diff options
author | Konstantin Käfer <mail@kkaefer.com> | 2017-01-19 16:36:19 +0100 |
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committer | Konstantin Käfer <mail@kkaefer.com> | 2017-01-23 17:02:40 +0100 |
commit | a37ae27aed97af00a12cb5123264f47bd1fe3427 (patch) | |
tree | 78fefe5b4d14dd74efcc23ff2a1a34199cf34131 /src | |
parent | f1c3cfb7e2d46a4563d680bcab888fa01b2ca160 (diff) | |
download | qtlocation-mapboxgl-a37ae27aed97af00a12cb5123264f47bd1fe3427.tar.gz |
[core] fix rendering 180° line joins
Diffstat (limited to 'src')
-rw-r--r-- | src/mbgl/programs/line_program.hpp | 2 | ||||
-rw-r--r-- | src/mbgl/renderer/line_bucket.cpp | 16 |
2 files changed, 13 insertions, 5 deletions
diff --git a/src/mbgl/programs/line_program.hpp b/src/mbgl/programs/line_program.hpp index 9b97cc47a9..4c2f76f402 100644 --- a/src/mbgl/programs/line_program.hpp +++ b/src/mbgl/programs/line_program.hpp @@ -49,7 +49,7 @@ struct LineAttributes : gl::Attributes< static_cast<int16_t>((p.y * 2) | t.y) }, { - // add 128 to store an byte in an unsigned byte + // add 128 to store a byte in an unsigned byte static_cast<uint8_t>(::round(extrudeScale * e.x) + 128), static_cast<uint8_t>(::round(extrudeScale * e.y) + 128), diff --git a/src/mbgl/renderer/line_bucket.cpp b/src/mbgl/renderer/line_bucket.cpp index 007060bd1b..6921b364d8 100644 --- a/src/mbgl/renderer/line_bucket.cpp +++ b/src/mbgl/renderer/line_bucket.cpp @@ -139,7 +139,14 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) { // Determine the normal of the join extrusion. It is the angle bisector // of the segments between the previous line and the next line. - Point<double> joinNormal = util::unit(*prevNormal + *nextNormal); + // In the case of 180° angles, the prev and next normals cancel each other out: + // prevNormal + nextNormal = (0, 0), its magnitude is 0, so the unit vector would be + // undefined. In that case, we're keeping the joinNormal at (0, 0), so that the cosHalfAngle + // below will also become 0 and miterLength will become Infinity. + Point<double> joinNormal = *prevNormal + *nextNormal; + if (joinNormal.x != 0 || joinNormal.y != 0) { + joinNormal = util::unit(joinNormal); + } /* joinNormal prevNormal * ↖ ↑ @@ -155,7 +162,8 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) { // Find the cosine of the angle between the next and join normals // using dot product. The inverse of that is the miter length. const double cosHalfAngle = joinNormal.x * nextNormal->x + joinNormal.y * nextNormal->y; - const double miterLength = cosHalfAngle != 0 ? 1 / cosHalfAngle: 1; + const double miterLength = + cosHalfAngle != 0 ? 1 / cosHalfAngle : std::numeric_limits<double>::infinity(); const bool isSharpCorner = cosHalfAngle < COS_HALF_SHARP_CORNER && prevCoordinate && nextCoordinate; @@ -189,7 +197,7 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) { if (currentJoin == LineJoinType::Bevel) { // The maximum extrude length is 128 / 63 = 2 times the width of the line - // so if miterLength >= 2 we need to draw a different type of bevel where. + // so if miterLength >= 2 we need to draw a different type of bevel here. if (miterLength > 2) { currentJoin = LineJoinType::FlipBevel; } @@ -216,7 +224,7 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) { if (miterLength > 100) { // Almost parallel lines - joinNormal = *nextNormal; + joinNormal = *nextNormal * -1.0; } else { const double direction = prevNormal->x * nextNormal->y - prevNormal->y * nextNormal->x > 0 ? -1 : 1; const double bevelLength = miterLength * util::mag(*prevNormal + *nextNormal) / |