nuclear@1: #ifndef _MSC_VER
nuclear@1: #include <alloca.h>
nuclear@1: #else
nuclear@1: #include <malloc.h>
nuclear@1: #endif
nuclear@1: #include "vein.h"
nuclear@1: #include "geom.h"
nuclear@1: 
nuclear@1: Vein::Vein()
nuclear@1: {
nuclear@1: 	gen_dist = 8.0;
nuclear@1: 	subdiv = 8;
nuclear@1: 	ring_subdiv = 16;
nuclear@1: 	rad = 1.0;
nuclear@1: 
nuclear@1: 	idxbuf = 0;
nuclear@1: }
nuclear@1: 
nuclear@1: Vein::~Vein()
nuclear@1: {
nuclear@1: 	delete [] idxbuf;
nuclear@1: }
nuclear@1: 
nuclear@1: Vector3 Vein::calc_center(const Vector3 &ppos) const
nuclear@1: {
nuclear@1: 	// TODO add variation
nuclear@1: 	return Vector3(0.0, 0.0, ppos.z);
nuclear@1: }
nuclear@1: 
nuclear@1: Vector3 Vein::calc_dir(const Vector3 &ppos) const
nuclear@1: {
nuclear@1: 	// TODO add variation
nuclear@1: 	return Vector3(0, 0, 1);
nuclear@1: }
nuclear@1: 
nuclear@1: void Vein::build_idxbuf()
nuclear@1: {
nuclear@1: 	delete [] idxbuf;
nuclear@1: 
nuclear@1: 	int nfaces = subdiv * ring_subdiv;
nuclear@1: 	int nidx = nfaces * 4;
nuclear@1: 	idxbuf = new unsigned int[nidx];
nuclear@1: 	unsigned int *idxptr = idxbuf;
nuclear@1: 
nuclear@1: 	for(int i=0; i<subdiv; i++) {
nuclear@1: 		for(int j=0; j<ring_subdiv; j++) {
nuclear@1: 			idxptr[0] = i * ring_subdiv + j;
nuclear@1: 			idxptr[1] = i * ring_subdiv + ((j + 1) % ring_subdiv);
nuclear@1: 			idxptr[2] = idxptr[1] + ring_subdiv;
nuclear@1: 			idxptr[3] = idxptr[0] + ring_subdiv;
nuclear@1: 			idxptr += 4;
nuclear@1: 		}
nuclear@1: 	}
nuclear@1: }
nuclear@1: 
nuclear@1: void Vein::draw(const Vector3 &ppos) const
nuclear@1: {
nuclear@1: 	float start_z = ppos.z - gen_dist / 2.0;
nuclear@1: 	float dz = gen_dist / subdiv;
nuclear@1: 
nuclear@1: 	int nslices = subdiv + 1;
nuclear@1: 	int nverts = nslices * ring_subdiv;
nuclear@1: 	int nfaces = subdiv * ring_subdiv;
nuclear@1: 	Vertex *vbuf = (Vertex*)alloca(nverts * sizeof *vbuf);
nuclear@1: 	Vertex *vptr = vbuf;
nuclear@1: 
nuclear@1: 	Vector3 pt = ppos;
nuclear@1: 	pt.z = start_z;
nuclear@1: 
nuclear@1: 	for(int i=0; i<nslices; i++) {
nuclear@1: 		Vector3 cent = calc_center(pt);
nuclear@1: 		Vector3 dir = calc_dir(pt);
nuclear@1: 		Vector3 up(0, 1, 0);
nuclear@1: 		Vector3 right = cross_product(up, dir);
nuclear@1: 		up = cross_product(dir, right);
nuclear@1: 
nuclear@1: 		Matrix3x3 vrot{right, up, dir};
nuclear@1: 		//Quaternion vrot(dri, dtheta);
nuclear@1: 
nuclear@1: 		float theta = 0.0, dtheta = 2.0 * M_PI / ring_subdiv;
nuclear@1: 		for(int j=0; j<ring_subdiv; j++) {
nuclear@1: 			Vector3 vec = Vector3{-cos(theta) * rad, sin(theta) * rad, 0.0} + cent;
nuclear@1: 			vec.transform(vrot);
nuclear@1: 
nuclear@1: 			vptr->pos = vec;
nuclear@1: 			vptr->norm = cent - vec;
nuclear@1: 			vptr->tang = Vector3();	// TODO
nuclear@1: 			vptr->tc = Vector2();	// TODO
nuclear@1: 			vptr++;
nuclear@1: 
nuclear@1: 			theta += dtheta;
nuclear@1: 		}
nuclear@1: 
nuclear@1: 		pt.z += dz;
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	// also create the index buffer if it's not valid
nuclear@1: 	if(!idxbuf) {
nuclear@1: 		((Vein*)this)->build_idxbuf();
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	// awesome, now draw it
nuclear@1: 	draw_mesh(GL_QUADS, nfaces * 4, vbuf, idxbuf);
nuclear@1: }