diff options
Diffstat (limited to 'src/mbgl/map/transform_state.cpp')
| -rw-r--r-- | src/mbgl/map/transform_state.cpp | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/src/mbgl/map/transform_state.cpp b/src/mbgl/map/transform_state.cpp index d79a65c61e..18d2c24aee 100644 --- a/src/mbgl/map/transform_state.cpp +++ b/src/mbgl/map/transform_state.cpp @@ -27,7 +27,7 @@ void TransformState::matrixFor(mat4& matrix, const UnwrappedTileID& tileID) cons matrix::scale(matrix, matrix, s / util::EXTENT, s / util::EXTENT, 1); } -void TransformState::getProjMatrix(mat4& projMatrix, uint16_t nearZ) const { +void TransformState::getProjMatrix(mat4& projMatrix, uint16_t nearZ, bool aligned) const { if (size.isEmpty()) { return; } @@ -63,8 +63,8 @@ void TransformState::getProjMatrix(mat4& projMatrix, uint16_t nearZ) const { matrix::rotate_z(projMatrix, projMatrix, getAngle() + getNorthOrientationAngle()); - matrix::translate(projMatrix, projMatrix, pixel_x() - size.width / 2.0f, - pixel_y() - size.height / 2.0f, 0); + const double dx = pixel_x() - size.width / 2.0f, dy = pixel_y() - size.height / 2.0f; + matrix::translate(projMatrix, projMatrix, dx, dy, 0); if (axonometric) { // mat[11] controls perspective @@ -77,6 +77,21 @@ void TransformState::getProjMatrix(mat4& projMatrix, uint16_t nearZ) const { matrix::scale(projMatrix, projMatrix, 1, 1, 1.0 / Projection::getMetersPerPixelAtLatitude(getLatLng(LatLng::Unwrapped).latitude(), getZoom())); + + // Make a second projection matrix that is aligned to a pixel grid for rendering raster tiles. + // We're rounding the (floating point) x/y values to achieve to avoid rendering raster images to fractional + // coordinates. Additionally, we adjust by half a pixel in either direction in case that viewport dimension + // is an odd integer to preserve rendering to the pixel grid. We're rotating this shift based on the angle + // of the transformation so that 0°, 90°, 180°, and 270° rasters are crisp, and adjust the shift so that + // it is always <= 0.5 pixels. + if (aligned) { + const float xShift = float(size.width % 2) / 2, yShift = float(size.height % 2) / 2; + const double angleCos = std::cos(angle), angleSin = std::sin(angle); + double devNull; + const float dxa = -std::modf(dx, &devNull) + angleCos * xShift + angleSin * yShift; + const float dya = -std::modf(dy, &devNull) + angleCos * yShift + angleSin * xShift; + matrix::translate(projMatrix, projMatrix, dxa > 0.5 ? dxa - 1 : dxa, dya > 0.5 ? dya - 1 : dya, 0); + } } #pragma mark - Dimensions |