一、手机GPU对于目标平台的不支持
这边需要参考具体手机GPU对图形API的支持性，下面是Unity官方文档对Supported #pragma target的描述：
Here is the list of shader models supported, with roughly increasing set of capabilities (and in some cases higher platform/GPU requirements):
#pragma target 2.0
Works on all platforms supported by Unity. DX9 shader model 2.0.
Limited amount of arithmetic & texture instructions; 8 interpolators; no vertex texture sampling; no derivatives in fragment shaders
; no explicit LOD
texture sampling.
#pragma target 2.5 (default)Almost the same as 3.0 target (see below), except still only has 8 interpolators, and does not have explicit LOD texture sampling.
Compiles into DX11 feature level 9.3 on Windows Phone.
#pragma target 3.0DX9 shader model 3.0: derivative instructions, texture LOD sampling, 10 interpolators, more math/texture instructions allowed.
Not supported on DX11 feature level 9.x GPUs (e.g. most Windows Phone devices).
Might not be fully supported by some OpenGL ES 2.0 devices, depending on driver extensions present and features used.
#pragma target 3.5 (or es3.0)OpenGL ES 3.0 capabilities (DX10 SM4.0 on D3D platforms, just without geometry shaders).
Not supported on DX11 9.x (WinPhone), OpenGL ES 2.0.
Supported on DX11+, OpenGL 3.2+, OpenGL ES 3+, Metal, Vulkan, PS4
/XB1 consoles.
Native integer operations in shaders, texture arrays, etc
.
#pragma target 4.0DX11 shader model 4.0.
Not supported on DX11 9.x (WinPhone), OpenGL ES 2.0/3.0/3.1, Metal.
Supported on DX11+, OpenGL 3.2+, OpenGL ES 3.1+AEP, Vulkan, PS4/XB1 consoles.
Has geometry shaders and everything that es3.0 target has.
#pragma target 4.5 (or es3.1)OpenGL ES 3.1 capabilities (DX11 SM5.0 on D3D platforms, just without tessellation shaders).
Not supported on DX11 before SM5.0, OpenGL before 4.3 (i.e. Mac), OpenGL ES 2.0/3.0.
Supported on DX11+ SM5.0, OpenGL 4.3+, OpenGL ES 3.1, Metal, Vulkan, PS4/XB1 consoles.
Has compute shaders, random access texture writes, atomics etc. No geometry or tessellation shaders.
#pragma target 4.6 (or gl4.1)OpenGL 4.1 capabilities (DX11 SM5.0 on D3D platforms, just without compute shaders). This is basically the highest OpenGL level supported by Macs.
Not supported on DX11 before SM5.0, OpenGL before 4.1, OpenGL ES 2.0/3.0/3.1, Metal.
Supported on DX11+ SM5.0, OpenGL 4.1+, OpenGL ES 3.1+AEP, Vulkan, Metal (without geometry), PS4/XB1 consoles.
#pragma target 5.0DX11 shader model 5.0.
Not supported on DX11 before SM5.0, OpenGL before 4.3 (i.e. Mac), OpenGL ES 2.0/3.0/3.1, Metal.
Supported on DX11+ SM5.0, OpenGL 4.3+, OpenGL ES 3.1+AEP, Vulkan, Metal (without geometry), PS4/XB1 consoles.
简而言之就是shader的pragma描述的对应平台相对的OpenGL版本你的手机集成的GPU是否支持。
如果不支持，shader最后的fallback语句，可能就会导致shader出现一些诡异的问题。
具体设备对应的GPU型号可以去CPU天梯图啊什么的搜索到，然后百度GPU对应的API平台。
二、#pragma对平台支持的剔除
一次项目中发现的问题，没仔细看还真是不知道- -，如下：
#pragma exclude_renderers gles3 metal d3d11_9x xbox360 xboxone ps3 ps4 psp2
exclude_renderers
exclude...剔除...也就是后面写的那些全不支持了，安卓平台的gles和ios的metal都被剔除了，所以打包之后肯定是会出问题...
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原文链接：https://blog.csdn.net/qq302756113/article/details/83001165