Add support for reading GLSL from files with ShaderEffect

An enabler for using file selectors instead of writing GraphicsInfo-based
conditions in the vertexShader and fragmentShader properties.

[ChangeLog][QtQuick] ShaderEffect with OpenGL now supports reading GLSL
shader sources from local files and from the resource system. Whenever a
fragmentShader or vertexShader property is a valid such URL, the value is
treated as a file specification instead of actual source code.

Change-Id: I9df2a397adc8f82f1eb6b83d27e9e3d9d1a02f46
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/quick/items/qquickopenglshadereffect.cpp b/src/quick/items/qquickopenglshadereffect.cpp
index 312721ed04..1e66971fdb 100644
--- a/src/quick/items/qquickopenglshadereffect.cpp
+++ b/src/quick/items/qquickopenglshadereffect.cpp
@@ -51,6 +51,7 @@
 #include "qquickshadereffectsource_p.h"
 #include "qquickshadereffectmesh_p.h"
 
+#include <QtQml/qqmlfile.h>
 #include <QtCore/qsignalmapper.h>
 
 QT_BEGIN_NAMESPACE
@@ -321,6 +322,20 @@ void QQuickOpenGLShaderEffectCommon::updateShader(QQuickItem *item, Key::ShaderT
     if (shaderType == Key::VertexShader)
         attributes.clear();
 
+    // A qrc or file URL means the shader source is to be read from the specified file.
+    QUrl srcUrl(QString::fromUtf8(source.sourceCode[shaderType]));
+    if (!srcUrl.scheme().compare(QLatin1String("qrc"), Qt::CaseInsensitive) || srcUrl.isLocalFile()) {
+        const QString fn = QQmlFile::urlToLocalFileOrQrc(srcUrl);
+        QFile f(fn);
+        if (f.open(QIODevice::ReadOnly | QIODevice::Text)) {
+            source.sourceCode[shaderType] = f.readAll();
+            f.close();
+        } else {
+            qWarning("ShaderEffect: Failed to read %s", qPrintable(fn));
+            source.sourceCode[shaderType] = QByteArray();
+        }
+    }
+
     const QByteArray &code = source.sourceCode[shaderType];
     if (code.isEmpty()) {
         // Optimize for default code.