These changes are necessary for programs whose set of active attributes is not fixed at compile time by a template parameter pack, but rather varies based on the generated shader text at runtime. In such cases, the attribute location of a given named attribute may vary between instances of the same Program.
Previously, attribute bindings were implicitly associated with a location based on template parameter order, and -1 was used to indicate an inactive attribute. This left us unable to disable the appropriate attribute when it went from active to inactive. Now, the state tracker for bindings explicitly associates locations and state, and an empty optional is used to indicate an inactive attribute.
In addition, a gl::VertexArray class is now exposed, allowing more flexibility in the relationship between Programs, Segments, and attribute bindings. In this commit, that relationship does not change, but the subsequent commit adjusts it to match gl-js, reduce rebinds, and work around buggy VAO implementations.
VertexArray uses a pimpl idiom in order to support implementations that lack the VAO extension. In that case, all VertexArrays share global binding state, reflecting the platform reality in the absence of VAOs, while still providing a uniform API.
port https://github.com/mapbox/mapbox-gl-js/pull/4781
This improves legibility of labels that follow lines in pitched views.
The previous approach used the limited information in the shader to
calculate put the glyph in approximatelyright place. The new approach
does this more accurately by doing it on the cpu where we have access to
the entire line geometry.
Viewport-aligned curved labels start to look very strange in the distance. Until we have a better system for projecting them, just prevent them from showing.
The current value is not passed to `SymbolSizeBinder::uniformValues`, so we shouldn't check `currentValue.isConstant()` in `SymbolSizeBinder::attributeBindings`. If it were true, then we might end up using attribute bindings that are appropriate only for a constant property, but uniform bindings that are appropriate only for a source or composite function.
Instead, just wait for a new bucket to be generated. This will happen automatically, since icon/text-size are layout properties.
* Add simple unit tests for SymbolSizeBinder
* Fix bug in symbol size uniform value calculation
For camera functions we were setting the zoom levels in "covering ranges" to
`[(zoom stop <= tile zoom), (zoom stop >= 1 + tile zoom)]`, but then evaluating
the function at `[tile_zoom, tile_zoom + 1]`.
* Check for it != end() before accessing it->first
* Always return image metrics exclusive of padding
* Work with integer coordinates whenever possible
* Eliminate redundant SpriteAtlasElement members
* Fix asymmetric re-padding in getIconQuad when pixelRatio != 1
* Add explanatory comments
Moves the following to the renderer directory and out of the style namespace:
* CascadeParameters
* PropertyEvaluationParameters
* UpdateParameters
* PropertyEvaluator
* DataDrivenPropertyEvaluator
* CrossFadedPropertyEvaluator
* PaintPropertyBinder
* PaintProperyStatistics
* PossiblyEvaluatedPropertyValue
* TransitioningLight
* EvaluatedLight
* Update gl-js and generate style code
* Factor out packUint8Pair() helper function
* Draft implementation of DDS for {text,icon}-size
Ports https://github.com/mapbox/mapbox-gl-js/pull/4455
* Fix text-size/composite-function-line-placement test
* Refactor to PaintPropertyBinders-like strategy
* Dedupe gl::Program construction
* Use exponential function base for interpolation
* Dedupe coveringZoomStops method
* Fixup tests
* Fix CI errors (hidden within #if block)
PaintPropertyBinder and subclass templates were being instantiated for every unique attribute type (e.g. a_color, a_fill_color, a_halo_color) even though they behave identically for a given property value type (e.g. Color). To fix this, a unique type such as a_color no longer derives from gl::Attribute<...> -- instead it has an inner Type typedef, which should be used wherever neither a unique type nor attribute name is required. This reduces binary size substantially:
VM SIZE FILE SIZE
++++++++++++++ GROWING ++++++++++++++
-------------- SHRINKING --------------
-2.0% -49.3Ki __TEXT,__text -49.3Ki -2.0%
-3.1% -5.21Ki [None] -2.79Ki -1.6%
-2.1% -4.12Ki __TEXT,__const -4.12Ki -2.1%
-1.4% -4.04Ki __TEXT,__gcc_except_tab -4.04Ki -1.4%
-19.3% -3.62Ki __DATA,__data -3.62Ki -19.3%
-2.5% -1.65Ki __TEXT,__unwind_info -1.65Ki -2.5%
-4.2% -8 __DATA,__mod_init_func 0 [ = ]
-1.9% -68.0Ki TOTAL -65.6Ki -1.9%
