Working on interpolation

CHARACTER_INTERPOLATION.md

@@ -0,0 +1,67 @@
+# Character Presentation Interpolation
+
+The authoritative game simulation still advances in exact 100 ms ticks. Character
+interpolation is a rendering-only feature and does not modify `CharacterState`,
+network commands, tick IDs, state hashes, or deterministic lockstep behavior.
+
+## How it works
+
+Each runtime `Character` keeps two presentation samples:
+
+- `previous`: the visual values received at the preceding completed simulation tick;
+- `current`: the visual values received at the latest completed simulation tick.
+
+Rendering calculates an alpha from the real elapsed time since the latest completed
+tick, clamped to the 100 ms simulation interval. It renders the delayed
+`previous -> current` transition. This introduces at most one simulation tick of
+presentation latency, but it avoids predicting a state that has not arrived from
+the authoritative simulation.
+
+The following values are interpolated:
+
+- Position uses linear interpolation.
+- Facing angle uses the shortest angular path, including wraparound at ±π.
+- Animation frame remains fractional and is interpolated when both samples use
+  the same animation state. Looping clips treat the last frame to first frame
+  transition as a cyclic interval instead of interpolating backward through the
+  entire clip.
+
+The interpolated values are used by mesh, weapon, shadow, night-lighting, name,
+and health-bar rendering. The local camera and shadow-map center follow the same
+interpolated player position; otherwise the camera would jump to the newest
+authoritative position while the player model was still in its presentation
+transition. Gameplay queries, commands, callbacks, collision, and presentation
+events continue to use the authoritative snapshot.
+
+## Other presentation animations
+
+Teleport-zone star particles are advanced by `Location::updatePresentation()`
+once per render frame using the real frame delta. They are no longer advanced
+only from the 100 ms simulation-tick callback, so their visual motion remains
+continuous without affecting teleport activation or other authoritative state.
+
+Dialogue typewriter text and cutscene presentation timers use the same
+per-render-frame path. This keeps character reveals, subtitle timing, fades, and
+cutscene image poses smooth instead of stepping in 100 ms increments.
+
+## Animation skinning
+
+GPU and CPU bone interpolation receive the fractional render frame instead of an
+integer-truncated frame. Bone positions are linearly interpolated and bone
+rotations use spherical interpolation as before. Frames at the end of a clip are
+clamped to the final keyframe.
+
+## Discontinuities
+
+The presentation buffer is reset instead of blended when a character is first
+observed, changes animation state or enabled state, or has not received a tick
+for a sufficiently long gap. This prevents stale positions, animation clips, or
+disabled characters from producing visible interpolation artifacts.
+
+## Local and networked games
+
+Local games continue accumulating wall-clock remainder time and executing exact
+100 ms simulation updates. Networked games continue consuming only contiguous
+server tick messages. Both paths publish completed snapshots to the same runtime
+presentation objects; interpolation only changes how those snapshots are drawn
+between updates.

src/BoneAnimatedModelNew.cpp

@@ -722,9 +722,10 @@ namespace FRG
 		return -1;
 	}
 
-	void BoneSystemNew::Interpolate(int frame)
+	void BoneSystemNew::Interpolate(float frame)
 	{
 		int startingKeyFrame = -1;
+		int nextKeyFrame = -1;
 		for (int i = 0; i < static_cast<int>(animations[0].keyFrames.size()) - 1; i++)
 		{
 			int oldFrame = animations[0].keyFrames[i].frame;
@@ -732,22 +733,29 @@ namespace FRG
 			if (frame >= oldFrame && frame < nextFrame)
 			{
 				startingKeyFrame = i;
+				nextKeyFrame = i + 1;
 				break;
 			}
 		}
 
 		if (startingKeyFrame == -1)
 		{
-			logger() << "Exception here: frame number is out of range of keyframes. Frame: " << frame << std::endl;
-			throw std::runtime_error("Exception here");
+			if (animations[0].keyFrames.size() < 2)
+				return;
+			startingKeyFrame = static_cast<int>(animations[0].keyFrames.size()) - 1;
+			nextKeyFrame = 0;
 		}
 
