Skip to content

vello classic: fix comment about tile inclusion in coarse shader #1333

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
tomcur wants to merge 1 commit into
base: main
Choose a base branch
from
+12 −6
Open

vello classic: fix comment about tile inclusion in coarse shader #1333

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 6 additions & 3 deletions vello_shaders/shader/coarse.wgsl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -332,9 +332,12 @@ fn main(
let even_odd = (draw_flags & DRAW_INFO_FLAGS_FILL_RULE_BIT) != 0u;
let n_segs = tile.segment_count_or_ix;

// If this draw object represents an even-odd fill and we know that no line segment
// crosses this tile and then this draw object should not contribute to the tile if its
// backdrop (i.e. the winding number of its top-left corner) is even.
// If no line segment crosses this tile and the backdrop (i.e. the winding number of
// its top-left corner) and fill rule are such that the tile is completely uncovered,
// and we're not blending, then the tile is completely clear. This draw object should
// then not contribute to the tile, unless it is a clip. If the draw object is a clip,
// the "clear" logic is inversed: the draw object doesn't contribute only when the
// tile is completely covered.
let backdrop_clear = select(tile.backdrop, abs(tile.backdrop) & 1, even_odd) == 0;
let include_tile = n_segs != 0u || (backdrop_clear == is_clip) || is_blend;
if include_tile {
Expand Down
9 changes: 6 additions & 3 deletions vello_shaders/src/cpu/coarse.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -272,9 +272,12 @@ fn coarse_main(
let even_odd = (draw_flags & DRAW_INFO_FLAGS_FILL_RULE_BIT) != 0;
let n_segs = tile.segment_count_or_ix;

// If this draw object represents an even-odd fill and we know that no line segment
// crosses this tile and then this draw object should not contribute to the tile if its
// backdrop (i.e. the winding number of its top-left corner) is even.
// If no line segment crosses this tile and the backdrop (i.e. the winding number of
// its top-left corner) and fill rule are such that the tile is completely uncovered,
// and we're not blending, then the tile is completely clear. This draw object should
// then not contribute to the tile, unless it is a clip. If the draw object is a clip,
// the "clear" logic is inversed: the draw object doesn't contribute only when the
// tile is completely covered.
let backdrop_clear = if even_odd {
tile.backdrop.abs() & 1
} else {
Expand Down