GeoMobileDemo

Overview

GeoMobileDemo (also known as Enlighten Palace) is an iOS/Android application that demonstrates how Enlighten can be used in conjunction with OpenGL ES 2.0 to achieve real-time radiosity lighting on mobile devices. The app uses the familiar Arches scene, lit with a directional light (the sun) and an emissive environment light (the sky). The lighting is fully dynamic with Enlighten computing directional irradiance for a single system every frame while taking advantage of Enlighten's temporal coherence optimisation. A probe set is also generated in order to light the character model in the scene, which is considered dynamic geometry. The app also transitions to a night time setting, demonstrating how a combination of Enlighten's baked and dynamic lighting can be used effectively.

In terms of rendering, GeoMobileDemo uses a forward technique with a shadow mapped directional light. A diffuse-only material is used for all sections of the Arches apart from the tiled floor which uses a normal map and an approximated Blinn-Phong model for direct specular reflections. Depending on the capabilities of the device, indirect specular reflections are either approximated in the same way or rendered using dynamic specular directional irradiance cube maps generated by the Enlighten runtime. The irradiance and directional irradiance textures are sampled in the arches fragment shader providing the indirect light contribution whereas the character fragment shader uses the L1 spherical harmonic coefficients computed by Enlighten. The indirect and direct lighting are then combined prior to the application of a simple tone mapping operator.

How to use GeoMobileDemo

There are two light modes in GeoMobileDemo. In daylight mode drag your finger across the screen horizontally or vertically to change the direction of the sunlight. Switch to day-night cycle mode to simulate lighting conditions over the period of a day. In this mode, drag your finger left to rewind and pause the simulation. Drag your finger right to fast forward and resume.

Use the left and right arrow buttons to switch between a number of cameras positioned around the scene. Tap the camera button to move the camera along a preset path. Tap it again to pause the camera and show the thumbstick controls. The left stick controls movement while the right stick controls your view.

Tap the Enlighten logo to open/close the rendering options menu. Direct light, indirect light, specular highlights and scene textures can all be toggled on and off while the app is running. The irradiance light map texture and light probe set that is generated by Enlighten in real-time to light the Arches and character model can be also be shown using this menu.