assimp/code/StandardShapes.cpp

/*
Open Asset Import Library (ASSIMP)
----------------------------------------------------------------------

Copyright (c) 2006-2008, ASSIMP Development Team
All rights reserved.

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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the ASSIMP team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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*/

/** @file Implementation of the StandardShapes class
 */

#include "AssimpPCH.h"
#include "StandardShapes.h"

namespace Assimp	{

	// note - flip the face order
#define ADD_TRIANGLE(n0,n1,n2) \
	positions.push_back(n2); \
	positions.push_back(n1); \
	positions.push_back(n0);

#	define ADD_PENTAGON(n0,n1,n2,n3,n4) \
	if (polygons) \
	{ \
		positions.push_back(n0); \
		positions.push_back(n1); \
		positions.push_back(n2); \
		positions.push_back(n3); \
		positions.push_back(n4); \
	} \
	else \
	{ \
		ADD_TRIANGLE(n0, n1, n2) \
		ADD_TRIANGLE(n0, n2, n3) \
		ADD_TRIANGLE(n0, n3, n4) \
	}

#	define ADD_QUAD(n0,n1,n2,n3) \
	if (polygons) \
	{ \
		positions.push_back(n0); \
		positions.push_back(n1); \
		positions.push_back(n2); \
		positions.push_back(n3); \
	} \
	else \
	{ \
		ADD_TRIANGLE(n0, n1, n2) \
		ADD_TRIANGLE(n0, n2, n3) \
	}


// ------------------------------------------------------------------------------------------------
void Subdivide(std::vector<aiVector3D>& positions)
{
	// assume this to be constant - input must be a Platonic primitive!
	const float fl1 = positions[0].Length();

	unsigned int origSize = (unsigned int)positions.size();
	for (unsigned int i = 0 ; i < origSize ; i+=3)
	{
		aiVector3D& tv0 = positions[i];
		aiVector3D& tv1 = positions[i+1];
		aiVector3D& tv2 = positions[i+2];

		aiVector3D a = tv0, b = tv1, c = tv2;
		aiVector3D v1 = aiVector3D(a.x+b.x, a.y+b.y, a.z+b.z).Normalize()*fl1;
		aiVector3D v2 = aiVector3D(a.x+c.x, a.y+c.y, a.z+c.z).Normalize()*fl1;
		aiVector3D v3 = aiVector3D(b.x+c.x, b.y+c.y, b.z+c.z).Normalize()*fl1;

		tv0 = v1; tv1 = v3; tv2 = v2; // overwrite the original
		ADD_TRIANGLE(v2, v1, a);
		ADD_TRIANGLE(v3, v2, c);
		ADD_TRIANGLE(v1, v3, b);
	}
}

// ------------------------------------------------------------------------------------------------
aiMesh* StandardShapes::MakeMesh(const std::vector<aiVector3D>& positions,
	unsigned int numIndices)
{
	if (positions.size() & numIndices || positions.empty() || !numIndices)return NULL;

	// Determine which kinds of primitives the mesh will consist of
	aiMesh* out = new aiMesh();
	switch (numIndices)
	{
	case 1:
		out->mPrimitiveTypes = aiPrimitiveType_POINT;
		break;
	case 2:
		out->mPrimitiveTypes = aiPrimitiveType_LINE;
		break;
	case 3:
		out->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
		break;
	default:
		out->mPrimitiveTypes = aiPrimitiveType_POLYGON;
		break;
	};

	out->mNumFaces = (unsigned int)positions.size() / numIndices;
	out->mFaces = new aiFace[out->mNumFaces];
	for (unsigned int i = 0, a = 0; i < out->mNumFaces;++i)
	{
		aiFace& f = out->mFaces[i];
		f.mNumIndices = numIndices;
		f.mIndices = new unsigned int[numIndices];
		for (unsigned int i = 0; i < numIndices;++i,++a)
			f.mIndices[i] = a;
	}
	out->mNumVertices = (unsigned int)positions.size();
	out->mVertices = new aiVector3D[out->mNumVertices];
	::memcpy(out->mVertices,&positions[0],out->mNumVertices*sizeof(aiVector3D));
	return out;
}

// ------------------------------------------------------------------------------------------------
aiMesh* StandardShapes::MakeMesh ( unsigned int (*GenerateFunc)(
	std::vector<aiVector3D>&))
{
	std::vector<aiVector3D> temp;
	unsigned num = (*GenerateFunc)(temp);
	return MakeMesh(temp,num);
}

