X-Git-Url: http://git.mutantstargoat.com?p=hair;a=blobdiff_plain;f=src%2Fhair.cc;h=b99d133994ac0028d5fde2b6f13bf7db68f4634e;hp=e4843fb0c9168a058946e31cb6e1e45c6e68d5ef;hb=a65a977df6fa8fee831c91cdc754d62e023b6630;hpb=da5cbacf755273da510c37c819a59c7fe9894c4e

diff --git a/src/hair.cc b/src/hair.cc
index e4843fb..b99d133 100644
--- a/src/hair.cc
+++ b/src/hair.cc
@@ -1,3 +1,6 @@
+#include <GL/glew.h>
+
+#include <float.h>
 #include <gmath/gmath.h>
 #include <stdlib.h>
 #include <string>
@@ -5,13 +8,24 @@
 #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)
 {
@@ -25,7 +39,7 @@ 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;
@@ -36,11 +50,18 @@ static Vec3 calc_rand_point(const Triangle &tr, Vec3 *bary)
 
 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;
@@ -53,10 +74,15 @@ static void get_spawn_triangles(const Mesh *m, float thresh, std::vector<Triangl
 			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)
@@ -65,6 +91,11 @@ 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++) {
@@ -75,24 +106,109 @@ bool Hair::init(const Mesh *m, int max_num_spawns, float thresh)
 		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;
+
+		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;
 }