-		int modifiedFrameNumber = frame - animations[0].keyFrames[startingKeyFrame].frame;
-		int diffFrames = animations[0].keyFrames[startingKeyFrame + 1].frame - animations[0].keyFrames[startingKeyFrame].frame;
-		float t = (modifiedFrameNumber + 0.f) / diffFrames;
+		float modifiedFrameNumber = frame - animations[0].keyFrames[startingKeyFrame].frame;
+		int diffFrames = nextKeyFrame == 0
+			? animations[0].keyFrames.back().frame -
+				animations[0].keyFrames.front().frame + 1
+			: animations[0].keyFrames[nextKeyFrame].frame -
+				animations[0].keyFrames[startingKeyFrame].frame;
+		float t = diffFrames > 0 ? modifiedFrameNumber / diffFrames : 0.0f;
 
 		std::vector<Bone>& oneFrameBones = animations[0].keyFrames[startingKeyFrame].bones;
-		std::vector<Bone>& nextFrameBones = animations[0].keyFrames[startingKeyFrame + 1].bones;
+		std::vector<Bone>& nextFrameBones = animations[0].keyFrames[nextKeyFrame].bones;
 
 		std::vector<Matrix4f> skinningMatrixForEachBone(currentBones.size());
 
@@ -906,9 +914,10 @@ namespace FRG
 		}
 	}
 
-	void GpuSkinningShaderDataNew::ComputeSkinningMatrices(const std::vector<Bone>& startBones, const std::vector<AnimationKeyFrame>& keyFrames, int frame)
+	void GpuSkinningShaderDataNew::ComputeSkinningMatrices(const std::vector<Bone>& startBones, const std::vector<AnimationKeyFrame>& keyFrames, float frame)
 	{
 		int startingKeyFrame = -1;
+		int nextKeyFrame = -1;
 		for (size_t i = 0; i < keyFrames.size() - 1; i++)
 		{
 			int oldFrame = keyFrames[i].frame;
@@ -916,6 +925,7 @@ namespace FRG
 			if (frame >= oldFrame && frame < nextFrame)
 			{
 				startingKeyFrame = static_cast<int>(i);
+				nextKeyFrame = static_cast<int>(i + 1);
 				break;
 			}
 		}
@@ -924,16 +934,23 @@ namespace FRG
 
 		if (startingKeyFrame == -1)
 		{
-			for (auto& m : skinningMatrices) m = Matrix4f::Identity();
-			return;
+			if (keyFrames.size() < 2)
+			{
+				for (auto& m : skinningMatrices) m = Matrix4f::Identity();
+				return;
+			}
+			startingKeyFrame = static_cast<int>(keyFrames.size()) - 1;
+			nextKeyFrame = 0;
 		}
 
-		int modifiedFrameNumber = frame - keyFrames[startingKeyFrame].frame;
-		int diffFrames = keyFrames[startingKeyFrame + 1].frame - keyFrames[startingKeyFrame].frame;
-		float t = (modifiedFrameNumber + 0.f) / diffFrames;
+		float modifiedFrameNumber = frame - keyFrames[startingKeyFrame].frame;
+		int diffFrames = nextKeyFrame == 0
+			? keyFrames.back().frame - keyFrames.front().frame + 1
+			: keyFrames[nextKeyFrame].frame - keyFrames[startingKeyFrame].frame;
+		float t = diffFrames > 0 ? modifiedFrameNumber / diffFrames : 0.0f;
 
 		const std::vector<Bone>& oneFrameBones = keyFrames[startingKeyFrame].bones;
-		const std::vector<Bone>& nextFrameBones = keyFrames[startingKeyFrame + 1].bones;
+		const std::vector<Bone>& nextFrameBones = keyFrames[nextKeyFrame].bones;
 
 		for (size_t i = 0; i < startBones.size(); i++)
 		{

src/BoneAnimatedModelNew.h

@@ -67,7 +67,7 @@ namespace FRG
 		void LoadFromFile(const std::string& fileName, const std::string& ZIPFileName = "");
 		void LoadFromBinaryFile(const std::string& fileName, const std::string& ZIPFileName = "");
 
-		void Interpolate(int frame);
+		void Interpolate(float frame);
 
 		int findBoneIndex(const std::string& name) const;
 	};
@@ -94,14 +94,14 @@ namespace FRG
 
 		void prepareGpuSkinningVBOs(BoneSystemNew& model);
 		void RenderVBO(Renderer& renderer, const std::vector<std::string>& meshNamesOrdered);
-		void ComputeSkinningMatrices(const std::vector<Bone>& startBones, const std::vector<AnimationKeyFrame>& keyFrames, int frame);
+		void ComputeSkinningMatrices(const std::vector<Bone>& startBones, const std::vector<AnimationKeyFrame>& keyFrames, float frame);
 	};
 
 	struct BoneAnimationDataNew
 	{
 		BoneSystemNew model;
 		float currentFrame = 0.f;
-		int lastFrame = -1;
+		float lastFrame = -1.0f;
 		int totalFrames = 1;
 
