Merge branch 'master' into bounce

Ball.cpp

@@ -2,25 +2,27 @@
 #include <iostream>
 #include <cmath>
 
-Ball::Ball(const Point& _center, double _min_height, double _v_x,
+Ball::Ball(const Point& _center, double _min_height, double _v_x, double _v_z,
         double _p, double _q) :
     Center(_center),
-    surface(_center, _p, _q),
-    init_h(_center.z),
+    surface(_center, min_height, _p, _q),
+    init_h(_center.y),
     min_height(_min_height),
     bounce_number(0.0),
     crt_time(0),
-    A(_center.z),
+    A(_center.y),
     B(0),
-    U(sqrt(2 * G_CTE * _center.z)),
-    T(sqrt(2.0 * _center.z / G_CTE)),
-    v_x(_v_x)
+    U(sqrt(2 * G_CTE * _center.y)),
+    T(sqrt(2.0 * _center.y / G_CTE)),
+    v_x(_v_x),
+    v_z(_v_z)
 {
 }
 
 void Ball::_compute_pos(double dt) {
-    Center.z = fmax(0.0, A + B * crt_time - (G_CTE / 2) * crt_time * crt_time + min_height);
+    Center.y = fmax(0.0, A + B * crt_time - (G_CTE / 2) * crt_time * crt_time + min_height);
     Center.x += dt * v_x;
+    Center.z += dt * v_z;
     surface.update_center_pos(Center);
 }
 
@@ -40,19 +42,27 @@ void Ball::_compute_U_n() {
     U *= 0.5;
 }
 
-void Ball::_compute_v_x() {
-    v_x *= 0.5;
+void Ball::_compute_v_x(Point normal) {
+    double factor = normal.x / (4*(normal.x + normal.z));
+    v_x *= (0.5 + factor);
+}
+
+void Ball::_compute_v_z(Point normal) {
+    double factor = normal.x / (4*(normal.x + normal.z));
+    v_z *= (0.5 + factor);
 }
 
 void Ball::update_pos(double dt) {
     crt_time += dt;
     if (crt_time >= T) {
+        Point normal = surface.getNormalVector();
         bounce_number += 1;
         _compute_U_n();
         _compute_A_n();
         _compute_B_n();
         _compute_T_n();
-        _compute_v_x();
+        _compute_v_x(normal);
+        _compute_v_z(normal);
         std::cout << "New bounce :";
         std::cout << "U:" << U << ":";
         std::cout << "A:" << A << ":";
@@ -67,7 +77,7 @@ std::ostream& operator<< (std::ostream &out, Ball const& data) {
     out << "t:" << data.access_crt_time() << ":";
     out << "T:" << data.accessT() << ":";
     out << center.x << ':';
-    out << center.y << ':';
     out << center.z << ':';
+    out << center.y << ':';
     return out;
 }

Ball.hpp

@@ -24,16 +24,17 @@ class Ball {
         size_t bounce_number;
         double crt_time;
         double A, B, U, T; // Coefficients for the physical model.
-        double v_x;
+        double v_x, v_z;
         void _compute_pos(double dt);
-        void _compute_v_x();
+        void _compute_v_x(Point normal);
+        void _compute_v_z(Point normal);
         void _compute_A_n();
         void _compute_B_n();
         void _compute_U_n();
         void _compute_T_n();
     public:
         Ball(const Point& _center, double _min_height, double _v_x,
-                double p, double q);
+                double _v_z, double p, double q);
         void update_pos(double dt);
         Point getCenter() const {return Center;}
         double accessT() const { return T;}

Makefile

@@ -11,6 +11,7 @@ OBJS=Implicit.o \
 	 Mesh.o \
 	 spheroid.o \
 	 Ball.o \
+	 PerlinNoise.o \
 	 util/ObjParser.o \
 	 MarchingCubes.o \
 	 _gen/marching_cubes_data.o \

