add baraff and witkin's mass-spring-based cloth

examples/testbed/tests/spring_cloth_test.h

@@ -0,0 +1,91 @@
+/*
+* Copyright (c) 2016-2016 Irlan Robson http://www.irlan.net
+*
+* This software is provided 'as-is', without any express or implied
+* warranty.  In no event will the authors be held liable for any damages
+* arising from the use of this software.
+* Permission is granted to anyone to use this software for any purpose,
+* including commercial applications, and to alter it and redistribute it
+* freely, subject to the following restrictions:
+* 1. The origin of this software must not be misrepresented; you must not
+* claim that you wrote the original software. If you use this software
+* in a product, an acknowledgment in the product documentation would be
+* appreciated but is not required.
+* 2. Altered source versions must be plainly marked as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef SPRING_CLOTH_TESH_H
+#define SPRING_CLOTH_TESH_H
+
+extern DebugDraw* g_debugDraw;
+extern Camera g_camera;
+extern Settings g_settings;
+
+class SpringCloth : public Test
+{
+public:
+	SpringCloth()
+	{
+		g_camera.m_zoom = 25.0f;
+
+		b3SpringClothDef def;
+		def.allocator = &m_clothAllocator;
+		def.mesh = m_meshes + e_clothMesh;
+		def.density = 0.2f;
+		def.ks = 100000.0f;
+		def.kd = 100.0f;
+		def.gravity.Set(2.5f, 5.0f, -10.0f);
+
+		m_cloth.Initialize(def);
+
+		m_aabb.m_lower.Set(-5.0f, -1.0f, -6.0f);
+		m_aabb.m_upper.Set(5.0f, 1.0f, -4.0f);
+
+		for (u32 i = 0; i < def.mesh->vertexCount; ++i)
+		{
+			if (m_aabb.Contains(def.mesh->vertices[i]))
+			{
+				m_cloth.SetType(i, e_staticMass);
+			}
+		}		
+	}
+
+	void Step()
+	{
+		float32 dt = g_settings.hertz > 0.0f ? 1.0f / g_settings.hertz : 0.0f;
+
+		if (g_settings.pause)
+		{
+			if (g_settings.singleStep)
+			{
+				g_settings.singleStep = false;
+			}
+			else
+			{
+				dt = 0.0f;
+			}
+		}
+
+		m_cloth.Step(dt);
+		m_cloth.Draw(g_debugDraw);
+
+		b3SpringClothStep step = m_cloth.GetStep();
+
+		char text[256];
+		sprintf(text, "Iterations = %u", step.iterations);
+		g_debugDraw->DrawString(text, b3Color_white);
+	}
+
+	static Test* Create()
+	{
+		return new SpringCloth();
+	}
+
+	b3StackAllocator m_clothAllocator;
+	b3SpringCloth m_cloth;
+	b3AABB3 m_aabb;
+};
+
+#endif