Add draft for multiple particle types

The type was changed from int to float, because comparing the int to values (e.g. type == 1) never returned true...

Shader/particle_render.gs

@@ -14,20 +14,20 @@ layout(max_vertices = 4) out;
 in vec3 color_pass[];
 in float lifetime_pass[];
 in float size_pass[];
-in int type_pass[];
+in float type_pass[];
 
 smooth out vec2 tex_coords;
 flat out vec4 color_part;
 
 void main() {
-  if(type_pass[0] != 0) {
+  if(type_pass[0] != 0.0) {
     // This is not a generator particle
 
     vec3 old_pos = gl_in[0].gl_Position.xyz - camera_pos;
     float size = size_pass[0];
     mat4 view_projection_matrix = projection * view;
     
-    color_part = vec4(color_pass[0], lifetime_pass[0]);
+    color_part = vec4(color_pass[0], 1.0);
        
     vec3 pos = old_pos + (-quad1 - quad2) * size;
     tex_coords = vec2(0.0, 0.0);

Shader/particle_render.vs

@@ -4,12 +4,12 @@ layout (location = 0) in vec3 position;
 layout (location = 2) in vec3 color;
 layout (location = 3) in float lifetime;
 layout (location = 4) in float size;
-layout (location = 5) in int type;
+layout (location = 5) in float type;
 
 out vec3 color_pass;
 out float lifetime_pass;
 out float size_pass;
-out int type_pass;
+out float type_pass;
 
 void main()
 {

Shader/particle_update.gs

@@ -10,7 +10,7 @@ in vec3 velocity_pass[];
 in vec3 color_pass[];
 in float lifetime_pass[];
 in float size_pass[];
-in int type_pass[];
+in float type_pass[];
 
 // All that we send further
 out vec3 position_out;
@@ -18,7 +18,7 @@ out vec3 velocity_out;
 out vec3 color_out;
 out float lifetime_out;
 out float size_out;
-out int type_out;
+out float type_out;
 
 uniform vec3 spawn_position; // Position where new particles are spawned
 uniform vec3 spawn_gravity; // Gravity vector for particles - updates velocity of particles 
@@ -55,15 +55,15 @@ void main() {
   position_out = position_pass[0];
   velocity_out = velocity_pass[0];
 
-  if(type_pass[0] != 0) position_out += velocity_out * time_passed;
-  if(type_pass[0] != 0) velocity_out += spawn_gravity * time_passed;
+  if(type_pass[0] != 0.0) position_out += velocity_out * time_passed;
+  if(type_pass[0] != 0.0) velocity_out += spawn_gravity * time_passed;
 
   color_out = color_pass[0];
   lifetime_out = lifetime_pass[0] - time_passed;
   size_out = size_pass[0];
   type_out = type_pass[0];
     
-  if(type_out == 0) {
+  if(type_out == 0.0) {
     // This is the emitter particle
     EmitVertex();
     EndPrimitive();
@@ -80,14 +80,50 @@ void main() {
       color_out = spawn_color;
       lifetime_out = spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one();
       size_out = spawn_size;
-      type_out = 1;
+      type_out = 1.0;
 
       EmitVertex();
       EndPrimitive();
     }
   } else if (lifetime_out > 0.0) {
       // This is a normal particle which is still alive
+      EmitVertex();
+      EndPrimitive(); 
+  } else if (type_out == 1.0) {
+    // The lifetime is over -- transform this particle in a new one or discard
+    for(int i = 0; i < 5; i++) {
+      // Keep the position
+      velocity_out = spawn_velocity_min + vec3(
+          spawn_velocity_range.x * random_zero_to_one(),
+          spawn_velocity_range.y * random_zero_to_one(),
+          spawn_velocity_range.z * random_zero_to_one()
+      );
+
+      color_out = vec3(1.0, 0, 0);
+      lifetime_out = spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one();
+      size_out = spawn_size;
+      type_out = 2.0;
+
+      EmitVertex();
+      EndPrimitive();
+    } 
+  } else if (type_out == 2.0) {
+    // The lifetime is over -- transform this particle in a new one or discard
+    for(int i = 0; i < 5; i++) {
+      // Keep the position
+      velocity_out = spawn_velocity_min + vec3(
+          spawn_velocity_range.x * random_zero_to_one(),
+          spawn_velocity_range.y * random_zero_to_one(),
+          spawn_velocity_range.z * random_zero_to_one()
+      );
+
+      color_out = vec3(0.0, 1.0, 0);
+      lifetime_out = spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one();
+      size_out = spawn_size;
+      type_out = 3.0;
+
       EmitVertex();
       EndPrimitive();
     } 
   }
+}