PerlinNoise.cpp

@@ -0,0 +1,123 @@
+#include "PerlinNoise.hpp"
+
+Point vector_product(Point u, Point v) {
+    Point u_v(0,0,0);
+    u_v.x = u.y* v.z - u.z * v.y;
+    u_v.y = u.z* v.x - u.x * v.z;
+    u_v.z = u.x* v.y - u.y * v.x;
+    return u_v;
+}
+
+PerlinNoise::PerlinNoise() : ImplicitSurface(Point(0,0,0)) {
+    // permutation vector (source : http://mrl.nyu.edu/~perlin/noise/)
+    p = {
+		151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,
+		8,99,37,240,21,10,23,190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,
+		35,11,32,57,177,33,88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,
+		134,139,48,27,166,77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,
+		55,46,245,40,244,102,143,54, 65,25,63,161,1,216,80,73,209,76,132,187,208, 89,
+		18,169,200,196,135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,
+		250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,
+		189,28,42,223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167,
+		43,172,9,129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,
+		97,228,251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,
+		107,49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
+        138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 };
+    // Duplication of the permutation vector.
+    p.insert(p.end(), p.begin(), p.end());
+}
+
+PerlinNoise::PerlinNoise(unsigned int seed) : ImplicitSurface(Point(0,0,0)) {
+	p.resize(256);
+
+	// Fill p with values from 0 to 255
+	std::iota(p.begin(), p.end(), 0);
+
+	// Initialize a random engine with seed
+	std::default_random_engine engine(seed);
+
+	// Shuffle  using the above random engine
+	std::shuffle(p.begin(), p.end(), engine);
+
+	// Duplicate the permutation vector
+	p.insert(p.end(), p.begin(), p.end());
+}
+
+double PerlinNoise::operator() (double x, double y, double z) const {
+    return z - noise(x, y, 0);
+}
+
+double PerlinNoise::noise(double _x, double _y, double _z) const {
+    int X = (int) floor(_x) & 255;
+    int Y = (int) floor(_y) & 255;
+    int Z = (int) floor(_z) & 255;
+
+    _x -= floor(_x);
+    _y -= floor(_y);
+    _z -= floor(_z);
+
+    double u = fade(_x);
+    double v = fade(_y);
+    double w = fade(_z);
+
+    int A = p[X] + Y;
+    int AA = p[A] + Z;
+    int AB = p[A + 1] + Z;
+    int B = p[X + 1] + Y;
+    int BA = p[B] + Z;
+    int BB = p[B + 1] + Z;
+
+    double res = lerp(
+       w,
+       lerp(
+           v,
+           lerp(u, grad(p[AA], _x, _y, _z), grad(p[BA], _x-1, _y, _z)),
+           lerp(u, grad(p[AB], _x, _y-1, _z), grad(p[BB], _x-1, _y-1, _z))
+       ),
+       lerp(
+           v,
+           lerp(
+               u,
+               grad(p[AA+1], _x, _y, _z-1),
+               grad(p[BA+1], _x-1, _y, _z-1)
+           ),
+           lerp(
+               u,
+               grad(p[AB+1], _x, _y-1, _z-1),
+               grad(p[BB+1], _x-1, _y-1, _z-1)
+           )
+       )
+    );
+	return (res + 1.0)/2.0;
+}
+
+double PerlinNoise::noise(double _x, double _y) const {
+    return noise(_x, _y, 0);
+}
+
+double PerlinNoise::fade(double t) const {
+    return t * t * t * (t * (t * 6 - 15) + 10);
+}
+
+double PerlinNoise::lerp(double t, double a, double b) const {
+    return a + t * (b-a);
+}
+
+double PerlinNoise::grad(int hash, double x, double y, double z)  const {
+	int h = hash & 15;
+	// Convert lower 4 bits of hash into 12 gradient directions
+	double u = h < 8 ? x : y,
+		   v = h < 4 ? y : h == 12 || h == 14 ? x : z;
+	return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
+}
+
+Point PerlinNoise::normal_vector(double x, double y) {
+    double n_x_y = noise(x, y, 0);
+    double n_dx_y = noise(x + 0.01, y, 0);
+    double n_x_dy = noise(x, y + 0.01, 0);
+    Point product = vector_product(
+       Point(0.01, 0, n_dx_y - n_x_y),
+       Point(0, 0.01, (n_x_dy - n_x_y))
+    );
+    return product;
+}

