Cg FAQ

Cg Language

What is Cg?

C for Graphics. Cg is the high-level GPU shader authoring language designed, developed and implemented by NVIDIA.

Is Cg Proprietary?

The Cg Language Specification is published and open in the sense that other vendors may implement products based on it.

Does Cg replace OpenGL or Direct3D?

Cg layers on top of OpenGL, DirectX 9, 10 or 11.

The Cg compiler outputs assembly, GLSL or HLSL code in various formats supported by OpenGL or DirectX.

Does Cg replace C/C++?

Cg is a GPU shading language. A shading language is a type of programming language that tells the GPU how to shade pixels. The main program will still be written in C, C++, C#, Java, Python or other CPU programming language.

What's the difference between the Cg language and a Cg compiler?

The Cg language has a syntax and grammar suitable for real-time programmable GPUs.

A Cg compiler is an application that accepts Cg language input, and produces output in one of the assembly language, GLSL or HLSL formats that are accepted by modern GPUs.

Platforms

What platforms are supported by the NVIDIA Cg Toolkit?

• Windows 32-bit, 64-bit
• Linux 32-bit, 64-bit
• Mac OS X ppc, i386 and x86_64
• Solaris 32-bit, 64-bit

How will Cg support future GPUs?

Cg is designed to provide support for very sophisticated programmable GPUs. NVIDIA provides access to new GPU architectures by updating the supported profiles and adding new ones over time.

NVIDIA Cg Toolkit

What is NVIDIA providing to developers?

NVIDIA provides developers with the NVIDIA Cg Toolkit, comprising of:

• Compiler
• Runtime Libraries
• Language Specification
• Standard Library
• Reference Manual
• User's Manual
• Example programs, shaders and effects for OpenGL and Direct3D

Will there be further versions of the tookit?

Further versions of the Cg Toolkit will support and include:

• Additional profiles
• Additional examples
• Increasing optimization of the compiler

Does the Cg Compiler perform platform specific optimizations?

Yes, the NVIDIA Cg Compiler aggressively optimizes shaders for multiple target GPU architectures.

How do I get started with Cg?

Start by learning about the technology.

Then look at The Cg Tutorial book, which presents the Cg language in an organized manner.

Download the current release of the Cg Toolkit.

Who is Using Cg?

Hundreds of developers endorse Cg

Hundreds of developers began training on an earlier incarnation of Cg beginning late in 2001, and many contributed to the evolution of the language.

Some developers supporting Cg include: Auran, Bethesda Softworks, Beyond Games, Bioware, Blizzard Entertainment, Cat Daddy, CodeCult, Codemasters, Contraband, Core Design, Croteam, Cryptic Studios, Crytek, Dark Black, Destineer, Electronic Arts, Elixir, EMG, Ensemble Studios, Fox Interactive, Grin, Headgate, High Voltage, id Software, Inevitable, Ion Storm, Kaboom, Kuju, Lego Media, Lionhead, Lithtech, Massive, Maxis, Nadeo, NAMCO, NemoSoft, Novalogic, Pivotal, Rage Sheffield, Relic Entertainment, Ritual, Sega-AM2 Co. Ltd., Sony Online Entertainment, SpinVector, Steel Monkeys, Transgaming, Valve, Vupine and more.

Middleware developers endorsing Cg

NDL, Criterion and Intrinsic Graphics. DCC applications and tools such as Dassault Systems Catia and 3DVia, Alias|Wavefront Maya, Discreet 3ds max, Softimage|XSI and Right Hemisphere's Deep Exploration are embedding Cg into the digital artist's workflow.