Allows passing struct by value, utilizing constant memory on the device

Author: rosenrodt

include/boost/compute/types/struct.hpp

@@ -168,6 +168,14 @@ inline std::string adapt_struct_insert_member(T (Struct::*)[N], const char *name
                ) \
                << "}"; \
     } \
+    template<> \
+    struct set_kernel_arg<type> \
+    { \
+        void operator()(kernel &kernel_, size_t index, const type &c) \
+        { \
+            kernel_.set_arg(index, sizeof(type), &c); \
+        } \
+    }; \
     }}}
 
 #endif // BOOST_COMPUTE_TYPES_STRUCT_HPP

test/test_struct.cpp

@@ -23,6 +23,8 @@
 #include <boost/compute/type_traits/type_definition.hpp>
 #include <boost/compute/utility/source.hpp>
 
+#include "check_macros.hpp"
+
 namespace compute = boost::compute;
 
 // example code defining an atom class
@@ -131,6 +133,37 @@ BOOST_AUTO_TEST_CASE(custom_kernel)
     queue.enqueue_1d_range_kernel(custom_kernel, 0, atoms.size(), 1);
 }
 
+BOOST_AUTO_TEST_CASE(custom_kernel_set_struct_by_value)
+{
+    std::string source = BOOST_COMPUTE_STRINGIZE_SOURCE(
+        __kernel void custom_kernel(Atom atom,
+                                    __global float *position,
+                                    __global int *number)
+        {
+            position[0] = atom.x;
+			position[1] = atom.y;
+			position[2] = atom.z;
+            number[0] = atom.number;
+        }
+    );
+    source = compute::type_definition<chemistry::Atom>() + "\n" + source;
+    compute::program program =
+        compute::program::build_with_source(source, context);
+	compute::kernel custom_kernel = program.create_kernel("custom_kernel");
+
+	chemistry::Atom atom(1.0f, 2.0f, 3.0f, 4);
+    compute::vector<float> position(3);
+    compute::vector<int> number(1);
+	
+	custom_kernel.set_arg(0, atom);
+	custom_kernel.set_arg(1, position);
+	custom_kernel.set_arg(2, number);
+    queue.enqueue_task(custom_kernel);
+
+    CHECK_RANGE_EQUAL(float, 3, position, (1.0f, 2.0f, 3.0f));
+    BOOST_CHECK_EQUAL(number.at(0), 4);
+}
+
 // Creates a StructWithArray containing 'x', 'y', 'z'.
 StructWithArray make_struct_with_array(int x, int y, int z)
 {