samples: add the DeformedHeightFieldShapeTest class

src/test/java/testjoltjni/app/samples/shapes/DeformedHeightFieldShapeTest.java

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+/*
+Copyright (c) 2024 Stephen Gold
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+package testjoltjni.app.samples.shapes;
+import com.github.stephengold.joltjni.*;
+import com.github.stephengold.joltjni.enumerate.*;
+import com.github.stephengold.joltjni.operator.Op;
+import java.nio.FloatBuffer;
+import java.util.function.BiFunction;
+import testjoltjni.app.samples.*;
+import testjoltjni.app.testframework.Perlin;
+/**
+ * A line-for-line Java translation of the Jolt Physics deformed heightfield-shape test.
+ * <p>
+ * Compare with the original by Jorrit Rouwe at
+ * https://github.com/jrouwe/JoltPhysics/blob/master/Samples/Tests/Shapes/DeformedHeightFieldShapeTest.cpp
+ */
+class DeformedHeightFieldShapeTest extends Test{
+BodyId mHeightFieldID=new BodyId();
+float mTime;
+float[]mHeightSamples;
+static final int cBlockSize=4,cSampleCount=128;
+static final int cBlockMask=cBlockSize-1;
+ShapeRefC mHeightField;
+
+public void Initialize()
+{
+	final float cCellSize = 1.0f;
+	final float cMaxHeight = 2.5f;
+	final float cSphereRadius = 2.0f;
+
+	// Create height samples
+	mHeightSamples=new float[cSampleCount * cSampleCount];
+	for (int y = 0; y < cSampleCount; ++y)
+		for (int x = 0; x < cSampleCount; ++x)
+			mHeightSamples[y * cSampleCount + x] = cMaxHeight * Perlin.Noise3((float)(x) * 8.0f / cSampleCount, 0, (float)(y) * 8.0f / cSampleCount, 256, 256, 256);
+
+	// Determine scale and offset of the terrain
+	Vec3 offset=new Vec3(-0.5f * cCellSize * cSampleCount, 0, -0.5f * cCellSize * cSampleCount);
+	Vec3 scale=new Vec3(cCellSize, 1.0f, cCellSize);
+
+	// Create height field
+	HeightFieldShapeSettings settings=new HeightFieldShapeSettings(mHeightSamples, offset, scale, cSampleCount);
+	settings.setBlockSize ( cBlockSize);
+	settings.setBitsPerSample ( 8);
+	settings.setMinHeightValue ( -15.0f);
+	mHeightField = (settings.create().get());
+	mHeightFieldID = mBodyInterface.createAndAddBody(new BodyCreationSettings(mHeightField, RVec3.sZero(), Quat.sIdentity(), EMotionType.Static, Layers.NON_MOVING), EActivation.DontActivate);
+
+	// Spheres on top of the terrain
+	ShapeRefC sphere_shape = new SphereShape(cSphereRadius).toRefC();
+	for (float t = 0.2f; t < 12.4f; t += 0.1f)
+	{
+		// Get the center of the path
+		Vec3 center = Op.add(offset , GetPathCenter(t));
+
+		// Cast a ray onto the terrain
+		RShapeCast shape_cast=new RShapeCast(sphere_shape, Vec3.sReplicate(1.0f), RMat44.sTranslation(Op.add(new RVec3(0, 10, 0) , center)),new Vec3(0, -20, 0));
+		ClosestHitCastShapeCollector collector=new ClosestHitCastShapeCollector();
+		mPhysicsSystem.getNarrowPhaseQuery().castShape(shape_cast,new ShapeCastSettings(){ }, RVec3.sZero(), collector);
+		if (collector.getHit().getBodyId2() == mHeightFieldID)
+		{
+			// Create sphere on terrain
+			BodyCreationSettings bcs=new BodyCreationSettings(sphere_shape, shape_cast.getPointOnRay(collector.getHit().getFraction()), Quat.sIdentity(), EMotionType.Dynamic, Layers.MOVING);
