From ac113eac9f645309ef1347ffc2eca5f139abaecc Mon Sep 17 00:00:00 2001
From: "Kaelthas_Spellsinger@o2.pl"
 <Kaelthas_Spellsinger@o2.pl@75d07b2b-3a1a-0410-a2c5-0572b91ccdca>
Date: Thu, 25 Aug 2011 18:18:32 +0000
Subject: [PATCH] Support for image sphere projection on a mesh.

git-svn-id: http://jmonkeyengine.googlecode.com/svn/trunk@8092 75d07b2b-3a1a-0410-a2c5-0572b91ccdca
---
 .../blender/textures/UVCoordinatesGenerator.java   |   5 +-
 .../blender/textures/UVProjectionGenerator.java    | 101 +++++++++++----------
 2 files changed, 54 insertions(+), 52 deletions(-)

diff --git a/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVCoordinatesGenerator.java b/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVCoordinatesGenerator.java
index 221d799b3..fe6c36d0e 100644
--- a/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVCoordinatesGenerator.java
+++ b/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVCoordinatesGenerator.java
@@ -101,7 +101,7 @@ public class UVCoordinatesGenerator {
 		VertexBuffer result = new VertexBuffer(VertexBuffer.Type.TexCoord);
 		Mesh mesh = geometries.get(0).getMesh();
 		BoundingBox bb = UVCoordinatesGenerator.getBoundingBox(geometries);
-
+		
 		switch (texco) {
 			case TEXCO_ORCO:
 				float[] uvCoordinates = null;
@@ -118,7 +118,8 @@ public class UVCoordinatesGenerator {
 							 uvCoordinates = UVProjectionGenerator.tubeProjection(mesh, bt);
 							break;
 						case PROJECTION_SPHERE:
-							uvCoordinates = UVProjectionGenerator.sphereProjection(mesh, bb);
+							BoundingSphere bs = UVCoordinatesGenerator.getBoundingSphere(geometries);
+							uvCoordinates = UVProjectionGenerator.sphereProjection(mesh, bs);
 							break;
 						default:
 							throw new IllegalStateException("Unknown projection type: " + projection);
diff --git a/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVProjectionGenerator.java b/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVProjectionGenerator.java
index 3d860ff9d..00615574d 100644
--- a/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVProjectionGenerator.java
+++ b/engine/src/blender/com/jme3/scene/plugins/blender/textures/UVProjectionGenerator.java
@@ -3,6 +3,7 @@ package com.jme3.scene.plugins.blender.textures;
 import java.nio.FloatBuffer;
 
