[core] Dynamic program compilation for data-driven properties

1 files changed, 34 insertions, 1 deletions

diff --git a/src/mbgl/programs/program.hpp b/src/mbgl/programs/program.hpp
index 3351f5eeae..36bbdf349e 100644
--- a/src/mbgl/programs/program.hpp
+++ b/src/mbgl/programs/program.hpp
@@ -9,18 +9,21 @@
 #include <mbgl/shaders/shaders.hpp>
 #include <mbgl/util/io.hpp>
 
+#include <unordered_map>
+
 namespace mbgl {
 
 template <class Shaders,
           class Primitive,
           class LayoutAttrs,
           class Uniforms,
-          class PaintProperties>
+          class PaintProps>
 class Program {
 public:
     using LayoutAttributes = LayoutAttrs;
     using LayoutVertex = typename LayoutAttributes::Vertex;
 
+    using PaintProperties = PaintProps;
     using PaintPropertyBinders = typename PaintProperties::Binders;
     using PaintAttributes = typename PaintPropertyBinders::Attributes;
     using Attributes = gl::ConcatenateAttributes<LayoutAttributes, PaintAttributes>;
@@ -71,4 +74,34 @@ public:
     }
 };
 
+template <class Program>
+class ProgramMap {
+public:
+    using PaintProperties = typename Program::PaintProperties;
+    using PaintPropertyBinders = typename Program::PaintPropertyBinders;
+    using Bitset = typename PaintPropertyBinders::Bitset;
+
+    ProgramMap(gl::Context& context_, ProgramParameters parameters_)
+        : context(context_),
+          parameters(std::move(parameters_)) {
+    }
+
+    Program& get(const typename PaintProperties::PossiblyEvaluated& currentProperties) {
+        Bitset bits = PaintPropertyBinders::constants(currentProperties);
+        auto it = programs.find(bits);
+        if (it != programs.end()) {
+            return it->second;
+        }
+        return programs.emplace(std::piecewise_construct,
+                                std::forward_as_tuple(bits),
+                                std::forward_as_tuple(context,
+                                    parameters.withAdditionalDefines(PaintPropertyBinders::defines(currentProperties)))).first->second;
+    }
+
+private:
+    gl::Context& context;
+    ProgramParameters parameters;
+    std::unordered_map<Bitset, Program> programs;
+};
+
 } // namespace mbgl