From bdaedb601ce3f3bd87cc8fb773ae8ac912fd457b Mon Sep 17 00:00:00 2001 From: Paul Trojahn Date: Tue, 8 Oct 2019 20:52:30 +0200 Subject: Fix draw_rect OpenGL uses the diamond exit rule to rasterize lines. If we don't shift the points down and to the right by 0.5, the line can sometimes miss a pixel when it shouldn't. The final fragment of a line isn't drawn. By drawing the lines clockwise, we can avoid a missing pixel in the rectangle. See section 3.4.1 in the OpenGL 1.5 specification. Fixes #32279 --- drivers/gles3/rasterizer_canvas_gles3.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/gles3') diff --git a/drivers/gles3/rasterizer_canvas_gles3.cpp b/drivers/gles3/rasterizer_canvas_gles3.cpp index edffe852a2..e09ba755ea 100644 --- a/drivers/gles3/rasterizer_canvas_gles3.cpp +++ b/drivers/gles3/rasterizer_canvas_gles3.cpp @@ -548,8 +548,10 @@ void RasterizerCanvasGLES3::_canvas_item_render_commands(Item *p_item, Item *cur if (line->width <= 1) { Vector2 verts[2] = { - Vector2(line->from.x, line->from.y), - Vector2(line->to.x, line->to.y) + // Offset the line slightly to make sure we always draw the pixel at the from coordinate. + // Without this, corners of rectangles might be missing a pixel. (See diamond exit rule and #32657) + Vector2(Math::floor(line->from.x) + 0.5, Math::floor(line->from.y) + 0.5), + Vector2(Math::floor(line->to.x) + 0.5, Math::floor(line->to.y) + 0.5) }; #ifdef GLES_OVER_GL -- cgit v1.2.3