I have a small texture, multiplied with help GL_REPEAT on all window. How with the help a glClipPlane to cut off it so that there was a rectangular on the center of the sizes w x h?

sample:

static bool t = true;

matrix_push(); // save current matrix

matrix_pure_reset(); // normalize matrix

matrix_move_z(-8.0f); // move to (0,0,-8)

glEnable(GL_CLIP_PLANE0);

draw_background(BGquads.bits(), &texQuads, 32, width(), height(), t); // draw quads

matrix_pop(); // restore matrix

write_gl_matrix(); // and write it

double e[4] = {150, 0, 0, 0}; // try to cut of pixels on the right hand

glClipPlane(GL_CLIP_PLANE0, e);

glDisable(GL_CLIP_PLANE0);

matrix_move_z(-7.0f);

// bind and draw another texture (Porche)

Result:

http://ksquirrel.sourceforge.net/IMG/error3.png

Whats wrong ?

Thanks.