Why not do this directly in QML with Rectangle items? -- Louai
> -----Original Message----- > From: interest-bounces+louai.al-khanji=theqtcompany....@qt-project.org > [mailto:interest-bounces+louai.al-khanji=theqtcompany.com@qt- > project.org] On Behalf Of Nuno Santos > Sent: Tuesday, November 11, 2014 1:17 PM > To: Interests Qt > Subject: [Interest] Using QSGVertexColorMaterial transparency > > Hi, > > I want to give a flashing effect on a quad. My idea is to draw two quads. One > with the base color, and one above it with a white color but with > transparency oscillating. This will give the flashing effect. > > I'm not being able to do it with QSGVertexColorMaterial. There is no opacity > on quad there is placed above. I have found the following post answer but I > still can't understand it quite well. > > "The blend mode used by the scene graph is glBlendFunc(GL_ONE, > GL_ONE_MINUS_SRC_ALPHA) which gives you premultiplied blending. A > "valid" color in premultiplied mode must have r <= a (same for g and b of > course). If it doesn't, then that color channel will overflow, giving you > additive blending instead." > > Will it be possible to implement this with a QSGVertexColorMaterial? > > // quad below > > v[0].set(_rect.left(), _rect.bottom(), r, g, b, a); > v[1].set(_rect.left(), _rect.top(), r, g, b, a); > v[2].set(_rect.right(), _rect.top(), r, g, b, a); > > v[3].set(_rect.left(), _rect.bottom(), r, g, b, a); > v[4].set(_rect.right(), _rect.top(), r, g, b, a); > v[5].set(_rect.right(), _rect.bottom(), r, g, b, a); > > // flashing quad above > > a=128+128*qSin(phase),r=0xff,g=0xff,b=0xff; > > v[6].set(_rect.left(), _rect.bottom(), r, g, b, a); > v[7].set(_rect.left(), _rect.top(), r, g, b, a); > v[8].set(_rect.right(), _rect.top(), r, g, b, a); > > v[9].set(_rect.left(), _rect.bottom(), r, g, b, a); > v[10].set(_rect.right(), _rect.top(), r, g, b, a); > v[11].set(_rect.right(), _rect.bottom(), r, g, b, a); > > Thanks, > > Regards, > > Nuno > > > _______________________________________________ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