// ------------------------------------------------------------------------------------------------
aiMesh* StandardShapes::MakeMesh ( unsigned int (*GenerateFunc)(
	std::vector<aiVector3D>&, bool))
{
	std::vector<aiVector3D> temp;
	unsigned num = (*GenerateFunc)(temp,true);
	return MakeMesh(temp,num);
}

// ------------------------------------------------------------------------------------------------
aiMesh* StandardShapes::MakeMesh (unsigned int num,  void (*GenerateFunc)(
	unsigned int,std::vector<aiVector3D>&))
{
	std::vector<aiVector3D> temp;
	(*GenerateFunc)(num,temp);
	return MakeMesh(temp,3);
}

// ------------------------------------------------------------------------------------------------
unsigned int StandardShapes::MakeIcosahedron(std::vector<aiVector3D>& positions)
{
	positions.reserve(positions.size()+60);

	const float t = (1.f + 2.236067977f)/2.f;
	const float s = sqrt(1.f + t*t);
	
	const aiVector3D v0  = aiVector3D(t,1.f, 0.f)/s;
	const aiVector3D v1  = aiVector3D(-t,1.f, 0.f)/s;
	const aiVector3D v2  = aiVector3D(t,-1.f, 0.f)/s;
	const aiVector3D v3  = aiVector3D(-t,-1.f, 0.f)/s;
	const aiVector3D v4  = aiVector3D(1.f, 0.f, t)/s;
	const aiVector3D v5  = aiVector3D(1.f, 0.f,-t)/s;
	const aiVector3D v6  = aiVector3D(-1.f, 0.f,t)/s;
	const aiVector3D v7  = aiVector3D(-1.f, 0.f,-t)/s;
	const aiVector3D v8  = aiVector3D(0.f, t, 1.f)/s;
	const aiVector3D v9  = aiVector3D(0.f,-t, 1.f)/s;
	const aiVector3D v10 = aiVector3D(0.f, t,-1.f)/s;
	const aiVector3D v11 = aiVector3D(0.f,-t,-1.f)/s;

	ADD_TRIANGLE(v0,v8,v4);
	ADD_TRIANGLE(v0,v5,v10);
	ADD_TRIANGLE(v2,v4,v9);
	ADD_TRIANGLE(v2,v11,v5);

	ADD_TRIANGLE(v1,v6,v8);
	ADD_TRIANGLE(v1,v10,v7);
	ADD_TRIANGLE(v3,v9,v6);
	ADD_TRIANGLE(v3,v7,v11);

	ADD_TRIANGLE(v0,v10,v8);
	ADD_TRIANGLE(v1,v8,v10);
	ADD_TRIANGLE(v2,v9,v11);
	ADD_TRIANGLE(v3,v11,v9);

	ADD_TRIANGLE(v4,v2,v0);
	ADD_TRIANGLE(v5,v0,v2);
	ADD_TRIANGLE(v6,v1,v3);
	ADD_TRIANGLE(v7,v3,v1);

	ADD_TRIANGLE(v8,v6,v4);
	ADD_TRIANGLE(v9,v4,v6);
	ADD_TRIANGLE(v10,v5,v7);
	ADD_TRIANGLE(v11,v7,v5);
	return 3;
}

// ------------------------------------------------------------------------------------------------
unsigned int StandardShapes::MakeDodecahedron(std::vector<aiVector3D>& positions,
	bool polygons /*= false*/)
{
	positions.reserve(positions.size()+108);

	const float a = 1.f / 1.7320508f;
	const float b = sqrt((3.f-2.23606797f)/6.f);
	const float c = sqrt((3.f+2.23606797f)/6.f);

	const aiVector3D v0  = aiVector3D(a,a,a);
	const aiVector3D v1  = aiVector3D(a,a,-a);
	const aiVector3D v2  = aiVector3D(a,-a,a);
	const aiVector3D v3  = aiVector3D(a,-a,-a);
	const aiVector3D v4  = aiVector3D(-a,a,a);
	const aiVector3D v5  = aiVector3D(-a,a,-a);
	const aiVector3D v6  = aiVector3D(-a,-a,a);
	const aiVector3D v7  = aiVector3D(-a,-a,-a);
	const aiVector3D v8  = aiVector3D(b,c,0.f);
	const aiVector3D v9  = aiVector3D(-b,c,0.f);
	const aiVector3D v10 = aiVector3D(b,-c,0.f);
	const aiVector3D v11 = aiVector3D(-b,-c,0.f);
	const aiVector3D v12 = aiVector3D(c, 0.f, b);
	const aiVector3D v13 = aiVector3D(c, 0.f, -b);
	const aiVector3D v14 = aiVector3D(-c, 0.f, b);
	const aiVector3D v15 = aiVector3D(-c, 0.f, -b);
	const aiVector3D v16 = aiVector3D(0.f, b, c);
	const aiVector3D v17 = aiVector3D(0.f, -b, c);
	const aiVector3D v18 = aiVector3D(0.f, b, -c);
	const aiVector3D v19 = aiVector3D(0.f, -b, -c);

