Temporary movement code.

src/gameplaysceneclassic.cpp

@@ -62,7 +62,7 @@ namespace cloonel {
 	void GameplaySceneClassic::Prepare() {
 		std::unique_ptr<MoverSine> moverSine(new MoverSine());
 		std::unique_ptr<Character> player(new Character("resources/graphics/player.png", SDLObject(), ushort2(80, 120)));
-		std::unique_ptr<MoverLeftRight> moverLeftRight(new MoverLeftRight());
+		std::unique_ptr<MoverLeftRight> moverLeftRight(new MoverLeftRight(1.5f, 5.0f, 40.0f));
 
 		player->Prepare();
 		moverSine->RegisterPlaceable(player.get());

src/moverleftright.cpp

@@ -18,27 +18,49 @@
 */
 
 #include "moverleftright.hpp"
+#include <algorithm>
+#include <cmath>
 
 namespace cloonel {
+	namespace {
+		float Clamp ( float parValue, float parMin, float parMax ) __attribute__((pure));
+		float Clamp ( float parValue, float parMin, float parMax ) {
+			assert(parMin <= parMax);
+			return std::max(parMin, std::min(parMax, parValue));
+		}
+	} //unnamed namespace
+
 	///--------------------------------------------------------------------------
 	///--------------------------------------------------------------------------
-	MoverLeftRight::MoverLeftRight() :
-		m_movement(0.0f),
-		m_velocity(320.0f),
-		m_step(0.0f)
+	MoverLeftRight::MoverLeftRight (float parMaxVelocity, float parMass, float parForce) :
+		//TODO: mass does not belong to here
+		m_velocity(0.0f),
+		m_maxVelocity(parMaxVelocity),
+		m_invMass(1.0f / parMass),
+		m_force(parForce),
+		m_movementTarget(0.0f)
 	{
 	}
 
 	///--------------------------------------------------------------------------
 	///--------------------------------------------------------------------------
 	void MoverLeftRight::ApplyMotion (float parDelta) {
-		m_step = m_velocity * parDelta * m_movement;
+		//TODO: implement a movement that is more mathematically correct and
+		//that feels nice.
+
+		//const float forceDirection = std::abs(m_movementTarget) * 2.0f - 1.0f;
+		const float notMoving = 1.0f - std::abs(m_movementTarget);
+		const float friction = 1.757f * m_velocity * notMoving * parDelta;
+		m_velocity += m_movementTarget * m_force * m_invMass * parDelta - std::copysign(friction, m_velocity);
+		m_velocity = Clamp(m_velocity, -m_maxVelocity, m_maxVelocity);
+		if (m_movementTarget == 0.0f and std::abs(m_velocity) < 0.1f)
+			m_velocity = 0.0f;
 	}
 
 	///--------------------------------------------------------------------------
 	///--------------------------------------------------------------------------
 	float2 MoverLeftRight::GetOffset() const {
-		return float2(m_step, 0.0f);
+		return float2(m_velocity, 0.0f);
 	}
 
 	///--------------------------------------------------------------------------
@@ -46,13 +68,13 @@ namespace cloonel {
 	void MoverLeftRight::SetMovement (MovementDirectionType parDirection) {
 		switch (parDirection) {
 		case MovementDirection_Left:
-			m_movement = -1.0f;
+			m_movementTarget = -1.0f;
 			break;
 		case MovementDirection_Right:
-			m_movement = 1.0f;
+			m_movementTarget = 1.0f;
 			break;
 		case MovementDirection_Still:
-			m_movement = 0.0f;
+			m_movementTarget = 0.0f;
 			break;
 		}
 	}

src/moverleftright.hpp

@@ -31,7 +31,7 @@ namespace cloonel {
 			MovementDirection_Still
 		};
 
-		MoverLeftRight ( void );
+		MoverLeftRight ( float parMaxVelocity, float parMass, float parForce );
 		virtual ~MoverLeftRight ( void ) noexcept = default;
 
 		void SetMovement ( MovementDirectionType parDirection );
@@ -40,9 +40,11 @@ namespace cloonel {
 		virtual float2 GetOffset ( void ) const;
 		virtual void ApplyMotion ( float parDelta );
 
-		float m_movement;
 		float m_velocity;
-		float m_step;
+		float m_maxVelocity;
+		float m_invMass;
+		float m_force;
+		float m_movementTarget;
 	};
 } //namespace cloonel