3ds.cpp

// 3ds.cpp -


#include "main.h"
#include "3ds.h"


///////////////////////////////// CLOAD3DS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This constructor initializes the tChunk data
/////
///////////////////////////////// CLOAD3DS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

CLoad3DS::CLoad3DS()
{
	m_CurrentChunk = new tChunk;				// Initialize and allocate our current chunk
	m_TempChunk = new tChunk;					// Initialize and allocate a temporary chunk
}

///////////////////////////////// IMPORT 3DS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This is called by the client to open the .3ds file, read it, then clean up
/////
///////////////////////////////// IMPORT 3DS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

bool CLoad3DS::Import3DS(CModel *pModel, char *strFileName)
{
	char strMessage[255] = {0};

	// Open the 3DS file
	m_FilePointer = fopen(strFileName, "rb");

	// Make sure we have a valid file pointer (we found the file)
	if(!m_FilePointer) 
	{
		sprintf(strMessage, "Unable to find the file: %s!", strFileName);
		MessageBox(NULL, strMessage, "Error", MB_OK);
		return false;
	}

	// Once we have the file open, we need to read the very first data chunk
	// to see if it's a 3DS file.  That way we don't read an invalid file.
	// If it is a 3DS file, then the first chunk ID will be equal to PRIMARY (some hex num)

	// Read the first chuck of the file to see if it's a 3DS file
	ReadChunk(m_CurrentChunk);

	// Make sure this is a 3DS file
	if (m_CurrentChunk->ID != PRIMARY)
	{
		sprintf(strMessage, "Unable to load PRIMARY chuck from file: %s!", strFileName);
		MessageBox(NULL, strMessage, "Error", MB_OK);
		return false;
	}

	// Now we actually start reading in the data.  ProcessNextChunk() is recursive

	// Begin loading objects, by calling this recursive function
	ProcessNextChunk(pModel, m_CurrentChunk);

	// After we have read the whole 3DS file, we want to calculate our own vertex normals.
	pModel->ComputeNormals();

	// Clean up after everything
	CleanUp();

	return true;
}

///////////////////////////////// CLEAN UP \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function cleans up our allocated memory and closes the file
/////
///////////////////////////////// CLEAN UP \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::CleanUp()
{

	fclose(m_FilePointer);						// Close the current file pointer
	delete m_CurrentChunk;						// Free the current chunk
	delete m_TempChunk;							// Free our temporary chunk
}


///////////////////////////////// PROCESS NEXT CHUNK\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads the main sections of the .3DS file, then dives deeper with recursion
/////
///////////////////////////////// PROCESS NEXT CHUNK\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ProcessNextChunk(CModel *pModel, tChunk *pPreviousChunk)
{
	t3DObject newObject = {0};					// This is used to add to our object list
	tMaterialInfo newTexture = {0};				// This is used to add to our material list
	unsigned int version = 0;					// This will hold the file version
	int buffer[50000] = {0};					// This is used to read past unwanted data

	m_CurrentChunk = new tChunk;				// Allocate a new chunk				

	// Below we check our chunk ID each time we read a new chunk.  Then, if
	// we want to extract the information from that chunk, we do so.
	// If we don't want a chunk, we just read past it.  

	// Continue to read the sub chunks until we have reached the length.
	// After we read ANYTHING we add the bytes read to the chunk and then check
	// check against the length.
	while (pPreviousChunk->bytesRead < pPreviousChunk->length)
	{
		// Read next Chunk
		ReadChunk(m_CurrentChunk);

		// Check the chunk ID
		switch (m_CurrentChunk->ID)
		{
		case VERSION:							// This holds the version of the file
			
			// This chunk has an unsigned short that holds the file version.
			// Since there might be new additions to the 3DS file format in 4.0,
			// we give a warning to that problem.

