Added scale and color interpolation

src/Systems/ParticleSystem.cpp

@@ -27,9 +27,10 @@ void Systems::ParticleSystem::UpdateEntity(double dt, EntityID entity, EntityID
 		std::list<ParticleData>::iterator it;
 		for(it = m_ParticleEmitter[entity].begin(); it == m_ParticleEmitter[entity].end();)
 		{
-			it->TimeLived += dt;
 			auto particleComponent = m_World->GetComponent<Components::Particle>(it->ParticleID, "Particle");
-			if(it->TimeLived > particleComponent->LifeTime)
+			
+			int timeLived = glfwGetTime() - it->SpawnTime; 
+			if(timeLived > particleComponent->LifeTime)
 			{
 				m_ParticleEmitter[entity].erase(it);
 				break;
@@ -39,7 +40,20 @@ void Systems::ParticleSystem::UpdateEntity(double dt, EntityID entity, EntityID
 				it++;
 			}
 
+			// Interpolates the color for each color channel by the start and end value. Decides how much the color should be interpolated based on time.
+			// How big fraction the color is multiplied with
+			float timeProgress = timeLived / particleComponent->LifeTime; 
+			// The difference between the start and end value
+			float deltaColor = glm::abs(particleComponent->ColorSpectrum[0].r - particleComponent->ColorSpectrum[1].r); 
+			it->color.r = particleComponent->ColorSpectrum[0].r + deltaColor * timeProgress;
+			deltaColor = glm::abs(particleComponent->ColorSpectrum[0].g - particleComponent->ColorSpectrum[1].g);
+			it->color.g = particleComponent->ColorSpectrum[0].g + deltaColor * timeProgress;
+			deltaColor = glm::abs(particleComponent->ColorSpectrum[0].b - particleComponent->ColorSpectrum[1].b);
+			it->color.b = particleComponent->ColorSpectrum[0].b + deltaColor * timeProgress;
 
+			//Interpolates the scale for the particle
+			float deltaScale = glm::abs(particleComponent->ScaleSpectrum[0] - particleComponent->ScaleSpectrum[1]);
+			it->Scale = particleComponent->ScaleSpectrum[0] + deltaScale * timeProgress;
 		}
 	}
 }
@@ -56,13 +70,25 @@ void Systems::ParticleSystem::SpawnParticles(EntityID emitterID, float spawnCoun
 	for(int i = 0; i < spawnCount; i++)
 	{
 		auto ent = m_World->CreateEntity();
+		
 		auto transform = m_World->AddComponent<Components::Transform>(ent, "Transform");
 		transform->Position = glm::vec3(0);
+		
 		auto particle = m_World->AddComponent<Components::Particle>(ent, "Particle");
 		particle->LifeTime = 4;
+		Color startColor = {.4f, .45f, .2f};
+		particle->ColorSpectrum.push_back(startColor);
+		Color endColor = {0.f, 45.f, 23.f};
+		particle->ColorSpectrum.push_back(endColor);
+		particle->ScaleSpectrum.push_back(1);
+		particle->ScaleSpectrum.push_back(30);
+
 		ParticleData data;
 		data.ParticleID = ent;
-		data.TimeLived = 0;
+		data.SpawnTime = glfwGetTime();
+		data.color = particle->ColorSpectrum[0];
+		data.Scale = particle->ScaleSpectrum[0];
+
 		m_ParticleEmitter[emitterID].push_back(data);
 	}
 }

src/Systems/ParticleSystem.h

@@ -5,6 +5,8 @@
 #include "Components/Transform.h"
 #include "Components/ParticleEmitter.h"
 #include "Components/Particle.h"
+#include "Color.h"
+#include <GLFW/glfw3.h>
 
 
 namespace Systems
@@ -13,7 +15,9 @@ namespace Systems
 	struct ParticleData
 	{
 		EntityID ParticleID;
-		double TimeLived;
+		double SpawnTime;
+		float Scale;
+		Color color;
 	};
 
 class ParticleSystem : public System