Move body transforms to updateCL, fixes first person body jitter (thx Valerok)

Author: yohjimane

src/xrGame/Actor.cpp

@@ -1034,8 +1034,21 @@ float CActor::currentFOV()
     }
 }
 
+extern float g_first_person_body_offset;
 void CActor::UpdateCL()
 {
+    if (m_firstPersonBody)
+    {
+        // adjust body position
+        Fvector camdir = { cam_Active()->Direction().x, 0.f, cam_Active()->Direction().z }; // ignore Y (vertical) value
+        firstPersonBodyXform.set(XFORM());
+        firstPersonBodyXform.c.add(camdir.normalize().mul(g_first_person_body_offset)); // push model back so it doesn't look weird (default value: -0.75f)
+        // Update head position
+        IKinematics* realBodyK = Visual()->dcast_PKinematics();
+        headPosition.set(firstPersonBodyXform);
+        headPosition.mulB_43(realBodyK->LL_GetTransform(realBodyK->LL_BoneID("bip01_head")));
+    }
+
     if (g_Alive() && Level().CurrentViewEntity() == this)
     {
         if (CurrentGameUI() && !CurrentGameUI()->TopInputReceiver() && !m_holder)
@@ -1515,6 +1528,8 @@ void CActor::shedule_Update(u32 DT)
 #include "debug_renderer.h"
 void CActor::renderable_Render(u32 context_id, IRenderable* root)
 {
+    if (m_firstPersonBody)
+        XFORM().translate_over(firstPersonBodyXform.c); // move our original body to where our first person body is, so shadow renders in correct place
     VERIFY(_valid(XFORM()));
     inherited::renderable_Render(context_id, root);
     CInventoryOwner::renderable_Render(context_id, root);
@@ -1528,7 +1543,6 @@ bool CActor::renderable_ShadowGenerate()
     return inherited::renderable_ShadowGenerate();
 }
 
-extern float g_first_person_body_offset;
 void CActor::RenderFirstPersonBody(u32 context_id, IRenderable* root)
 {
     if (!(psActorFlags.test(AF_FIRST_PERSON_BODY) && cam_active == eacFirstEye))
@@ -1544,14 +1558,8 @@ void CActor::RenderFirstPersonBody(u32 context_id, IRenderable* root)
     IKinematics* kinematics = m_firstPersonBody->dcast_PKinematics();
     IKinematics* realBodyK = Visual()->dcast_PKinematics();
 
-    // adjust body position
-    Fvector camdir = { cam_Active()->Direction().x, 0.f, cam_Active()->Direction().z }; // ignore Y (vertical) value
-    Fmatrix trans = XFORM();
-    trans.c.add(camdir.normalize().mul(g_first_person_body_offset)); // push model back so it doesn't look weird (default value: -0.75f)
-    XFORM().translate_over(trans.c); // move our original body to where our first person body is, so shadow renders in correct place
-
     // Add body to render
-    GEnv.Render->add_Visual(context_id, root, m_firstPersonBody, trans);
+    GEnv.Render->add_Visual(context_id, root, m_firstPersonBody, firstPersonBodyXform);
     m_firstPersonBody->getVisData().hom_frame = Device.dwFrame;
 
     // Copy transforms from actual body visual, excluding bones we don't want to animate
@@ -1561,27 +1569,22 @@ void CActor::RenderFirstPersonBody(u32 context_id, IRenderable* root)
         if (m_firstPersonBodyBonesToIgnoreAnims[i])
             continue;
 
-        kinematics->LL_GetTransform(i).set(realBodyK->LL_GetTransform(i));
         kinematics->LL_GetTransform_R(i).set(realBodyK->LL_GetTransform_R(i));
     }
 
     // Hide bones
     for (auto [boneId, vis] : m_firstPersonBodyBonesToHide)
         kinematics->LL_SetBoneVisible(boneId, !vis, true);
 
-    // Update head position
-    headPosition.set(trans);
-    headPosition.mulB_43(realBodyK->LL_GetTransform(realBodyK->LL_BoneID("bip01_head")));
-
 #ifdef DEBUG
     Fvector ypr;
-    trans.getHPB(ypr);
+    firstPersonBodyXform.getHPB(ypr);
     string1024 text;
     CGameFont* F = UI().Font().pFontArial14;
     F->SetAligment(CGameFont::alLeft);
     F->OutSetI(-.9, 0);
     F->SetColor(color_rgba(255, 0, 0, 255));
-    xr_sprintf(text, "first person body position [%3.3f %3.3f %3.3f]", trans.c.x, trans.c.y, trans.c.z);
+    xr_sprintf(text, "first person body position [%3.3f %3.3f %3.3f]", firstPersonBodyXform.c.x, firstPersonBodyXform.c.y, firstPersonBodyXform.c.z);
     F->OutNext(text);
     xr_sprintf(text, "head position [%3.3f %3.3f %3.3f]", headPosition.c.x, headPosition.c.y, headPosition.c.z);
     F->OutNext(text);

src/xrGame/Actor.h

@@ -107,6 +107,7 @@ class CActor : public CEntityAlive,
     IRenderVisual* m_firstPersonBody{};
     xr_unordered_map<u16, bool> m_firstPersonBodyBonesToHide;
     xr_unordered_map<u16, bool> m_firstPersonBodyBonesToIgnoreAnims;
+    Fmatrix firstPersonBodyXform{};
     Fmatrix headPosition{};
 
     void feel_sound_new(IGameObject* who, int type, const CSound_UserDataPtr& user_data,