The Evolution of DirectX: What’s Missing in DirectX 11 Compared to 9?

DirectX, a set of application programming interfaces (APIs) developed by Microsoft, has been a cornerstone of game development and graphics processing for decades. With each new iteration, DirectX has brought about significant improvements and additions to its feature set. However, some features that were present in earlier versions, such as DirectX 9, are conspicuously absent in DirectX 11. In this article, we’ll delve into the missing properties and explore the reasons behind their omission.

The Rise of DirectX 11

Released in 2009, DirectX 11 marked a significant leap forward in graphics processing, introducing features like multi-threading, tessellation, and compute shaders. These advancements enabled developers to create more complex and visually stunning games, taking advantage of the latest hardware capabilities.

// DirectX 11's new features:
// 1. Multi-threading: improved performance by leveraging multiple CPU cores
// 2. Tessellation: increased geometric detail and reduced polygon count
// 3. Compute shaders: enabled general-purpose computing on the GPU

The Missing Properties: A Comparative Analysis

While DirectX 11 introduced many exciting features, some properties present in DirectX 9 are notably absent or have been modified. Let’s examine these differences and understand why they were removed or changed.

1. Fixed-Function Pipeline (FFP)

In DirectX 9, the fixed-function pipeline (FFP) allowed for a more straightforward, hardware-controlled rendering pipeline. This pipeline was optimized for performance but limited in flexibility. In DirectX 11, the FFP was replaced by the programmable pipeline, which offers more flexibility but requires more effort from developers to optimize performance.

2. Vertex and Pixel Shaders 1.x/2.x

DirectX 9 supported vertex and pixel shaders up to version 2.x. These shaders were simpler and more limited in their capabilities compared to later versions. DirectX 11 introduced newer shader models (4.x and 5.x), which offer more features and flexibility but require more complex code and increased computational power.

• Vertex Shaders 1.x/2.x:
  • Limited instruction count
  • No support for geometry shaders
• Pixel Shaders 1.x/2.x:
  • Limited texture sampling
  • No support for texture arrays

3. Texture Formats and Compression

DirectX 9 supported a range of texture formats, including some that are no longer present in DirectX 11. The newer version has more advanced texture compression formats, such as BC7 and BC6H, but has removed some of the older formats.

1. Removed texture formats:
   • DX1-DX4 (DXT1-DXT4)
   • UYYV and UYVY
2. New texture formats:
   • BC7 (block compression)
   • BC6H (floating-point compression)

Why Were These Properties Removed?

The omission of these properties in DirectX 11 can be attributed to several factors:

• Modern hardware capabilities**: Newer graphics hardware is capable of handling more complex and efficient rendering pipelines, making some of the older features redundant.
• Performance optimization**: By removing less-efficient features, DirectX 11 encourages developers to use more optimized and performance-friendly techniques.
• Increased flexibility**: The programmable pipeline and newer shader models offer more flexibility and control, allowing developers to create more complex and visually stunning graphics.
• Industry trends**: The shift towards more modern and efficient rendering techniques is driven by industry trends and the need for better performance and visual quality.

// DirectX 11's improved features:
// 1. Multi-threading: improved performance
// 2. Tessellation: increased geometric detail
// 3. Compute shaders: enabled general-purpose computing