diff --git a/examples/testbed/framework/debug_draw.h b/examples/testbed/framework/debug_draw.h index ecc7a0d..ee560f2 100644 --- a/examples/testbed/framework/debug_draw.h +++ b/examples/testbed/framework/debug_draw.h @@ -91,6 +91,8 @@ public: void DrawSolidTriangle(const b3Vec3& normal, const b3Vec3& p1, const b3Vec3& p2, const b3Vec3& p3, const b3Color& color); + void DrawSolidTriangle(const b3Vec3& normal, const b3Vec3& p1, const b3Color& color1, const b3Vec3& p2, const b3Color& color2, const b3Vec3& p3, const b3Color& color3); + void DrawPolygon(const b3Vec3* vertices, u32 count, const b3Color& color); void DrawSolidPolygon(const b3Vec3& normal, const b3Vec3* vertices, u32 count, const b3Color& color); diff --git a/examples/testbed/framework/debug_draw_2.cpp b/examples/testbed/framework/debug_draw_2.cpp index fe676c4..6d090cd 100644 --- a/examples/testbed/framework/debug_draw_2.cpp +++ b/examples/testbed/framework/debug_draw_2.cpp @@ -1140,6 +1140,16 @@ void DebugDraw::DrawSolidTriangle(const b3Vec3& normal, const b3Vec3& p1, const DrawTriangle(p2, p3, p3, edgeColor); } +void DebugDraw::DrawSolidTriangle(const b3Vec3& normal, const b3Vec3& p1, const b3Color& color1, const b3Vec3& p2, const b3Color& color2, const b3Vec3& p3, const b3Color& color3) +{ + m_triangles->Vertex(p1, color1, normal); + m_triangles->Vertex(p2, color2, normal); + m_triangles->Vertex(p3, color3, normal); + + b3Color edgeColor(0.0f, 0.0f, 0.0f, 1.0f); + DrawTriangle(p2, p3, p3, edgeColor); +} + void DebugDraw::DrawPolygon(const b3Vec3* vertices, u32 count, const b3Color& color) { b3Vec3 p1 = vertices[count - 1]; diff --git a/examples/testbed/tests/tension_mapping.h b/examples/testbed/tests/tension_mapping.h new file mode 100644 index 0000000..e824a66 --- /dev/null +++ b/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 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 \ No newline at end of file diff --git a/include/bounce/dynamics/cloth/spring_cloth.h b/include/bounce/dynamics/cloth/spring_cloth.h index 02e36e3..5e20a08 100644 --- a/include/bounce/dynamics/cloth/spring_cloth.h +++ b/include/bounce/dynamics/cloth/spring_cloth.h @@ -20,6 +20,7 @@ #define B3_SPRING_CLOTH_H #include +#include #define B3_CLOTH_SHAPE_CAPACITY 32 @@ -163,6 +164,10 @@ public: // Return the kinetic (or dynamic) energy in this system. float32 GetEnergy() const; + // Return the tension forces (due to springs) of each point mass. + // Units are kg * m / s^2 + void GetTension(b3Array& tensions) const; + // Add a shape to the list of shapes in this cloth. // The cloth will be able to respond to collisions with each shape in the list of shapes. void AddShape(b3Shape* shape); diff --git a/src/bounce/dynamics/cloth/spring_cloth.cpp b/src/bounce/dynamics/cloth/spring_cloth.cpp index 90edbf8..fb2db21 100644 --- a/src/bounce/dynamics/cloth/spring_cloth.cpp +++ b/src/bounce/dynamics/cloth/spring_cloth.cpp @@ -297,6 +297,70 @@ void b3SpringCloth::AddShape(b3Shape* shape) m_shapes[m_shapeCount++] = shape; } +void b3SpringCloth::GetTension(b3Array& T) const +{ + B3_ASSERT(T.Count() == 0); + + T.Resize(m_massCount); + + for (u32 i = 0; i < T.Count(); ++i) + { + T[i].SetZero(); + } + + // T = F - mg + for (u32 i = 0; i < m_springCount; ++i) + { + b3Spring* S = m_springs + i; + + b3SpringType type = S->type; + u32 i1 = S->i1; + u32 i2 = S->i2; + float32 L0 = S->L0; + float32 ks = S->ks; + float32 kd = S->kd; + + b3Vec3 x1 = m_x[i1]; + b3Vec3 v1 = m_v[i1]; + + b3Vec3 x2 = m_x[i2]; + b3Vec3 v2 = m_v[i2]; + + // Strech + b3Vec3 dx = x1 - x2; + float32 L = b3Length(dx); + + float32 s = 1.0f; + if (L > 0.0f) + { + s -= L0 / L; + } + + b3Vec3 sf1 = -ks * s * dx; + b3Vec3 sf2 = -sf1; + + T[i1] += sf1; + T[i2] += sf2; + + // Damping + b3Vec3 dv = v1 - v2; + + b3Vec3 df1 = -kd * dv; + b3Vec3 df2 = -df1; + + T[i1] += df1; + T[i2] += df2; + } + + for (u32 i = 0; i < T.Count(); ++i) + { + if (m_types[i] == b3MassType::e_staticMass) + { + T[i].SetZero(); + } + } +} + static B3_FORCE_INLINE void b3MakeTangents(b3Vec3& t1, b3Vec3& t2, const b3Vec3& dv, const b3Vec3& n) { t1 = dv - b3Dot(dv, n) * n;