Reflective Circles

This is a simple 2D ray-tracer with an interactive GUI, written in C++, which tries to find all possible light paths from one point to another through a set of reflective circles.

Build

To compile under any OS you need Qt SDK installed. Go to "ReflectiveCircles" dir and launch : qmake "CONFIG+=debug" or qmake "CONFIG+=release" It will create Makefile-s. Then launch : make, mingw32-make, or whatever your make command is. If everything is OK this will produce a binary called circles(.exe) in the corresponding bin sub-folder.

Usage

Just start the binary from bin sub-folder. It will open a GUI. There you can set up a scene with source point A, destination B and several circles, using the mouse and piking the drawing mode first from the left. You can set the number of reflections using the "Reflections" spin box. You can also load a scene from the "File" menu - an example scene file "input.txt" is provided in the "scenes" dir. You can save the scene in a file using "Save" from the "File" menu. Start ray tracing with the "Find Path" button. "Reset" button clears the scene. Rendering is done in a separate thread and can be stopped with the "Stop" button.

Note: The task is solved exactly only in the simplest case (no reflections). In the other cases it is solved approximately, casting random rays in the scene, tracing them and remembering these, which come close to the target point. The target point itself is made "bigger". So each time you press "Find Path" button you may get different solutions.

ToDo

• use references instead of pointers where it is more appropriate
• use smart pointers or stack objects where possible
• replace dynamic_casts with something better
• do ray tracing in parallel: use a thread pool
• don't calculate the distance twice - pass it from intersect() to reflect()...
• make MAX_NUM_RAYS configurable
• UI control to delete figures?
• better resize policy or disable resizing
• partial re-paint - only re-paint changed objects, if possible
• cast rays only to the figures, take clipping into account
• think of/search for a data structure to store the figures optimized for ray tracing
• use homogenious (4D) coordinates or OpenGL vectors?
• use the GPU hardware (OpenGL, OpenCL)
• write special shader function for every point on the circles to reflect the ray?
• optimize the closest rays to hit point B? we can start from B...
• ability to draw polygons, not only circles

Screenshots