hi all i am trying thecode from lesson 20 and trying to mask but it dont success and it just show nothing or if i delete the : glEnable(GL_BLEND); // Enable Blending glDisable(GL_DEPTH_TEST); i just see a black picture's background and here is my full code of it : glEnable(GL_BLEND); // Enable Blending glDisable(GL_DEPTH_TEST); glBlendFunc(GL_DST_COLOR,GL_ZERO); glBindTexture(GL_TEXTURE_2D, texture[4]); glBegin(GL_QUADS); glTexCoord2f(0.0,1.0); glVertex3f(-1.0,1.0,0.0); glTexCoord2f(1.0,1.0);glVertex3f(1.0,1.0,0.0); glTexCoord2f(1.0,0.0);glVertex3f(1.0,0.0,0.0); glTexCoord2f(0.0,0.0);glVertex3f(-1.0,0.0,0.0); glEnd(); glBlendFunc(GL_ONE, GL_ONE); glBindTexture(GL_TEXTURE_2D, texture[2]); glBegin(GL_QUADS); glColor4f(1.0f,1.0f,1.0f,0.5f); glTexCoord2f(0.0,1.0); glVertex3f(-1.0,1.0,0.0); glTexCoord2f(1.0,1.0);glVertex3f(1.0,1.0,0.0); glTexCoord2f(1.0,0.0);glVertex3f(1.0,0.0,0.0); glTexCoord2f(0.0,0.0);glVertex3f(-1.0,0.0,0.0); glEnd(); glEnable(GL_DEPTH_TEST); // Enable Depth Testing glDisable(GL_BLEND); ______________ does anyone know what is this happening? if yes plz help me... thx