add tension mapping test

examples/testbed/tests/tension_mapping.h

@@ -0,0 +1,162 @@
+/*
+* 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 TENSION_MAPPING_H
+#define TENSION_MAPPING_H
+
+extern DebugDraw* g_debugDraw;
+extern Camera g_camera;
+extern Settings g_settings;
+
+// Hot/Cold color map
+// See http://paulbourke.net/miscellaneous/colourspace/
+static inline b3Color Color(float32 x, float32 a, float32 b)
+{
+	x = b3Clamp(x, a, b);
+
+	float32 d = b - a;
+
+	b3Color c(1.0f, 1.0f, 1.0f); 
+
+	if (x < a + 0.25f * d) 
+	{
+		c.r = 0.0f;
+		c.g = 4.0f * (x - a) / d;
+		return c;
+	}
+	
+	if (x < a + 0.5f * d) 
+	{
+		c.r = 0.0f;
+		c.b = 1.0f + 4.0f * (a + 0.25f * d - x) / d;
+		return c;
+	}
+
+	if (x < a + 0.75f * d) 
+	{
+		c.r = 4.0f * (x - a - 0.5f * d) / d;
+		c.b = 0.0f;
+		return c;
+	}
+
+	c.g = 1.0f + 4.0f * (a + 0.75f * d - x) / d;
+	c.b = 0.0f;
+	return c;
+}
+
+class TensionMapping : public SpringClothTest
+{
+public:
+	TensionMapping()
+	{
+		b3SpringClothDef def;
+		def.allocator = &m_clothAllocator;
+		def.mesh = &m_clothMesh;
+		def.density = 0.2f;
+		def.ks = 100000.0f;
+		def.gravity.Set(0.0f, -10.0f, 0.0f);
+
+		m_cloth.Initialize(def);
+
+		b3AABB3 aabb;
+		aabb.m_lower.Set(-5.0f, -1.0f, -6.0f);
+		aabb.m_upper.Set(5.0f, 1.0f, -4.0f);
+
+		for (u32 i = 0; i < def.mesh->vertexCount; ++i)
+		{
+			if (aabb.Contains(def.mesh->vertices[i]))
+			{
+				m_cloth.SetType(i, b3MassType::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.Apply();
+		
+		b3StackArray<b3Vec3, 100> T;
+		m_cloth.GetTension(T);
+
+		for (u32 i = 0; i < m_clothMesh.triangleCount; ++i)
+		{
+			b3Triangle* t = m_clothMesh.triangles + i;
+
+			const float32 kMaxT = 100000.0f;
+
+			b3Vec3 f1 = T[t->v1];
+			float32 L1 = b3Length(f1);
+			b3Color c1 = Color(L1, 0.0f, kMaxT);
+
+			b3Vec3 f2 = T[t->v2];
+			float32 L2 = b3Length(f2);
+			b3Color c2 = Color(L2, 0.0f, kMaxT);
+
+			b3Vec3 f3 = T[t->v3];
+			float32 L3 = b3Length(f3);
+			b3Color c3 = Color(L3, 0.0f, kMaxT);
+
+			b3Vec3 v1 = m_clothMesh.vertices[t->v1];
+			b3Vec3 v2 = m_clothMesh.vertices[t->v2];
+			b3Vec3 v3 = m_clothMesh.vertices[t->v3];
+
+			b3Vec3 n1 = b3Cross(v2 - v1, v3 - v1);
+			n1.Normalize();
+
+			b3Vec3 n2 = -n1;
+
+			g_debugDraw->DrawSolidTriangle(n1, v1, c1, v2, c2, v3, c3);
+			g_debugDraw->DrawSolidTriangle(n2, v1, c1, v3, c3, v2, c2);
+		}
+
+		b3SpringClothStep step = m_cloth.GetStep();
+
+		char text[256];
+		sprintf(text, "Iterations = %u", step.iterations);
+		g_debugDraw->DrawString(text, b3Color_white);
+
+		if (m_clothDragger.IsSelected() == true)
+		{
+			g_debugDraw->DrawSegment(m_clothDragger.GetPointA(), m_clothDragger.GetPointB(), b3Color_white);
+		}
+	}
+
+	static Test* Create()
+	{
+		return new TensionMapping();
+	}
+
+	b3GridMesh<10, 10> m_clothMesh;
+};
+
+#endif