nodes: moved matrix input on "video input" elsewhere

Rather than plugging a matrix into the video input node, the matrix is now
multiplied by the video input using a math node. This is probably more
sensible from a user perspective.

This also means the renderer is tolerant of texture sizes that are not equal
to the sequence size, however most nodes will downsample the texture to the
sequence size (and if not, it will be downsampled once it is cached). Textures
will still *always* be in reference space and the sequence's format. This seems
like the best compromise between backend and frontend congruity.

app/node/math/math/math.h

@@ -42,6 +42,7 @@ public:
   virtual Capabilities GetCapabilities(const NodeValueDatabase&) const override;
   virtual QString ShaderID(const NodeValueDatabase&) const override;
   virtual QString ShaderFragmentCode(const NodeValueDatabase&) const override;
+  virtual QString ShaderVertexCode(const NodeValueDatabase&input) const override;
 
   virtual NodeValue InputValueFromTable(NodeInput* input, NodeValueDatabase &db, bool take) const override;
 
@@ -53,7 +54,6 @@ public:
   NodeInput* param_a_in() const;
   NodeInput* param_b_in() const;
 
-private:
   enum Operation {
     kOpAdd,
     kOpSubtract,
@@ -63,7 +63,9 @@ private:
   };
 
   Operation GetOperation() const;
+  void SetOperation(Operation o);
 
+private:
   enum Pairing {
     kPairNone = -1,
 
@@ -96,21 +98,13 @@ private:
     const NodeValue& GetMostLikelyValueB() const;
 
   private:
-    static Pairing GetMostLikelyPairingInternal(const QVector<int> &a, const QVector<int> &b, const int &weight_a, const int &weight_b);
-
     static QVector<int> GetPairLikelihood(const NodeValueTable& table);
 
-    const NodeValue &GetMostLikelyValue(const NodeValueTable& table, const QVector<int>& likelihood) const;
-
     Pairing most_likely_pairing_;
 
-    const NodeValueTable& table_a_;
+    NodeValue most_likely_value_a_;
 
-    const NodeValueTable& table_b_;
-
-    QVector<int> pair_likelihood_a_;
-
-    QVector<int> pair_likelihood_b_;
+    NodeValue most_likely_value_b_;
 
   };