Add block tetrahedral mesh for convenience

include/bounce/bounce.h

@@ -73,6 +73,7 @@
 #include <bounce/cloth/garment/garment_mesh.h>
 
 #include <bounce/softbody/softbody_mesh.h>
+#include <bounce/softbody/block_softbody_mesh.h>
 #include <bounce/softbody/softbody.h>
 #include <bounce/softbody/softbody_node.h>
 

include/bounce/softbody/block_softbody_mesh.h

@@ -0,0 +1,123 @@
+/*
+* Copyright (c) 2016-2019 Irlan Robson https://irlanrobson.github.io
+*
+* 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 B3_BLOCK_SOFT_BODY_MESH_H
+#define B3_BLOCK_SOFT_BODY_MESH_H
+
+#include <bounce/softbody/softbody_mesh.H>
+
+template<u32 W = 1, u32 H = 1, u32 D = 1>
+struct b3BlockSoftBodyMesh : public b3SoftBodyMesh
+{
+	b3Vec3 blockVertices[(W + 1) * (H + 1) * (D + 1)];
+	b3SoftBodyMeshTetrahedron blockTetrahedrons[5 * W * H * D];
+
+	b3BlockSoftBodyMesh()
+	{
+		vertexCount = 0;
+		for (u32 x = 0; x <= W; ++x)
+		{
+			for (u32 y = 0; y <= H; ++y)
+			{
+				for (u32 z = 0; z <= D; ++z)
+				{
+					blockVertices[vertexCount++].Set(x, y, z);
+				}
+			}
+		}
+
+		B3_ASSERT(vertexCount == (W + 1) * (H + 1) * (D + 1));
+
+		b3Vec3 translation;
+		translation.x = -0.5f * float32(W);
+		translation.y = -0.5f * float32(H);
+		translation.z = -0.5f * float32(D);
+
+		for (u32 i = 0; i < vertexCount; ++i)
+		{
+			blockVertices[i] += translation;
+		}
+
+		tetrahedronCount = 0;
+		for (u32 x = 0; x < W; ++x)
+		{
+			for (u32 y = 0; y < H; ++y)
+			{
+				for (u32 z = 0; z < D; ++z)
+				{
+					//     4*-----*7
+					//     /|    /|
+					//    / |   / |
+					//  5*-----*6 |
+					//   | 0*--|--*3
+					//   | /   | /
+					//   |/    |/
+					//  1*-----*2
+					u32 v0 = (x * (H + 1) + y) * (D + 1) + z;
+					u32 v1 = v0 + 1;
+					u32 v3 = ((x + 1) * (H + 1) + y) * (D + 1) + z;
+					u32 v2 = v3 + 1;
+					u32 v7 = ((x + 1) * (H + 1) + (y + 1)) * (D + 1) + z;
+					u32 v6 = v7 + 1;
+					u32 v4 = (x * (H + 1) + (y + 1)) * (D + 1) + z;
+					u32 v5 = v4 + 1;
+
+					if ((x + y + z) % 2 == 1)
+					{
+						// CCW
+						//blockTetrahedrons[tetrahedronCount++] = { v1, v2, v6, v3 };
+						//blockTetrahedrons[tetrahedronCount++] = { v3, v6, v4, v7 };
+						//blockTetrahedrons[tetrahedronCount++] = { v1, v4, v6, v5 };
+						//blockTetrahedrons[tetrahedronCount++] = { v1, v3, v4, v0 };
+						//blockTetrahedrons[tetrahedronCount++] = { v1, v6, v4, v3 };
+
+						// CW
+						blockTetrahedrons[tetrahedronCount++] = { v2, v1, v6, v3 };
+						blockTetrahedrons[tetrahedronCount++] = { v6, v3, v4, v7 };
+						blockTetrahedrons[tetrahedronCount++] = { v4, v1, v6, v5 };
+						blockTetrahedrons[tetrahedronCount++] = { v3, v1, v4, v0 };
+						blockTetrahedrons[tetrahedronCount++] = { v6, v1, v4, v3 };
+					}
+					else
+					{
+						// CCW
+						//blockTetrahedrons[tetrahedronCount++] = { v2, v0, v5, v1 };
+						//blockTetrahedrons[tetrahedronCount++] = { v2, v7, v0, v3 };
+						//blockTetrahedrons[tetrahedronCount++] = { v2, v5, v7, v6 };
+						//blockTetrahedrons[tetrahedronCount++] = { v0, v7, v5, v4 };
+						//blockTetrahedrons[tetrahedronCount++] = { v2, v0, v7, v5 };
+
+						// CW
+						blockTetrahedrons[tetrahedronCount++] = { v0, v2, v5, v1 };
+						blockTetrahedrons[tetrahedronCount++] = { v7, v2, v0, v3 };
+						blockTetrahedrons[tetrahedronCount++] = { v5, v2, v7, v6 };
+						blockTetrahedrons[tetrahedronCount++] = { v7, v0, v5, v4 };
+						blockTetrahedrons[tetrahedronCount++] = { v0, v2, v7, v5 };
+					}
+				}
+			}
+		}
+
+		B3_ASSERT(tetrahedronCount == 5 * W * H * D);
+
+		vertices = blockVertices;
+		tetrahedrons = blockTetrahedrons;
+	}
+};
+
+#endif