Jump to content
  • Advertisement
Sign in to follow this  
Dreq

OpenGL Changing pixels on a texture

This topic is 4852 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I have a pretty good 2D OpenGL (ortho mode) engine working now with 32-bit RGBA png texture support. My question is -- if I want to be able to change one pixel in a texture, or create an empty texture and manually write pixel data to it, how would I do that (or what tutorials out there have examples of that).

Share this post


Link to post
Share on other sites
Advertisement
Let's say you draw your whole screen and you want to make a copy from it the before sending the buffer use this
glReadPixels(0,0,XSizeofTheCopy,YSizeofTheCopy,GL_RGBA,GL_UNSIGNED_BYTE,ImagePtr);
this mean you'll make a copy from your scene to an array
unsigned char *ImagePtr=new unsigned char[XSizeofTheCopy*YSizeofTheCopy*4];

bye

Share this post


Link to post
Share on other sites
Just change the pixels in the array you have your texture stored in, then:
glBind(GL_TEXTURE_2D, myTexture); // bind your texture
glTexImage2D(GL_TEXTURE_2D, 0, colorBytes, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, myTextureData); // and update the copy on the graphics card

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!