qcam: Add ViewFinderGL class to accelerate the format conversion

The viewfinderGL accelerates the format conversion by using OpenGL ES
shader.

The minimum Qt version is bumped to v5.4, as QOpenGLWidget wasn't
available before that.

Signed-off-by: Show Liu <show.liu@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/src/qcam/viewfinder_gl.h b/src/qcam/viewfinder_gl.h
new file mode 100644
index 00000000..69502b7a
--- /dev/null
+++ b/src/qcam/viewfinder_gl.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Linaro
+ *
+ * viewfinder_GL.h - OpenGL Viewfinder for rendering by OpenGL shader
+ *
+ */
+#ifndef __VIEWFINDER_GL_H__
+#define __VIEWFINDER_GL_H__
+
+#include <QImage>
+#include <QMutex>
+#include <QOpenGLBuffer>
+#include <QOpenGLFunctions>
+#include <QOpenGLShader>
+#include <QOpenGLShaderProgram>
+#include <QOpenGLTexture>
+#include <QOpenGLWidget>
+#include <QSize>
+
+#include <libcamera/buffer.h>
+#include <libcamera/formats.h>
+
+#include "viewfinder.h"
+
+class ViewFinderGL : public QOpenGLWidget,
+		     public ViewFinder,
+		     protected QOpenGLFunctions
+{
+	Q_OBJECT
+
+public:
+	ViewFinderGL(QWidget *parent = nullptr);
+	~ViewFinderGL();
+
+	const QList<libcamera::PixelFormat> &nativeFormats() const override;
+
+	int setFormat(const libcamera::PixelFormat &format, const QSize &size) override;
+	void render(libcamera::FrameBuffer *buffer, MappedBuffer *map) override;
+	void stop() override;
+
+	QImage getCurrentImage() override;
+
+Q_SIGNALS:
+	void renderComplete(libcamera::FrameBuffer *buffer);
+
+protected:
+	void initializeGL() override;
+	void paintGL() override;
+	void resizeGL(int w, int h) override;
+	QSize sizeHint() const override;
+
+private:
+	bool selectFormat(const libcamera::PixelFormat &format);
+
+	void configureTexture(unsigned int id);
+	bool createFragmentShader();
+	bool createVertexShader();
+	void removeShader();
+	void doRender();
+
+	/* Captured image size, format and buffer */
+	libcamera::FrameBuffer *buffer_;
+	libcamera::PixelFormat format_;
+	QSize size_;
+	unsigned char *yuvData_;
+
+	/* OpenGL components for rendering */
+	QOpenGLShader *fragmentShader_;
+	QOpenGLShader *vertexShader_;
+	QOpenGLShaderProgram shaderProgram_;
+
+	/* Vertex buffer */
+	QOpenGLBuffer vertexBuffer_;
+
+	/* Fragment and Vertex shader file name */
+	QString fragmentShaderSrc_;
+	QString vertexShaderSrc_;
+
+	/* YUV texture planars and parameters */
+	GLuint id_u_;
+	GLuint id_v_;
+	GLuint id_y_;
+	GLuint textureUniformU_;
+	GLuint textureUniformV_;
+	GLuint textureUniformY_;
+	QOpenGLTexture textureU_;
+	QOpenGLTexture textureV_;
+	QOpenGLTexture textureY_;
+	unsigned int horzSubSample_;
+	unsigned int vertSubSample_;
+
+	QMutex mutex_; /* Prevent concurrent access to image_ */
+};
+
+#endif /* __VIEWFINDER_GL_H__ */