 		GpuSkinningShaderDataNew gpuSkinningShaderData;

src/Character.cpp

@@ -52,6 +52,11 @@ Eigen::Vector3f Character::getCurrentNavigationTarget() const {
     return state ? state->getCurrentNavigationTarget() : Eigen::Vector3f::Zero();
 }
 
+Eigen::Vector3f Character::renderPosition() const {
+    auto state = stateSnapshot();
+    return state ? interpolatedState(*state).position : Eigen::Vector3f::Zero();
+}
+
 float Character::getHp() const {
     auto state = stateSnapshot();
     return state ? state->getHp() : 0.f;
@@ -163,6 +168,62 @@ AnimationState Character::resolveActiveState(const CharacterState& state) const
     return AnimationState::STAND;
 }
 
+CharacterState Character::interpolatedState(const CharacterState& state) const {
+    if (!hasPresentationSample_ || !currentPresentationSample_.enabled || !state.enabled) {
+        return state;
+    }
+
+    constexpr float kSimulationTickMs = 100.0f;
+    const auto now = std::chrono::steady_clock::now();
+    const float elapsedMs = static_cast<float>(
+        std::chrono::duration_cast<std::chrono::milliseconds>(
+            now - lastPresentationUpdate_).count());
+    const float alpha = (std::max)(0.0f, (std::min)(1.0f, elapsedMs / kSimulationTickMs));
+
+    CharacterState result = state;
+    result.position = previousPresentationSample_.position +
+        alpha * (currentPresentationSample_.position - previousPresentationSample_.position);
+
+    constexpr float kPi = 3.14159265358979323846f;
+    constexpr float kTwoPi = 2.0f * kPi;
+    float angleDelta = currentPresentationSample_.facingAngle -
+        previousPresentationSample_.facingAngle;
+    while (angleDelta > kPi) angleDelta -= kTwoPi;
+    while (angleDelta < -kPi) angleDelta += kTwoPi;
+    result.facingAngle = previousPresentationSample_.facingAngle + alpha * angleDelta;
+    if (previousPresentationSample_.currentState == state.currentState &&
+        currentPresentationSample_.currentState == state.currentState) {
+        float previousFrame = previousPresentationSample_.animationFrame;
+        float currentFrame = currentPresentationSample_.animationFrame;
+        const auto animationIndex = static_cast<std::size_t>(state.currentState);
+        const int frameCount = animationIndex < state.animationFrameCounts.size()
+            ? state.animationFrameCounts[animationIndex] : 1;
+        if (frameCount > 1 && currentFrame < previousFrame)
+            currentFrame += static_cast<float>(frameCount);
+        result.animationFrame = previousFrame + alpha * (currentFrame - previousFrame);
+    }
+    return result;
+}
+
+void Character::updateAnimationForRender(const CharacterState& state) {
+    auto it = animations.find(state.currentState);
+    if (it == animations.end()) return;
+
+    auto& anim = it->second;
+    anim.currentFrame = (std::min)(
+        state.animationFrame, static_cast<float>((std::max)(0, anim.totalFrames)));
+    if (std::abs(anim.currentFrame - anim.lastFrame) <= 0.0001f) return;
+
+    if (!anim.model.animations.empty() && !anim.model.animations[0].keyFrames.empty()) {
+        anim.gpuSkinningShaderData.ComputeSkinningMatrices(
+            anim.model.startBones, anim.model.animations[0].keyFrames,
+            anim.currentFrame);
+        if (!state.useGpuSkinning)
+            anim.model.Interpolate(anim.currentFrame);
+    }
+    anim.lastFrame = anim.currentFrame;
+}
+
 void Character::update(int64_t deltaMs, const CharacterUpdateEvents* events) {
     if (hitSparkEmitter.isConfigured()) {
         hitSparkEmitter.update(static_cast<float>(deltaMs));
@@ -172,6 +233,26 @@ void Character::update(int64_t deltaMs, const CharacterUpdateEvents* events) {
     if (!stateSnapshot) return;
     const CharacterState& state = *stateSnapshot;
 
