Add initial prototype.

3-mid/physics/implement/box2d/contrib/testbed/tests/collision_processing.cpp

@@ -0,0 +1,191 @@
+// MIT License
+
+// Copyright (c) 2019 Erin Catto
+
+// 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.
+
+#include "test.h"
+
+#include <algorithm>
+
+// This test shows collision processing and tests
+// deferred body destruction.
+class CollisionProcessing : public Test
+{
+public:
+	CollisionProcessing()
+	{
+		// Ground body
+		{
+			b2EdgeShape shape;
+			shape.SetTwoSided(b2Vec2(-50.0f, 0.0f), b2Vec2(50.0f, 0.0f));
+
+			b2FixtureDef sd;
+			sd.shape = &shape;;
+
+			b2BodyDef bd;
+			b2Body* ground = m_world->CreateBody(&bd);
+			ground->CreateFixture(&sd);
+		}
+
+		float xLo = -5.0f, xHi = 5.0f;
+		float yLo = 2.0f, yHi = 35.0f;
+
+		// Small triangle
+		b2Vec2 vertices[3];
+		vertices[0].Set(-1.0f, 0.0f);
+		vertices[1].Set(1.0f, 0.0f);
+		vertices[2].Set(0.0f, 2.0f);
+
+		b2PolygonShape polygon;
+		polygon.Set(vertices, 3);
+
+		b2FixtureDef triangleShapeDef;
+		triangleShapeDef.shape = &polygon;
+		triangleShapeDef.density = 1.0f;
+
+		b2BodyDef triangleBodyDef;
+		triangleBodyDef.type = b2_dynamicBody;
+		triangleBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+
+		b2Body* body1 = m_world->CreateBody(&triangleBodyDef);
+		body1->CreateFixture(&triangleShapeDef);
+
+		// Large triangle (recycle definitions)
+		vertices[0] *= 2.0f;
+		vertices[1] *= 2.0f;
+		vertices[2] *= 2.0f;
+		polygon.Set(vertices, 3);
+
+		triangleBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+
+		b2Body* body2 = m_world->CreateBody(&triangleBodyDef);
+		body2->CreateFixture(&triangleShapeDef);
+		
+		// Small box
+		polygon.SetAsBox(1.0f, 0.5f);
+
+		b2FixtureDef boxShapeDef;
+		boxShapeDef.shape = &polygon;
+		boxShapeDef.density = 1.0f;
+
+		b2BodyDef boxBodyDef;
+		boxBodyDef.type = b2_dynamicBody;
+		boxBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+
+		b2Body* body3 = m_world->CreateBody(&boxBodyDef);
+		body3->CreateFixture(&boxShapeDef);
+
+		// Large box (recycle definitions)
+		polygon.SetAsBox(2.0f, 1.0f);
+		boxBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+		
+		b2Body* body4 = m_world->CreateBody(&boxBodyDef);
+		body4->CreateFixture(&boxShapeDef);
+
+		// Small circle
+		b2CircleShape circle;
+		circle.m_radius = 1.0f;
+
+		b2FixtureDef circleShapeDef;
+		circleShapeDef.shape = &circle;
+		circleShapeDef.density = 1.0f;
+
+		b2BodyDef circleBodyDef;
+		circleBodyDef.type = b2_dynamicBody;
+		circleBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+
+		b2Body* body5 = m_world->CreateBody(&circleBodyDef);
+		body5->CreateFixture(&circleShapeDef);
+
+		// Large circle
+		circle.m_radius *= 2.0f;
+		circleBodyDef.position.Set(RandomFloat(xLo, xHi), RandomFloat(yLo, yHi));
+
+		b2Body* body6 = m_world->CreateBody(&circleBodyDef);
+		body6->CreateFixture(&circleShapeDef);
+	}
+
+	void Step(Settings& settings) override
+	{
+		Test::Step(settings);
+
+		// We are going to destroy some bodies according to contact
+		// points. We must buffer the bodies that should be destroyed
+		// because they may belong to multiple contact points.
+		const int32 k_maxNuke = 6;
+		b2Body* nuke[k_maxNuke];
+		int32 nukeCount = 0;
+
+		// Traverse the contact results. Destroy bodies that
+		// are touching heavier bodies.
+		for (int32 i = 0; i < m_pointCount; ++i)
+		{
+			ContactPoint* point = m_points + i;
+
+			b2Body* body1 = point->fixtureA->GetBody();
+			b2Body* body2 = point->fixtureB->GetBody();
+			float mass1 = body1->GetMass();
+			float mass2 = body2->GetMass();
+
+			if (mass1 > 0.0f && mass2 > 0.0f)
+			{
+				if (mass2 > mass1)
+				{
+					nuke[nukeCount++] = body1;
+				}
+				else
+				{
+					nuke[nukeCount++] = body2;
+				}
+
+				if (nukeCount == k_maxNuke)
+				{
+					break;
+				}
+			}
+		}
+
+		// Sort the nuke array to group duplicates.
+		std::sort(nuke, nuke + nukeCount);
+
+		// Destroy the bodies, skipping duplicates.
+		int32 i = 0;
+		while (i < nukeCount)
+		{
+			b2Body* b = nuke[i++];
+			while (i < nukeCount && nuke[i] == b)
+			{
+				++i;
+			}
+
+			if (b != m_bomb)
+			{
+				m_world->DestroyBody(b);
+			}
+		}
+	}
+
+	static Test* Create()
+	{
+		return new CollisionProcessing;
+	}
+};
+
+static int testIndex = RegisterTest("Examples", "Collision Processing", CollisionProcessing::Create);