	ADD_PENTAGON(v0, v8, v9, v4, v16);
	ADD_PENTAGON(v0, v12, v13, v1, v8);
	ADD_PENTAGON(v0, v16, v17, v2, v12);
	ADD_PENTAGON(v8, v1, v18, v5, v9);
	ADD_PENTAGON(v12, v2, v10, v3, v13);
	ADD_PENTAGON(v16, v4, v14, v6, v17);
	ADD_PENTAGON(v9, v5, v15, v14, v4);

	ADD_PENTAGON(v6, v11, v10, v2, v17);
	ADD_PENTAGON(v3, v19, v18, v1, v13);
	ADD_PENTAGON(v7, v15, v5, v18, v19);
	ADD_PENTAGON(v7, v11, v6, v14, v15);
	ADD_PENTAGON(v7, v19, v3, v10, v11);
	return (polygons ? 5 : 3);
}

// ------------------------------------------------------------------------------------------------
unsigned int StandardShapes::MakeOctahedron(std::vector<aiVector3D>& positions)
{
	positions.reserve(positions.size()+24);

	const aiVector3D v0  = aiVector3D(1.0f, 0.f, 0.f) ;
	const aiVector3D v1  = aiVector3D(-1.0f, 0.f, 0.f);
	const aiVector3D v2  = aiVector3D(0.f, 1.0f, 0.f);
	const aiVector3D v3  = aiVector3D(0.f, -1.0f, 0.f);
	const aiVector3D v4  = aiVector3D(0.f, 0.f, 1.0f);
	const aiVector3D v5  = aiVector3D(0.f, 0.f, -1.0f);

	ADD_TRIANGLE(v4,v0,v2);
	ADD_TRIANGLE(v4,v2,v1);
	ADD_TRIANGLE(v4,v1,v3);
	ADD_TRIANGLE(v4,v3,v0);

	ADD_TRIANGLE(v5,v2,v0);
	ADD_TRIANGLE(v5,v1,v2);
	ADD_TRIANGLE(v5,v3,v1);
	ADD_TRIANGLE(v5,v0,v3);
	return 3;
}

// ------------------------------------------------------------------------------------------------
unsigned int StandardShapes::MakeTetrahedron(std::vector<aiVector3D>& positions)
{
	positions.reserve(positions.size()+9);

	const float a = 1.41421f/3.f;
	const float b = 2.4494f/3.f;

	const aiVector3D v0  = aiVector3D(0.f,0.f,1.f);
	const aiVector3D v1  = aiVector3D(2*a,0,-1.f/3.f);
	const aiVector3D v2  = aiVector3D(-a,b,-1.f/3.f);
	const aiVector3D v3  = aiVector3D(-a,-b,-1.f/3.f);

	ADD_TRIANGLE(v0,v1,v2);
	ADD_TRIANGLE(v0,v2,v3);
	ADD_TRIANGLE(v0,v3,v1);
	ADD_TRIANGLE(v1,v3,v2);
	return 3;
}

// ------------------------------------------------------------------------------------------------
unsigned int StandardShapes::MakeHexahedron(std::vector<aiVector3D>& positions,
	bool polygons /*= false*/)
{
	positions.reserve(positions.size()+36);
	const float length = 1.f/1.73205080f;

	const aiVector3D v0  = aiVector3D(-1.f,-1.f,-1.f)*length;
	const aiVector3D v1  = aiVector3D(1.f,-1.f,-1.f)*length;
	const aiVector3D v2  = aiVector3D(1.f,1.f,-1.f)*length;
	const aiVector3D v3  = aiVector3D(-1.f,1.f,-1.f)*length;
	const aiVector3D v4  = aiVector3D(-1.f,-1.f,1.f)*length;
	const aiVector3D v5  = aiVector3D(1.f,-1.f,1.f)*length;
	const aiVector3D v6  = aiVector3D(1.f,1.f,1.f)*length;
	const aiVector3D v7  = aiVector3D(-1.f,1.f,1.f)*length;

