Fix Blend Space 2D to use corrected additive blending

#561
This commit is contained in:
Wojtek Figat
2021-07-01 12:39:26 +02:00
parent 36367c04af
commit 9e3d7cbbc9

View File

@@ -7,6 +7,18 @@
#include "Engine/Animations/AlphaBlend.h"
#include "Engine/Animations/InverseKinematics.h"
namespace
{
void BlendAdditiveWeightedRotation(Quaternion& base, Quaternion& additive, float weight)
{
// Pick a shortest path between rotation to fix blending artifacts
additive *= weight;
if (Quaternion::Dot(base, additive) < 0)
additive *= -1;
base += additive;
}
}
int32 AnimGraphExecutor::GetRootNodeIndex(Animation* anim)
{
// TODO: cache the root node index (use dictionary with Animation* -> int32 for fast lookups)
@@ -288,31 +300,46 @@ Variant AnimGraphExecutor::SampleAnimationsWithBlend(AnimGraphNode* node, bool l
const auto mappingC = animC->GetMapping(_graph.BaseModel);
Transform tmp, t;
const auto emptyNodes = GetEmptyNodes();
ASSERT(Math::Abs(alphaA + alphaB + alphaC - 1.0f) <= ANIM_GRAPH_BLEND_THRESHOLD); // Assumes weights are normalized
for (int32 i = 0; i < nodes->Nodes.Count(); i++)
{
const int32 nodeToChannelA = mappingA->At(i);
const int32 nodeToChannelB = mappingB->At(i);
const int32 nodeToChannelC = mappingC->At(i);
tmp = t = emptyNodes->Nodes[i];
// Calculate the animated node transformations
t = emptyNodes->Nodes[i];
if (nodeToChannelA != -1)
{
// Override
tmp = t;
animA->Data.Channels[nodeToChannelA].Evaluate(animPosA, &tmp, false);
Transform::Lerp(t, tmp, alphaA, t);
t.Translation = tmp.Translation * alphaA;
t.Orientation = tmp.Orientation * alphaA;
t.Scale = tmp.Scale * alphaA;
}
nodes->Nodes[i] = t;
}
for (int32 i = 0; i < nodes->Nodes.Count(); i++)
{
const int32 nodeToChannelB = mappingB->At(i);
const int32 nodeToChannelC = mappingC->At(i);
t = nodes->Nodes[i];
if (nodeToChannelB != -1)
{
// Additive
tmp = emptyNodes->Nodes[i];
animB->Data.Channels[nodeToChannelB].Evaluate(animPosB, &tmp, false);
Transform::Lerp(t, tmp, alphaB, t);
t.Translation += tmp.Translation * alphaB;
t.Scale += tmp.Scale * alphaB;
BlendAdditiveWeightedRotation(t.Orientation, tmp.Orientation, alphaB);
}
if (nodeToChannelC != -1)
{
// Additive
tmp = emptyNodes->Nodes[i];
animC->Data.Channels[nodeToChannelC].Evaluate(animPosC, &tmp, false);
Transform::Lerp(t, tmp, alphaC, t);
t.Translation += tmp.Translation * alphaC;
t.Scale += tmp.Scale * alphaC;
BlendAdditiveWeightedRotation(t.Orientation, tmp.Orientation, alphaC);
}
// Write blended transformation
t.Orientation.Normalize();
nodes->Nodes[i] = t;
}