+    const auto now = std::chrono::steady_clock::now();
+    PresentationSample sample;
+    sample.position = state.position;
+    sample.facingAngle = state.facingAngle;
+    sample.animationFrame = state.animationFrame;
+    sample.currentState = state.currentState;
+    sample.enabled = state.enabled;
+    const bool largeGap = hasPresentationSample_ &&
+        std::chrono::duration_cast<std::chrono::milliseconds>(
+            now - lastPresentationUpdate_).count() > 250;
+    if (!hasPresentationSample_ || largeGap ||
+        currentPresentationSample_.enabled != sample.enabled) {
+        previousPresentationSample_ = sample;
+    } else {
+        previousPresentationSample_ = currentPresentationSample_;
+    }
+    currentPresentationSample_ = sample;
+    lastPresentationUpdate_ = now;
+    hasPresentationSample_ = true;
+
     if (events) {
         if (events->deathAnimationComplete && onDeathAnimComplete)
             onDeathAnimComplete();
@@ -183,22 +264,7 @@ void Character::update(int64_t deltaMs, const CharacterUpdateEvents* events) {
     }
 
     if (!state.enabled) return;
-    auto it = animations.find(state.currentState);
-    if (it == animations.end()) return;
-
-    auto& anim = it->second;
-    anim.currentFrame = (std::min)(
-        state.animationFrame, static_cast<float>((std::max)(0, anim.totalFrames - 1)));
-
-    if (static_cast<int>(anim.currentFrame) != anim.lastFrame) {
-        anim.gpuSkinningShaderData.ComputeSkinningMatrices(
-            anim.model.startBones, anim.model.animations[0].keyFrames,
-            static_cast<int>(anim.currentFrame));
-        if (!state.useGpuSkinning) {
-            anim.model.Interpolate(static_cast<int>(anim.currentFrame));
-        }
-        anim.lastFrame = static_cast<int>(anim.currentFrame);
-    }
+    updateAnimationForRender(state);
 }
 
 void Character::draw(Renderer& renderer) {
@@ -211,8 +277,9 @@ void Character::draw(Renderer& renderer) {
 
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (!state.enabled) return;
+    updateAnimationForRender(state);
 
     if (state.useGpuSkinning) {
         drawGpuSkinning(renderer, state);
@@ -270,7 +337,7 @@ void Character::drawGpuSkinning(Renderer& renderer, const CharacterState& state)
         if (anim.model.animations.empty() || anim.model.animations[0].keyFrames.empty()) return;
         anim.gpuSkinningShaderData.ComputeSkinningMatrices(
             anim.model.startBones, anim.model.animations[0].keyFrames,
-            static_cast<int>(anim.currentFrame));
+            anim.currentFrame);
         if (anim.gpuSkinningShaderData.skinningMatrices.empty()) return;
     }
 
@@ -328,7 +395,7 @@ bool Character::prepareGpuSkinning(const CharacterState& state) {
         if (anim.model.animations.empty() || anim.model.animations[0].keyFrames.empty()) return false;
         anim.gpuSkinningShaderData.ComputeSkinningMatrices(
             anim.model.startBones, anim.model.animations[0].keyFrames,
-            static_cast<int>(anim.currentFrame));
+            anim.currentFrame);
         if (anim.gpuSkinningShaderData.skinningMatrices.empty()) return false;
     }
     return true;
@@ -370,8 +437,9 @@ void Character::drawAttachedWeapon(Renderer& renderer, const CharacterState& sta
 void Character::drawShadowDepth(Renderer& renderer) {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (!state.enabled) return;
+    updateAnimationForRender(state);
     if (state.useGpuSkinning) {
         drawShadowDepthGpuSkinning(renderer, state);
     } else {
@@ -453,8 +521,9 @@ void Character::drawShadowDepthGpuSkinning(Renderer& renderer, const CharacterSt
 void Character::drawWithShadow(Renderer& renderer, const Eigen::Matrix4f& lightFromCamera, GLuint shadowMapTex, const Eigen::Vector3f& lightDirCamera) {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (!state.enabled) return;
+    updateAnimationForRender(state);
     if (hitSparkEmitter.isConfigured() && hitSparkEmitter.getActiveParticleCount() > 0) {
         hitSparkEmitter.draw(renderer, 1.0f, Environment::width, Environment::height, false);
     }
@@ -603,8 +672,9 @@ void Character::drawNight(Renderer& renderer,
 {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (!state.enabled) return;
+    updateAnimationForRender(state);
     if (hitSparkEmitter.isConfigured() && hitSparkEmitter.getActiveParticleCount() > 0) {
         hitSparkEmitter.draw(renderer, 1.0f, Environment::width, Environment::height, false);
     }
@@ -766,8 +836,9 @@ void Character::drawNightWithShadow(Renderer& renderer,
 {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (!state.enabled) return;
+    updateAnimationForRender(state);
     if (hitSparkEmitter.isConfigured() && hitSparkEmitter.getActiveParticleCount() > 0) {
         hitSparkEmitter.draw(renderer, 1.0f, Environment::width, Environment::height, false);
     }
@@ -1014,7 +1085,7 @@ void Character::drawName(TextRenderer& textRenderer,
 {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (state.isPlayer)    return;
     if (state.npcName.empty()) return;
 
