高级着色器语言

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高级着色器语言High Level Shader Language,简称HLSL),由微軟擁有及開發的一種語言,只能供微軟的Direct3D以及XNA使用。HLSL是GLSL的先辈,同時不能與OpenGL標準兼容。他跟NvidiaCg非常相似。

HLSL的主要作用為將一些複雜的圖像處理,快速而又有效率地在顯示卡上完成,與組合式或低階Shader Language相比,能降低在編寫複雜特殊效果時所發生編程錯誤的機會。

Shader model 比較[编辑]

Pixel shader 比較[编辑]

Pixel shader 版本 2.0 2.0a 2.0b 3.0[1] 4.0[2]
Dependent texture limit 8 Unlimited 8 Unlimited Unlimited
Texture instruction limit 32 Unlimited Unlimited Unlimited Unlimited
Position register No No No Yes Yes
Instruction slots 32 + 64 512 512 ≥ 512 ≥ 65536
Executed instructions 32 + 64 512 512 65536 Unlimited
Texture indirections 4 No limit 4 No Limit No Limit
Interpolated registers 2 + 8 2 + 8 2 + 8 10 32
Instruction predication No Yes No Yes No
Index input registers No No No Yes Yes
Temp registers 12 22 32 32 4096
Constant registers 32 32 32 224 16x4096
Arbitrary swizzling No Yes No Yes Yes
Gradient instructions No Yes No Yes Yes
Loop count register No No No Yes Yes
Face register (2-sided lighting) No No No Yes Yes
Dynamic flow control No No No 24 Yes
Bitwise Operators No No No No Yes
Native Integers No No No No Yes
  • PS 2.0 = DirectX 9.0 original Shader Model 2 specification.
  • PS 2.0a = NVIDIA GeForce FX-optimized model.
  • PS 2.0b = ATI Radeon X700, X800, X850 shader model, DirectX 9.0b.
  • PS 3.0 = Shader Model 3.
  • PS 4.0 = Shader Model 4.

"32 + 64" for Executed Instructions means "32 texture instructions and 64 arithmetic instructions."

Vertex shader 比較[编辑]

Vertex shader 版本 VS 2.0 VS 2.0a VS 3.0[1] VS 4.0[2]
# of instruction slots 256 256 ≥ 512 4096
Max # of instructions executed 65536 65536 65536 65536
Instruction Predication No Yes Yes Yes
Temp Registers 12 13 32 4096
# constant registers ≥ 256 ≥ 256 ≥ 256 16x4096
Static Flow Control Yes Yes Yes Yes
Dynamic Flow Control No Yes Yes Yes
Dynamic Flow Control Depth No 24 24 Yes
Vertex Texture Fetch No No Yes Yes
# of texture samplers N/A N/A 4 128
en:Geometry instancing support No No Yes Yes
Bitwise Operators No No No Yes
Native Integers No No No Yes
  • VS 2.0 = DirectX 9.0 original Shader Model specification.
  • VS 2.0a = NVIDIA GeForce FX-optimized model.
  • VS 3.0 = Shader Model 3.
  • VS 4.0 = Shader Model 4.

範例[编辑]

灰階貼圖用
  • 灰階值 = 0.3 x 紅 + 0.59 x 綠 + 0.11 x 藍
sampler2D Texture0;

float4 ps_main( float2 texCoord  : TEXCOORD0 ) : COLOR
{
   float4 _inColor = tex2D( Texture0, texCoord );
   float gray = 0.3*_inColor.x + 0.59*_inColor.y + 0.11*_inColor.z;
   float4 _outColor = float4(gray, gray, gray, 1.0);
   
   return _outColor;
}

注釋[编辑]

  1. ^ 1.0 1.1 Shader Model 3.0, Ashu Rege, NVIDIA Developer Technology Group, 2004.
  2. ^ 2.0 2.1 The Direct3D 10 System, David Blythe, Microsoft Corporation, 2006.

外部連結[编辑]