Question

I have no idea what’s wrong. Everything seems to be fine. Here’s code (texture is loaded, just drawing) :

glBegin( GL_QUADS );
    float TX1,TX2,TY1,TY2;

    TX1=some_numbers_check_below_code;
    TX2=some_numbers_check_below_code;
    TY1=some_numbers_check_below_code;
    TY2=some_numbers_check_below_code;

    glTexCoord2f(TX1,TY2);
    glVertex3f( float(RectOutput.x), float(RectOutput.y), 0.0f );

    glTexCoord2f(TX2,TY2);
    glVertex3f( float(RectOutput.x+InputWidth), float(RectOutput.y), 0.0f );

    glTexCoord2i(TX2,TY1);
    glVertex3f( float(RectOutput.x+InputWidth), float(RectOutput.y+InputHeight), 0.0f );(InputY)/float(Input.H)) );

    glTexCoord2f(TX1,TY1);
    glVertex3f( float(RectOutput.x), float(RectOutput.y+InputHeight), 0.0f );

glEnd();

It’s okay with :

TX1=0.0;
TX2=1.0;
TY1=1.0;
TY2=0.0;

(Good : https://i.stack.imgur.com/2Bj8i.png)

But gets broken with (eg.) :

TX1=0.0;
TX2=0.5;
TY1=1.0;
TY2=0.5;

(Like this : https://i.stack.imgur.com/Xem99.png)

Really, it annoys me. Probably problem isn’t in this code. Everything should be fine … but it’s not.

Any ideas?

Answer 1

“I have no idea what’s wrong. Everything seems to be fine”. Great then, no need to answer!

You should first explain what do you expect to get in second case. I am not an OpenGL expert, but your second set of coordinates seem broken.

The first one: 0,0 -> 1,0 -> 1,1 -> 0,1:

  0     1
0 x---->x
  |     |
  |     |
  |     v
1 x<----x

The second one: 0,.5 -> .5,.5 -> .5,1 -> 0,1:

  0     1
0 +-----+
  |     |
  x->x  |
  |  v  |
1 +--x->x

If you want to scale the texture (but I don’t know as you haven’t written what is supposed to be the result) then this is obviously wrong.