Jump to content

  • Log In with Google      Sign In   
  • Create Account


Losing clarity


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
3 replies to this topic

#1 metamind   Members   -  Reputation: 113

Like
0Likes
Like

Posted 25 March 2013 - 09:20 AM

Hi,

 

I have a capture card (Blackmagic intensity pro) that is capturing the screen of another machine. I am capturing it as a texture fine (I can dump the texture to an image file). I am capturing 1280 x 720px.

 

I then create a 1280 x 720 quad and texture the quad using the texture. However, result has lost a lot of clarity, expecially with text.

 

I am using orthonormal projection

 

        gluOrtho2D(0, mFrameWidth * iNumProjectors, 0, mFrameHeight);
 

 

Setting up the texture (I have tried both linear and nearest).

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );

        //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );

        //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );

 

 

Rendering code

                glBegin(GL_QUADS);

                    glTexCoord2f(1.0f, 0.0f);    glVertex2i(mFrameWidth - 1,    mFrameHeight - 1);    // Top right

                    glTexCoord2f(1.0f, 0.0f);    glVertex2i(0,                mFrameHeight - 1);    // Top left

                    glTexCoord2f(1.0f, 1.0f);    glVertex2i(0,                0);    // Bottom left

                    glTexCoord2f(1.0f, 1.0f);    glVertex2i(mFrameWidth,        0);    // Bottom right

                glEnd();

 

Not sure what else to try.



Sponsor:

#2 Brother Bob   Moderators   -  Reputation: 7784

Like
0Likes
Like

Posted 25 March 2013 - 09:26 AM

Drop the -1 from your coordinates, or you will project a your 1280x720 on a region that is 1279x719 pixels and this downscaling the image slightly.



#3 metamind   Members   -  Reputation: 113

Like
0Likes
Like

Posted 25 March 2013 - 11:57 AM

I did try various combinations. This is what it looks like with:

 

                glBegin(GL_QUADS);
                    glTexCoord2f(1.0f, 0.0f);    glVertex2i(mFrameWidth,    mFrameHeight);    // Top right
                    glTexCoord2f(0.0f, 0.0f);    glVertex2i(0,            mFrameHeight);    // Top left
                    glTexCoord2f(0.0f, 1.0f);    glVertex2i(0,            0);    // Bottom left
                    glTexCoord2f(1.0f, 1.0f);    glVertex2i(mFrameWidth, 0);    // Bottom right
                glEnd();

 

and

 

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );

 

2013-03-25.png



#4 Vortez   Crossbones+   -  Reputation: 2688

Like
0Likes
Like

Posted 02 April 2013 - 11:39 PM

You should use GL_NEAREST for this. Something is not to scale here, either you're drawing the image to small or bigger, or the image is at the wrong resolution, make sure your window client area is the right size, not the window itself, also make sure you're not using mipmap.

 

And why is the half right of the picture black???

 

More info on how your drawing it and the size of the window would help too.


Edited by jbadams, 04 April 2013 - 05:41 AM.
Restored post contents from history.





Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS