// fill the entire texture memory with the colour
function fill(unsigned char *my_data, unsigned int num_bytes, unsigned int colour)
{
// we want: r,g,b,a
unsigned char *byte_ptr = static_cast<unsigned char *>( &colour );
for( int i = 0; i < num_bytes; i += 4 ) {
memcpy( my_data, byte_ptr, 4 );
}
}
is there a better way than this to fill memory with a single value?
Author
Hi, I'm trying to set an area of (pre-allocated) memory with an single 4-byte value. Here's my code... I'm not sure this is the best/quickest way to do this. Can anyone offer a faster alternative?
Many thanks
jimbogd
In what language is code?
If C++ (what's with "function"?) then:
If C++ (what's with "function"?) then:
std::fill(reinterpret_cast<unsigned int*>(my_data), reinterpret_cast<unsigned int*>(my_data + num_bytes), colour);
Author
Quote:Original post by bubu LV
In what language is code?
If C++ (what's with "function"?) then:
*** Source Snippet Removed ***
Hi, sorry, yes its C++. I put "function" by mistake... should have been "void". My VB background punching through! ;)
cheers
jimbogd
Author
Hi, thanks for the code.
One question: why use reinterpret_cast instead of static_cast in this instance?
thanks again,
jimbogd
One question: why use reinterpret_cast instead of static_cast in this instance?
thanks again,
jimbogd
Quote:Original post by jimbogd
Hi, thanks for the code.
One question: why use reinterpret_cast instead of static_cast in this instance?
thanks again,
jimbogd
reinterpret_cast casts unrelated integer-types (integer-to/from-pointer, pointer-to/from-pointer), while static_cast is for related types. In short, reinterpret_cast casts the underlaying bitpattern into a different type, while static_cast casts logical value (integer value 1 may not have the same bit pattern as floatingpoint value 1, but they have the same logical value).
In bubu LV's code, he use reinterpret_cast because he casts from one pointer type to another unrelated pointer type. You should have done that in your code aswell, becuase pointers to different types are not related.
This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement
