From bce3cadfd5a6396c4c21d975e13060d94accfa17 Mon Sep 17 00:00:00 2001
From: Lynix <lynix680@gmail.com>
Date: Tue, 20 Jan 2015 17:48:11 +0100
Subject: [PATCH] (ParticleEmitter) Added lag compensation

Former-commit-id: 914a976ba52b2629190ded068cc23e1cf7dee4d4
---
 include/Nazara/Graphics/ParticleEmitter.hpp |  5 +++++
 src/Nazara/Graphics/ParticleEmitter.cpp     | 25 ++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/Nazara/Graphics/ParticleEmitter.hpp b/include/Nazara/Graphics/ParticleEmitter.hpp
index 5e73426d5..6298c196c 100644
--- a/include/Nazara/Graphics/ParticleEmitter.hpp
+++ b/include/Nazara/Graphics/ParticleEmitter.hpp
@@ -23,9 +23,13 @@ class NAZARA_API NzParticleEmitter : public NzNode
 
 		virtual void Emit(NzParticleSystem& system, float elapsedTime) const;
 
+		void EnableLagCompensation(bool enable);
+
 		unsigned int GetEmissionCount() const;
 		float GetEmissionRate() const;
 
+		bool IsLagCompensationEnabled() const;
+
 		void SetEmissionCount(unsigned int count);
 		void SetEmissionRate(float rate);
 
@@ -35,6 +39,7 @@ class NAZARA_API NzParticleEmitter : public NzNode
 	private:
 		virtual void SetupParticles(NzParticleMapper& mapper, unsigned int count) const = 0;
 
+		bool m_lagCompensationEnabled;
 		mutable float m_emissionAccumulator;
 		float m_emissionRate;
 		unsigned int m_emissionCount;
diff --git a/src/Nazara/Graphics/ParticleEmitter.cpp b/src/Nazara/Graphics/ParticleEmitter.cpp
index 46500f082..33eda8002 100644
--- a/src/Nazara/Graphics/ParticleEmitter.cpp
+++ b/src/Nazara/Graphics/ParticleEmitter.cpp
@@ -13,6 +13,7 @@
 #include <Nazara/Graphics/Debug.hpp>
 
 NzParticleEmitter::NzParticleEmitter() :
+m_lagCompensationEnabled(false),
 m_emissionAccumulator(0.f),
 m_emissionRate(0.f),
 m_emissionCount(1)
@@ -34,20 +35,37 @@ void NzParticleEmitter::Emit(NzParticleSystem& system, float elapsedTime) const
 		if (emissionCount >= 1.f)
 		{
 			// On calcule le nombre maximum de particules pouvant être émises cette fois-ci
-			unsigned int maxParticleCount = static_cast<unsigned int>(emissionCount)*m_emissionCount;
+			unsigned int emissionCountInt = static_cast<unsigned int>(emissionCount);
+			unsigned int maxParticleCount = emissionCountInt*m_emissionCount;
 
 			// On récupère le nombre de particules qu'il est possible de créer selon l'espace libre
 			unsigned int particleCount = std::min(maxParticleCount, system.GetMaxParticleCount() - system.GetParticleCount());
+			if (particleCount == 0)
+				return;
 
 			// Et on émet nos particules
 			void* particles = system.GenerateParticles(particleCount);
 			NzParticleMapper mapper(particles, system.GetDeclaration());
 
 			SetupParticles(mapper, particleCount);
+
+			if (m_lagCompensationEnabled)
+			{
+				// On va maintenant appliquer les contrôleurs
+				float accumulator = 0.f;
+				float invEmissionRate = 1.f/m_emissionRate;
+				for (unsigned int i = 1; i <= emissionCountInt; ++i)
+					system.ApplyControllers(mapper, std::min(m_emissionCount*i, particleCount), 20*invEmissionRate, accumulator);
+			}
 		}
 	}
 }
 
+void NzParticleEmitter::EnableLagCompensation(bool enable)
+{
+	m_lagCompensationEnabled = enable;
+}
+
 unsigned int NzParticleEmitter::GetEmissionCount() const
 {
 	return m_emissionCount;
@@ -58,6 +76,11 @@ float NzParticleEmitter::GetEmissionRate() const
 	return m_emissionRate;
 }
 
+bool NzParticleEmitter::IsLagCompensationEnabled() const
+{
+	return m_lagCompensationEnabled;
+}
+
 void NzParticleEmitter::SetEmissionCount(unsigned int count)
 {
 	m_emissionCount = count;