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.

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.

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 );