) - (ret[2] * ret[2])));
part = (packed >> 30) & 3;
@ -432,38 +436,39 @@ namespace MiniGLM
auto ret = std::max_element(tmp_2.begin(), tmp_2.end(),
[](float a, float b) { return std::abs(a) < std::abs(b); });
int extra_2_bit = int(std::distance(tmp_2.begin(), ret));
float sqrt_2 = sqrtf(2.0f);
switch (extra_2_bit)
{
case 0:
{
float neg = tmp_2[0] < 0.0f ? -1.0f : 1.0f;
tmp_3[0] = tmp_2[1] * neg;
tmp_3[1] = tmp_2[2] * neg;
tmp_3[2] = tmp_2[3] * neg;
tmp_3[0] = tmp_2[1] * neg * sqrt_2;
tmp_3[1] = tmp_2[2] * neg * sqrt_2;
tmp_3[2] = tmp_2[3] * neg * sqrt_2;
break;
}
case 1:
{
float neg = tmp_2[1] < 0.0f ? -1.0f : 1.0f;
tmp_3[0] = tmp_2[0] * neg;
tmp_3[1] = tmp_2[2] * neg;
tmp_3[2] = tmp_2[3] * neg;
tmp_3[0] = tmp_2[0] * neg * sqrt_2;
tmp_3[1] = tmp_2[2] * neg * sqrt_2;
tmp_3[2] = tmp_2[3] * neg * sqrt_2;
break;
}
case 2:
{
float neg = tmp_2[2] < 0.0f ? -1.0f : 1.0f;
tmp_3[0] = tmp_2[0] * neg;
tmp_3[1] = tmp_2[1] * neg;
tmp_3[2] = tmp_2[3] * neg;
tmp_3[0] = tmp_2[0] * neg * sqrt_2;
tmp_3[1] = tmp_2[1] * neg * sqrt_2;
tmp_3[2] = tmp_2[3] * neg * sqrt_2;
break;
}
case 3:
{
float neg = tmp_2[3] < 0.0f ? -1.0f : 1.0f;
tmp_3[0] = tmp_2[0] * neg;
tmp_3[1] = tmp_2[1] * neg;
tmp_3[2] = tmp_2[2] * neg;
tmp_3[0] = tmp_2[0] * neg * sqrt_2;
tmp_3[1] = tmp_2[1] * neg * sqrt_2;
tmp_3[2] = tmp_2[2] * neg * sqrt_2;
break;
}
default: