QShaderProgram: handle binding = auto replacement for raw shader code

binding = auto replacement only took place when using shader graphs.
This meant providing shader code that used binding = auto or that included
snippets that themselves used binding = auto (such as phong.inc.frag)
would fail.

For that reason, that replacement was moved from the shadergraph builder
to QShaderProgramPrivate so that it can be used for both cases: raw
shader code or shader graphs.

Change-Id: I298a82b83b1181d7a0f19a2e2fefc3aeb9eb81c4
Pick-to: 6.0 6.0.0
Reviewed-by: Mike Krus <mike.krus@kdab.com>

3 files changed, 78 insertions, 46 deletions

diff --git a/src/render/materialsystem/qshaderprogram.cpp b/src/render/materialsystem/qshaderprogram.cpp
index 50eb26a30..1c5eed7f8 100644
--- a/src/render/materialsystem/qshaderprogram.cpp
+++ b/src/render/materialsystem/qshaderprogram.cpp
@@ -44,6 +44,7 @@
 #include <QFile>
 #include <QFileInfo>
 #include <QUrl>
+#include <QRegularExpression>
 
 /*!
     \class Qt3DRender::QShaderProgram
@@ -672,6 +673,71 @@ QByteArray QShaderProgramPrivate::deincludify(const QString &filePath)
     return deincludify(contents, filePath);
 }
 
+QByteArray QShaderProgramPrivate::resolveAutoBindingIndices(const QByteArray &content,
+                                                            int &currentBinding,
+                                                            int &currentInputLocation,
+                                                            int &currentOutputLocation)
+{
+    QString shaderCode = QString::fromUtf8(content);
+
+    // This lambda will replace all occurrences of a string (e.g. "binding = auto") by another,
+    // with the incremented int passed as argument (e.g. "binding = 1", "binding = 2" ...)
+    const auto replaceAndIncrement = [&](const QRegularExpression &regexp,
+            int &variable,
+            const QString &replacement) noexcept {
+        int matchStart = 0;
+        do {
+            matchStart = shaderCode.indexOf(regexp, matchStart);
+            if (matchStart != -1) {
+                const auto match = regexp.match(QStringView{shaderCode}.mid(matchStart));
+                const auto length = match.capturedLength(0);
+
+                shaderCode.replace(matchStart, length, replacement.arg(variable++));
+            }
+        } while (matchStart != -1);
+    };
+
+    // 1. Handle uniforms
+    {
+        thread_local const QRegularExpression bindings(
+                    QStringLiteral("binding\\s*=\\s*auto"));
+
+        replaceAndIncrement(bindings, currentBinding, QStringLiteral("binding = %1"));
+    }
+
+    // 2. Handle inputs
+    {
+        thread_local const QRegularExpression inLocations(
+                    QStringLiteral("location\\s*=\\s*auto\\s*\\)\\s*in\\s+"));
+
+        replaceAndIncrement(inLocations, currentInputLocation,
+                            QStringLiteral("location = %1) in "));
+    }
+
+    // 3. Handle outputs
+    {
+        thread_local const QRegularExpression outLocations(
+                    QStringLiteral("location\\s*=\\s*auto\\s*\\)\\s*out\\s+"));
+
+        replaceAndIncrement(outLocations, currentOutputLocation,
+                            QStringLiteral("location = %1) out "));
+    }
+
+    return shaderCode.toUtf8();
+}
+
+QByteArray QShaderProgramPrivate::resolveAutoBindingIndices(const QByteArray &content)
+{
+    int currentBinding = 2; // Qt3D default uniforms are 0 and 1
+    int currentInputLocation = 0;
+    int currentOutputLocation = 0;
+
+    return QShaderProgramPrivate::resolveAutoBindingIndices(content,
+                                                            currentBinding,
+                                                            currentInputLocation,
+                                                            currentOutputLocation);
+}
+
 QByteArray QShaderProgramPrivate::deincludify(const QByteArray &contents, const QString &filePath)
 {
     QByteArrayList lines = contents.split('\n');
@@ -710,7 +776,8 @@ QByteArray QShaderProgramPrivate::deincludify(const QByteArray &contents, const
 QByteArray QShaderProgram::loadSource(const QUrl &sourceUrl)
 {
     // TO DO: Handle remote path
-    return QShaderProgramPrivate::deincludify(Qt3DCore::QUrlHelper::urlToLocalFileOrQrc(sourceUrl));
+    const QByteArray deincluded = QShaderProgramPrivate::deincludify(Qt3DCore::QUrlHelper::urlToLocalFileOrQrc(sourceUrl));
+    return QShaderProgramPrivate::resolveAutoBindingIndices(deincluded);
 }
 
