Add test

src/sfizz/modulations/ModMatrix.cpp

@@ -13,6 +13,7 @@
 #include "SIMDHelpers.h"
 #include "Debug.h"
 #include <absl/container/flat_hash_map.h>
+#include <absl/strings/string_view.h>
 #include <vector>
 #include <algorithm>
 
@@ -382,4 +383,45 @@ bool ModMatrix::validSource(SourceId id) const
     return static_cast<unsigned>(id.number()) < impl_->sources_.size();
 }
 
+std::string ModMatrix::toDotGraph() const
+{
+    const Impl& impl = *impl_;
+
+    struct Edge {
+        std::string source;
+        std::string target;
+    };
+
+    // collect all connections as string pairs
+    std::vector<Edge> edges;
+    for (const Impl::Target& target : impl.targets_) {
+        for (const auto& cs : target.connectedSources) {
+            const Impl::Source& source = impl.sources_[cs.first];
+            Edge e;
+            e.source = source.key.toString();
+            e.target = target.key.toString();
+            edges.push_back(std::move(e));
+        }
+    }
+
+    // alphabetic sort, to produce stable output for unit testing
+    auto compare = [](const Edge& a, const Edge& b) -> bool {
+        std::pair<absl::string_view, absl::string_view> aa{a.source, a.target};
+        std::pair<absl::string_view, absl::string_view> bb{b.source, b.target};
+        return aa < bb;
+    };
+    std::sort(edges.begin(), edges.end(), compare);
+
+    // write dot graph
+    std::string dot;
+    dot.reserve(1024);
+    absl::StrAppend(&dot, "digraph {" "\n");
+    for (const Edge& e : edges) {
+        absl::StrAppend(&dot, "\t" "\"", e.source, "\""
+                        " -> " "\"", e.target, "\"" "\n");
+    }
+    absl::StrAppend(&dot, "}" "\n");
+    return dot;
+}
+
 } // namespace sfz

src/sfizz/modulations/ModMatrix.h

@@ -167,6 +167,11 @@ public:
      */
     bool validSource(SourceId id) const;
 
+    /**
+     * @brief Get a representation of the matrix written as a Dot graph.
+     */
+    std::string toDotGraph() const;
+
 private:
     struct Impl;
     std::unique_ptr<Impl> impl_;

tests/ModulationsT.cpp

@@ -6,6 +6,7 @@
 
 #include "sfizz/modulations/ModId.h"
 #include "sfizz/modulations/ModKey.h"
+#include "sfizz/Synth.h"
 #include "catch2/catch.hpp"
 
 TEST_CASE("[Modulations] Identifiers")
@@ -74,3 +75,24 @@ TEST_CASE("[Modulations] Display names")
         REQUIRE(!sfz::ModKey(id).toString().empty());
     });
 }
+
+TEST_CASE("[Modulations] Connection graph from SFZ")
+{
+    sfz::Synth synth;
+    synth.loadSfzString("/modulation.sfz", R"(
+<region>
+sample=*sine
+amplitude_oncc20=59 amplitude_curvecc20=3
+pitch_oncc42=71 pitch_smoothcc42=32
+pan_oncc36=14.5 pan_stepcc36=1.5
+width_oncc425=29
+)");
+    const std::string graph = synth.getResources().modMatrix.toDotGraph();
+    REQUIRE(graph == R"(digraph {
+	"Controller 20 {curve=3, smooth=0, value=59, step=0}" -> "Amplitude"
+	"Controller 36 {curve=0, smooth=0, value=14.5, step=1.5}" -> "Pan"
+	"Controller 42 {curve=0, smooth=32, value=71, step=0}" -> "Pitch"
+	"Controller 425 {curve=0, smooth=0, value=29, step=0}" -> "Width"
+}
+)");
+}