dark-hammer / 3rdparty / assimp / src / TerragenLoader.cpp

The branch '0.4.7' does not exist.
/*
---------------------------------------------------------------------------
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 
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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
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  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,
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---------------------------------------------------------------------------
*/

/** @file Implementation of the Terragen importer class */

#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_TERRAGEN_IMPORTER
#include "TerragenLoader.h"

using namespace Assimp;

static const aiImporterDesc desc = {
	"Terragen Heightmap Importer",
	"",
	"",
	"http://www.planetside.co.uk/",
	aiImporterFlags_SupportBinaryFlavour,
	0,
	0,
	0,
	0,
	"ter" 
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
TerragenImporter::TerragenImporter()
: configComputeUVs (false)
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
TerragenImporter::~TerragenImporter()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool TerragenImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	// check file extension 
	std::string extension = GetExtension(pFile);
	
	if( extension == "ter")
		return true;

	if(  !extension.length() || checkSig)	{
		/*  If CanRead() is called in order to check whether we
		 *  support a specific file extension in general pIOHandler
		 *  might be NULL and it's our duty to return true here.
		 */
		if (!pIOHandler)return true;
		const char* tokens[] = {"terragen"};
		return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
// Build a string of all file extensions supported
const aiImporterDesc* TerragenImporter::GetInfo () const
{
	return &desc;
}

// ------------------------------------------------------------------------------------------------
// Setup import properties
void TerragenImporter::SetupProperties(const Importer* pImp)
{
	// AI_CONFIG_IMPORT_TER_MAKE_UVS
	configComputeUVs = ( 0 != pImp->GetPropertyInteger(AI_CONFIG_IMPORT_TER_MAKE_UVS,0) );
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void TerragenImporter::InternReadFile( const std::string& pFile, 
	aiScene* pScene, IOSystem* pIOHandler)
{
	IOStream* file = pIOHandler->Open( pFile, "rb");

	// Check whether we can read from the file
	if( file == NULL)
		throw DeadlyImportError( "Failed to open TERRAGEN TERRAIN file " + pFile + ".");

	// Construct a stream reader to read all data in the correct endianess
	StreamReaderLE reader(file);
	if(reader.GetRemainingSize() < 16)
		throw DeadlyImportError( "TER: file is too small" );

	// Check for the existence of the two magic strings 'TERRAGEN' and 'TERRAIN '
	if (::strncmp((const char*)reader.GetPtr(),AI_TERR_BASE_STRING,8))
		throw DeadlyImportError( "TER: Magic string \'TERRAGEN\' not found" );

	if (::strncmp((const char*)reader.GetPtr()+8,AI_TERR_TERRAIN_STRING,8))
		throw DeadlyImportError( "TER: Magic string \'TERRAIN\' not found" );

	unsigned int x = 0,y = 0,mode = 0;
	float rad  = 6370.f;
	(void)rad;


	aiNode* root = pScene->mRootNode = new aiNode();
	root->mName.Set("<TERRAGEN.TERRAIN>");

	// Default scaling is 30
	root->mTransformation.a1 = root->mTransformation.b2 = root->mTransformation.c3 = 30.f;

	// Now read all chunks until we're finished or an EOF marker is encountered
	reader.IncPtr(16);
	while (reader.GetRemainingSize() >= 4)	
	{
		const char* head = (const char*)reader.GetPtr();
		reader.IncPtr(4);

		// EOF, break in every case
		if (!::strncmp(head,AI_TERR_EOF_STRING,4))
			break;

