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| author | Paul Trojahn <paul.trojahn@gmail.com> | 2019-10-08 20:52:30 +0200 |
|---|---|---|
| committer | Paul Trojahn <paul.trojahn@gmail.com> | 2019-10-11 10:26:53 +0200 |
| commit | bdaedb601ce3f3bd87cc8fb773ae8ac912fd457b (patch) | |
| tree | 184dd2d6c3728864a8c6ea228dff24cca20c6693 /drivers/gles3 | |
| parent | 2078dcbe15e7b1a25bc06b0834a007d63c7ccd01 (diff) | |
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
Diffstat (limited to 'drivers/gles3')
| -rw-r--r-- | drivers/gles3/rasterizer_canvas_gles3.cpp | 6 |
1 files changed, 4 insertions, 2 deletions
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 |