			// Read the file version and add the bytes read to our bytesRead variable
			m_CurrentChunk->bytesRead += fread(&version, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);

			// If the file version is over 3, give a warning that there could be a problem
			if (version > 0x03)
				MessageBox(NULL, "This 3DS file is over version 3 so it may load incorrectly", "Warning", MB_OK);
			break;

		case OBJECTINFO:						// This holds the version of the mesh
			
			// This chunk holds the version of the mesh.  It is also the head of the MATERIAL
			// and OBJECT chunks.  From here on we start reading in the material and object info.

			// Read the next chunk
			ReadChunk(m_TempChunk);

			// Get the version of the mesh
			m_TempChunk->bytesRead += fread(&version, 1, m_TempChunk->length - m_TempChunk->bytesRead, m_FilePointer);

			// Increase the bytesRead by the bytes read from the last chunk
			m_CurrentChunk->bytesRead += m_TempChunk->bytesRead;

			// Go to the next chunk, which is the object has a texture, it should be MATERIAL, then OBJECT.
			ProcessNextChunk(pModel, m_CurrentChunk);
			break;

		case MATERIAL:							// This holds the material information

			// This chunk is the header for the material info chunks

			// Increase the number of materials
			pModel->numOfMaterials++;

			// Add a empty texture structure to our texture list.
			// If you are unfamiliar with STL's "vector" class, all push_back()
			// does is add a new node onto the list.  I used the vector class
			// so I didn't need to write my own link list functions.  
			pModel->pMaterials.push_back(newTexture);

			// Proceed to the material loading function
			ProcessNextMaterialChunk(pModel, m_CurrentChunk);
			break;

		case OBJECT:							// This holds the name of the object being read
				
			// This chunk is the header for the object info chunks.  It also
			// holds the name of the object.

			// Increase the object count
			pModel->numOfObjects++;
		
			// Add a new tObject node to our list of objects (like a link list)
			pModel->pObject.push_back(newObject);
			
			// Initialize the object and all it's data members
			memset(&(pModel->pObject[pModel->numOfObjects - 1]), 0, sizeof(t3DObject));

			// Get the name of the object and store it, then add the read bytes to our byte counter.
			m_CurrentChunk->bytesRead += GetString(pModel->pObject[pModel->numOfObjects - 1].strName);
			
			// Now proceed to read in the rest of the object information
			ProcessNextObjectChunk(pModel, &(pModel->pObject[pModel->numOfObjects - 1]), m_CurrentChunk);
			break;

		case EDITKEYFRAME:

			// Because I wanted to make this a SIMPLE tutorial as possible, I did not include
			// the key frame information.  This chunk is the header for all the animation info.
			// In a later tutorial this will be the subject and explained thoroughly.

			//ProcessNextKeyFrameChunk(pModel, m_CurrentChunk);

			// Read past this chunk and add the bytes read to the byte counter
			m_CurrentChunk->bytesRead += fread(buffer, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;

		default: 
			
			// If we didn't care about a chunk, then we get here.  We still need
			// to read past the unknown or ignored chunk and add the bytes read to the byte counter.
			m_CurrentChunk->bytesRead += fread(buffer, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;
		}

		// Add the bytes read from the last chunk to the previous chunk passed in.
		pPreviousChunk->bytesRead += m_CurrentChunk->bytesRead;
	}

	// Free the current chunk and set it back to the previous chunk (since it started that way)
	delete m_CurrentChunk;
	m_CurrentChunk = pPreviousChunk;
}


///////////////////////////////// PROCESS NEXT OBJECT CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function handles all the information about the objects in the file
/////
///////////////////////////////// PROCESS NEXT OBJECT CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ProcessNextObjectChunk(CModel *pModel, t3DObject *pObject, tChunk *pPreviousChunk)
{
	int buffer[50000] = {0};					// This is used to read past unwanted data

	// Allocate a new chunk to work with
	m_CurrentChunk = new tChunk;

	// Continue to read these chunks until we read the end of this sub chunk
	while (pPreviousChunk->bytesRead < pPreviousChunk->length)
	{
		// Read the next chunk
		ReadChunk(m_CurrentChunk);

		// Check which chunk we just read
		switch (m_CurrentChunk->ID)
		{
		case OBJECT_MESH:					// This lets us know that we are reading a new object
		
