3ds.cpp

S.C.O.U.R.G.E.是一款类似Rogue的游戏

    // Read in the array of vertices (an array of 3 floats)
    pPreviousChunk->bytesRead += fread(pObject->pVerts, 1, pPreviousChunk->length - pPreviousChunk->bytesRead, m_FilePointer);
	if(SDL_BYTEORDER == SDL_BIG_ENDIAN) {
	  for(int i = 0; i < pObject->numOfVerts; i++) {
		/* Note: byteswapping floats works on my powerbook, but I think
		   this may cause problems in the future. Floats and doubles aren't
		   as easy to change from LE to BE as ints.
		*/
		float f;
		BSWAPF(pObject->pVerts[i].x, f);
		pObject->pVerts[i].x = f;
		BSWAPF(pObject->pVerts[i].y, f);
		pObject->pVerts[i].y = f;
		BSWAPF(pObject->pVerts[i].z, f);
		pObject->pVerts[i].z = f;
	  }
	}

    // 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(t3DModel *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);
}


/////////////////////////////////////////////////////////////////////////////////
//
// * QUICK NOTES * 
//
// This was a HUGE amount of knowledge and probably the largest tutorial yet!
// In the next tutorial we will show you how to load a text file format called .obj.
// This is the most common 3D file format that almost ANY 3D software will import.
//
// Once again I should point out that the coordinate system of OpenGL and 3DS Max are different.
// Since 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.  Also, because we swap the Y and Z we need to negate 
// the Z to make it come out correctly.  This is also explained and done in ReadVertices().
//
// CHUNKS: What is a chunk anyway?
// 
// "The chunk ID is a unique code which identifies the type of data in this chunk 
// and also may indicate the existence of subordinate chunks. The chunk length indicates 
// the length of following data to be associated with this chunk. Note, this may 
// contain more data than just this chunk. If the length of data is greater than that 
// needed to fill in the information for the chunk, additional subordinate chunks are 
// attached to this chunk immediately following any data needed for this chunk, and 
// should be parsed out. These subordinate chunks may themselves contain subordinate chunks. 
// Unfortunately, there is no indication of the length of data, which is owned by the current 
// chunk, only the total length of data attached to the chunk, which means that the only way 
// to parse out subordinate chunks is to know the exact format of the owning chunk. On the 
// other hand, if a chunk is unknown, the parsing program can skip the entire chunk and 
// subordinate chunks in one jump. " - Jeff Lewis ([e-mail])
//
// In a short amount of words, a chunk is defined this way:
// 2 bytes - Stores the chunk ID (OBJECT, MATERIAL, PRIMARY, etc...)
// 4 bytes - Stores the length of that chunk.  That way you know when that
//           chunk is done and there is a new chunk.
//
// So, to start reading the 3DS file, you read the first 2 bytes of it, then
// the length (using fread()).  It should be the PRIMARY chunk, otherwise it isn't
// a .3DS file.  
//
// Below is a list of the order that you will find the chunks and all the know chunks.
// If you go to www.wosit.org you can find a few documents on the 3DS file format.
// You can also take a look at the 3DS Format.rtf that is included with this tutorial.
//
//
//
//      MAIN3DS  (0x4D4D)
//     |
//     +--EDIT3DS  (0x3D3D)
//     |  |
//     |  +--EDIT_MATERIAL (0xAFFF)
//     |  |  |
//     |  |  +--MAT_NAME01 (0xA000) (See mli Doc) 
//     |  |
//     |  +--EDIT_CONFIG1  (0x0100)
//     |  +--EDIT_CONFIG2  (0x3E3D) 
//     |  +--EDIT_VIEW_P1  (0x7012)
//     |  |  |
//     |  |  +--TOP            (0x0001)
//     |  |  +--BOTTOM         (0x0002)
//     |  |  +--LEFT           (0x0003)
//     |  |  +--RIGHT          (0x0004)
//     |  |  +--FRONT          (0x0005) 
//     |  |  +--BACK           (0x0006)
//     |  |  +--USER           (0x0007)
//     |  |  +--CAMERA         (0xFFFF)
//     |  |  +--LIGHT          (0x0009)
//     |  |  +--DISABLED       (0x0010)  
