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Unity Engine

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Script Reference

Unity Engine

Branch based on platform features

Use platform difference helpers to make shader behaviour conditional on platform functionality.
読み終わるまでの所要時間 3 分最終更新 1ヶ月前
Direct use of these platform macros is discouraged, as they don't always contribute to the future-proofing of your code. For example, if you're writing a Shader that checks for D3D11, you may want to ensure that, in the future, the check is extended to include Vulkan. Instead, Unity defines several helper macros (in 
HLSLSupport.cginc
):

Macro:

Use:

UNITY_BRANCH
Add this before conditional statements to tell the compiler that this should be compiled into an actual branch. Expands to 
[branch]
when on HLSL platforms.
UNITY_FLATTEN
Add this before conditional statements to tell the compiler that this should be flattened to avoid an actual branch instruction. Expands to 
[flatten]
when on HLSL platforms.
UNITY_LOOP
This macro makes Unity generate code that instructs the shader compiler to keep the 
for
loop as a loop instead of unrolling it into a fixed set of operations. For an example of how to use the macro, refer to Render additional lights in a shader.
UNITY_NO_SCREENSPACE_SHADOWS
Defined on platforms that do not use cascaded screenspace shadowmaps (mobile platforms).
UNITY_NO_LINEAR_COLORSPACE
Defined on platforms that do not support Linear color space (mobile platforms).
UNITY_NO_RGBM
Defined on platforms where RGBM compression for lightmaps is not used (mobile platforms).
UNITY_NO_DXT5nm
Defined on platforms that do not use DXT5nm normal-map compression (mobile platforms).
UNITY_FRAMEBUFFER_FETCH_AVAILABLE
Defined on platforms where "framebuffer color fetch" functionality can be available (generally iOS platforms).
UNITY_USE_RGBA_FOR_POINT_SHADOWS
Defined on platforms where point light shadowmaps use RGBA Textures with encoded depth (other platforms use single-channel floating point Textures).
UNITY_ATTEN_CHANNEL
Defines which channel of light attenuation Texture contains the data; used in per-pixel lighting code. Defined to either 'r' or 'a'.
UNITY_HALF_TEXEL_OFFSET
Defined on platforms that need a half-texel offset adjustment in mapping texels to pixels.
UNITY_UV_STARTS_AT_TOP
Always defined with value of 1 or 0. A value of 1 is on platforms where Texture V coordinate is 0 at the "top" of the Texture. Direct3D-like platforms use value of 1; OpenGL-like platforms use value of 0.
UNITY_MIGHT_NOT_HAVE_DEPTH_Texture
Defined if a platform might emulate shadow maps or depth Textures by manually rendering depth into a Texture.
UNITY_PROJ_COORD(a)
Given a 4-component vector, this returns a Texture coordinate suitable for projected Texture reads. On most platforms this returns the given value directly.
UNITY_NEAR_CLIP_VALUE
Defined to the value of near clipping plane. Direct3D-like platforms use 1.0 while OpenGL-like platforms use -1.0.
UNITY_VPOS_TYPE
Defines the data type required for pixel position input (VPOS): 
float2
on D3D9, 
float4
elsewhere.
UNITY_CAN_COMPILE_TESSELLATION
Defined when the Shader compiler "understands" the tessellation Shader HLSL syntax (currently only D3D11).
UNITY_INITIALIZE_OUTPUT(type,name)
Initializes the variable name of given type to zero.
UNITY_COMPILER_HLSL
, 
UNITY_COMPILER_HLSL2GLSL
, 
UNITY_COMPILER_CG
Indicates which Shader compiler is being used to compile Shaders. See documentation on Shader compilation for more details. Use this if you run into very specific Shader syntax handling differences between the compilers, and want to write different code for each compiler.
  • UNITY_REVERSED_Z
    - defined on plaftorms using reverse Z buffer. Stored Z values are in the range 1..0 instead of 0..1.

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