文章目录
前言
在之前的文章中，我们学习了 ShaderLab 中 BuildIn Render Pipeline 下的Shader书写。在这篇文章中，我们来了解一下 URP 下 的最简Shader怎么编写。
一、 我们先了解一下 Shader Graph 怎么操作
1、了解一下 Shader Graph 的面板信息
2、修改Shader路径
3、鼠标中键 或 Alt + 鼠标左键 移动画布
4、鼠标右键 打开创建节点菜单
5、把ShaderGraph节点转化为 Shader 代码
- 可以直接 查看 或 复制 编译后的Shader
6、可以看出 URP 和 BuildIn RP 大体框架一致
二、把ShaderGraph转化后的 Shader 只保留最基础的通用前向渲染Pass
因为是由ShaderGraph转化过来的。所以，这里虽然简化了。但是，还是过于臃肿，在之后的文章中，我们来优化一下
Shader "MyShader/P2_10"
{
Properties {}
SubShader
{
Tags
{
"RenderPipeline"="UniversalPipeline"
"RenderType"="Opaque"
"Queue"="Geometry"
}
Pass
{
Name "Universal Forward"
Tags
{
// LightMode: <None>
}
// Render State
Cull Back
Blend One Zero
ZTest LEqual
ZWrite On
// Debug
// <None>
// --------------------------------------------------
// Pass
HLSLPROGRAM
// Pragmas
#pragma target 2.0
#pragma multi_compile_instancing
#pragma multi_compile_fog
#pragma instancing_options renderinglayer
#pragma vertex vert
#pragma fragment frag
// Keywords
#pragma multi_compile _ LIGHTMAP_ON
#pragma multi_compile _ DIRLIGHTMAP_COMBINED
#pragma shader_feature _ _SAMPLE_GI
#pragma multi_compile_fragment _ _DBUFFER_MRT1 _DBUFFER_MRT2 _DBUFFER_MRT3
#pragma multi_compile_fragment _ DEBUG_DISPLAY
#pragma multi_compile_fragment _ _SCREEN_SPACE_OCCLUSION
// GraphKeywords: <None>
// Defines
#define ATTRIBUTES_NEED_NORMAL
#define ATTRIBUTES_NEED_TANGENT
#define VARYINGS_NEED_POSITION_WS
#define VARYINGS_NEED_NORMAL_WS
#define FEATURES_GRAPH_VERTEX
/* WARNING: $splice Could not find named fragment 'PassInstancing' */
#define SHADERPASS SHADERPASS_UNLIT
#define _FOG_FRAGMENT 1
/* WARNING: $splice Could not find named fragment 'DotsInstancingVars' */
// custom interpolator pre-include
/* WARNING: $splice Could not find named fragment 'sgci_CustomInterpolatorPreInclude' */
// Includes
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Texture.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl"
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/TextureStack.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DBuffer.hlsl"
#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/ShaderPass.hlsl"
// --------------------------------------------------
// Structs and Packing
// custom interpolators pre packing
/* WARNING: $splice Could not find named fragment 'CustomInterpolatorPrePacking' */
struct Attributes
{
float3 positionOS : POSITION;
float3 normalOS : NORMAL;
float4 tangentOS : TANGENT;
#if UNITY_ANY_INSTANCING_ENABLED
uint instanceID : INSTANCEID_SEMANTIC;
#endif
};
struct Varyings
{
float4 positionCS : SV_POSITION;
float3 positionWS;
float3 normalWS;
#if UNITY_ANY_INSTANCING_ENABLED
uint instanceID : CUSTOM_INSTANCE_ID;
#endif
#if (defined(UNITY_STEREO_MULTIVIEW_ENABLED)) || (defined(UNITY_STEREO_INSTANCING_ENABLED) && (defined(SHADER_API_GLES3) || defined(SHADER_API_GLCORE)))
uint stereoTargetEyeIndexAsBlendIdx0 : BLENDINDICES0;
#endif
#if (defined(UNITY_STEREO_INSTANCING_ENABLED))
uint stereoTargetEyeIndexAsRTArrayIdx : SV_RenderTargetArrayIndex;
