[core] Split layer type specific code in mbgl::Programs

Progams code for a certain layer type is encapsulted within
a dedicated `<layer type>Programs` class, inherited from
the generic base `LayerTypePrograms` class.

`mbgl::Programs::get<layer type>Programs()` lazily initializes the
layer type-specific programs code using pointer to the base class,
which allows LTO to remove this code from binaries (if the corresponding
`get<layer type>Programs()` method can never be invoked).

1 files changed, 10 insertions, 0 deletions

diff --git a/src/mbgl/programs/hillshade_program.hpp b/src/mbgl/programs/hillshade_program.hpp
index 5f9b4d1c2f..aaef884b80 100644
--- a/src/mbgl/programs/hillshade_program.hpp
+++ b/src/mbgl/programs/hillshade_program.hpp
@@ -2,6 +2,7 @@
 
 #include <mbgl/programs/program.hpp>
 #include <mbgl/programs/attributes.hpp>
+#include <mbgl/programs/hillshade_prepare_program.hpp>
 #include <mbgl/programs/uniforms.hpp>
 #include <mbgl/shaders/hillshade.hpp>
 #include <mbgl/util/geometry.hpp>
@@ -52,4 +53,13 @@ public:
 using HillshadeLayoutVertex = HillshadeProgram::LayoutVertex;
 using HillshadeAttributes = HillshadeProgram::Attributes;
 
+class HillshadeLayerPrograms final : public LayerTypePrograms  {
+public:
+    HillshadeLayerPrograms(gl::Context& context, const ProgramParameters& programParameters)
+        : hillshade(context, programParameters),
+          hillshadePrepare(context, programParameters) {}
+    HillshadeProgram hillshade;
+    HillshadePrepareProgram hillshadePrepare;
+};
+
 } // namespace mbgl