 import com.jme3.bounding.BoundingBox;
+import com.jme3.bounding.BoundingSphere;
 import com.jme3.math.FastMath;
 import com.jme3.math.Triangle;
 import com.jme3.math.Vector3f;
@@ -172,55 +173,55 @@ import com.jme3.scene.plugins.blender.textures.UVCoordinatesGenerator.BoundingTu
 	 *            the bounding box for projecting
 	 * @return UV coordinates after the projection
 	 */
-	public static float[] sphereProjection(Mesh mesh, BoundingBox bb) {
-		return null;// TODO: implement
-		// Vector2f[] uvTable = new Vector2f[vertexList.size()];
-		// Ray ray = new Ray();
-		// CollisionResults cr = new CollisionResults();
-		// Vector3f yVec = new Vector3f();
-		// Vector3f zVec = new Vector3f();
-		// for(Geometry geom : geometries) {
-		// if(materialHelper.hasTexture(geom.getMaterial())) {//generate only
-		// when material has a texture
-		// geom.getMesh().updateBound();
-		// BoundingSphere bs = this.getBoundingSphere(geom.getMesh());
-		// float r2 = bs.getRadius() * bs.getRadius();
-		// yVec.set(0, -bs.getRadius(), 0);
-		// zVec.set(0, 0, -bs.getRadius());
-		// Vector3f center = bs.getCenter();
-		// ray.setOrigin(center);
-		// //we cast each vertex of the current mesh on the bounding box to
-		// determine the UV-coordinates
-		// for(int i=0;i<geom.getMesh().getIndexBuffer().size();++i) {
-		// int index = geom.getMesh().getIndexBuffer().get(i);
-		//
-		// ray.setOrigin(vertexList.get(index));
-		// ray.setDirection(normalList.get(index));
-		//
-		// //finding collision point
-		// cr.clear();
-		// bs.collideWith(ray, cr);//there is ALWAYS one collision
-		// Vector3f p = cr.getCollision(0).getContactPoint();
-		// p.subtractLocal(center);
-		// //arcLength = FastMath.acos(p.dot(yVec)/(p.length * yVec.length)) * r
-		// <- an arc length on the sphere (from top to the point on
-		// the sphere)
-		// //but yVec.length == r and p.length == r so: arcLength =
-		// FastMath.acos(p.dot(yVec)/r^2)/r
-		// //U coordinate is as follows: u = arcLength / PI*r
-		// //so to compute it faster we just write: u =
-		// FastMath.acos(p.dot(yVec)/r^2) / PI;
-		// float u = FastMath.acos(p.dot(yVec)/r2) / FastMath.PI;
-		// //we use similiar method to compute v
-		// //the only difference is that we need to cast the p vector on ZX
-		// plane
-		// //and use its length instead of r
-		// p.y = 0;
-		// float v = FastMath.acos(p.dot(zVec)/(bs.getRadius()*p.length())) /
-		// FastMath.PI;
-		// uvTable[index] = new Vector2f(u, v);
-		// }
-		// }
-		// }
+	public static float[] sphereProjection(Mesh mesh, BoundingSphere bs) {
+		FloatBuffer positions = mesh.getFloatBuffer(VertexBuffer.Type.Position);
+		float[] uvCoordinates = new float[positions.limit() / 3 * 2];
+		Vector3f v = new Vector3f();
+		float cx = bs.getCenter().x, cy = bs.getCenter().y, cz = bs.getCenter().z;
+		Vector3f uBase = new Vector3f(0, -1, 0);
+		Vector3f vBase = new Vector3f(0, 0, -1);
+
+		for (int i = 0, j = 0; i < positions.limit(); i += 3, j += 2) {
+			// calculating U
+			v.set(positions.get(i)-cx, positions.get(i + 1)-cy, 0);
+			v.normalizeLocal();
+			float angle = v.angleBetween(uBase);// result between [0; PI]
+			if (v.x < 0) {// the angle should be greater than PI, we're on the other part of the image then
+				angle = FastMath.TWO_PI - angle;
+			}
+			uvCoordinates[j] = angle / FastMath.TWO_PI;
+
+			// calculating V
+			v.set(positions.get(i)-cx, positions.get(i + 1)-cy, positions.get(i + 2)-cz);
+			v.normalizeLocal();
+			angle = v.angleBetween(vBase);// result between [0; PI]
+			uvCoordinates[j+1] = angle / FastMath.PI;
+		}
+		
+		//looking for splitted triangles
+		Triangle triangle = new Triangle();
+		for(int i=0;i<mesh.getTriangleCount();++i) {
+			mesh.getTriangle(i, triangle);
+			float sgn1 = Math.signum(triangle.get1().x-cx);
+			float sgn2 = Math.signum(triangle.get2().x-cx);
+			float sgn3 = Math.signum(triangle.get3().x-cx);
+			float xSideFactor = sgn1 + sgn2 + sgn3;
+			float ySideFactor = Math.signum(triangle.get1().y-cy)+
+					   Math.signum(triangle.get2().y-cy)+
+					   Math.signum(triangle.get3().y-cy);
+			if((xSideFactor>-3 || xSideFactor<3) && ySideFactor<0) {//the triangle is on the splitting plane
+				//indexOfUcoord = (indexOfTriangle*3 + indexOfTrianglesVertex)*2
+				if(sgn1==1.0f) {
+					uvCoordinates[i*3*2] += 1.0f;
+				}
+				if(sgn2==1.0f) {
+					uvCoordinates[(i*3+1)*2] += 1.0f;
+				}
+				if(sgn3==1.0f) {
+					uvCoordinates[(i*3+2)*2] += 1.0f;
+				}
+			}
+		}
+		return uvCoordinates;
 	}
 }
-- 
2.11.0