From 63041d5b7091adfb01e2507630c685af26f9e166 Mon Sep 17 00:00:00 2001
From: Luke Street <luke@street.dev>
Date: Sat, 12 Mar 2022 13:55:12 -0500
Subject: [PATCH] CAnimSource: Fixes for frame interpolation

---
 Runtime/Character/CAnimSource.cpp | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/Runtime/Character/CAnimSource.cpp b/Runtime/Character/CAnimSource.cpp
index 689bf6380..b3bef0e07 100644
--- a/Runtime/Character/CAnimSource.cpp
+++ b/Runtime/Character/CAnimSource.cpp
@@ -45,7 +45,7 @@ std::unique_ptr<float[]> RotationAndOffsetStorage::GetRotationsAndOffsets(const
                                                                           const std::vector<zeus::CVector3f>& offs,
                                                                           u32 frameCount) {
   u32 size = DataSizeInBytes(rots.size() / frameCount, offs.size() / frameCount, frameCount);
-  std::unique_ptr<float[]> ret(new float[(size / 4 + 1) * 4]);
+  auto ret = std::make_unique<float[]>((size / 4 + 1) * 4);
   CopyRotationsAndOffsets(rots, offs, frameCount, ret.get());
   return ret;
 }
@@ -118,6 +118,7 @@ CAnimSource::CAnimSource(CInputStream& in, IObjectStore& store)
 
 void CAnimSource::GetSegStatementSet(const CSegIdList& list, CSegStatementSet& set, const CCharAnimTime& time) const {
   const auto frameIdx = u32(time / x8_interval);
+  const auto nextFrameIdx = (frameIdx + 1) % x10_frameCount;
   float remTime = time.GetSeconds() - frameIdx * x8_interval.GetSeconds();
   if (std::fabs(remTime) < 0.00001f) {
     remTime = 0.f;
@@ -131,7 +132,7 @@ void CAnimSource::GetSegStatementSet(const CSegIdList& list, CSegStatementSet& s
     const u8 rotIdx = x20_rotationChannels[id];
     if (rotIdx != 0xff) {
       const float* frameDataA = &x40_data.x0_storage[frameIdx * floatsPerFrame + rotIdx * 4];
-      const float* frameDataB = &x40_data.x0_storage[(frameIdx + 1) * floatsPerFrame + rotIdx * 4];
+      const float* frameDataB = &x40_data.x0_storage[nextFrameIdx * floatsPerFrame + rotIdx * 4];
 
       const zeus::CQuaternion quatA(frameDataA[0], frameDataA[1], frameDataA[2], frameDataA[3]);
       const zeus::CQuaternion quatB(frameDataB[0], frameDataB[1], frameDataB[2], frameDataB[3]);
@@ -141,7 +142,7 @@ void CAnimSource::GetSegStatementSet(const CSegIdList& list, CSegStatementSet& s
       if (transIdx != 0xff) {
         const float* frameVecDataA = &x40_data.x0_storage[frameIdx * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
         const float* frameVecDataB =
-            &x40_data.x0_storage[(frameIdx - 1) * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
+            &x40_data.x0_storage[nextFrameIdx * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
         const zeus::CVector3f vecA(frameVecDataA[0], frameVecDataA[1], frameVecDataA[2]);
         const zeus::CVector3f vecB(frameVecDataB[0], frameVecDataB[1], frameVecDataB[2]);
         set[id].x10_offset = zeus::CVector3f::lerp(vecA, vecB, t);
@@ -164,7 +165,8 @@ const std::vector<CBoolPOINode>& CAnimSource::GetBoolPOIStream() const { return
 zeus::CQuaternion CAnimSource::GetRotation(const CSegId& seg, const CCharAnimTime& time) const {
   u8 rotIdx = x20_rotationChannels[seg];
   if (rotIdx != 0xff) {
-    u32 frameIdx = unsigned(time / x8_interval);
+    const auto frameIdx = u32(time / x8_interval);
+    const auto nextFrameIdx = (frameIdx + 1) % x10_frameCount;
     float remTime = time.GetSeconds() - frameIdx * x8_interval.GetSeconds();
     if (std::fabs(remTime) < 0.00001f)
       remTime = 0.f;
@@ -172,7 +174,7 @@ zeus::CQuaternion CAnimSource::GetRotation(const CSegId& seg, const CCharAnimTim
 
     const u32 floatsPerFrame = x40_data.x10_transPerFrame * 3 + x40_data.xc_rotPerFrame * 4;
     const float* frameDataA = &x40_data.x0_storage[frameIdx * floatsPerFrame + rotIdx * 4];
-    const float* frameDataB = &x40_data.x0_storage[(frameIdx + 1) * floatsPerFrame + rotIdx * 4];
+    const float* frameDataB = &x40_data.x0_storage[nextFrameIdx * floatsPerFrame + rotIdx * 4];
 
     zeus::CQuaternion quatA(frameDataA[0], frameDataA[1], frameDataA[2], frameDataA[3]);
     zeus::CQuaternion quatB(frameDataB[0], frameDataB[1], frameDataB[2], frameDataB[3]);
@@ -189,7 +191,8 @@ zeus::CVector3f CAnimSource::GetOffset(const CSegId& seg, const CCharAnimTime& t
     if (transIdx == 0xff)
       return {};
 
-    u32 frameIdx = unsigned(time / x8_interval);
+    const auto frameIdx = u32(time / x8_interval);
+    const auto nextFrameIdx = (frameIdx + 1) % x10_frameCount;
     float remTime = time.GetSeconds() - frameIdx * x8_interval.GetSeconds();
     if (std::fabs(remTime) < 0.00001f)
       remTime = 0.f;
@@ -198,7 +201,7 @@ zeus::CVector3f CAnimSource::GetOffset(const CSegId& seg, const CCharAnimTime& t
     const u32 floatsPerFrame = x40_data.x10_transPerFrame * 3 + x40_data.xc_rotPerFrame * 4;
     const u32 rotFloatsPerFrame = x40_data.xc_rotPerFrame * 4;
     const float* frameDataA = &x40_data.x0_storage[frameIdx * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
-    const float* frameDataB = &x40_data.x0_storage[(frameIdx - 1) * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
+    const float* frameDataB = &x40_data.x0_storage[nextFrameIdx * floatsPerFrame + rotFloatsPerFrame + transIdx * 3];
     zeus::CVector3f vecA(frameDataA[0], frameDataA[1], frameDataA[2]);
     zeus::CVector3f vecB(frameDataB[0], frameDataB[1], frameDataB[2]);
     return zeus::CVector3f::lerp(vecA, vecB, t);