		// Number of x-data points
		if (!::strncmp(head,AI_TERR_CHUNK_XPTS,4))
		{
			x = (uint16_t)reader.GetI2();
		}
		// Number of y-data points
		else if (!::strncmp(head,AI_TERR_CHUNK_YPTS,4))
		{
			y = (uint16_t)reader.GetI2();
		}
		// Squared terrains width-1. 
		else if (!::strncmp(head,AI_TERR_CHUNK_SIZE,4))
		{
			x = y = (uint16_t)reader.GetI2()+1;
		}
		// terrain scaling
		else if (!::strncmp(head,AI_TERR_CHUNK_SCAL,4))
		{
			root->mTransformation.a1 = reader.GetF4();
			root->mTransformation.b2 = reader.GetF4();
			root->mTransformation.c3 = reader.GetF4();
		}
		// mapping == 1: earth radius
		else if (!::strncmp(head,AI_TERR_CHUNK_CRAD,4))
		{
			rad = reader.GetF4();
		}
		// mapping mode
		else if (!::strncmp(head,AI_TERR_CHUNK_CRVM,4))
		{
			mode = reader.GetI1();
			if (0 != mode)
				DefaultLogger::get()->error("TER: Unsupported mapping mode, a flat terrain is returned");
		}
		// actual terrain data
		else if (!::strncmp(head,AI_TERR_CHUNK_ALTW,4))
		{
			float hscale  = (float)reader.GetI2()  / 65536;
			float bheight = (float)reader.GetI2();

			if (!hscale)hscale = 1;

			// Ensure we have enough data
			if (reader.GetRemainingSize() < x*y*2)
				throw DeadlyImportError("TER: ALTW chunk is too small");

			if (x <= 1 || y <= 1)
				throw DeadlyImportError("TER: Invalid terrain size");

			// Allocate the output mesh
			pScene->mMeshes = new aiMesh*[pScene->mNumMeshes = 1];
			aiMesh* m = pScene->mMeshes[0] = new aiMesh();

			// We return quads
			aiFace* f = m->mFaces = new aiFace[m->mNumFaces = (x-1)*(y-1)];
			aiVector3D* pv = m->mVertices = new aiVector3D[m->mNumVertices = m->mNumFaces*4];
			
			aiVector3D *uv( NULL );
			float step_y( 0.0f ), step_x( 0.0f );
			if (configComputeUVs) {
				uv = m->mTextureCoords[0] = new aiVector3D[m->mNumVertices];
				step_y = 1.f/y;
				step_x = 1.f/x;
			}
			const int16_t* data = (const int16_t*)reader.GetPtr();

			for (unsigned int yy = 0, t = 0; yy < y-1;++yy)	{
				for (unsigned int xx = 0; xx < x-1;++xx,++f)	{

					// make verts
					const float fy = (float)yy, fx = (float)xx;
					register unsigned tmp,tmp2;
					*pv++ = aiVector3D(fx,fy,    (float)data[(tmp2=x*yy)    + xx] * hscale + bheight);
					*pv++ = aiVector3D(fx,fy+1,  (float)data[(tmp=x*(yy+1)) + xx] * hscale + bheight);
					*pv++ = aiVector3D(fx+1,fy+1,(float)data[tmp  + xx+1]         * hscale + bheight);
					*pv++ = aiVector3D(fx+1,fy,  (float)data[tmp2 + xx+1]         * hscale + bheight);

					// also make texture coordinates, if necessary
					if (configComputeUVs) {
						*uv++ = aiVector3D( step_x*xx,     step_y*yy,     0.f );
						*uv++ = aiVector3D( step_x*xx,     step_y*(yy+1), 0.f );
						*uv++ = aiVector3D( step_x*(xx+1), step_y*(yy+1), 0.f );
						*uv++ = aiVector3D( step_x*(xx+1), step_y*yy,     0.f );
					}

					// make indices
					f->mIndices = new unsigned int[f->mNumIndices = 4];
					for (unsigned int i = 0; i < 4;++i)
						f->mIndices[i] = t++;
				}
			}

			// Add the mesh to the root node
			root->mMeshes = new unsigned int[root->mNumMeshes = 1];
			root->mMeshes[0] = 0;
		}

		// Get to the next chunk (4 byte aligned)
		unsigned dtt;
		if ((dtt = reader.GetCurrentPos() & 0x3))
			reader.IncPtr(4-dtt);
	}

	// Check whether we have a mesh now
	if (pScene->mNumMeshes != 1)
		throw DeadlyImportError("TER: Unable to load terrain");

	// Set the AI_SCENE_FLAGS_TERRAIN bit
	pScene->mFlags |= AI_SCENE_FLAGS_TERRAIN;
}

#endif // !! ASSIMP_BUILD_NO_TERRAGEN_IMPORTER
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