http://irrlicht.sourceforge.net/phpBB2/viewtopic.php?t=31995

Add an optional startPosition parameter to createFlyCircleAnimator() to allow specifying a start position on the circle. New unit test added.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@2105 dfc29bdd-3216-0410-991c-e03cc46cb475

changes.txt

@@ -1,5 +1,7 @@
 Changes in version 1.6
 
+ - Added an startPosition parameter to createFlyCircleAnimator() to allow starting the animator at any position on the circle.
+
  - Many uses of dimension2d<s32> changed to dimension2d<u32>, including IImage, ITexture and screen dimensions.  You will have to change (at least) createDevice() calls to use dimension2d<u32>
 
  - Added IFileSystem::createMemoryWriteFile() to allow creation of an IWriteFile interface that uses an application supplied memory buffer.

include/ISceneManager.h

@@ -1039,6 +1039,8 @@ namespace scene
 		 \param radius: Radius of the circle.
 		 \param speed: The orbital speed, in radians per millisecond.
 		 \param direction: Specifies the upvector used for alignment of the mesh.
+		 \param startPosition: The position on the circle where the animator will
+			begin. Value is in multiples  of a circle, i.e. 0.5 is half way around.
 		 \return The animator. Attach it to a scene node with ISceneNode::addAnimator()
 		 and the animator will animate it.
 		 If you no longer need the animator, you should call ISceneNodeAnimator::drop().
@@ -1046,7 +1048,8 @@ namespace scene
 		virtual ISceneNodeAnimator* createFlyCircleAnimator(
 				const core::vector3df& center=core::vector3df(0.f,0.f,0.f),
 				f32 radius=100.f, f32 speed=0.001f,
-				const core::vector3df& direction=core::vector3df(0.f, 1.f, 0.f)) = 0;
+				const core::vector3df& direction=core::vector3df(0.f, 1.f, 0.f),
+				f32 startPosition = 0.f) = 0;
 
 		//! Creates a fly straight animator, which lets the attached scene node fly or move along a line between two points.
 		/** \param startPoint: Start point of the line.

source/Irrlicht/CSceneManager.cpp

@@ -1521,10 +1521,14 @@ ISceneNodeAnimator* CSceneManager::createRotationAnimator(const core::vector3df&
 //! creates a fly circle animator, which lets the attached scene node fly around a center.
 ISceneNodeAnimator* CSceneManager::createFlyCircleAnimator(
 		const core::vector3df& center, f32 radius, f32 speed,
-		const core::vector3df& direction)
+		const core::vector3df& direction,
+		f32 startPosition)
 {
+	const f32 orbitDurationMs = (core::DEGTORAD * 360.f) / speed;
+	u32 effectiveTime = os::Timer::getTime() + (u32)(orbitDurationMs * startPosition);
+
 	ISceneNodeAnimator* anim = new CSceneNodeAnimatorFlyCircle(
-			os::Timer::getTime(), center,
+			effectiveTime, center,
 			radius, speed, direction);
 	return anim;
 }

source/Irrlicht/CSceneManager.h

@@ -281,13 +281,17 @@ namespace scene
 		//! creates a fly circle animator
 		/** Lets the attached scene node fly around a center.
 		\param center Center relative to node origin
-		\param speed rotation speed
-		\return Animator. Attach it to a scene node with ISceneNode::addAnimator()
-		and the animator will animate it. */
+		 \param speed: The orbital speed, in radians per millisecond.
+		 \param direction: Specifies the upvector used for alignment of the mesh.
+		 \param startPosition: The position on the circle where the animator will
+			begin. Value is in multiples  of a circle, i.e. 0.5 is half way around.
+		 \return The animator. Attach it to a scene node with ISceneNode::addAnimator()
+		 */
 		virtual ISceneNodeAnimator* createFlyCircleAnimator(
 				const core::vector3df& center=core::vector3df(0.f, 0.f, 0.f),
 				f32 radius=100.f, f32 speed=0.001f,
-				const core::vector3df& direction=core::vector3df(0.f, 1.f, 0.f));
+				const core::vector3df& direction=core::vector3df(0.f, 1.f, 0.f),
+				f32 startPosition = 0.f);
 
 		//! Creates a fly straight animator, which lets the attached scene node
 		//! fly or move along a line between two points.

source/Irrlicht/CSceneNodeAnimatorFlyCircle.cpp

@@ -38,9 +38,15 @@ void CSceneNodeAnimatorFlyCircle::animateNode(ISceneNode* node, u32 timeMs)
 	if ( 0 == node )
 		return;
 
-	const f32 t = (timeMs-StartTime) * Speed;
+	f32 time;
 
