# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1440294324 -10800
# Node ID 1e8d90aeae34d1b63caf143462f3b1547a72d397
# Parent  7b1fa527b51bc0aeee502d9776890885d54c26a1
added Mesh::texcoord_gen_cylinder()

diff -r 7b1fa527b51b -r 1e8d90aeae34 src/mesh.cc
--- a/src/mesh.cc	Sun Aug 23 04:31:29 2015 +0300
+++ b/src/mesh.cc	Sun Aug 23 04:45:24 2015 +0300
@@ -982,6 +982,29 @@
 	}
 }
 
+void Mesh::texcoord_gen_cylinder()
+{
+	if(!nverts) return;
+
+	if(!has_attrib(MESH_ATTR_TEXCOORD)) {
+		// allocate texture coordinate attribute array
+		set_attrib_data(MESH_ATTR_TEXCOORD, 2, nverts);
+	}
+
+	for(unsigned int i=0; i<nverts; i++) {
+		Vector3 pos = get_attrib(MESH_ATTR_VERTEX, i);
+
+		float rho = sqrt(pos.x * pos.x + pos.z * pos.z);
+		float theta = rho == 0.0 ? 0.0 : atan2(pos.z / rho, pos.x / rho);
+
+		float u = theta / (2.0 * M_PI) + 0.5;
+		float v = pos.y;
+
+		set_attrib(MESH_ATTR_TEXCOORD, i, Vector4(u, v, 0, 1));
+	}
+}
+
+
 void Mesh::dump(FILE *fp) const
 {
 	if(!has_attrib(MESH_ATTR_VERTEX)) {
diff -r 7b1fa527b51b -r 1e8d90aeae34 src/mesh.h
--- a/src/mesh.h	Sun Aug 23 04:31:29 2015 +0300
+++ b/src/mesh.h	Sun Aug 23 04:45:24 2015 +0300
@@ -232,6 +232,7 @@
 	void texcoord_apply_xform(const Matrix4x4 &xform);
 	void texcoord_gen_plane(const Vector3 &norm, const Vector3 &tang);
 	void texcoord_gen_box();
+	void texcoord_gen_cylinder();
 
 	void dump(FILE *fp) const;
 };