@@ -1037,10 +1108,11 @@ void Character::drawPlayerName(
 {
     auto snapshot = stateSnapshot();
     if (!snapshot) return;
+    CharacterState state = interpolatedState(*snapshot);
     static const std::array<float, 4> color = {0.f, 1.f, 0.f, 1.f};
     drawCharacterNameLabel(
         textRenderer, cameraViewMatrix, projectionMatrix,
-        *snapshot, displayName, color);
+        state, displayName, color);
 }
 
 void Character::drawHealthBar(Renderer& renderer,
@@ -1049,7 +1121,7 @@ void Character::drawHealthBar(Renderer& renderer,
 {
     auto stateSnapshot = this->stateSnapshot();
     if (!stateSnapshot) return;
-    const CharacterState& state = *stateSnapshot;
+    CharacterState state = interpolatedState(*stateSnapshot);
     if (state.isPlayer || !state.canAttack) return;
     if (!state.enabled) return;
     if (state.hp <= 0.f) return;

src/Character.h

@@ -12,6 +12,7 @@
 #include <vector>
 #include <unordered_map>
 #include <utility>
+#include <chrono>
 #include "dialogue/TranslationDatabase.h"
 #include "AudioPlayerAsync.h"
 
@@ -94,6 +95,7 @@ public:
     bool            isMoving() const;
     Eigen::Vector3f getRequestedWalkTarget() const;
     Eigen::Vector3f getCurrentNavigationTarget() const;
+    Eigen::Vector3f renderPosition() const;
     float           getHp() const;
 
     // ---- Weapon rendering data (initialized from state.creationInfo by createFromState) ----
@@ -124,7 +126,22 @@ private:
     VertexRenderStruct healthBarMesh;
     std::unordered_map<std::string, std::shared_ptr<Texture>> meshTextures;
 
+    struct PresentationSample {
+        Eigen::Vector3f position = Eigen::Vector3f::Zero();
+        float facingAngle = 0.0f;
+        float animationFrame = 0.0f;
+        AnimationState currentState = AnimationState::STAND;
+        bool enabled = true;
+    };
+
+    PresentationSample previousPresentationSample_;
+    PresentationSample currentPresentationSample_;
+    std::chrono::steady_clock::time_point lastPresentationUpdate_;
+    bool hasPresentationSample_ = false;
+
     AnimationState resolveActiveState(const CharacterState& state) const;
+    CharacterState interpolatedState(const CharacterState& state) const;
+    void updateAnimationForRender(const CharacterState& state);
     bool           prepareGpuSkinning(const CharacterState& state);
     void           drawAttachedWeapon(Renderer& renderer, const CharacterState& state);
 

src/Game.cpp

@@ -1194,6 +1194,8 @@ namespace FRG
 						simulationAccumulatorMs -= kSimulationTickMs;
 					}
 				}
+				if (Location* location = currentLocation())
+					location->updatePresentation(delta);
 #if defined(NETWORK)
 				if (remoteCampaignActive && websocketGameClient &&
 					websocketGameClient->connectionFailed()) {

src/Location.cpp

@@ -1011,7 +1011,7 @@ namespace FRG
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraInclination, Eigen::Vector3f::UnitX())).toRotationMatrix());
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraAzimuth, Eigen::Vector3f::UnitY())).toRotationMatrix());
 		const Eigen::Vector3f camTarget =
-			playerState ? playerState->position : Eigen::Vector3f::Zero();
+			player ? player->renderPosition() : Eigen::Vector3f::Zero();
 		renderer.TranslateMatrix({ -camTarget.x(), -camTarget.y(), -camTarget.z() });
 		renderer.TranslateMatrix({ 0, -1.f, 0 });
 
