matrix = ((fxMatrix)&d3dMatrix); //Evil?

Posted by Xilliah on Stack Overflow See other posts from Stack Overflow or by Xilliah
Published on 2011-01-03T11:38:42Z Indexed on 2011/01/03 12:54 UTC
Read the original article Hit count: 166

Filed under:

c++

|

conversion

|

matrix

|

directx

|

vtable

I've been using

matrix = *((fxMatrix*)&d3dMatrix);

for quite a while. It worked fine until my screen turned black and received a bucket of frustration on my desk.

fxMatrix contains 4 fxVectors. fxVector used to be 16 bytes, but now it was suddenly 20. This was because it inherited fxStreamable, which added the vTable.

So one solution is of course just to not inherit fxStreamable, and leave a comment saying that it must always be 16 bytes and never more.

Another solution would be to make conversion functions, and copy the matrix completely. This makes it more secure, but has an impact on the performance. I suppose this is the best idea.

Another solution is to not convert at all, and stick to D3DXMATRIX, but this makes the engine inconsistent and I personally really dislike this idea.

What is your opinion?

© Stack Overflow or respective owner

Related posts about c++

Which C++ book shold I get between "C++ Primer" vs "C++ Primer Plus"

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to learn C++ by using Vim and MinGW as compiler. I'm interesting at "C++ Primer (4th Edition)" and "C++ Primer Plus (5th Edition)" but I don't know how about it different. It has no book store that I can review those books, so I want to know, what is the different between those book and which… >>> More
C++ : C++ Primer (Stanley Lipmann) or The C++ programming language (special edition)

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a Computer Science degree (long2 time ago) .. I do know Java OOP but i am now trying to pick up C++. I do have C and of course data structure using C or pascal. I have started reading Bjarne Stroustrup book (The C++ Programming Language - Special Edition) but find it extremely difficult esp… >>> More
I need help on my C++ assignment using MS Visual C++

as seen on Stack Overflow - Search for 'Stack Overflow'
Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This… >>> More
Managed c++ std::string not accessible in unmanaged c++

as seen on Stack Overflow - Search for 'Stack Overflow'
In unmanaged c++ dll i have a function which takes constant std::string as argument Prototype : void read ( const std::string &imageSpec_ ) I call this function from managed c++ dll by passing a std::string. When i debug the unmanaged c++ code the parameter imageSpec_ shows the value correctly… >>> More
The Definitive C++ Book Guide and List

as seen on Stack Overflow - Search for 'Stack Overflow'
After more than a few questions about deciding on C++ books I thought we could make a better community wiki version. Providing QUALITY books and an approximate skill level. Maybe we can add a short blurb/description about each book that you have personally read / benefited from. Feel free to debate… >>> More

Related posts about conversion

Conversion constructor vs. conversion operator: precedence

as seen on Stack Overflow - Search for 'Stack Overflow'
Reading some questions here on SO about conversion operators and constructors got me thinking about the interaction between them, namely when there is an 'ambiguous' call. Consider the following code: class A; class B { public: B(){} B(const A&) //conversion constructor … >>> More
Conversion of bytes into a type without changing the application (ie storing the conversion method i

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there a way to store a conversion strategy (for converting some bytes) into a database and then execute it on the run time. If one were to store a complete java file, you would need to compile it, store the class and some how inject into the already running system. I am not sure how this would… >>> More
General type conversion without risking Exceptions

as seen on Stack Overflow - Search for 'Stack Overflow'
I am working on a control that can take a number of different datatypes (anything that implements IComparable). I need to be able to compare these with another variable passed in. If the main datatype is a DateTime, and I am passed a String, I need to attempt to convert the String to a DateTime… >>> More
Create a Unit Conversion Application with the Zend_Measure Component

as seen on Internet.com - Search for 'Internet.com'
Learn how to create a simple conversion calculator using the Zend Framework's Zend_Measure component ... >>> More
Create a Unit Conversion Application with the Zend_Measure Component

as seen on Internet.com - Search for 'Internet.com'
Learn how to create a simple conversion calculator using the Zend Framework's Zend_Measure component ... >>> More