			// We found a new object, so let's read in it's info using recursion
			ProcessNextObjectChunk(pModel, pObject, m_CurrentChunk);
			break;

		case OBJECT_VERTICES:				// This is the objects vertices
			ReadVertices(pObject, m_CurrentChunk);
			break;

		case OBJECT_FACES:					// This is the objects face information
			ReadVertexIndices(pObject, m_CurrentChunk);
			break;

		case OBJECT_MATERIAL:				// This holds the material name that the object has
			
			// This chunk holds the name of the material that the object has assigned to it.
			// This could either be just a color or a texture map.  This chunk also holds
			// the faces that the texture is assigned to (In the case that there is multiple
			// textures assigned to one object, or it just has a texture on a part of the object.
			// Since most of my game objects just have the texture around the whole object, and 
			// they aren't multitextured, I just want the material name.

			// We now will read the name of the material assigned to this object
			ReadObjectMaterial(pModel, pObject, m_CurrentChunk);			
			break;

		case OBJECT_UV:						// This holds the UV texture coordinates for the object

			// This chunk holds all of the UV coordinates for our object.  Let's read them in.
			ReadUVCoordinates(pObject, m_CurrentChunk);
			break;

		default:  

			// Read past the ignored or unknown chunks
			m_CurrentChunk->bytesRead += fread(buffer, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;
		}

		// Add the bytes read from the last chunk to the previous chunk passed in.
		pPreviousChunk->bytesRead += m_CurrentChunk->bytesRead;
	}

	// Free the current chunk and set it back to the previous chunk (since it started that way)
	delete m_CurrentChunk;
	m_CurrentChunk = pPreviousChunk;
}


///////////////////////////////// PROCESS NEXT MATERIAL CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function handles all the information about the material (Texture)
/////
///////////////////////////////// PROCESS NEXT MATERIAL CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ProcessNextMaterialChunk(CModel *pModel, tChunk *pPreviousChunk)
{
	int buffer[50000] = {0};					// This is used to read past unwanted data

	// Allocate a new chunk to work with
	m_CurrentChunk = new tChunk;

	// Continue to read these chunks until we read the end of this sub chunk
	while (pPreviousChunk->bytesRead < pPreviousChunk->length)
	{
		// Read the next chunk
		ReadChunk(m_CurrentChunk);

		// Check which chunk we just read in
		switch (m_CurrentChunk->ID)
		{
		case MATNAME:							// This chunk holds the name of the material
			
			// Here we read in the material name
			m_CurrentChunk->bytesRead += fread(pModel->pMaterials[pModel->numOfMaterials - 1].strName, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;

		case MATDIFFUSE:						// This holds the R G B color of our object
			ReadColorChunk(&(pModel->pMaterials[pModel->numOfMaterials - 1]), m_CurrentChunk);
			break;
		
		case MATMAP:							// This is the header for the texture info
			
			// Proceed to read in the material information
			ProcessNextMaterialChunk(pModel, m_CurrentChunk);
			break;

		case MATMAPFILE:						// This stores the file name of the material

			// Here we read in the material's file name
			m_CurrentChunk->bytesRead += fread(pModel->pMaterials[pModel->numOfMaterials - 1].strFile, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;
		
		default:  

			// Read past the ignored or unknown chunks
			m_CurrentChunk->bytesRead += fread(buffer, 1, m_CurrentChunk->length - m_CurrentChunk->bytesRead, m_FilePointer);
			break;
		}

		// Add the bytes read from the last chunk to the previous chunk passed in.
		pPreviousChunk->bytesRead += m_CurrentChunk->bytesRead;
	}

	// Free the current chunk and set it back to the previous chunk (since it started that way)
	delete m_CurrentChunk;
	m_CurrentChunk = pPreviousChunk;
}

///////////////////////////////// READ CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in a chunk ID and it's length in bytes
/////
///////////////////////////////// READ CHUNK \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadChunk(tChunk *pChunk)
{
	// This reads the chunk ID which is 2 bytes.
	// The chunk ID is like OBJECT or MATERIAL.  It tells what data is
	// able to be read in within the chunks section.  
	pChunk->bytesRead = fread(&pChunk->ID, 1, 2, m_FilePointer);

