+#include <GL/glew.h>
+
+#include <float.h>
#include <gmath/gmath.h>
#include <stdlib.h>
#include <string>
#include "kdtree.h"
#include "hair.h"
+/* spring constant */
+
+#define K_ANC 4.0
+#define DAMPING 1.5
+
struct Triangle {
Vec3 v[3];
Vec3 n[3];
};
-Hair::Hair() {}
-Hair::~Hair() {}
+Hair::Hair()
+{
+ hair_length = 0.5;
+}
+
+Hair::~Hair()
+{
+}
static Vec3 calc_rand_point(const Triangle &tr, Vec3 *bary)
{
float c = 1 - (u + v);
- Vec3 rp = u * tr.v[0] + v * tr.v[1] + c * tr.v[3];
+ Vec3 rp = u * tr.v[0] + v * tr.v[1] + c * tr.v[2];
bary->x = u;
bary->y = v;
static void get_spawn_triangles(const Mesh *m, float thresh, std::vector<Triangle> *faces)
{
+ if (!m) {
+ fprintf(stderr, "Func: %s, invalid mesh.\n", __func__);
+ exit(1);
+ }
+ float min_y = FLT_MAX;
+ float max_y = -FLT_MAX;
+
for(size_t i=0; i<m->indices.size() / 3; i++) {
bool is_spawn = true;
int idx[3];
for(int j=0; j<3; j++) {
- idx[j] = i * 3 + j;
+ idx[j] = m->indices[i * 3 + j];
float c = (m->colors[idx[j]].x + m->colors[idx[j]].y + m->colors[idx[j]].z) / 3;
if (c >= thresh) {
is_spawn = false;
for(int j=0; j<3; j++) {
t.v[j] = m->vertices[idx[j]];
t.n[j] = m->normals[idx[j]];
+ if(t.v[j].y < min_y)
+ min_y = t.v[j].y;
+ if(t.v[j].y > max_y)
+ max_y = t.v[j].y;
}
faces->push_back(t);
}
}
+/* printf("spawn tri AABB: min y: %f max y: %f\n", min_y, max_y);*/
}
bool Hair::init(const Mesh *m, int max_num_spawns, float thresh)
kdtree *kd = kd_create(3);
const float min_dist = 0.05;
+ if(!m) {
+ fprintf(stderr, "Func %s: invalid mesh.\n", __func__);
+ return false;
+ }
+
get_spawn_triangles(m, thresh, &faces);
for(int i = 0; i < max_num_spawns; i++) {
Vec3 rpoint = calc_rand_point(rtriangle, &bary);
kdres *res = kd_nearest3f(kd, rpoint.x, rpoint.y, rpoint.z);
- if (!kd_res_end(res)) {
+
+ if (res && !kd_res_end(res)) {
Vec3 nearest;
kd_res_item3f(res, &nearest.x, &nearest.y, &nearest.z);
if(distance_sq(rpoint, nearest) < min_dist * min_dist)
continue;
}
+ HairStrand strand;
/* weighted sum of the triangle's vertex normals */
- Vec3 spawn_dir = rtriangle.n[0] * bary.x + rtriangle.n[1] * bary.y + rtriangle.n[2] * bary.z;
- spawn_directions.push_back(normalize(spawn_dir));
- spawn_points.push_back(rpoint);
+ strand.spawn_dir = normalize(rtriangle.n[0] * bary.x + rtriangle.n[1] * bary.y + rtriangle.n[2] * bary.z);
+ strand.spawn_pt = rpoint;
+ hair.push_back(strand);
+
kd_insert3f(kd, rpoint.x, rpoint.y, rpoint.z, 0);
}
kd_free(kd);
+
+ for(size_t i=0; i<hair.size(); i++) {
+ hair[i].pos = hair[i].spawn_pt + hair[i].spawn_dir * hair_length;
+ }
return true;
}
+static Vec3 dbg_force;
void Hair::draw() const
{
+ glPushAttrib(GL_ENABLE_BIT);
+// glDisable(GL_DEPTH_TEST);
+ glDisable(GL_LIGHTING);
+ glPointSize(5);
+ glLineWidth(3);
+
+ glBegin(GL_LINES);
+ for(size_t i=0; i<hair.size(); i++) {
+ glColor3f(1, 0, 1);
+ Vec3 p = xform * hair[i].spawn_pt;
+ glVertex3f(p.x, p.y, p.z);
+ Vec3 dir = normalize(hair[i].pos - p) * hair_length;
+ Vec3 end = p + dir;
+ glVertex3f(end.x, end.y, end.z);
+/*
+ glColor3f(1, 1, 0);
+ glVertex3f(hair[i].pos.x, hair[i].pos.y, hair[i].pos.z);
+ Vec3 fend = hair[i].pos + dbg_force * 2.0;
+ glVertex3f(fend.x, fend.y, fend.z);
+ */
+ }
+ glEnd();
+
+ /*
+ glBegin(GL_POINTS);
+ glColor3f(0.5, 1.0, 0.5);
+ for(size_t i = 0; i < hair.size(); i++) {
+ Vec3 p = xform * (hair[i].spawn_pt + hair[i].spawn_dir * hair_length);
+ glVertex3f(p.x, p.y, p.z);
+ }
+ glEnd();*/
+
+ glPopAttrib();
+}
+
+void Hair::set_transform(Mat4 &xform)
+{
+ this->xform = xform;
+}
+
+void Hair::update(float dt)
+{
+ for(size_t i = 0; i < hair.size(); i++) {
+ /* in local space */
+ Vec3 hair_end = hair[i].spawn_pt + hair[i].spawn_dir * hair_length;
+ Vec3 anchor = xform * hair_end;
+
+ Vec3 force = (anchor - hair[i].pos) * K_ANC;
+
+ Vec3 accel = force; /* mass 1 */
+ hair[i].velocity += ((-hair[i].velocity * DAMPING) + accel) * dt;
+ Vec3 new_pos = hair[i].pos + hair[i].velocity * dt;
+
+ /* collision detection with the head */
+ Vec3 normal = xform.upper3x3() * hair[i].spawn_dir;
+ Vec3 root = xform * hair[i].spawn_pt;
+ Vec3 dir = new_pos - root;
+
+ normal.normalize();
+
+ /* angle that will cause the hair to be rendered inside the head */
+ float d = dot(dir, normal);
+ if(d < 0) {
+ new_pos += -d * normal;
+ }
+
+ hair[i].pos = handle_collision(new_pos);
+
+ dbg_force = force;
+ }
+}
+
+void Hair::add_collider(CollSphere *cobj) {
+ colliders.push_back(cobj);
+}
+
+Vec3 Hair::handle_collision(const Vec3 &v) const
+{
+ /* if we transform the center and the radius of the collider sphere
+ * we might end up with a spheroid, so better just multiply the
+ * position with the inverse transform before check for collisions :*/
+
+ Vec3 new_v = inverse(xform) * v;
+
+ for(size_t i=0; i<colliders.size(); i++) {
+ if(colliders[i]->contains(new_v)) {
+ new_v = colliders[i]->project_surf(new_v);
+ }
+ }
+ return xform * new_v;
}
projects / hair / blobdiff