Re-add libassimp 3.1.1 to 3rd party

Previously the assimp library was a dependency that was
always built, but it is possible to use an external
system version if one is available.  It is however non-
trivial to provide the dependency on platforms other
than Linux, so now we provide a copy of libassimp for
use when it is not already available.

This commit is a combination of reverting commit
672b3e47299f6ba0034f73b252d0436b55fb3085 which removed
assimp and introduced the scene parser, and adding the
logic to use the system version when available.

Change-Id: Ia05f9a92b8d82f19a0db3588b2bbeafe71404386
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 176 insertions, 0 deletions

diff --git a/src/3rdparty/assimp/code/FixNormalsStep.cpp b/src/3rdparty/assimp/code/FixNormalsStep.cpp
new file mode 100644
index 000000000..f95dfbc5f
--- /dev/null
+++ b/src/3rdparty/assimp/code/FixNormalsStep.cpp
@@ -0,0 +1,176 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2012, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms, 
+with or without modification, are permitted provided that the following 
+conditions are met:
+
+* 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
+  materials provided with the distribution.
+
+* 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 team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to invert
+ * all normals in meshes with infacing normals.
+ */
+
+#include "AssimpPCH.h"
+
+// internal headers
+#include "FixNormalsStep.h"
+
+using namespace Assimp;
+
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FixInfacingNormalsProcess::FixInfacingNormalsProcess()
+{
+	// nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FixInfacingNormalsProcess::~FixInfacingNormalsProcess()
+{
+	// nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FixInfacingNormalsProcess::IsActive( unsigned int pFlags) const
+{
+	return (pFlags & aiProcess_FixInfacingNormals) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FixInfacingNormalsProcess::Execute( aiScene* pScene)
+{
+	DefaultLogger::get()->debug("FixInfacingNormalsProcess begin");
+
+	bool bHas = false;
+	for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
+		if(ProcessMesh( pScene->mMeshes[a],a))bHas = true;
+
+	if (bHas)
+		 DefaultLogger::get()->debug("FixInfacingNormalsProcess finished. Found issues.");
+	else DefaultLogger::get()->debug("FixInfacingNormalsProcess finished. No changes to the scene.");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Apply the step to the mesh
+bool FixInfacingNormalsProcess::ProcessMesh( aiMesh* pcMesh, unsigned int index)
+{
+	ai_assert(NULL != pcMesh);
+
+	// Nothing to do if there are no model normals
+	if (!pcMesh->HasNormals())return false;
+
+	// Compute the bounding box of both the model vertices + normals and
+	// the umodified model vertices. Then check whether the first BB
+	// is smaller than the second. In this case we can assume that the
+	// normals need to be flipped, although there are a few special cases ..
+	// convex, concave, planar models ...
+
+	aiVector3D vMin0 (1e10f,1e10f,1e10f);
+	aiVector3D vMin1 (1e10f,1e10f,1e10f);
+	aiVector3D vMax0 (-1e10f,-1e10f,-1e10f);
+	aiVector3D vMax1 (-1e10f,-1e10f,-1e10f);
+
+	for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
+	{
+		vMin1.x = std::min(vMin1.x,pcMesh->mVertices[i].x);
+		vMin1.y = std::min(vMin1.y,pcMesh->mVertices[i].y);
+		vMin1.z = std::min(vMin1.z,pcMesh->mVertices[i].z);
+
+		vMax1.x = std::max(vMax1.x,pcMesh->mVertices[i].x);
+		vMax1.y = std::max(vMax1.y,pcMesh->mVertices[i].y);
+		vMax1.z = std::max(vMax1.z,pcMesh->mVertices[i].z);
+
+		const aiVector3D vWithNormal = pcMesh->mVertices[i] + pcMesh->mNormals[i];
+
+		vMin0.x = std::min(vMin0.x,vWithNormal.x);
+		vMin0.y = std::min(vMin0.y,vWithNormal.y);
+		vMin0.z = std::min(vMin0.z,vWithNormal.z);
+
+		vMax0.x = std::max(vMax0.x,vWithNormal.x);
+		vMax0.y = std::max(vMax0.y,vWithNormal.y);
+		vMax0.z = std::max(vMax0.z,vWithNormal.z);
+	}
+
+	const float fDelta0_x = (vMax0.x - vMin0.x);
+	const float fDelta0_y = (vMax0.y - vMin0.y);
+	const float fDelta0_z = (vMax0.z - vMin0.z);
+
+	const float fDelta1_x = (vMax1.x - vMin1.x);
+	const float fDelta1_y = (vMax1.y - vMin1.y);
+	const float fDelta1_z = (vMax1.z - vMin1.z);
+
+	// Check whether the boxes are overlapping
+	if ((fDelta0_x > 0.0f) != (fDelta1_x > 0.0f))return false;
+	if ((fDelta0_y > 0.0f) != (fDelta1_y > 0.0f))return false;
+	if ((fDelta0_z > 0.0f) != (fDelta1_z > 0.0f))return false;
+
+	// Check whether this is a planar surface
+	const float fDelta1_yz = fDelta1_y * fDelta1_z;
+
+	if (fDelta1_x < 0.05f * sqrtf( fDelta1_yz ))return false;
+	if (fDelta1_y < 0.05f * sqrtf( fDelta1_z * fDelta1_x ))return false;
+	if (fDelta1_z < 0.05f * sqrtf( fDelta1_y * fDelta1_x ))return false;
+
+	// now compare the volumes of the bounding boxes
+	if (::fabsf(fDelta0_x * fDelta1_yz) <
+		::fabsf(fDelta1_x * fDelta1_y * fDelta1_z))
+	{
+		if (!DefaultLogger::isNullLogger())
+		{
+			char buffer[128]; // should be sufficiently large
+			::sprintf(buffer,"Mesh %i: Normals are facing inwards (or the mesh is planar)",index);
+			DefaultLogger::get()->info(buffer);
+		}
+
+		// Invert normals
+		for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
+			pcMesh->mNormals[i] *= -1.0f;
+
+		// ... and flip faces
+		for (unsigned int i = 0; i < pcMesh->mNumFaces;++i)
+		{
+			aiFace& face = pcMesh->mFaces[i];
+			for( unsigned int b = 0; b < face.mNumIndices / 2; b++)
+				std::swap( face.mIndices[b], face.mIndices[ face.mNumIndices - 1 - b]);
+		}
+		return true;
+	}
+	return false;
+}