Intel announced today that it has been working with Funcom to enhance the visual effects in its Windows* and Android* versions of LEGO* Minifigures Online, a fun-packed online game. The companies used the unique pixel synchronization capabilities of Intel® Iris™ graphics to enable more realistic smoke, clouds, and shadows. The game can also run in a low power mode extending play time by more than 80% when running on Intel devices.
As a follow-up to Adaptive Volumetric Shadow Maps for DirectX* 11, we present a port of the same algorithm adapted for Android* devices that support OpenGL ES* 3.1 and the GL_INTEL_fragment_shader_ordering OpenGL* extension.
One of the new features of DirectX* 12 is Rasterizer Ordered Views, which allow read/write access to resources, such as buffers, textures, and texture arrays, without multisampling from multiple threads and without generating memory conflicts through the use of atomic functions. This feature means resources created with Unordered Access Views (UAV) can mark in the pixel shader code certain resources to follow strict ordering rules similar to those used to ensure the correct pixel blending during draw operations. Raster ordered views (ROVs) allow the creation of a whole range of new algorithms, such as Order Independent Transparency (OIT), Adaptive Volumetric Shadow Maps (AVSM), and custom blending operations, that are not possible in the fixed function blending pipeline.
We introduce adaptive volumetric shadow maps (AVSM), a real-time shadow algorithm that supports high-quality shadowing from dynamic volumetric media such as hair and smoke. The key contribution of AVSM is the introduction of a streaming simplification algorithm that generates an accurate volumetric light attenuation function using a small fixed memory footprint. This compression strategy leads to high performance because the visibility data can remain in on-chip memory during simplification and can be efficiently sampled during rendering. We demonstrate that AVSM compression closely approximates the ground-truth correct solution and performs competitively to existing real-time rendering techniques while providing higher quality volumetric shadows.