I am trying to draw a rectangle with 4 lines (left one). But no matter how I draw (strip, loop, plain lines) the result is the right side one - it is missing pixels at the corners.
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Is there a way to get the left hand side result?
EDIT
Can't post code since it depends a lot on the underlying framework, but all draw calls are nothing more than glDrawElements with index buffer pointing to 4 vertices, no alpha tests.
After fiddling with coordinates as suggested arrived at this interesting result (iOS simulator):
Notice only upper left corner is missing pixels for some rectangles... All rectangles are drawn in GL_LINES mode within single draw elements call. No other things are drawn.
EDIT 2
OpenGL FAQ question 14.100 states that
OpenGL doesn't provide a mechanism to cleanly join lines that share common vertices nor to cleanly cap the endpoints.