Add support for include in shader sources

Implement our own custom include pragma. This is essential for
introducing features that involve common snippets of code,
for example lighting.

Change-Id: Ia94d2492b399b5fb879ff2729654962677334a29
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 27 insertions, 8 deletions

diff --git a/src/render/materialsystem/qshaderprogram.cpp b/src/render/materialsystem/qshaderprogram.cpp
index da0de2422..6a2dc310d 100644
--- a/src/render/materialsystem/qshaderprogram.cpp
+++ b/src/render/materialsystem/qshaderprogram.cpp
@@ -40,6 +40,7 @@
 #include <Qt3DCore/private/qurlhelper_p.h>
 #include <QDebug>
 #include <QFile>
+#include <QFileInfo>
 #include <QUrl>
 
 QT_BEGIN_NAMESPACE
@@ -227,17 +228,35 @@ QByteArray QShaderProgram::shaderCode(ShaderType type) const
     }
 }
 
+static QByteArray deincludify(const QString &filePath)
+{
+    QFile f(filePath);
+    if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        qWarning() << "Could not read shader source file:" << f.fileName();
+        return QByteArray();
+    }
+
+    QByteArray contents = f.readAll();
+    QByteArrayList lines = contents.split('\n');
+    const QByteArray includeDirective = QByteArrayLiteral("#pragma include");
+    for (int i = 0; i < lines.count(); ++i) {
+        if (lines[i].startsWith(includeDirective)) {
+            QByteArray includeFileName = lines[i].mid(includeDirective.count() + 1);
+            lines.removeAt(i);
+            QByteArray includedContents = deincludify(QFileInfo(filePath).absolutePath() + QChar('/') + includeFileName);
+            lines.insert(i, includedContents);
+            QString lineDirective = QString(QStringLiteral("#line %1")).arg(i + 2);
+            lines.insert(i + 1, lineDirective.toUtf8());
+        }
+    }
+
+    return lines.join('\n');
+}
+
 QByteArray QShaderProgram::loadSource(const QUrl &sourceUrl)
 {
     // TO DO: Handle remote path
-    QString filePath = Qt3DCore::QUrlHelper::urlToLocalFileOrQrc(sourceUrl);
-
-    QFile f(filePath);
-    if (!f.exists())
-        qWarning() << "Couldn't read shader source file:" << sourceUrl;
-    else
-        f.open(QIODevice::ReadOnly | QIODevice::Text);
-    return f.readAll();
+    return deincludify(Qt3DCore::QUrlHelper::urlToLocalFileOrQrc(sourceUrl));
 }
 
 } // of namespace Qt3DRender