#endif
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
FRONT_FACE_TYPE cullFace : FRONT_FACE_SEMANTIC;
#endif
};
struct SurfaceDescriptionInputs
{
};
struct VertexDescriptionInputs
{
float3 ObjectSpaceNormal;
float3 ObjectSpaceTangent;
float3 ObjectSpacePosition;
};
struct PackedVaryings
{
float4 positionCS : SV_POSITION;
float3 positionWS : INTERP0;
float3 normalWS : INTERP1;
#if UNITY_ANY_INSTANCING_ENABLED
uint instanceID : CUSTOM_INSTANCE_ID;
#endif
#if (defined(UNITY_STEREO_MULTIVIEW_ENABLED)) || (defined(UNITY_STEREO_INSTANCING_ENABLED) && (defined(SHADER_API_GLES3) || defined(SHADER_API_GLCORE)))
uint stereoTargetEyeIndexAsBlendIdx0 : BLENDINDICES0;
#endif
#if (defined(UNITY_STEREO_INSTANCING_ENABLED))
uint stereoTargetEyeIndexAsRTArrayIdx : SV_RenderTargetArrayIndex;
#endif
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
FRONT_FACE_TYPE cullFace : FRONT_FACE_SEMANTIC;
#endif
};
PackedVaryings PackVaryings(Varyings input)
{
PackedVaryings output;
ZERO_INITIALIZE(PackedVaryings, output);
output.positionCS = input.positionCS;
output.positionWS.xyz = input.positionWS;
output.normalWS.xyz = input.normalWS;
#if UNITY_ANY_INSTANCING_ENABLED
output.instanceID = input.instanceID;
#endif
#if (defined(UNITY_STEREO_MULTIVIEW_ENABLED)) || (defined(UNITY_STEREO_INSTANCING_ENABLED) && (defined(SHADER_API_GLES3) || defined(SHADER_API_GLCORE)))
output.stereoTargetEyeIndexAsBlendIdx0 = input.stereoTargetEyeIndexAsBlendIdx0;
#endif
#if (defined(UNITY_STEREO_INSTANCING_ENABLED))
output.stereoTargetEyeIndexAsRTArrayIdx = input.stereoTargetEyeIndexAsRTArrayIdx;
#endif
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
output.cullFace = input.cullFace;
#endif
return output;
}
Varyings UnpackVaryings(PackedVaryings input)
{
Varyings output;
output.positionCS = input.positionCS;
output.positionWS = input.positionWS.xyz;
output.normalWS = input.normalWS.xyz;
#if UNITY_ANY_INSTANCING_ENABLED
output.instanceID = input.instanceID;
#endif
#if (defined(UNITY_STEREO_MULTIVIEW_ENABLED)) || (defined(UNITY_STEREO_INSTANCING_ENABLED) && (defined(SHADER_API_GLES3) || defined(SHADER_API_GLCORE)))
output.stereoTargetEyeIndexAsBlendIdx0 = input.stereoTargetEyeIndexAsBlendIdx0;
#endif
#if (defined(UNITY_STEREO_INSTANCING_ENABLED))
output.stereoTargetEyeIndexAsRTArrayIdx = input.stereoTargetEyeIndexAsRTArrayIdx;
#endif
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
output.cullFace = input.cullFace;
#endif
return output;
}
// --------------------------------------------------
// Graph
// Graph Properties
CBUFFER_START(UnityPerMaterial)
CBUFFER_END
// Object and Global properties
// Graph Includes
// GraphIncludes: <None>
// -- Property used by ScenePickingPass
#ifdef SCENEPICKINGPASS
float4 _SelectionID;
#endif
// -- Properties used by SceneSelectionPass
#ifdef SCENESELECTIONPASS
int _ObjectId;
int _PassValue;
#endif
// Graph Functions
// GraphFunctions: <None>
// Custom interpolators pre vertex