	ADD_QUAD(v0,v3,v2,v1);
	ADD_QUAD(v0,v1,v5,v4);
	ADD_QUAD(v0,v4,v7,v3);
	ADD_QUAD(v6,v5,v1,v2);
	ADD_QUAD(v6,v2,v3,v7);
	ADD_QUAD(v6,v7,v4,v5);
	return (polygons ? 4 : 3);
}

// Cleanup ...
#undef ADD_TRIANGLE
#undef ADD_QUAD
#undef ADD_PENTAGON

// ------------------------------------------------------------------------------------------------
void StandardShapes::MakeSphere(unsigned int	tess,
	std::vector<aiVector3D>& positions)
{
	// Reserve enough storage. Every subdivision
	// splits each triangle in 4, the icosahedron consists of 60 verts
	positions.reserve(positions.size()+60 * integer_pow(4, tess));

	// Construct an icosahedron to start with 
	MakeIcosahedron(positions);

	// ... and subdivide it until the requested output
	// tesselation is reached
	for (unsigned int i = 0; i<tess;++i)
		Subdivide(positions);
}

// ------------------------------------------------------------------------------------------------
void StandardShapes::MakeCone(float height,float radius1,
	float radius2,unsigned int tess, 
	std::vector<aiVector3D>& positions,bool bOpen /*= false */)
{
	// Sorry, a cone with less than 3 segments makes 
	// ABSOLUTELY NO SENSE
	if (tess < 3 || !height)
		return;

	// No negative radii
	radius1 = fabs(radius1);
	radius2 = fabs(radius2);

	float halfHeight = height / 2;

	// radius1 is always the smaller one
	if (radius2 > radius1)
	{
		std::swap(radius2,radius1);
		halfHeight = -halfHeight;
	}

	// Use a large epsilon to check whether the cone is pointy
	if (radius1 < (radius2-radius1)*10e-3f)radius1 = 0.f;

	// We will need 3*2 verts per segment + 3*2 verts per segment
	// if the cone is closed
	const unsigned int mem = tess*6 + (!bOpen ? tess*3 * (radius1 ? 2 : 1) : 0);
	positions.reserve(mem);

	// Now construct all segments
	const float angle_delta = (float)AI_MATH_TWO_PI / tess;
	const float angle_max   = (float)AI_MATH_TWO_PI;

	float s = 1.f; // cos(angle == 0);
	float t = 0.f; // sin(angle == 0);

	for (float angle = 0.f; angle < angle_max; )
	{
		const aiVector3D v1 = aiVector3D (s * radius1, -halfHeight, t * radius1 );
		const aiVector3D v2 = aiVector3D (s * radius2,  halfHeight, t * radius2 );

		const float next = angle + angle_delta;
		float s2 = cos(next);
		float t2 = sin(next);

		const aiVector3D v3 = aiVector3D (s2 * radius2,  halfHeight, t2 * radius2 );
		const aiVector3D v4 = aiVector3D (s2 * radius1, -halfHeight, t2 * radius1 );

		positions.push_back(v1);
		positions.push_back(v3);
		positions.push_back(v2);
		positions.push_back(v4);
		positions.push_back(v3);
		positions.push_back(v1);

		if (!bOpen)
		{
			// generate the end 'cap'
			positions.push_back(aiVector3D(s * radius2,  halfHeight, t * radius2 ));
			positions.push_back(aiVector3D(0.f, halfHeight, 0.f));
			positions.push_back(aiVector3D(s2 * radius2,  halfHeight, t2 * radius2 ));

			if (radius1)
			{
				// generate the other end 'cap'
				positions.push_back(aiVector3D(s * radius1,  -halfHeight, t * radius1 ));
				positions.push_back(aiVector3D(0.f, -halfHeight, 0.f));
				positions.push_back(aiVector3D(s2 * radius1,  -halfHeight, t2 * radius1 ));
			}
		}
		s = s2;
		t = t2;
		angle = next;
	}
}

// ------------------------------------------------------------------------------------------------
void StandardShapes::MakeCircle(
	const aiVector3D&	center, 
	const aiVector3D&	normal, 
	float				radius,
	unsigned int		tess,
	std::vector<aiVector3D>& positions)
{
	// todo
}

} // ! Assimp