//     |  |  +--BOGUS          (0x0011)
//     |  |
//     |  +--EDIT_VIEW_P2  (0x7011)
//     |  |  |
//     |  |  +--TOP            (0x0001)
//     |  |  +--BOTTOM         (0x0002)
//     |  |  +--LEFT           (0x0003)
//     |  |  +--RIGHT          (0x0004)
//     |  |  +--FRONT          (0x0005) 
//     |  |  +--BACK           (0x0006)
//     |  |  +--USER           (0x0007)
//     |  |  +--CAMERA         (0xFFFF)
//     |  |  +--LIGHT          (0x0009)
//     |  |  +--DISABLED       (0x0010)  
//     |  |  +--BOGUS          (0x0011)
//     |  |
//     |  +--EDIT_VIEW_P3  (0x7020)
//     |  +--EDIT_VIEW1    (0x7001) 
//     |  +--EDIT_BACKGR   (0x1200) 
//     |  +--EDIT_AMBIENT  (0x2100)
//     |  +--EDIT_OBJECT   (0x4000)
//     |  |  |
//     |  |  +--OBJ_TRIMESH   (0x4100)      
//     |  |  |  |
//     |  |  |  +--TRI_VERTEXL          (0x4110) 
//     |  |  |  +--TRI_VERTEXOPTIONS    (0x4111)
//     |  |  |  +--TRI_MAPPINGCOORS     (0x4140) 
//     |  |  |  +--TRI_MAPPINGSTANDARD  (0x4170)
//     |  |  |  +--TRI_FACEL1           (0x4120)
//     |  |  |  |  |
//     |  |  |  |  +--TRI_SMOOTH            (0x4150)   
//     |  |  |  |  +--TRI_MATERIAL          (0x4130)
//     |  |  |  |
//     |  |  |  +--TRI_LOCAL            (0x4160)
//     |  |  |  +--TRI_VISIBLE          (0x4165)
//     |  |  |
//     |  |  +--OBJ_LIGHT    (0x4600)
//     |  |  |  |
//     |  |  |  +--LIT_OFF              (0x4620)
//     |  |  |  +--LIT_SPOT             (0x4610) 
//     |  |  |  +--LIT_UNKNWN01         (0x465A) 
//     |  |  | 
//     |  |  +--OBJ_CAMERA   (0x4700)
//     |  |  |  |
//     |  |  |  +--CAM_UNKNWN01         (0x4710)
//     |  |  |  +--CAM_UNKNWN02         (0x4720)  
//     |  |  |
//     |  |  +--OBJ_UNKNWN01 (0x4710)
//     |  |  +--OBJ_UNKNWN02 (0x4720)
//     |  |
//     |  +--EDIT_UNKNW01  (0x1100)
//     |  +--EDIT_UNKNW02  (0x1201) 
//     |  +--EDIT_UNKNW03  (0x1300)
//     |  +--EDIT_UNKNW04  (0x1400)
//     |  +--EDIT_UNKNW05  (0x1420)
//     |  +--EDIT_UNKNW06  (0x1450)
//     |  +--EDIT_UNKNW07  (0x1500)
//     |  +--EDIT_UNKNW08  (0x2200)
//     |  +--EDIT_UNKNW09  (0x2201)
//     |  +--EDIT_UNKNW10  (0x2210)
//     |  +--EDIT_UNKNW11  (0x2300)
//     |  +--EDIT_UNKNW12  (0x2302)
//     |  +--EDIT_UNKNW13  (0x2000)
//     |  +--EDIT_UNKNW14  (0xAFFF)
//     |
//     +--KEYF3DS (0xB000)
//        |
//        +--KEYF_UNKNWN01 (0xB00A)
//        +--............. (0x7001) ( viewport, same as editor )
//        +--KEYF_FRAMES   (0xB008)
//        +--KEYF_UNKNWN02 (0xB009)
//        +--KEYF_OBJDES   (0xB002)
//           |
//           +--KEYF_OBJHIERARCH  (0xB010)
//           +--KEYF_OBJDUMMYNAME (0xB011)
//           +--KEYF_OBJUNKNWN01  (0xB013)
//           +--KEYF_OBJUNKNWN02  (0xB014)
//           +--KEYF_OBJUNKNWN03  (0xB015)  
//           +--KEYF_OBJPIVOT     (0xB020)  
//           +--KEYF_OBJUNKNWN04  (0xB021)  
//           +--KEYF_OBJUNKNWN05  (0xB022)  
//
// Once you know how to read chunks, all you have to know is the ID you are looking for
// and what data is stored after that ID.  You need to get the file format for that.
// I can give it to you if you want, or you can go to www.wosit.org for several versions.
// Because this is a proprietary format, it isn't a official document.
//
// I know there was a LOT of information blown over, but it is too much knowledge for
// one tutorial.  In the animation tutorial that I eventually will get to, some of
// the things explained here will be explained in more detail.  I do not claim that
// this is the best .3DS tutorial, or even a GOOD one :)  But it is a good start, and there
// isn't much code out there that is simple when it comes to reading .3DS files.
// So far, this is the best I have seen.  That is why I made it :)
// 
// I would like to thank www.wosit.org and Terry Caton ([e-mail]) for his help on this.
//
// Let me know if this helps you out!
// 
// 
// Ben Humphrey (DigiBen)
// Game Programmer
// [e-mail]
// Co-Web Host of www.GameTutorials.com
//
//