PerlinNoise.hpp

@@ -0,0 +1,23 @@
+/**
+ * Perlin Noise implementation for the ground (header file)
+ **/
+#include "Implicit.hpp"
+#include <cmath>
+#include <random>
+#include <vector>
+#include <algorithm>
+
+class PerlinNoise : public ImplicitSurface {
+    std::vector<int> p;
+    public:
+        PerlinNoise();
+        PerlinNoise(unsigned int seed);
+        double operator() (double _x, double _y, double _z) const;
+        double noise(double x, double y) const;
+        Point normal_vector(double x, double y);
+    private:
+        double noise(double x, double y, double z) const;
+        double fade(double t) const;
+        double lerp(double t, double a, double b) const;
+        double grad(int hash, double x, double y, double z) const;
+};

main_ball.cpp

@@ -10,8 +10,8 @@ using namespace std;
 
 int main(int argc, char** argv) {
     int i;
-    Point center(0,0,10);
-    Ball ball(center, 0, 0.25, 1, 1);
+    Point center(0,10,0);
+    Ball ball(center, 0, 0.25, 0,  1, 1);
     for(i=0; i< 10000; i++) {
         ball.update_pos(0.001);
         cout << ball << "\n";

spheroid.cpp

@@ -4,18 +4,17 @@
 
 #include "spheroid.hpp"
 
-Spheroid::Spheroid(const Point& _center, double _p, double _q) :
-    ImplicitSurface(_center), init_p(_p), p(_p), q(_q), stiffness(0) {
-        _compute_volume();
-    }
+Spheroid::Spheroid(const Point& _center, double _min_p, double _p, double _q) :
+    ImplicitSurface(_center), normal_vector(Point(0,0,1)), min_p(_min_p),
+    init_p(_p), p(_p), q(_q), stiffness(0)
+{
+    _compute_volume();
+}
 
 void Spheroid::_compute_volume() {
     V = (4/3) * PI * p * q * q;
 }
 
-void Spheroid::set_stiffness(size_t _stiffness) {
-    stiffness = _stiffness;
-}
 
 
 void Spheroid::update_radius() {
@@ -32,8 +31,8 @@ void Spheroid::update_center_pos(Point& _center) {
 }
 
 void Spheroid::check_horizontal_plan_collision(double& height) {
-    if ((center.z - p) <= height) {
-        p = fmin(init_p, center.z-height);
+    if ((center.y - p) <= height) {
+        p = fmin(init_p, center.y-height);
         update_radius();
     }
 }
@@ -51,3 +50,27 @@ void Spheroid::check_vertical_plan_collision(double& abscissa) {
         }
     }
 }
+
+Cuboid Spheroid::max_bounding_box() const {
+    double max_radius = sqrt((3/4) * V / PI / min_p);
+    double max_height = init_p;
+    Point _bd1(max_radius, max_radius, max_height);
+    Point _bd2(-max_radius, -max_radius, -max_height);
+    return Cuboid(_bd1, _bd2);
+}
+
+void Spheroid::check_perlin_collision(PerlinNoise perlin) {
+    double height = perlin.noise(center.x, center.z);
+    if ((center.y - p) <= height) {
+        p = fmin(init_p, center.z- height );
+        normal_vector = perlin.normal_vector(center.x, center.z);
+        update_radius();
+    }
+}
+
+
+double Spheroid::operator() (double _x, double _y, double _z) const {
+            return (pow(_x, 2) / pow(q, 2)
+                  + pow(_y, 2) / pow(q, 2)
+                  + pow(_z, 2) / pow(p, 2) -1);
+}

spheroid.hpp

@@ -7,23 +7,22 @@
 #include <cmath>
 #include "Implicit.hpp"
 #include "common_structures.hpp"
+#include "PerlinNoise.hpp"
 
 const double PI = 3.141592653589793;
 
 class Spheroid : public ImplicitSurface {
     public:
-        Spheroid(const Point& _center, double _p, double _q);
+        Spheroid(const Point& _center, double _min_p, double _p, double _q);
         void update_center_pos(Point& _center);
         void update_radius();
         void update_height();
-        void set_stiffness(size_t _stiffness);
         void check_horizontal_plan_collision(double& height);
         void check_vertical_plan_collision(double& abscissa);
-        double operator() (double _x, double _y, double _z) const {
-            return (pow(_x, 2) / pow(q, 2)
-                  + pow(_y, 2) / pow(q, 2)
-                  + pow(_z, 2) / pow(p, 2) -1);
-        }
+        Cuboid max_bounding_box() const;
+        void check_perlin_collision(PerlinNoise perlin);
+        Point getNormalVector() const { return normal_vector;}
+        double operator() (double _x, double _y, double _z) const;
     private:
         /**
          * p corresponds to the half-height of the ball,
@@ -31,7 +30,8 @@ class Spheroid : public ImplicitSurface {
          * V is the volume. Extremely useful to have a constant volume in the
          * ball
         **/
-        double init_p, p, q;
+        Point normal_vector;
+        double min_p, init_p, p, q;
         size_t stiffness;
         double V;
         void _compute_volume();