QShaderGenerator: Don't crash when a node has multiple outputs

It was already possible to declare a node prototype with multiple
outputs, but trying to assign to all those outputs was not possible and
instead resulted in a crash.

It is now possible to declare nodes like this without crashing:
"SEPERATE_XYZ": {
  "inputs": ["vector"],
  "outputs": ["x", "y", "z"],
  "rules": [
    {
        "substitution": "float $x = $vector.x;
                         float $y = $vector.y;
                         float $z = $vector.z;"
    }
  ]
}

Change-Id: I748e77e84c9120dc688c573eee33dc13c6bfbace
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

2 files changed, 112 insertions, 28 deletions

diff --git a/src/gui/util/qshadergenerator.cpp b/src/gui/util/qshadergenerator.cpp
index 7ea42a7c9a..244b95605b 100644
--- a/src/gui/util/qshadergenerator.cpp
+++ b/src/gui/util/qshadergenerator.cpp
@@ -346,10 +346,10 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
     code << QByteArrayLiteral("void main()");
     code << QByteArrayLiteral("{");
 
-    const QRegularExpression localToGlobalRegExp(QStringLiteral("^.*\\s+(\\w+)\\s*=\\s*((?:\\w+\\(.*\\))|(?:\\w+)).*;$"));
-    const QRegularExpression temporaryVariableToAssignmentRegExp(QStringLiteral("^(.*\\s+(v\\d+))\\s*=\\s*(.*);$"));
+    const QRegularExpression localToGlobalRegExp(QStringLiteral("[^;]*\\s+(\\w+)\\s*=\\s*((?:\\w+\\(.*\\))|(?:\\w+))[^;]*;"));
+    const QRegularExpression temporaryVariableToAssignmentRegExp(QStringLiteral("([^;]*\\s+(v\\d+))\\s*=\\s*([^;]*);"));
     const QRegularExpression temporaryVariableInAssignmentRegExp(QStringLiteral("\\W*(v\\d+)\\W*"));
-    const QRegularExpression outputToTemporaryAssignmentRegExp(QStringLiteral("^\\s*(\\w+)\\s*=\\s*(.*);$"));
+    const QRegularExpression outputToTemporaryAssignmentRegExp(QStringLiteral("\\s*(\\w+)\\s*=\\s*([^;]*);"));
 
     struct Variable;
 
@@ -517,14 +517,31 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
         // Substitute variable names by generated vN variable names
         const QByteArray substitutionedLine = replaceParameters(line, node, format);
 
-        Variable *v = nullptr;
+        QRegularExpressionMatchIterator matches;
 
         switch (node.type()) {
-        // Record name of temporary variable that possibly references a global input
-        // We will replace the temporary variables by the matching global variables later
-        case QShaderNode::Input: {
-            const QRegularExpressionMatch match = localToGlobalRegExp.match(QString::fromUtf8(substitutionedLine));
-            if (match.hasMatch()) {
+        case QShaderNode::Input:
+            matches = localToGlobalRegExp.globalMatch(QString::fromUtf8(substitutionedLine));
+            break;
+        case QShaderNode::Function:
+            matches = temporaryVariableToAssignmentRegExp.globalMatch(QString::fromUtf8(substitutionedLine));
+            break;
+        case QShaderNode::Output:
+            matches = outputToTemporaryAssignmentRegExp.globalMatch(QString::fromUtf8(substitutionedLine));
+            break;
+        case QShaderNode::Invalid:
+            break;
+        }
+
+        while (matches.hasNext()) {
+            QRegularExpressionMatch match = matches.next();
+
+            Variable *v = nullptr;
+
+            switch (node.type()) {
+            // Record name of temporary variable that possibly references a global input
+            // We will replace the temporary variables by the matching global variables later
+            case QShaderNode::Input: {
                 const QString localVariable = match.captured(1);
                 const QString globalVariable = match.captured(2);
 
@@ -535,13 +552,10 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
                 Assignment assignment;
                 assignment.expression = globalVariable;
                 v->assignment = assignment;
+                break;
             }
-            break;
-        }
 
-        case QShaderNode::Function: {
-            const QRegularExpressionMatch match = temporaryVariableToAssignmentRegExp.match(QString::fromUtf8(substitutionedLine));
-            if (match.hasMatch()) {
+            case QShaderNode::Function: {
                 const QString localVariableDeclaration = match.captured(1);
                 const QString localVariableName = match.captured(2);
                 const QString assignmentContent = match.captured(3);
@@ -554,13 +568,10 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
 
                 // Find variables that may be referenced in the assignment
                 gatherTemporaryVariablesFromAssignment(v, assignmentContent);
+                break;
             }
-            break;
-        }
 
