texture under a point and stretch

Hello OpenGLrs,

I have a plane as big as my viewport with a texture mapped on it.
Then there is a cursor with five points arranged as a cross. For each of them I computer the correspondent texture coordinate as

txt.x = pp[i].x/windw.with;
txt.y = pp[i].y/ widnw.height;

So I change the position of the central point, without changing its texture coordinates. I was expecting a stretch of the portion of the image but it doesn’t happen anything. So I wonder why? does texture mapping works only over polygons?

Thanks for any help.

What you describe should indeed stretch the texture.
Can you post the relevant code, the texture coordinates, vertex coordinates, tex gen modes, render commands, viewport, etc ?

weird… well my points are arranged in a cross like this:


and my window is 300 x 400. So each point as coordinates in Pixels (x,y) and I generate texture coordinates like (x/300, y/400) which produces cooridnates in [0,1]. So, I positioned the cross, I press left-mouse to set up the texture coordinates, and I move the central point without updating it texture coordinate. If I render the cross as a sequence of 4 quads and I move the central point, it works.

As I asked above, show your code !