qt5base-lts/examples/opengl/hellogl2/glwidget.h
Laszlo Agocs 5621a7c501 Fix composition for windows with alpha
While we will cover the entire surface with our textured quads, the clear
is still necessary in order to make top-levels with TranslucentBackground
render correctly: We don't want to blend transparent areas with undefined
content that is in the surface's framebuffer.

Blending is problematic for alpha values. We now prevent the blended alpha
from being written out. This ensures that in examples like qquickviewcomparison,
where the backingstore image contains an alpha of 0.5 while the QQuickWidget
texture 1.0, the result is still an alpha value of 1.0 in the final image.
Writing out an alpha of 0.5 would break on systems where windows get an alpha
buffer by default.

hellogl2 can now take a --transparent parameter which makes the QOpenGLWidget
being cleared to transparent in order to verify it works in combination
with Qt::WA_TranslucentBackground.

The swapped red and blue problem is also corrected. RGBA8888 does not need
swizzling. The only format that needs this is RGB32.

Task-number: QTBUG-40716
Change-Id: I54a9fd3a91a1b59575b38cdb908835315514e40f
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
2014-08-13 16:14:19 +02:00

105 lines
3.4 KiB
C++

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#ifndef GLWIDGET_H
#define GLWIDGET_H
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLVertexArrayObject>
#include <QOpenGLBuffer>
#include <QMatrix4x4>
#include "logo.h"
QT_FORWARD_DECLARE_CLASS(QOpenGLShaderProgram)
class GLWidget : public QOpenGLWidget, protected QOpenGLFunctions
{
Q_OBJECT
public:
GLWidget(QWidget *parent = 0);
~GLWidget();
QSize minimumSizeHint() const Q_DECL_OVERRIDE;
QSize sizeHint() const Q_DECL_OVERRIDE;
public slots:
void setXRotation(int angle);
void setYRotation(int angle);
void setZRotation(int angle);
void cleanup();
signals:
void xRotationChanged(int angle);
void yRotationChanged(int angle);
void zRotationChanged(int angle);
protected:
void initializeGL() Q_DECL_OVERRIDE;
void paintGL() Q_DECL_OVERRIDE;
void resizeGL(int width, int height) Q_DECL_OVERRIDE;
void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
void mouseMoveEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
private:
void setupVertexAttribs();
bool m_core;
int m_xRot;
int m_yRot;
int m_zRot;
QPoint m_lastPos;
Logo m_logo;
QOpenGLVertexArrayObject m_vao;
QOpenGLBuffer m_logoVbo;
QOpenGLShaderProgram *m_program;
int m_projMatrixLoc;
int m_mvMatrixLoc;
int m_normalMatrixLoc;
int m_lightPosLoc;
QMatrix4x4 m_proj;
QMatrix4x4 m_camera;
QMatrix4x4 m_world;
bool m_transparent;
};
#endif