@@ -1088,7 +1088,7 @@ namespace FRG
 
 		auto playerState = player ? player->stateSnapshot() : nullptr;
 		const Eigen::Vector3f sceneCenter =
-			playerState ? playerState->position : Eigen::Vector3f::Zero();
+			player ? player->renderPosition() : Eigen::Vector3f::Zero();
 		shadowMap->updateLightSpaceMatrix(sceneCenter);
 
 		shadowMap->bind();
@@ -1206,7 +1206,7 @@ namespace FRG
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraAzimuth, Eigen::Vector3f::UnitY())).toRotationMatrix());
 		auto playerState = player ? player->stateSnapshot() : nullptr;
 		const Eigen::Vector3f camTarget =
-			playerState ? playerState->position : Eigen::Vector3f::Zero();
+			player ? player->renderPosition() : Eigen::Vector3f::Zero();
 		renderer.TranslateMatrix({ -camTarget.x(), -camTarget.y(), -camTarget.z() });
 		renderer.TranslateMatrix({ 0, -1.f, 0 });
 
@@ -1345,7 +1345,7 @@ namespace FRG
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraInclination, Eigen::Vector3f::UnitX())).toRotationMatrix());
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraAzimuth, Eigen::Vector3f::UnitY())).toRotationMatrix());
 		const Eigen::Vector3f camTarget =
-			playerState ? playerState->position : Eigen::Vector3f::Zero();
+			player ? player->renderPosition() : Eigen::Vector3f::Zero();
 		renderer.TranslateMatrix({ -camTarget.x(), -camTarget.y(), -camTarget.z() });
 		renderer.TranslateMatrix({ 0, -1.f, 0 });
 
@@ -1591,7 +1591,7 @@ namespace FRG
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraInclination, Eigen::Vector3f::UnitX())).toRotationMatrix());
 		renderer.RotateMatrix(Eigen::Quaternionf(Eigen::AngleAxisf(localState_->cameraAzimuth, Eigen::Vector3f::UnitY())).toRotationMatrix());
 		const Eigen::Vector3f camTarget =
-			playerState ? playerState->position : Eigen::Vector3f::Zero();
+			player ? player->renderPosition() : Eigen::Vector3f::Zero();
 		renderer.TranslateMatrix({ -camTarget.x(), -camTarget.y(), -camTarget.z() });
 		renderer.TranslateMatrix({ 0, -1.f, 0 });
 
@@ -1860,7 +1860,6 @@ namespace FRG
 
 		if (player) {
 			player->update(delta, eventFor(gameServer_.localPlayerId()));
-			dialogueSystem.update(static_cast<int>(delta));
 			auto playerState = player->stateSnapshot();
 			if (playerState) updateTriggerZones(playerState->position);
 		}
@@ -1896,8 +1895,6 @@ namespace FRG
 			}
 		}
 
-		for (auto& tz : teleportZones) tz.update(static_cast<float>(delta));
-
 		auto playerState = player ? player->stateSnapshot() : nullptr;
 		if (auto* tz = getTargetTeleportZone(*locationState); tz && playerState) {
 			float dist = (playerState->position - tz->position).norm();
@@ -2179,6 +2176,13 @@ namespace FRG
 		}
 	}
 
+	void Location::updatePresentation(int64_t delta)
+	{
+		dialogueSystem.update(static_cast<int>(delta));
+		for (auto& tz : teleportZones)
+			tz.update(static_cast<float>(delta));
+	}
+
 	bool Location::requestDialogueStart(const std::string& dialogueId)
 	{
 		return dialogueSystem.startDialogue(dialogueId);

src/Location.h

@@ -210,6 +210,7 @@ namespace FRG
 		bool setNavigationAreaAvailable(const std::string& areaName, bool available);
 
 		void update(int64_t deltaMs, const LocationSimulationEvents& events);
+		void updatePresentation(int64_t deltaMs);
 		// Purely visual feedback for click-triggered player routes. Disabling it
 		// also cancels an animation that is currently playing.
 		void setPathVisualizationEnabled(bool enabled);