-	node->setPosition(Center + Radius * ((VecU*cosf(t)) + (VecV*sinf(t))));
+	// Check for the condition where the StartTime is in the future.
+	if(StartTime > timeMs)
+		time = ((s32)timeMs - (s32)StartTime) * Speed;
+	else
+		time = (timeMs-StartTime) * Speed;
+
+	node->setPosition(Center + Radius * ((VecU*cosf(time)) + (VecV*sinf(time))));
 }
 
 

tests/flyCircleAnimator.cpp

@@ -0,0 +1,59 @@
+// Copyright (C) 2008-2009 Colin MacDonald
+// No rights reserved: this software is in the public domain.
+
+#include "testUtils.h"
+#include "irrlicht.h"
+
+using namespace irr;
+using namespace core;
+using namespace scene;
+using namespace video;
+
+/** Tests the offset capability of the fly circle animator */
+bool flyCircleAnimator(void)
+{
+    IrrlichtDevice *device = createDevice(video::EDT_BURNINGSVIDEO,
+										core::dimension2du(160,120), 32);
+    if (!device)
+        return false;
+
+    IVideoDriver* driver = device->getVideoDriver();
+    ISceneManager* smgr = device->getSceneManager();
+
+	const f32 offsetDegrees[] = { 0.f, 45.f, 135.f, 270.f };
+
+	for(u32 i = 0; i < sizeof(offsetDegrees) / sizeof(offsetDegrees[0]); ++i)
+	{
+		IBillboardSceneNode * node = smgr->addBillboardSceneNode();
+		// Have the animator rotate around the Z axis plane, rather than the default Y axis
+		ISceneNodeAnimator * animator =
+			smgr->createFlyCircleAnimator(vector3df(0, 0, 0), 30.f,
+											0.001f, vector3df(0, 0, 1),
+											(offsetDegrees[i] / 360.f));
+		if(!node || !animator)
+			return false;
+
+		node->setMaterialType(video::EMT_TRANSPARENT_ADD_COLOR );
+		node->setMaterialTexture(0, driver->getTexture("../media/particle.bmp"));
+		node->setMaterialFlag(video::EMF_LIGHTING, false);
+
+		node->addAnimator(animator);
+		animator->drop();
+	}
+
+	(void)smgr->addCameraSceneNode(0, vector3df(0, 0, -50), vector3df(0, 0, 0));
+
+	bool result = false;
+
+    // Don't do device->run() since I need the time to remain at 0.
+	if (driver->beginScene(true, true, video::SColor(0, 80, 80, 80)))
+	{
+		smgr->drawAll();
+		driver->endScene();
+		result = takeScreenshotAndCompareAgainstReference(driver, "-flyCircleAnimator.png", 100);
+	}
+
+    device->drop();
+
+    return result;
+}

tests/main.cpp

@@ -87,6 +87,7 @@ int main(int argumentCount, char * arguments[])
 	TEST(sceneNodeAnimator);
 	TEST(vectorPositionDimension2d);
 	TEST(writeImageToFile);
+	TEST(flyCircleAnimator);
 
 	const unsigned int numberOfTests = tests.size();
 

tests/tests-last-passed-at.txt

@@ -1,2 +1,2 @@
-Test suite pass at GMT Mon Jan 19 13:42:16 2009
+Test suite pass at GMT Tue Jan 20 12:53:02 2009
 

tests/tests.cbp

@@ -46,6 +46,7 @@
 		<Unit filename="drawRectOutline.cpp" />
 		<Unit filename="exports.cpp" />
 		<Unit filename="fast_atof.cpp" />
+		<Unit filename="flyCircleAnimator.cpp" />
 		<Unit filename="guiDisabledMenu.cpp" />
 		<Unit filename="irrCoreEquals.cpp" />
 		<Unit filename="line2dIntersectWith.cpp" />

tests/tests_vc8.vcproj

@@ -205,6 +205,10 @@
 				RelativePath=".\fast_atof.cpp"
 				>
 			</File>
+			<File
+				RelativePath=".\flyCircleAnimator.cpp"
+				>
+			</File>
 			<File
 				RelativePath=".\guiDisabledMenu.cpp"
 				>

tests/tests_vc9.vcproj

@@ -203,6 +203,10 @@
 				RelativePath=".\fast_atof.cpp"
 				>
 			</File>
+			<File
+				RelativePath=".\flyCircleAnimator.cpp"
+				>
+			</File>
 			<File
 				RelativePath=".\guiDisabledMenu.cpp"
 				>

tests/transparentAlphaChannelRef.cpp

@@ -40,7 +40,7 @@ bool testWithDriver(video::E_DRIVER_TYPE driverType)
 	smgr->drawAll();
 	driver->endScene();
 
-	bool result = takeScreenshotAndCompareAgainstReference(driver, "-transparentAlphaChannelRef.png", 99.88);
+	bool result = takeScreenshotAndCompareAgainstReference(driver, "-transparentAlphaChannelRef.png", 99.88f);
 
 	device->drop();