120 lines
3.7 KiB
C++
120 lines
3.7 KiB
C++
#include "GameCamera.h"
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#include "EngineCore/Game.h"
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#include "Actor/Map/GameMap.h"
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#include "Actor/Object/BaseObject.h"
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#include "Global/Global_Game.h"
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#include <algorithm>
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void GameCamera::SetFromActor(BaseObject *actor)
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{
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// 如果原来有跟随对象
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if (this->_FromActor)
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{
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this->_FromActor->RemoveCallbackOnUpdate("Camear Update");
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}
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this->_FromActor = actor;
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actor->SetCallbackOnUpdate("Camear Update", [](float deltaTime) mutable
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{ Global_Game::GetInstance().GetCamera()->Update(deltaTime); });
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}
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void GameCamera::Update(float deltaTime)
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{
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SyncPosByFromParent(deltaTime);
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}
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void GameCamera::SyncPos(float deltaTime)
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{
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}
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void GameCamera::SetPos(float x, float y, float z)
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{
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// this->X = x;
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// this->Y = y;
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// this->Z = z;
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}
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void GameCamera::AddPos(float x, float y, float z)
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{
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// this->X += x;
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// this->Y += y;
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// this->Z += z;
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}
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void GameCamera::SyncPosByFromParent(float deltaTime)
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{
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if (this->_FromActor == nullptr)
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{
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return;
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}
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float targetX = _FromActor->Position.x;
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float targetY = _FromActor->Position.y;
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if (_isSmoothMoving)
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{
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// 平滑移动计算
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Vec2 targetPosition(targetX, targetY);
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_currentPosition = SmoothDamp(_currentPosition, targetPosition, _velocity, _smoothTime, _maxSpeed, deltaTime);
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}
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else
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{
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_currentPosition.x = targetX;
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_currentPosition.y = targetY;
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}
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}
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Vec2 GameCamera::SmoothDamp(const Vec2 ¤t, const Vec2 &target, Vec2 ¤tVelocity, float smoothTime, float maxSpeed, float deltaTime)
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{
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// 平滑时间为0时直接返回目标位置并重置速度
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if (smoothTime <= 0.f)
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{
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currentVelocity = Vec2(0, 0);
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return target;
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}
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// 临界阻尼系数计算（避免过冲的核心参数）
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const float omega = 2.0f / smoothTime;
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const float x = omega * deltaTime;
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const float expTerm = 1.0f / (1.0f + x + 0.48f * x * x + 0.235f * x * x * x);
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// 计算当前位置与目标的差值
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Vec2 delta = target - current;
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// 计算目标速度（基于阻尼公式和当前差值）
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// 注意：这里先通过浮点计算保持精度，最后转换为整数
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const float tx = delta.x * (omega * omega * deltaTime) - currentVelocity.x * (1.0f + 0.48f * x) * x;
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const float ty = delta.y * (omega * omega * deltaTime) - currentVelocity.y * (1.0f + 0.48f * x) * x;
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Vec2 targetVelocity(tx, ty);
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// 应用速度衰减（指数平滑）
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currentVelocity += targetVelocity;
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currentVelocity = Vec2(currentVelocity.x * expTerm, currentVelocity.y * expTerm);
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// 限制最大速度（如果设置了maxSpeed）
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if (maxSpeed > 0)
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{
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// 计算当前速度的模长（浮点精度）
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const float speedSq = currentVelocity.x * currentVelocity.x + currentVelocity.y * currentVelocity.y;
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const float maxSpeedSq = maxSpeed * maxSpeed;
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if (speedSq > maxSpeedSq)
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{
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// 速度超限，按比例缩放至最大速度
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const float scale = maxSpeed / sqrtf(speedSq);
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currentVelocity = Vec2(currentVelocity.x * scale, currentVelocity.y * scale);
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}
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}
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// 计算新位置（当前位置 + 速度 * 时间）
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Vec2 newPos = current + Vec2(currentVelocity.x * deltaTime, currentVelocity.y * deltaTime);
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// 检测过冲：如果新位置已越过目标，直接锁定目标并重置速度
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// 点积 > 0 表示方向相反（已超过目标）
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const float dot = delta.x * (newPos.x - target.x) + delta.y * (newPos.y - target.y);
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if (dot > 0)
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{
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newPos = target;
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currentVelocity = Vec2(0, 0);
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}
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return newPos;
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} |