1.1
Orientation

- 1.1.1. Overview
- 1.1.2. Features

1.1.1
Overview
1
The r2 package provides a minimalist deferred rendering system.
1.1.2
Features
1.1.2.1 Features

- A deferred rendering core for opaque objects.
- A forward renderer, supporting a subset of the features of the deferred renderer, for rendering translucent objects.
- A full dynamic lighting system, including variance shadow mapping. The use of deferred rendering allows for potentially hundreds of dynamic lights per scene.
- Ready-to-use shaders providing surfaces with a wide variety of effects such as normal mapping, environment-mapped reflections, generic refraction, surface emission, mapped specular highlights, etc.
- A variety of postprocessing effects such as box blurring, screen-space ambient occlusion (SSAO), fast approximate antialiasing (FXAA), color correction, bloom, etc. Effects can be applied in any order.
- Explicit control over all resource loading and caching. For all transient resources, the programmer is required to provide the renderer with explicit pools, and the pools themselves are responsible for allocating and loading resources.
- Extensive use of static types. As with all io7m packages, there is extreme emphasis on using the type system to make it difficult to use the APIs incorrectly.
- Portability. The renderer will run on any system supporting OpenGL 3.3 and Java 8.

1.1.2.2 Non-features

- A scene graph. The renderer expects the programmer to provide a set of instances (with associated shaders) and lights once per frame, and the renderer will obediently draw exactly those instances. This frees the programmer from having to interact with a clumsy and type-unsafe object-oriented scene graph as with other 3D engines, and from having to try to crowbar their own program's data structures into an existing graph system.
- Spatial partitioning. The renderer knows nothing of the world the programmer is trying to render. The programmer is expected to have done the work of deciding which instances and lights contribute to the current image, and to provide only those lights and instances for the current frame. This means that the programmer is free to use any spatial partitioning system desired.
- Input handling. The renderer knows nothing about keyboards, mice, joysticks. The programmer passes an immutable snapshot of a scene to the renderer, and the renderer returns an image. This means that the programmer is free to use any input system desired without having to painfully integrate their own code with an existing input system as with other 3D engines.
- Audio. The renderer makes images, not sounds. This allows programmers to use any audio system they want in their programs.
- Skeletal animation. The input to the renderer is a set of triangle meshes in the form of vertex buffer objects. This means that the programmer is free to use any skeletal animation system desired, providing that the system is capable of producing vertex buffer objects of the correct type as a result.
- Model loading. The input to the renderer is a set of triangle meshes in the form of vertex buffer objects. This means that the programmer is free to use any model loading system desired, providing that the system is capable of producing vertex buffer objects of the correct type as a result.
- Future proofing. The average lifetime of a rendering system is about five years. Due to the extremely rapid pace of advancement in graphics hardware, the methods use to render graphics today will bear almost no relation to those used five years into the future. The r2 package is under no illusion that it will still be relevant in a decade's time. It is designed to get work done today, using exactly those techniques that are relevant today. It will not be indefinitely expanded and grown organically, as this would directly contradict the goal of having a minimalist and correct rendering system.
- OpenGL ES 2 support. The ES 2 standard was written as a reaction to the insane committee politics that plagued the OpenGL 2.* standards. It is crippled to the point that it essentially cannot support almost any of the rendering techniques present in the r2 package, and is becoming increasingly irrelevant as the much saner ES 3 is adopted by hardware vendors.