-        case QShaderNode::Output: {
-            const QRegularExpressionMatch match = outputToTemporaryAssignmentRegExp.match(QString::fromUtf8(substitutionedLine));
-            if (match.hasMatch()) {
+            case QShaderNode::Output: {
                 const QString outputDeclaration = match.captured(1);
                 const QString assignmentContent = match.captured(2);
 
@@ -575,17 +586,17 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
 
                 // Find variables that may be referenced in the assignment
                 gatherTemporaryVariablesFromAssignment(v, assignmentContent);
+                break;
+            }
+            case QShaderNode::Invalid:
+                break;
             }
-            break;
-        }
-        case QShaderNode::Invalid:
-            break;
-        }
 
-        LineContent lineContent;
-        lineContent.rawContent = QByteArray(QByteArrayLiteral("    ") + substitutionedLine);
-        lineContent.var = v;
-        lines << lineContent;
+            LineContent lineContent;
+            lineContent.rawContent = QByteArray(QByteArrayLiteral("    ") + substitutionedLine);
+            lineContent.var = v;
+            lines << lineContent;
+        }
     }
 
     // Go through all lines
diff --git a/tests/auto/gui/util/qshadergenerator/tst_qshadergenerator.cpp b/tests/auto/gui/util/qshadergenerator/tst_qshadergenerator.cpp
index 2b9b08a18a..76211f8358 100644
--- a/tests/auto/gui/util/qshadergenerator/tst_qshadergenerator.cpp
+++ b/tests/auto/gui/util/qshadergenerator/tst_qshadergenerator.cpp
@@ -199,6 +199,7 @@ private slots:
     void shouldUseGlobalVariableRatherThanTemporaries();
     void shouldGenerateTemporariesWisely();
     void shouldHandlePortNamesPrefixingOneAnother();
+    void shouldHandleNodesWithMultipleOutputPorts();
 };
 
 void tst_QShaderGenerator::shouldHaveDefaultState()
@@ -1299,6 +1300,78 @@ void tst_QShaderGenerator::shouldHandlePortNamesPrefixingOneAnother()
     QCOMPARE(code, expected.join("\n"));
 }
 
+void tst_QShaderGenerator::shouldHandleNodesWithMultipleOutputPorts()
+{
+    // GIVEN
+    const auto gl4 = createFormat(QShaderFormat::OpenGLCoreProfile, 4, 0);
+
+    auto input = createNode({
+                                createPort(QShaderNodePort::Output, "output0"),
+                                createPort(QShaderNodePort::Output, "output1")
+                            });
+    input.addRule(gl4, QShaderNode::Rule("vec4 $output0 = globalIn0;"
+                                         "float $output1 = globalIn1;",
+                                         QByteArrayList() << "in vec4 globalIn0;" << "in float globalIn1;"));
+
+    auto function = createNode({
+                                   createPort(QShaderNodePort::Input, "input0"),
+                                   createPort(QShaderNodePort::Input, "input1"),
+                                   createPort(QShaderNodePort::Output, "output0"),
+                                   createPort(QShaderNodePort::Output, "output1")
+                               });
+    function.addRule(gl4, QShaderNode::Rule("vec4 $output0 = $input0;"
+                                            "float $output1 = $input1;"));
+
+    auto output = createNode({
+                                 createPort(QShaderNodePort::Input, "input0"),
+                                 createPort(QShaderNodePort::Input, "input1")
+                             });
+
+    output.addRule(gl4, QShaderNode::Rule("globalOut0 = $input0;"
+                                          "globalOut1 = $input1;",
+                                          QByteArrayList() << "out vec4 globalOut0;" << "out float globalOut1;"));
+
+    // WHEN
+    const auto graph = [=] {
+        auto res = QShaderGraph();
+
+        res.addNode(input);
+        res.addNode(function);
+        res.addNode(output);
+
+        res.addEdge(createEdge(input.uuid(), "output0", function.uuid(), "input0"));
+        res.addEdge(createEdge(input.uuid(), "output1", function.uuid(), "input1"));
+
+        res.addEdge(createEdge(function.uuid(), "output0", output.uuid(), "input0"));
+        res.addEdge(createEdge(function.uuid(), "output1", output.uuid(), "input1"));
+
+        return res;
+    }();
+
+    auto generator = QShaderGenerator();
+    generator.graph = graph;
+    generator.format = gl4;
+
+    const auto code = generator.createShaderCode();
+
+    // THEN
+    const auto expected = QByteArrayList()
+            << "#version 400 core"
+            << ""
+            << "in vec4 globalIn0;"
+            << "in float globalIn1;"
+            << "out vec4 globalOut0;"
+            << "out float globalOut1;"
+            << ""
+            << "void main()"
+            << "{"
+            << "    globalOut0 = globalIn0;"
+            << "    globalOut1 = globalIn1;"
+            << "}"
+            << "";
+    QCOMPARE(code, expected.join("\n"));
+}
+
 QTEST_MAIN(tst_QShaderGenerator)
 
 #include "tst_qshadergenerator.moc"