Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
Solved

# Add two buffers

Posted on 1998-11-19
Medium Priority
235 Views
Hi!!

I've two buffers, named buf1 and buf2.

Buf1 contents a RGB file with this structure: R,G,B,R,G,B,...

Buf2 contents a RGBA file with this structure: R,G,B,A,R,G,B,A,...

I want to add these buffers in buf3, so that the result stored in buf3 will be the following:

R,G,B,R,G,B,...

Look that each component of buf3 is calculated:

(example for the first pixel addittion, the A range is from 0 to 1 (0 to 255))

R=R(buf1)(1-A)+R(buf2)
G=G(buf1)(1-A)+G(buf2)
B=B(buf1)(1-A)+B(buf2)

(The first A is used to do the fisrt RGB calculation, the second A is used to do the second RGB calculation, .....)

How can i do that???

0
Question by:Sol
[X]
###### Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

• Help others & share knowledge
• Earn cash & points
• Learn & ask questions
• 4
• 3

LVL 22

Accepted Solution

nietod earned 200 total points
ID: 1178212
0

LVL 22

Expert Comment

ID: 1178213
typedef unsigned char uByt; // for convenience.

void AddBuffs(uByt *DstPtr,uByt *RGBPtr, uByt *RGBAPtr,int Cnt)
{
while (Cnt--)
{
uByt RGB_R = *RGBPtr++;
uByt RGB_G = *RGBPtr++;
uByt RGB_B = *RGBPtr++;
uByt RGBA_R = *RGRAPtr++;
uByt RGBA_G = *RGRAPtr++;
uByt RGBA_B = *RGRAPtr++;
uByt RGBA_A = *RGRAPtr++;

*DstPtr++ = RGB_R*(1 - RGBA_A) + RGBA_R;
*DstPtr++ = RGB_G*(1 - RGBA_A) + RGBA_G;
*DstPtr++ = RGB_B*(1 - RGBA_A) + RGBA_B;
}
}

You probably can change the "names" to make the more intelligent.

Let me know if you have any questions.
0

Author Comment

ID: 1178214
Hi nietod!!

I'm going to try your answer... ;-D

Â¿would you suggest me the most simple or efficient way to visualize the final image (buf3) in screen?
0

LVL 22

Expert Comment

ID: 1178215
I'm not sure I understand that last question.  Do you mean how do you draw the image on the screen?  If so, it sounds like it is device independant bitmap.  (DIB).  Look at StretchDIBits or at CreateDIBitmap.  Those functions will get you started.  (either way will take about 20 lines of code though.)
0

LVL 22

Expert Comment

ID: 1178216
0

Author Comment

ID: 1178217
I'm sorry nietod!!

i've been ill for a long time, but now, i'm back again!! ;-D

Let me try the code... You'll have news...

thanks!!
0

Author Comment

ID: 1178218
Thank's nietod!!

It works fine!!
0

## Featured Post

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article is the first in a series of articles about the C/C++ Visual Studio Express debugger.  It provides a quick start guide in using the debugger. Part 2 focuses on additional topics in breakpoints.  Lastly, Part 3 focuses on thâ€¦
Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and â€¦
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relatâ€¦
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
###### Suggested Courses
Course of the Month9 days, 18 hours left to enroll

#### 610 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.