Look at all the pretty colours!

We now have color values for the field elements, which are gradually added to the particles as they move.

cloud.cpp

@@ -21,14 +21,20 @@ Cloud::Cloud(int num,
     particles = new Particle[count];
     
     for (i = 0; i < count; i++) {
-        particles[i].position.x = randFloat()*box.x;
-        particles[i].position.y = randFloat()*box.y;
-        particles[i].position.z = randFloat()*box.z;
+        float x = randFloat()*box.x;
+        float y = randFloat()*box.y;
+        float z = randFloat()*box.z;
+        particles[i].position.x = x;
+        particles[i].position.y = y;
+        particles[i].position.z = z;
                 
         particles[i].velocity.x = 0;  //randFloat() - 0.5;
         particles[i].velocity.y = 0;  //randFloat() - 0.5;
         particles[i].velocity.z = 0;  //randFloat() - 0.5;
         
+        particles[i].color = glm::vec3(x*0.8f/WORLD_SIZE + 0.2f,
+                                       y*0.8f/WORLD_SIZE + 0.2f,
+                                       z*0.8f/WORLD_SIZE + 0.2f);
     }
 }
 
@@ -38,7 +44,7 @@ void Cloud::render() {
     float particle_attenuation_quadratic[] =  { 0.0f, 0.0f, 2.0f };
     
     glEnable( GL_TEXTURE_2D );
-    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
+    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
     glPointParameterfvARB( GL_POINT_DISTANCE_ATTENUATION_ARB, particle_attenuation_quadratic );
     
     float maxSize = 0.0f;
@@ -52,6 +58,9 @@ void Cloud::render() {
     glBegin( GL_POINTS );
         for (int i = 0; i < count; i++)
         {
+            glColor3f(particles[i].color.x,
+                      particles[i].color.y,
+                      particles[i].color.z);
             glVertex3f(particles[i].position.x,
                        particles[i].position.y,
                        particles[i].position.z);
@@ -75,7 +84,7 @@ void Cloud::simulate (float deltaTime) {
                 
         // Interact with Field
         const float FIELD_COUPLE = 0.0000001;
-        field_interact(&particles[i].position, &particles[i].velocity, FIELD_COUPLE);
+        field_interact(&particles[i].position, &particles[i].velocity, &particles[i].color, FIELD_COUPLE);
         
         //  Bounce or Wrap 
         if (wrapBounds) {

cloud.h

@@ -22,7 +22,7 @@ public:
     
 private:
     struct Particle {
-        glm::vec3 position, velocity;
+        glm::vec3 position, velocity, color;
        } *particles;
     unsigned int count;
     glm::vec3 bounds;

field.cpp

@@ -7,15 +7,11 @@
 //
 
 #include "field.h"
+#include "glm/glm.hpp"
 #define FIELD_SCALE 0.00050
 
 //  A vector-valued field over an array of elements arranged as a 3D lattice 
 
-struct {
-    glm::vec3 val;
-} field[FIELD_ELEMENTS];
-
-
 int field_value(float *value, float *pos)
 // sets the vector value (3 floats) to field value at location pos in space.
 // returns zero if the location is outside world bounds
@@ -33,7 +29,6 @@ int field_value(float *value, float *pos)
     else return 0;
 }
 
-
 void field_init()
 //  Initializes the field to some random values
 {
@@ -43,7 +38,11 @@ void field_init()
         field[i].val.x = (randFloat() - 0.5)*FIELD_SCALE;
         field[i].val.y = (randFloat() - 0.5)*FIELD_SCALE;
         field[i].val.z = (randFloat() - 0.5)*FIELD_SCALE;
-    }       
+        // and set up the RGB values for each field element.
+        fieldcolors[i].rgb = glm::vec3(((i%10)*0.08) + 0.2f,
+                                       ((i%100)*0.008) + 0.2f,
+                                       (i*0.0008) + 0.2f);
+    }
 }
 
 void field_add(float* add, float *pos)
@@ -60,7 +59,7 @@ void field_add(float* add, float *pos)
     }
 }
 
-void field_interact(glm::vec3 * pos, glm::vec3 * vel, float coupling) {
+void field_interact(glm::vec3 * pos, glm::vec3 * vel, glm::vec3 * color, float coupling) {
      
     int index = (int)(pos->x/WORLD_SIZE*10.0) + 
     (int)(pos->y/WORLD_SIZE*10.0)*10 + 
@@ -72,6 +71,9 @@ void field_interact(glm::vec3 * pos, glm::vec3 * vel, float coupling) {
         glm::vec3 temp = *vel;
         temp *= coupling;
         field[index].val += temp;
+        
+        // add a fraction of the field color to the particle color
+        *color = (*color * 0.999f) + (fieldcolors[index].rgb * 0.001f);
     }
 }
 
@@ -172,3 +174,4 @@ void field_render()
 }
 
 
+

field.h

@@ -20,14 +20,22 @@
 #include "glm/glm.hpp"
 
 //  Field is a lattice of vectors uniformly distributed FIELD_ELEMENTS^(1/3) on side 
-
 const int FIELD_ELEMENTS = 1000;
 
+struct {
+    glm::vec3 val;
+} field[FIELD_ELEMENTS];
+
+// Pre-calculated RGB values for each field element
+struct {
+    glm::vec3 rgb;
+} fieldcolors[FIELD_ELEMENTS];
+
 void field_init();
 int field_value(float *ret, float *pos);
 void field_render();
 void field_add(float* add, float *loc);
-void field_interact(glm::vec3 * pos, glm::vec3 * vel, float coupling);
+void field_interact(glm::vec3 * pos, glm::vec3 * vel, glm::vec3 * color, float coupling);
 void field_simulate(float dt);
-
+glm::vec3 hsv2rgb(glm::vec3 in);
 #endif