Add support for parsing MLT-format vector tile sources (#3246)

Co-authored-by: Bart Louwers <bart@emeel.net>
Co-authored-by: Bart Louwers <bart.louwers@gmail.com>

src/mbgl/programs/programs.cpp

@@ -0,0 +1,78 @@
+#include <mbgl/programs/programs.hpp>
+#include <mbgl/programs/background_program.hpp>
+#include <mbgl/programs/circle_program.hpp>
+#include <mbgl/programs/heatmap_program.hpp>
+#include <mbgl/programs/hillshade_program.hpp>
+#include <mbgl/programs/fill_extrusion_program.hpp>
+#include <mbgl/programs/fill_program.hpp>
+#include <mbgl/programs/line_program.hpp>
+#include <mbgl/programs/raster_program.hpp>
+#include <mbgl/programs/symbol_program.hpp>
+#include <mbgl/util/logging.hpp>
+
+namespace mbgl {
+
+Programs::Programs(const ProgramParameters& programParameters_)
+    : programParameters(programParameters_) {}
+
+Programs::~Programs() = default;
+
+namespace {
+/// @brief Register a list of types with a shader registry instance
+/// @tparam ...T Type list parameter pack
+/// @param registry A shader registry instance
+/// programParameters_ ProgramParameters used to initialize each instance
+template <typename... T>
+void registerTypes(gfx::ShaderRegistry& registry, const ProgramParameters& programParameters_) {
+    /// The following fold expression will create a shared_ptr for every type
+    /// in the parameter pack and register it with the shader registry.
+
+    /// Registration calls are wrapped in a lambda that throws on registration
+    /// failure, we shouldn't expect registration to faill unless the shader
+    /// registry instance provided already has conflicting programs present.
+    (
+        [](bool expr) {
+            if (!expr) {
+                throw std::runtime_error("Failed to register " + std::string(T::Name) + " with shader registry!");
+            }
+        }(registry.getLegacyGroup().registerShader(std::make_shared<T>(programParameters_))),
+        ...);
+}
+} // namespace
+
+void Programs::registerWith(gfx::ShaderRegistry& registry) {
+#if MLN_LEGACY_RENDERER
+    /// The following types will be registered
+    registerTypes<BackgroundProgram,
+                  BackgroundPatternProgram,
+                  RasterProgram,
+                  HeatmapProgram,
+                  HeatmapTextureProgram,
+                  HillshadeProgram,
+                  HillshadePrepareProgram,
+                  FillProgram,
+                  FillPatternProgram,
+                  FillOutlineProgram,
+                  FillOutlinePatternProgram,
+                  FillExtrusionProgram,
+                  FillExtrusionPatternProgram,
+                  CircleProgram,
+                  LineProgram,
+                  LineGradientProgram,
+                  LineSDFProgram,
+                  LinePatternProgram,
+                  SymbolIconProgram,
+                  SymbolSDFIconProgram,
+                  SymbolSDFTextProgram,
+                  SymbolTextAndIconProgram,
+                  CollisionBoxProgram,
+                  CollisionCircleProgram,
+                  DebugProgram,
+                  ClippingMaskProgram>(registry, programParameters);
+#else
+    /// The following types will be registered
+    registerTypes<DebugProgram, ClippingMaskProgram>(registry, programParameters);
+#endif
+}
+
+} // namespace mbgl