 } // of namespace Qt3DRender
diff --git a/src/render/materialsystem/qshaderprogram_p.h b/src/render/materialsystem/qshaderprogram_p.h
index a3e5b2a3f..0f6d50ed5 100644
--- a/src/render/materialsystem/qshaderprogram_p.h
+++ b/src/render/materialsystem/qshaderprogram_p.h
@@ -80,6 +80,11 @@ public:
 
     static QByteArray deincludify(const QByteArray &contents, const QString &filePath);
     static QByteArray deincludify(const QString &filePath);
+    static QByteArray resolveAutoBindingIndices(const QByteArray &content,
+                                                int &currentBinding,
+                                                int &currentInputLocation,
+                                                int &currentOutputLocation);
+    static QByteArray resolveAutoBindingIndices(const QByteArray &content);
 };
 
 } // namespace Qt3DRender
diff --git a/src/render/shadergraph/qshadergenerator.cpp b/src/render/shadergraph/qshadergenerator.cpp
index 3795d3214..9bbc2b2d2 100644
--- a/src/render/shadergraph/qshadergenerator.cpp
+++ b/src/render/shadergraph/qshadergenerator.cpp
@@ -402,52 +402,12 @@ namespace
         void onInclude(QByteArrayList &code, const QByteArray &snippet) noexcept
         {
             const auto filepath = QString::fromUtf8(snippet.mid(strlen("#pragma include ")));
-            QString deincluded = QString::fromUtf8(QShaderProgramPrivate::deincludify(filepath));
-
-            // This lambda will replace all occurrences of a string (e.g. "binding = auto") by another,
-            // with the incremented int passed as argument (e.g. "binding = 1", "binding = 2" ...)
-            const auto replaceAndIncrement = [&deincluded](const QRegularExpression &regexp,
-                                                           int &variable,
-                                                           const QString &replacement) noexcept {
-                int matchStart = 0;
-                do {
-                    matchStart = deincluded.indexOf(regexp, matchStart);
-                    if (matchStart != -1) {
-                        const auto match = regexp.match(QStringView{deincluded}.mid(matchStart));
-                        const auto length = match.capturedLength(0);
-
-                        deincluded.replace(matchStart, length, replacement.arg(variable++));
-                    }
-                } while (matchStart != -1);
-            };
-
-            // 1. Handle uniforms
-            {
-                thread_local const QRegularExpression bindings(
-                        QStringLiteral("binding\\s?+=\\s?+auto"));
-
-                replaceAndIncrement(bindings, currentBinding, QStringLiteral("binding = %1"));
-            }
-
-            // 2. Handle inputs
-            {
-                thread_local const QRegularExpression inLocations(
-                        QStringLiteral("location\\s?+=\\s?+auto\\s?+\\)\\s?+in\\s+"));
-
-                replaceAndIncrement(inLocations, currentInputLocation,
-                                    QStringLiteral("location = %1) in "));
-            }
-
-            // 3. Handle outputs
-            {
-                thread_local const QRegularExpression outLocations(
-                        QStringLiteral("location\\s?+=\\s?+auto\\s?+\\)\\s?+out\\s+"));
-
-                replaceAndIncrement(outLocations, currentOutputLocation,
-                                    QStringLiteral("location = %1) out "));
-            }
+            const QByteArray deincluded = QShaderProgramPrivate::deincludify(filepath);
 
-            code << deincluded.toUtf8();
+            code << QShaderProgramPrivate::resolveAutoBindingIndices(deincluded,
+                                                                     currentBinding,
+                                                                     currentInputLocation,
+                                                                     currentOutputLocation);
         }
 
         int currentInputLocation { 0 };