Fix 1-pixel flickering between tiles on dark styles #12145
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src/geo/projection/globe_util.js
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| const tileHeight = n - s; | ||
| const toUv = 1.0 / GLOBE_VERTEX_GRID_SIZE; | ||
| const x = tileWidth * toUv; | ||
| const y = -tileHeight / GLOBE_LATITUDINAL_GRID_LOD_TABLE[latitudinalLod]; |
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how about toUvX and we could also refactor 1 / GLOBE_LATITUDINAL_GRID_LOD_TABLE(..) to toUvY
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I think it's unnecessary to have a separate variable toUv anymore
| const xScale = padding / tileWidth + 1; | ||
| const yScale = padding / tileHeight + 1; | ||
| const padMatrix = [xScale, 0, 0, 0, yScale, 0, -0.5 * padding / x, 0.5 * padding / y, 1]; | ||
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The code here has now become more complicated, perhaps we could add a comment along the lines of:
// latLon = gridMatrix * (p_grid + scale * (p_grid - grid_center)) which implies
// latLon = grdiMatrix * (p_grid + scale * p_grid - scale * grid_center)
// and the part in parentheses is another transformation which results in:
// latLon = gridMatrix * padMatrix * p_grid
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This is fairly trivial transformation matrix composition. Perhaps I could add a comment or two about coordinate spaces.
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indeed I was trying to capture the transformation from spaces as I think that might not be trivial at all for a person encountering it for the first time.
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The greenish looking render test |
This pull request fixes the flickering issue between tiles (#11858) by extruding vertices of globe tiles slightly towards the neighbouring tiles. Based on empirical testing I found
0.5pixels to be enough to stitch seams on all of my test devices using different pixel ratios. It should be noted that the texture sampling is unaffected even though tiles are scaled up by a tiny amount. Any possible extra fragments will have their uvs clamped to range[0, 1].Fixes #11858
Launch Checklist
@mapbox/map-design-team@mapbox/static-apisif this PR includes style spec API or visual changes@mapbox/gl-nativeif this PR includes shader changes or needs a native portmapbox-gl-jschangelog:<changelog>Fix pixel flickering between tiles on darker styles in globe view.</changelog>