diff options
Diffstat (limited to 'src/mbgl/shaders/symbol_sdf.cpp')
-rw-r--r-- | src/mbgl/shaders/symbol_sdf.cpp | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/src/mbgl/shaders/symbol_sdf.cpp b/src/mbgl/shaders/symbol_sdf.cpp index b4158bacc5..2050886957 100644 --- a/src/mbgl/shaders/symbol_sdf.cpp +++ b/src/mbgl/shaders/symbol_sdf.cpp @@ -73,6 +73,8 @@ uniform mat4 u_gl_coord_matrix; uniform bool u_is_text; uniform bool u_pitch_with_map; uniform highp float u_pitch; +uniform bool u_rotate_symbol; +uniform highp float u_aspect_ratio; uniform highp float u_camera_to_center_distance; uniform highp float u_collision_y_stretch; @@ -151,8 +153,21 @@ void main() { float fontScale = u_is_text ? size / 24.0 : size; - highp float angle_sin = sin(segment_angle); - highp float angle_cos = cos(segment_angle); + highp float symbol_rotation = 0.0; + if (u_rotate_symbol) { + // Point labels with 'rotation-alignment: map' are horizontal with respect to tile units + // To figure out that angle in projected space, we draw a short horizontal line in tile + // space, project it, and measure its angle in projected space. + vec4 offsetProjectedPoint = u_matrix * vec4(a_pos + vec2(1, 0), 0, 1); + + vec2 a = projectedPoint.xy / projectedPoint.w; + vec2 b = offsetProjectedPoint.xy / offsetProjectedPoint.w; + + symbol_rotation = atan((b.y - a.y) / u_aspect_ratio, b.x - a.x); + } + + highp float angle_sin = sin(segment_angle + symbol_rotation); + highp float angle_cos = cos(segment_angle + symbol_rotation); mat2 rotation_matrix = mat2(angle_cos, -1.0 * angle_sin, angle_sin, angle_cos); vec4 projected_pos = u_label_plane_matrix * vec4(a_projected_pos.xy, 0.0, 1.0); |