	// Then, we read the length of the chunk which is 4 bytes.
	// This is how we know how much to read in, or read past.
	pChunk->bytesRead += fread(&pChunk->length, 1, 4, m_FilePointer);
}

///////////////////////////////// GET STRING \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in a string of characters
/////
///////////////////////////////// GET STRING \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

int CLoad3DS::GetString(char *pBuffer)
{
	int index = 0;

	// Read 1 byte of data which is the first letter of the string
	fread(pBuffer, 1, 1, m_FilePointer);

	// Loop until we get NULL
	while (*(pBuffer + index++) != 0) {

		// Read in a character at a time until we hit NULL.
		fread(pBuffer + index, 1, 1, m_FilePointer);
	}

	// Return the string length, which is how many bytes we read in (including the NULL)
	return strlen(pBuffer) + 1;
}


///////////////////////////////// READ COLOR \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in the RGB color data
/////
///////////////////////////////// READ COLOR \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadColorChunk(tMaterialInfo *pMaterial, tChunk *pChunk)
{
	// Read the color chunk info
	ReadChunk(m_TempChunk);

	// Read in the R G B color (3 bytes - 0 through 255)
	m_TempChunk->bytesRead += fread(pMaterial->color, 1, m_TempChunk->length - m_TempChunk->bytesRead, m_FilePointer);

	// Add the bytes read to our chunk
	pChunk->bytesRead += m_TempChunk->bytesRead;
}


///////////////////////////////// READ VERTEX INDECES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in the indices for the vertex array
/////
///////////////////////////////// READ VERTEX INDECES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadVertexIndices(t3DObject *pObject, tChunk *pPreviousChunk)
{
	unsigned short index = 0;					// This is used to read in the current face index

	// In order to read in the vertex indices for the object, we need to first
	// read in the number of them, then read them in.  Remember,
	// we only want 3 of the 4 values read in for each face.  The fourth is
	// a visibility flag for 3D Studio Max that doesn't mean anything to us.

	// Read in the number of faces that are in this object (int)
	pPreviousChunk->bytesRead += fread(&pObject->numOfFaces, 1, 2, m_FilePointer);

	// Alloc enough memory for the faces and initialize the structure
	pObject->pFaces = new tFace [pObject->numOfFaces];
	memset(pObject->pFaces, 0, sizeof(tFace) * pObject->numOfFaces);

	// Go through all of the faces in this object
	for(int i = 0; i < pObject->numOfFaces; i++)
	{
		// Next, we read in the A then B then C index for the face, but ignore the 4th value.
		// The fourth value is a visibility flag for 3D Studio Max, we don't care about this.
		for(int j = 0; j < 4; j++)
		{
			// Read the first vertice index for the current face 
			pPreviousChunk->bytesRead += fread(&index, 1, sizeof(index), m_FilePointer);

			if(j < 3)
			{
				// Store the index in our face structure.
				pObject->pFaces[i].vertIndex[j] = index;
			}
		}
	}
}


///////////////////////////////// READ UV COORDINATES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in the UV coordinates for the object
/////
///////////////////////////////// READ UV COORDINATES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadUVCoordinates(t3DObject *pObject, tChunk *pPreviousChunk)
{
	// In order to read in the UV indices for the object, we need to first
	// read in the amount there are, then read them in.

	// Read in the number of UV coordinates there are (int)
	pPreviousChunk->bytesRead += fread(&pObject->numTexVertex, 1, 2, m_FilePointer);

	// Allocate memory to hold the UV coordinates
	pObject->pTexVerts = new CVector2D[pObject->numTexVertex];

	// Read in the texture coodinates (an array 2 float)
	pPreviousChunk->bytesRead += fread(pObject->pTexVerts, 1, pPreviousChunk->length - pPreviousChunk->bytesRead, m_FilePointer);
}


///////////////////////////////// READ VERTICES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in the vertices for the object
/////
///////////////////////////////// READ VERTICES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadVertices(t3DObject *pObject, tChunk *pPreviousChunk)
{
	// Like most chunks, before we read in the actual vertices, we need
	// to find out how many there are to read in.  Once we have that number
	// we then fread() them into our vertice array.

