Direct3D
Direct3D is a programming interface (API) from Microsoft for 3D computer graphics . Direct3D is part of DirectX . The company RenderMorphic , founded by Servan Keondjian in 1992 , was bought by Microsoft in 1995 in order to further develop its 3D API Reality Labs to Direct3D and to integrate it in DirectX 2.0 in 1996. Keondjian led the work and Doug Rabson served as chief developer of the Microsoft team that developed the 3D API for Windows 95. Upon completion, Keondjian and Rabson left the company.
Direct3D is used to give Windows applications the most direct possible access to the hardware of a computer. Direct3D is often used primarily for computer games , where it competes with the platform and operating system-independent OpenGL . Unlike OpenGL, Direct3D uses a left-handed coordinate system .
For a long time the independent programming interface DirectDraw for programming 2D computer graphics was integrated with DirectX 8.0 in Direct3D.
In addition to Direct3D, Windows also has the Graphics Device Interface (GDI) for graphics output . The GDI provides an abstract programming interface in which it makes little difference to the programmer whether drawing on a screen or on a printer. However, this abstraction makes the output itself much slower, among other things because the GDI has to reproduce complex drawing commands from basic operations. In contrast to Direct3D, the GDI is therefore primarily used to display normal desktop applications that are not too graphic-intensive. In the meantime, there are also other graphic interfaces in Windows, such as B. GDI + or Direct2D .
With Direct3D, on the other hand, applications can access the hardware directly bypassing GDI. If a device does not support a more complex command, Direct3D only returns an error message. It is then the task of the application to respond adequately to this error message - for example by emulating the command from basic operations, by displaying it less detailed or by sending an error message to the user.
Various graphics cards support Direct3D through device drivers that map the standardized Direct3D API commands to the graphics hardware. Direct3D differentiates between initializing and executing commands. Initializing commands convert more complex data structures - such as textures - into the graphics card-specific format, executing commands display the elements converted in this way. Since items can take some time to initialize and convert, it is common in games to do this while a new level is loading . Executing commands, on the other hand, are optimized for the highest possible speed.
Modern graphics cards provide so-called hardware shaders . These shaders are executable mini-programs that are used to create 3D effects. For the programming of the shaders, Microsoft defined its own machine language , which is predominantly supported directly in their chips by the two currently leading producers of graphics chips, NVIDIA and AMD . Nowadays, however, high-level languages such as HLSL or GLSL are mainly used for shader programming. Direct3D allows the available shader types ( vertex shaders , pixel shaders and geometry shaders ) to be controlled.
Supported Platforms
The first versions of Direct3D were developed for Windows 95 . The current Windows version of Direct3D is version 11.x, but like Direct3D 10, this is only supported in Windows Vista and Windows 7 , as well as Windows 8 in newer sub- versions . The still available version 9.0c supports both the successor to Windows 95 and - with Windows XP - the NT line.
The Xbox and Xbox 360 game consoles produced by Microsoft are also programmed with versions of Direct3D. In addition to these two platforms officially supported by Microsoft, there are two implementations of the Direct3D API for Linux, Cedega and Wine . The Sega Dreamcast was also compatible with Direct3D.
Feature levels
With Direct3D 10.1 the concept of feature levels was introduced.
| 9.1 | 9.2 | 9.3 | 10.0 | 10.1 | 11.0 | 11.1 | 12.0 | 12.1 | |
|---|---|---|---|---|---|---|---|---|---|
| Shader model | 2.0 | 2.0 | 4.0 (4.0_level_9_3) | 4.0 | 4.x | 5.0 | 5.0 | 5.1 | 5.1 |
| Geometry shader | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Stream Out | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| DirectCompute / Compute-Shader | No | No | No | part | part | Yes | Yes | Yes | Yes |
| Hull shader | No | No | No | No | No | Yes | Yes | Yes | Yes |
| Domain shader | No | No | No | No | No | Yes | Yes | Yes | Yes |
| Tiled Resources | No | No | No | No | No | part | part | Tier2 | Tier2 |
| Conservative rasterization | No | No | No | No | No | No | part | part | Tier1 |
| Rasterizer Order Views | No | No | No | No | No | No | part | part | Yes |
| Min / Max Filters | No | No | No | No | No | No | part | part | Yes |
| Map default buffer | No | No | No | No | No | part | part | part | part |
| Texture Resource Array | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Cubemap Resource Arrays | No | No | No | No | Yes | Yes | Yes | Yes | Yes |
| BC4 / BC5 compression | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| BC6H / BC7 compression | No | No | No | No | No | Yes | Yes | Yes | Yes |
| Alpha to coverage | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Extended formats | Yes | Yes | Yes | part | part | Yes | Yes | Yes | Yes |
| 10-bit per color channel | No | No | No | part | part | Yes | Yes | Yes | Yes |
| Logical operations (output merger) | No | No | No | part | part | part | Yes | Yes | Yes |
| Rasterization independent of the target | No | No | No | No | No | No | Yes | Yes | Yes |
| Multiple Render Target (MRT) with ForcedSampleCount 1 | No | No | No | part | part | part | Yes | Yes | Yes |
| Unordered Access View (UAV) slots | - | - | - | 1 | 1 | 8th | 64 | 64 | 64 |
| UAV in every stage | No | No | No | No | No | No | Yes | Yes | Yes |
| Max. ForcedSampleCount for UAV-only rendering | - | - | - | - | - | 8th | 16 | 16 | 16 |
| Constant buffer offsets and partial updates | Yes | Yes | Yes | part | part | part | Yes | Yes | Yes |
| 16 bit per pixel formats | part | part | part | part | part | part | Yes | Yes | Yes |
| Max. Texture size | 2048 | 2048 | 4096 | 8192 | 8192 | 16384 | 16384 | 16384 | 16384 |
| Max. Cubemap size | 512 | 512 | 4096 | 8192 | 8192 | 16384 | 16384 | 16384 | 16384 |
| Max. Volume spreading | 256 | 256 | 256 | 2048 | 2048 | 2048 | 2048 | 2048 | 2048 |
| Max. Texture repetitions | 128 | 2048 | 8192 | 8192 | 8192 | 16384 | 16384 | 16384 | 16384 |
| Max. Anisotropy | 2 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 |
| Max. Number of primitives | |||||||||
| Max. Input slots | 16 | 16 | 16 | 16 | 32 | 32 | 32 | 32 | 32 |
| Simultaneous render targets | 1 | 1 | 4th | 8th | 8th | 8th | 8th | 8th | 8th |
| Occlusion queries | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Separate alpha blend | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Mirror Once | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Overlapping vertex elements | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Independent write masks | No | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Instancing | No | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Textures that are not a multiple of 2 | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Constant buffer | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Max. Number of constant buffers per shader | - | - | - | 15th | 15th | 15th | 15th | 15th | 15th |
| Max. Number of constants in the constant buffer | - | - | - | 4096 | 4096 | 4096 | 4096 | 4096 | 4096 |
| Index buffer formats | 16-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit | 16-bit, 32-bit |
See also
literature
- Uli Theuerjahr: Direct3D Real Time Rendering for computer games. DirectX programming in C ++. Roulio Press, Schönberg 2007, ISBN 978-3-00-022340-2 .
Individual evidence
- ↑ Direct3D feature levels . MSDN. Retrieved September 30, 2014.
- ↑ Feature Level. In: indiedev.de. Archived from the original on October 6, 2014 ; accessed on June 25, 2020 .