Hi, I would like to be able to select at run-time how my entities are rendered (ideally on a per entity basis). I would like to have 3 choices: - 1. wireframe - 2. shaded - 3. shaded + wireframe
I had a look at the wire frame QML example, and translated it to C++. The code is working. I have simplified the fragment shader, as i don't need fancy light effect, other than a shaded color per face. These shaders allow me to achieve 2 & 3. But my feeling is that i need something completely different to render a 'transparent' wireframe only. Reading through OpenGL materials, it looks like i need things like glPolygonMode, reading through Qt3D leads me to QGeometryRenderer::PrimitiveType. But i am having problems connecting the dots. PrimitiveType is a property of QGeometryRenderer, which means that it is closely related with my buffer data and how the data are arranged within the buffer. So If i want to switch from 'shaded' to wireframe I need to change my data (and my shader code too), surely there is to be a way to use the same data buffer to achieve the 3 rendering modes. Should I use a 2 passes rendering? The first one renders (or not) the face shades and the second one renders (or not) the wireframes? Actually this should even be a 3 passes: back of wireframe (or not), shaded faces (or not) and front of wireframe (or not)... Is this the right approach? Or should I instead define 3 materials and simply switch the material as i want a different drawing style? Last thing is that my input data are triangulated polygon with holes, but i have as well access to the original polygon with holes alone. And i actually don't want to render the internal (triangulation) edges of my polygonal faces (up and down) or rectangular faces (side ones). So basically in shaded mode, i only need to calculate the color per geometric face (as oppose to triangular face) ... PS: I've spent serious time yesterday reading through https://learnopengl.com, although I think i now understand (way better) how OpenGL works and how to use it, Qt3D seems to be way more than a convenience wrapper around the OpenGL API. I couldn't find a place in Qt3D where you would manipulate OpenGL directly (eg calling glFooBar()). I am not even sure if it was design too do this sort of things. Thanks, Chris _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
