opengl - Why is GL_LINES blurry? -

consider following code:

glcolor4ub(255, 255, 255,255);  glbegin(gl_quads); glvertex2i(100, 100); glvertex2i(300, 100); glvertex2i(300, 101); glvertex2i(100, 101); glend();  gllinewidth(1);  glbegin(gl_lines); glvertex2i(100,200); glvertex2i(300,200); glend(); 

that results in following, don't understand:

i have not enabled (and have gone far disable) gl_line_smooth , gl_smooth. if global anti-aliasing "feature," shouldn't affect gl_quads well?

halp?

it because passed coordinate halfway between 2 pixels.

for quads, borders between pixels , give nice clean edges.

for lines, vertices between pixels causes half line fall on each. example, if using gllinewidth(2), work (half line 1 pixel, there's 1 pixel either side). gllinewidth(1), you're getting half pixel either side.