	// Read in the number of vertices (int)
	pPreviousChunk->bytesRead += fread(&(pObject->numOfVerts), 1, 2, m_FilePointer);

	// Allocate the memory for the verts and initialize the structure
	pObject->pVerts = new CVector[pObject->numOfVerts];
	memset(pObject->pVerts, 0, sizeof(CVector) * pObject->numOfVerts);

	// Read in the array of vertices (an array of 3 floats)
	pPreviousChunk->bytesRead += fread(pObject->pVerts, 1, pPreviousChunk->length - pPreviousChunk->bytesRead, m_FilePointer);

	// Now we should have all of the vertices read in.  Because 3D Studio Max
	// Models with the Z-Axis pointing up (strange and ugly I know!), we need
	// to flip the y values with the z values in our vertices.  That way it
	// will be normal, with Y pointing up.  If you prefer to work with Z pointing
	// up, then just delete this next loop.  Also, because we swap the Y and Z
	// we need to negate the Z to make it come out correctly.

	// Go through all of the vertices that we just read and swap the Y and Z values
	for(int i = 0; i < pObject->numOfVerts; i++)
	{
		// Store off the Y value
		float fTempY = pObject->pVerts[i].y;

		// Set the Y value to the Z value
		pObject->pVerts[i].y = pObject->pVerts[i].z;

		// Set the Z value to the Y value, 
		// but negative Z because 3D Studio max does the opposite.
		pObject->pVerts[i].z = -fTempY;
	}
}


///////////////////////////////// READ OBJECT MATERIAL \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*
/////
/////	This function reads in the material name assigned to the object and sets the materialID
/////
///////////////////////////////// READ OBJECT MATERIAL \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*

void CLoad3DS::ReadObjectMaterial(CModel *pModel, t3DObject *pObject, tChunk *pPreviousChunk)
{
	char strMaterial[255] = {0};			// This is used to hold the objects material name
	int buffer[50000] = {0};				// This is used to read past unwanted data

	// *What is a material?*  - A material is either the color or the texture map of the object.
	// It can also hold other information like the brightness, shine, etc... Stuff we don't
	// really care about.  We just want the color, or the texture map file name really.

	// Here we read the material name that is assigned to the current object.
	// strMaterial should now have a string of the material name, like "Material #2" etc..
	pPreviousChunk->bytesRead += GetString(strMaterial);

	// Now that we have a material name, we need to go through all of the materials
	// and check the name against each material.  When we find a material in our material
	// list that matches this name we just read in, then we assign the materialID
	// of the object to that material index.  You will notice that we passed in the
	// model to this function.  This is because we need the number of textures.
	// Yes though, we could have just passed in the model and not the object too.

	// Go through all of the textures
	for(int i = 0; i < pModel->numOfMaterials; i++)
	{
		// If the material we just read in matches the current texture name
		if(strcmp(strMaterial, pModel->pMaterials[i].strName) == 0)
		{
			// Set the material ID to the current index 'i' and stop checking
			pObject->materialID = i;

			// Now that we found the material, check if it's a texture map.
			// If the strFile has a string length of 1 and over it's a texture
			if(strlen(pModel->pMaterials[i].strFile) > 0) {

				// Set the object's flag to say it has a texture map to bind.
				pObject->bHasTexture = true;
			}	
			break;
		}
		else
		{
			// Set the ID to -1 to show there is no material for this object
			pObject->materialID = -1;
		}
	}

	// Read past the rest of the chunk since we don't care about shared vertices
	// You will notice we subtract the bytes already read in this chunk from the total length.
	pPreviousChunk->bytesRead += fread(buffer, 1, pPreviousChunk->length - pPreviousChunk->bytesRead, m_FilePointer);
}