Sunday, October 14, 2012

Qt5 and normal mapping - reloaded

(This is part II of the normal mapping journey, check the part I first for details.)

So you have all now played with Qt5 NMapper tool, right? Goody, that means we have gained experience of normal mapping and created some perfectly tuned normal mapped textures. Now it's time to use these in a separate application.

Let's assume that you are working on a 2D QML application, but would want 3D-looking effect into some part(s) of the UI. To visualize, here's an example NMapCarousel demo application:


(Qt5 NMap Carousel, running on PC and on Raspberry Pi)


Here normal mapping is used to make the carousel icons more dynamic by applying lighting. To increase the 3D impression, there are also extra shadows reflected behind the icons.

To implement something similar, here's how to proceed:

  1. If not already, setup Qt5 to your PC/Mac/RPi or equivalent platform.
  2. Create normal maps of your graphic assets using Gimp, Blender, Photoshop etc. tool of your choice. Name the normal mapped image with extra "n" in the end, so images are something like "thing.png" and "thingn.png".
  3. Test your graphics with NMapper by copying these images into "images" folder and adding "thing" into imageFiles array property. Play with the light intensity, diffuse, switching x&y coordinates etc. If you are not happy with the results, jump back to step 2 to edit the images and iterate.
  4. Make your own application. Copy NMapEffect.qml and NMapLightSource.qml from NMapper, use your freshly made images, the lighting settings you tested earlier and implement rest of the UI.
  5. Profit! (Sorry that this took a bit more steps than normally... but on the positive side there is no unknown ???-step in the middle!)

Source codes of this demo are available from here. I'm waiting to see cool normal mapping uses!

PS: To learn shaders from the master, check out Andrew's thndl.com!

Friday, October 12, 2012

Qt5 and normal mapping

This one has been on my "blog at some point" back burner for some time now...

'Normal mapping' is a graphics rendering technique used for faking the lighting conditions. In 3D software it is often used for bringing small bumps and dents of textures visible to achieve more realistic graphical appearance without using huge amount of polygons. Normal mapping is kinda advanced version of preceding 'Bump mapping'  technique. Where bump mapping uses just one channel for 'bumps', normal mapping uses 3-channel (RGB) bitmaps and can therefore contain more detailed normal vector information.

Normal mapping technique can also be used in 2D applications to get 3D'ish looking UI elements, which means it can be used also in normal non-Qt3D QML applications. Combining image textures with specifically made normal map textures using a suitable shader is all you need. And normal maps can be automatically created with Gimp, Blender, Photoshop etc. drawing tools, although for best results some tweaking may be required.

But enough about theoretical mumbling, here comes visuals:


(Qt5 NMapper tool, running on PC and on Raspberry Pi)


To experiment with normal mapping I implemented a simple Qt5 NMapper application. As seen from video, it can be used to play with different graphical assets, change lighting conditions, switch normal map x&y-coordinates etc. It also includes the essential 'cave mode' for wiggly fire light.. ;-)

Download NMapper application from here and try it on PC/Mac/RPi or equivalent platform with Qt5.

After this brief intro I'll make a follow-up post within few days about example usage. Have a hacking weekend everyone!