Shader/particle_update.vs

@@ -5,14 +5,14 @@ layout (location = 1) in vec3 velocity;
 layout (location = 2) in vec3 color;
 layout (location = 3) in float lifetime;
 layout (location = 4) in float size;
-layout (location = 5) in int type;
+layout (location = 5) in float type;
 
 out vec3 position_pass;
 out vec3 velocity_pass;
 out vec3 color_pass;
 out float lifetime_pass;
 out float size_pass;
-out int type_pass;
+out float type_pass;
 
 void main() {
   position_pass = position;

cpp/ParticleSystem.cpp

@@ -42,7 +42,7 @@ ParticleSystem::ParticleSystem() {
         glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Particle), (const GLvoid *)24); // Color
         glVertexAttribPointer(3, 1, GL_FLOAT, GL_FALSE, sizeof(Particle), (const GLvoid *)36); // Lifetime
         glVertexAttribPointer(4, 1, GL_FLOAT, GL_FALSE, sizeof(Particle), (const GLvoid *)40); // Size
-        glVertexAttribPointer(5, 1, GL_INT, GL_FALSE, sizeof(Particle), (const GLvoid *)44);   // Type
+        glVertexAttribPointer(5, 1, GL_FLOAT, GL_FALSE, sizeof(Particle), (const GLvoid *)44); // Type
     }
 
     current_read_buffer = 0;

cpp/RenderBackend.cpp

@@ -16,10 +16,10 @@ void RenderBackend::initialize_window(unsigned int width, unsigned int height, S
     glfwMakeContextCurrent(window);
     gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
 
-    glEnable(GL_DEPTH_TEST);
-    // glEnable(GL_CULL_FACE);
-    // glEnable(GL_BLEND);
-    // glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    // FIXME: Disabled because of a bug with particles: they're discarded as if the floor moves with the camera
+    // glEnable(GL_DEPTH_TEST);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 }
 
 bool RenderBackend::is_window_created() {

include/Gedeng/ParticleSystem.h

@@ -53,7 +53,7 @@ class ParticleSystem {
 
     int current_read_buffer;
     int current_particle_count;
-    const int max_particle_count = 1000; // FIXME: Increase
+    const int max_particle_count = 1000000;
 
     glm::mat4 projection_matrix, view_matrix;
     glm::vec3 quad1, quad2;
@@ -82,7 +82,7 @@ class ParticleSystem {
         glm::vec3 color;
         float lifetime;
         float size;
-        int type;
+        float type;
     };
 };
 

test/particle-demo/main.cpp

@@ -20,12 +20,12 @@ class ParticleApp : public Gedeng::Application {
           quad_mesh(Gedeng::QuadMesh(10.0)) {
         particles.set_position(glm::vec3(0.0f, 0.0f, -5.0f));
         particles.set_velocity(glm::vec3(-1, 0, -1), glm::vec3(1, 5, 1));
-        particles.set_gravity(glm::vec3(0, -1, 0));
+        particles.set_gravity(glm::vec3(0, -2, 0));
         particles.set_color(glm::vec3(0.0f, 0.5f, 1.0f));
-        particles.set_lifetime(5.0f, 10.0f);
+        particles.set_lifetime(1.0f, 1.5f);
         particles.set_size(0.1);
         particles.set_interval(0.05f);
-        particles.set_number_of_particles(50);
+        particles.set_number_of_particles(1);
         particles.set_texture(&albedo);
 
         camera.translate(glm::vec3(0.0, 2.0, 1.0));