+			mBodyInterface.createAndAddBody(bcs, EActivation.DontActivate);
+		}
+	}
+}
+
+Vec3 GetPathCenter(float inTime)
+{
+	final float cOffset = 5.0f;
+	final float cRadiusX = 60.0f;
+	final float cRadiusY = 25.0f;
+	final float cFallOff = 0.1f;
+	final float cAngularSpeed = 2.0f;
+	final float cDisplacementSpeed = 10.0f;
+
+	float fall_off = (float)Math.exp(-cFallOff * inTime);
+	float angle = cAngularSpeed * inTime;
+	return new Vec3(cRadiusX * Math.cos(angle) * fall_off + 64.0f, 0, cOffset + cDisplacementSpeed * inTime + cRadiusY * Math.sin(angle) * fall_off);
+}
+
+public void PrePhysicsUpdate(PreUpdateParams inParams)
+{
+	final float cPitRadius = 6.0f;
+	final float cPitHeight = 1.0f;
+	final float cSpeedScale = 2.0f;
+
+	// Calculate center of pit
+	Vec3 center = GetPathCenter(cSpeedScale * mTime);
+	mTime += inParams.mDeltaTime;
+
+	// Calculate affected area
+	int start_x = Math.max((int)Math.floor(center.getX() - cPitRadius) & ~cBlockMask, 0);
+	int start_y = Math.max((int)Math.floor(center.getZ() - cPitRadius) & ~cBlockMask, 0);
+	int count_x = Math.min(((int)Math.ceil(center.getX() + cPitRadius) + cBlockMask) & ~cBlockMask, cSampleCount) - start_x;
+	int count_y = Math.min(((int)Math.ceil(center.getZ() + cPitRadius) + cBlockMask) & ~cBlockMask, cSampleCount) - start_y;
+
+	if (count_x > 0 && count_y > 0)
+	{
+		// Remember COM before we change the height field
+		Vec3 old_com = mHeightField.getCenterOfMass();
+
+		// A function to calculate the delta height at a certain distance from the center of the pit
+		final float cHalfPi = 0.5f * Jolt.JPH_PI;
+		BiFunction<Float,Float,Float> pit_shape = (Float inDistanceX, Float inDistanceY)-> { return (Float)(float)Math.cos(Math.min(Math.sqrt(Jolt.square(inDistanceX) + Jolt.square(inDistanceY)) * cHalfPi / cPitRadius, cHalfPi)); };
+
+		AaBox affected_area=new AaBox();FloatBuffer b=Jolt.newDirectFloatBuffer(count_x*count_y);
+		for (int y = 0; y < count_y; ++y)
+			for (int x = 0; x < count_x; ++x)
+			{
+				// Update the height field
+				float delta = pit_shape.apply((float)(start_x) + x - center.getX(), (float)(start_y) + y - center.getZ()) * cPitHeight;
+				float h=(mHeightSamples[(start_y + y) * cSampleCount + start_x + x] -= delta);b.put(h);
+
+				// Keep track of affected area to wake up bodies
+				affected_area.encapsulate(((HeightFieldShape)mHeightField.getPtr()).getPosition(start_x + x, start_y + y));
+			}
+		((HeightFieldShape)mHeightField.getPtr()).setHeights(start_x, start_y, count_x, count_y, b, count_x, mTempAllocator);
+
+		// Notify the shape that it has changed its bounding box
+		mBodyInterface.notifyShapeChanged(mHeightFieldID, old_com, false, EActivation.DontActivate);
+
+		// Activate bodies in the affected area (a change in the height field doesn't wake up bodies)
+		affected_area.expandBy(Vec3.sReplicate(0.1f));
+		DefaultBroadPhaseLayerFilter broadphase_layer_filter = mPhysicsSystem.getDefaultBroadPhaseLayerFilter(Layers.MOVING);
+		DefaultObjectLayerFilter object_layer_filter = mPhysicsSystem.getDefaultLayerFilter(Layers.MOVING);
+		mBodyInterface.activateBodiesInAaBox(affected_area, broadphase_layer_filter, object_layer_filter);
+	}
+}
+}