Collada exporter now exports the camera matrix as "lookAt" values. The problem...

Collada exporter now exports the camera matrix as "lookAt" values. The problem with rotations was that the camera disregards the up-vector in rotations (also using lookAT is probably nicer anyway for cameras). This should likely also be fixed in the camera code. But there's more trouble it seems as for example projection matrix changes also don't register in the near/far values. I've just added a todo there in the Collada export. Meaning that orthographic camera export is still broken (still experimenting how to fix that best).


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4407 dfc29bdd-3216-0410-991c-e03cc46cb475

changes.txt

 --------------------------
 Changes in 1.9 (not yet released)
 
+- Collada exporter now exports the camera up-vector correctly.
 - Add IColladaMeshWriter::findGeometryNameForNode
 - Add getters IGUIButton::isDrawBorderEnabled and IGUIButton::isDrawBackgroundEnabled
 

source/Irrlicht/CColladaMeshWriter.cpp

@@ -661,6 +661,9 @@ void CColladaMeshWriter::writeNodeCameras(irr::scene::ISceneNode * node)
 			Writer->writeElement(L"orthographic", false);
 			Writer->writeLineBreak();
 
+			// TODO: Those values are not affected by the matrix set for the ortographic projection.
+			//		 We do not have those values so far in Irrlicht for orthogonal cameras.
+
 //			writeNode(L"xmag", core::stringw("1.0").c_str());	// TODO: do we need xmag, ymag?
 //			writeNode(L"ymag", core::stringw("1.0").c_str());
 			writeNode(L"aspect_ratio", core::stringw(cameraNode->getAspectRatio()).c_str());
@@ -740,16 +743,21 @@ void CColladaMeshWriter::writeSceneNode(irr::scene::ISceneNode * node )
 	{
 		writeMatrixElement(node->getRelativeTransformation());
 	}
+	else if ( isCamera(node) )
+	{
+		// TODO: We do not handle the case when ICameraSceneNode::getTargetAndRotationBinding() is false. Probably we would have to create a second
+		// node to do that.
+
+		// Note: We can't use rotations for the camera as Irrlicht does not regard the up-vector in rotations so far.
+		// We could maybe use projection matrices, but avoiding them might allow us to get rid of some DummyTransformationSceneNodes on 
+		// import in the future. So that's why we use the lookat element instead.
+
+		ICameraSceneNode * camNode = static_cast<ICameraSceneNode*>(node);
+		writeLookAtElement(camNode->getPosition(), camNode->getTarget(), camNode->getUpVector());
+	}
 	else
 	{
 		irr::core::vector3df rot(node->getRotation());
-		if ( isCamera(node) && !static_cast<ICameraSceneNode*>(node)->getTargetAndRotationBinding() )
-		{
-			ICameraSceneNode * camNode = static_cast<ICameraSceneNode*>(node);
-			const core::vector3df toTarget = camNode->getTarget() - camNode->getAbsolutePosition();
-			rot = toTarget.getHorizontalAngle();
-		}
-
 		writeTranslateElement( node->getPosition() );
 		writeRotateElement( irr::core::vector3df(1.f, 0.f, 0.f), rot.X );
 		writeRotateElement( irr::core::vector3df(0.f, 1.f, 0.f), rot.Y );
@@ -2229,6 +2237,18 @@ void CColladaMeshWriter::writeTranslateElement(const irr::core::vector3df& trans
 	Writer->writeLineBreak();
 }
 
+void CColladaMeshWriter::writeLookAtElement(const irr::core::vector3df& eyePos, const irr::core::vector3df& targetPos, const irr::core::vector3df& upVector)
+{
+	Writer->writeElement(L"lookat", false);
+
+	wchar_t tmpbuf[255];
+	swprintf(tmpbuf, 255, L"%f %f %f %f %f %f %f %f %f", eyePos.X, eyePos.Y, eyePos.Z, targetPos.X, targetPos.Y, targetPos.Z, upVector.X, upVector.Y, upVector.Z);
+	Writer->writeText(tmpbuf);
+
+	Writer->writeClosingTag(L"lookat");
+	Writer->writeLineBreak();
+}
+
 void CColladaMeshWriter::writeMatrixElement(const irr::core::matrix4& matrix)
 {
 	Writer->writeElement(L"matrix", false);

source/Irrlicht/CColladaMeshWriter.h

@@ -152,6 +152,7 @@ protected:
 	void writeRotateElement(const irr::core::vector3df& axis, irr::f32 angle);
 	void writeScaleElement(const irr::core::vector3df& scale);
 	void writeTranslateElement(const irr::core::vector3df& translate);
+	void writeLookAtElement(const irr::core::vector3df& eyePos, const irr::core::vector3df& targetPos, const irr::core::vector3df& upVector);
 	void writeMatrixElement(const irr::core::matrix4& matrix);
 
 	struct SComponentGlobalStartPos