Drawing order, rain adjustments

Author: Cheng Xie

src/cloud.cpp

@@ -14,6 +14,8 @@ Cloud::Cloud(float radius)
 
     setMaxParticleCount(100);
 
+    setRenderingOrder(RenderingOrder::YoungestFirst);
+    
     ParticleMaterial* material = static_cast<ParticleMaterial *>(material_);
     material->setHorizontal(true);
 }

src/common.h

@@ -7,6 +7,8 @@
 using std::string;
 #include <vector>
 using std::vector;
+#include <list>
+using std::list;
 #include <map>
 using std::map;
 #include <assert.h>

src/particlesystem.cpp

@@ -17,7 +17,6 @@ ParticleSystem::~ParticleSystem()
     delete mesh_;
 }
 
-// To Ken: This function can be ignored.
 void ParticleSystem::renderGeometry(DrawContext &context)
 {   
     update(context.deltaTime);
@@ -26,9 +25,25 @@ void ParticleSystem::renderGeometry(DrawContext &context)
         return;
     }
 
+    Particles particles = particles_;
+    
+    if (renderingOrder_ == RenderingOrder::Reversed) {
+        std::reverse(begin(particles), end(particles));
+    }
+    else if (renderingOrder_ == RenderingOrder::OldestFirst) {
+        std::sort(begin(particles), end(particles), [](const Particle& left, const Particle& right) {
+            return left.life > right.life;
+        });
+    }
+    else if (renderingOrder_ == RenderingOrder::YoungestFirst) {
+        std::sort(begin(particles), end(particles), [](const Particle& left, const Particle& right) {
+            return left.life < right.life;
+        });
+    }
+    
     VertexBufferDesc desc;
-    desc.bufferData = particles_.data();
-    desc.bufferSize = particles_.size() * sizeof(Particle);
+    desc.bufferData = particles.data();
+    desc.bufferSize = particles.size() * sizeof(Particle);
     desc.vertexElementSizes = {3, 1, 1, 3, 1};
     desc.stride = sizeof(Particle);
 
@@ -79,7 +94,7 @@ void ParticleSystem::update(float dt)
 
 void ParticleSystem::spawnParticle(Particle *particle)
 {
-
+    
 }
 
 void ParticleSystem::updateParticle(Particle &particle, float dt)
@@ -107,5 +122,16 @@ void ParticleSystem::setMaxParticleCount(int maxParticleCount)
     maxParticleCount_ = maxParticleCount;
 }
 
+RenderingOrder ParticleSystem::renderingOrder() const
+{
+    return renderingOrder_;
+}
+
+void ParticleSystem::setRenderingOrder(RenderingOrder renderingOrder)
+{
+    renderingOrder_ = renderingOrder;
+}
+
+
 
 

src/particlesystem.h

@@ -23,6 +23,13 @@ struct Particle
 };
 
 typedef vector<Particle> Particles;
+
+enum class RenderingOrder {
+    Default,
+    Reversed,
+    OldestFirst,
+    YoungestFirst,
+};
 
 class ParticleSystem : public SceneObject
 {
@@ -48,9 +55,12 @@ class ParticleSystem : public SceneObject
     uint32_t maxParticleCount() const;
     void setMaxParticleCount(int maxParticleCount);
 
+    RenderingOrder renderingOrder() const;
+    void setRenderingOrder(RenderingOrder renderingOrder);
+    
 protected:
     vector<Particle> particles_;
-
+    
 private:
     // time elapsed since the particle system was created
     float timeElapsed_ = 0;
@@ -62,6 +72,8 @@ class ParticleSystem : public SceneObject
     uint32_t emissionRate_ = 0;
 
     float numParticlesToSpawn_ = 0;
+    
+    RenderingOrder renderingOrder_ = RenderingOrder::Reversed;
 };
 
 #endif // PARTICLESYSTEM_H

src/rain.cpp

@@ -2,6 +2,8 @@
 #include "texture.h"
 #include "texturecache.h"
 #include "particlematerial.h"
+#include "drawcontext.h"
+#include "camera.h"
 
 Rain::Rain(float radius)
 {
@@ -20,14 +22,14 @@ Rain::Rain(float radius)
 
 void Rain::spawnParticle(Particle *particle)
 {
-    float speed = randf(60, 80);
+    float speed = randf(60, 100);
     vec3 velocity = {randf(0, 0.05), -1, randf(0, 0.1)};
     velocity *= speed;
 
     particle->velocity = velocity;
 
     float phi = randf(0, M_PI * 2);
-    float r = radius_ * randf();
+    float r = radius_ * randf(0.3, 1.0);
 
     float x = cosf(phi) * r;
     float y = 0;
@@ -39,7 +41,7 @@ void Rain::spawnParticle(Particle *particle)
 
     particle->size = 0.07;
 
-    float scale = randf(0.6f, 0.7f);
+    float scale = randf(0.6f, 0.8f);
     particle->color = {scale, scale, scale};
 
     particle->opacity = randf(0.4, 0.7);
@@ -48,6 +50,15 @@ void Rain::spawnParticle(Particle *particle)
 void Rain::updateParticle(Particle &particle, float dt)
 {
     particle.position += particle.velocity * dt;
-    
     particle.opacity = randf(0.4, 0.7);
 }
+
+void Rain::renderGeometry(DrawContext &context)
+{
+    ParticleSystem::renderGeometry(context);
+    transform().setToIdentity();
+    vec3 camPos = context.camera->position();
+    transform().translate(camPos.x(), camPos.y() + 30, camPos.z());
+}
+
+

src/rain.h

@@ -12,6 +12,8 @@ class Rain : public ParticleSystem
 
     virtual void updateParticle(Particle &particle, float dt) override;
 
+    virtual void renderGeometry(DrawContext &context) override;
+    
 private:
     float radius_;
 };

src/scene.cpp

@@ -30,7 +30,7 @@ Scene::~Scene()
     }
 
     delete skybox_;
-    delete tornado_;
+    //delete tornado_;
 }
 
 void Scene::initialize()
@@ -92,9 +92,7 @@ void Scene::initialize()
 
     // Rain
     Rain* rain = new Rain(30);
-    rain->transform().translate(0, 50, 0);
     sceneObjects_.push_back(rain);
-    
 }
 
 void Scene::render(DrawContext &context)
@@ -130,6 +128,11 @@ void Scene::setFogDensity(float fogDensity)
     fogDensity_ = fogDensity;
 }
 
+void Scene::update(float dt)
+{
+    
+}
+
 
 
 

src/scene.h

@@ -25,6 +25,8 @@ class Scene
     float fogDensity() const;
     void setFogDensity(float fogDensity);
 
+    void update(float dt);
+    
 private:
     SceneObjects sceneObjects_;
     Lights lights_;