# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1440293489 -10800
# Node ID 7b1fa527b51bc0aeee502d9776890885d54c26a1
# Parent  93ff21458a16d597d9e300af2c6e3bc57a55dbd9
added torus mesh gen

diff -r 93ff21458a16 -r 7b1fa527b51b src/meshgen.cc
--- a/src/meshgen.cc	Sun Aug 23 02:51:39 2015 +0300
+++ b/src/meshgen.cc	Sun Aug 23 04:31:29 2015 +0300
@@ -38,11 +38,11 @@
 
 	float u = 0.0;
 	for(int i=0; i<uverts; i++) {
-		float theta = SURAD(u * urange);
+		float theta = u * 2.0 * M_PI;
 
 		float v = 0.0;
 		for(int j=0; j<vverts; j++) {
-			float phi = SVRAD(v * vrange);
+			float phi = v * M_PI;
 
 			Vector3 pos = sphvec(theta, phi);
 
@@ -68,6 +68,81 @@
 	}
 }
 
+// -------- torus -----------
+static Vector3 torusvec(float theta, float phi, float mr, float rr)
+{
+	theta = -theta;
+
+	float rx = -cos(phi) * rr + mr;
+	float ry = sin(phi) * rr;
+	float rz = 0.0;
+
+	float x = rx * sin(theta) + rz * cos(theta);
+	float y = ry;
+	float z = -rx * cos(theta) + rz * sin(theta);
+
+	return Vector3(x, y, z);
+}
+
+void gen_torus(Mesh *mesh, float mainrad, float ringrad, int usub, int vsub, float urange, float vrange)
+{
+	if(usub < 4) usub = 4;
+	if(vsub < 2) vsub = 2;
+
+	int uverts = usub + 1;
+	int vverts = vsub + 1;
+
+	int num_verts = uverts * vverts;
+	int num_quads = usub * vsub;
+	int num_tri = num_quads * 2;
+
+	mesh->clear();
+	Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);
+	Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);
+	Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);
+	Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);
+	unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);
+
+	float du = urange / (float)(uverts - 1);
+	float dv = vrange / (float)(vverts - 1);
+
+	float u = 0.0;
+	for(int i=0; i<uverts; i++) {
+		float theta = u * 2.0 * M_PI;
+
+		float v = 0.0;
+		for(int j=0; j<vverts; j++) {
+			float phi = v * 2.0 * M_PI;
+
+			Vector3 pos = torusvec(theta, phi, mainrad, ringrad);
+			Vector3 cent = torusvec(theta, phi, mainrad, 0.0);
+
+			*varr++ = pos;
+			*narr++ = (pos - cent) / ringrad;
+
+			Vector3 pprev = torusvec(theta - 0.1f, phi, mainrad, ringrad);
+			Vector3 pnext = torusvec(theta + 0.1f, phi, mainrad, ringrad);
+
+			*tarr++ = (pnext - pprev).normalized();
+			*uvarr++ = Vector2(u * urange, v * vrange);
+
+			if(i < usub && j < vsub) {
+				int idx = i * vverts + j;
+				*idxarr++ = idx;
+				*idxarr++ = idx + 1;
+				*idxarr++ = idx + vverts + 1;
+
+				*idxarr++ = idx;
+				*idxarr++ = idx + vverts + 1;
+				*idxarr++ = idx + vverts;
+			}
+
+			v += dv;
+		}
+		u += du;
+	}
+}
+
 
 // -------- cylinder --------
 
diff -r 93ff21458a16 -r 7b1fa527b51b src/meshgen.h
--- a/src/meshgen.h	Sun Aug 23 02:51:39 2015 +0300
+++ b/src/meshgen.h	Sun Aug 23 04:31:29 2015 +0300
@@ -6,6 +6,7 @@
 class Mesh;
 
 void gen_sphere(Mesh *mesh, float rad, int usub, int vsub, float urange = 1.0, float vrange = 1.0);
+void gen_torus(Mesh *mesh, float mainrad, float ringrad, int usub, int vsub, float urange = 1.0, float vrange = 1.0);
 void gen_cylinder(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub = 0, float urange = 1.0, float vrange = 1.0);
 void gen_cone(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub = 0, float urange = 1.0, float vrange = 1.0);
 void gen_plane(Mesh *mesh, float width, float height, int usub = 1, int vsub = 1);