qcam: viewfinder_gl: Fix fragment shader rebuild when setting format

When setting a new format, the existing fragment shader is deleted and a
new shader should be created. However, the shader pointer isn't set to
nullptr after deleting it, resulting in the deleter shader being reused.
Fix it by managing shader pointers with std::unique_ptr<> to prevent
similar bugs from happening in the future.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/qcam/viewfinder_gl.cpp

@@ -33,7 +33,6 @@ static const QList<libcamera::PixelFormat> supportedFormats{
 
 ViewFinderGL::ViewFinderGL(QWidget *parent)
 	: QOpenGLWidget(parent), buffer_(nullptr), yuvData_(nullptr),
-	  vertexShader_(nullptr), fragmentShader_(nullptr),
 	  vertexBuffer_(QOpenGLBuffer::VertexBuffer),
 	  textureU_(QOpenGLTexture::Target2D),
 	  textureV_(QOpenGLTexture::Target2D),
@@ -58,8 +57,8 @@ int ViewFinderGL::setFormat(const libcamera::PixelFormat &format,
 	if (fragmentShader_) {
 		if (shaderProgram_.isLinked()) {
 			shaderProgram_.release();
-			shaderProgram_.removeShader(fragmentShader_);
-			delete fragmentShader_;
+			shaderProgram_.removeShader(fragmentShader_.get());
+			fragmentShader_.reset();
 		}
 	}
 
@@ -185,7 +184,7 @@ bool ViewFinderGL::selectFormat(const libcamera::PixelFormat &format)
 bool ViewFinderGL::createVertexShader()
 {
 	/* Create Vertex Shader */
-	vertexShader_ = new QOpenGLShader(QOpenGLShader::Vertex, this);
+	vertexShader_ = std::make_unique<QOpenGLShader>(QOpenGLShader::Vertex, this);
 
 	/* Compile the vertex shader */
 	if (!vertexShader_->compileSourceFile(":YUV.vert")) {
@@ -193,7 +192,7 @@ bool ViewFinderGL::createVertexShader()
 		return false;
 	}
 
-	shaderProgram_.addShader(vertexShader_);
+	shaderProgram_.addShader(vertexShader_.get());
 	return true;
 }
 
@@ -207,7 +206,7 @@ bool ViewFinderGL::createFragmentShader()
 	 * program. The #define macros stored in fragmentShaderDefines_, if
 	 * any, are prepended to the source code.
 	 */
-	fragmentShader_ = new QOpenGLShader(QOpenGLShader::Fragment, this);
+	fragmentShader_ = std::make_unique<QOpenGLShader>(QOpenGLShader::Fragment, this);
 
 	QFile file(fragmentShaderFile_);
 	if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
@@ -224,7 +223,7 @@ bool ViewFinderGL::createFragmentShader()
 		return false;
 	}
 
-	shaderProgram_.addShader(fragmentShader_);
+	shaderProgram_.addShader(fragmentShader_.get());
 
 	/* Link shader pipeline */
 	if (!shaderProgram_.link()) {
@@ -287,12 +286,6 @@ void ViewFinderGL::removeShader()
 		shaderProgram_.release();
 		shaderProgram_.removeAllShaders();
 	}
-
-	if (fragmentShader_)
-		delete fragmentShader_;
-
-	if (vertexShader_)
-		delete vertexShader_;
 }
 
 void ViewFinderGL::initializeGL()

src/qcam/viewfinder_gl.h

@@ -8,6 +8,8 @@
 #ifndef __VIEWFINDER_GL_H__
 #define __VIEWFINDER_GL_H__
 
+#include <memory>
+
 #include <QImage>
 #include <QMutex>
 #include <QOpenGLBuffer>
@@ -67,8 +69,8 @@ private:
 
 	/* Shaders */
 	QOpenGLShaderProgram shaderProgram_;
-	QOpenGLShader *vertexShader_;
-	QOpenGLShader *fragmentShader_;
+	std::unique_ptr<QOpenGLShader> vertexShader_;
+	std::unique_ptr<QOpenGLShader> fragmentShader_;
 	QString fragmentShaderFile_;
 	QStringList fragmentShaderDefines_;