/* WARNING: $splice Could not find named fragment 'CustomInterpolatorPreVertex' */
// Graph Vertex
struct VertexDescription
{
float3 Position;
float3 Normal;
float3 Tangent;
};
VertexDescription VertexDescriptionFunction(VertexDescriptionInputs IN)
{
VertexDescription description = (VertexDescription)0;
description.Position = IN.ObjectSpacePosition;
description.Normal = IN.ObjectSpaceNormal;
description.Tangent = IN.ObjectSpaceTangent;
return description;
}
// Custom interpolators, pre surface
#ifdef FEATURES_GRAPH_VERTEX
Varyings CustomInterpolatorPassThroughFunc(inout Varyings output, VertexDescription input)
{
return output;
}
#define CUSTOMINTERPOLATOR_VARYPASSTHROUGH_FUNC
#endif
// Graph Pixel
struct SurfaceDescription
{
float3 BaseColor;
};
SurfaceDescription SurfaceDescriptionFunction(SurfaceDescriptionInputs IN)
{
SurfaceDescription surface = (SurfaceDescription)0;
surface.BaseColor = IsGammaSpace() ? float3(0.5, 0.5, 0.5) : SRGBToLinear(float3(0.5, 0.5, 0.5));
return surface;
}
// --------------------------------------------------
// Build Graph Inputs
#ifdef HAVE_VFX_MODIFICATION
#define VFX_SRP_ATTRIBUTES Attributes
#define VFX_SRP_VARYINGS Varyings
#define VFX_SRP_SURFACE_INPUTS SurfaceDescriptionInputs
#endif
VertexDescriptionInputs BuildVertexDescriptionInputs(Attributes input)
{
VertexDescriptionInputs output;
ZERO_INITIALIZE(VertexDescriptionInputs, output);
output.ObjectSpaceNormal = input.normalOS;
output.ObjectSpaceTangent = input.tangentOS.xyz;
output.ObjectSpacePosition = input.positionOS;
return output;
}
SurfaceDescriptionInputs BuildSurfaceDescriptionInputs(Varyings input)
{
SurfaceDescriptionInputs output;
ZERO_INITIALIZE(SurfaceDescriptionInputs, output);
#ifdef HAVE_VFX_MODIFICATION
#if VFX_USE_GRAPH_VALUES
uint instanceActiveIndex = asuint(UNITY_ACCESS_INSTANCED_PROP(PerInstance, _InstanceActiveIndex));
/* WARNING: $splice Could not find named fragment 'VFXLoadGraphValues' */
#endif
/* WARNING: $splice Could not find named fragment 'VFXSetFragInputs' */
#endif
#if UNITY_UV_STARTS_AT_TOP
#else
#endif
#if defined(SHADER_STAGE_FRAGMENT) && defined(VARYINGS_NEED_CULLFACE)
#define BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN output.FaceSign = IS_FRONT_VFACE(input.cullFace, true, false);
#else
#define BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN
#endif
#undef BUILD_SURFACE_DESCRIPTION_INPUTS_OUTPUT_FACESIGN
return output;
}
// --------------------------------------------------
// Main
#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/Varyings.hlsl"
#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/UnlitPass.hlsl"
// --------------------------------------------------
// Visual Effect Vertex Invocations
#ifdef HAVE_VFX_MODIFICATION
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/VisualEffectVertex.hlsl"
#endif
ENDHLSL
}
}
FallBack "Hidden/Shader Graph/FallbackError"
}
1、我们看一下 URP Pass不可用后使用的默认Shader
使用的是内置渲染管线，返回颜色为洋葱紫
Shader "Hidden/Universal Render Pipeline/FallbackError"
{
SubShader
{
Tags
{
"RenderType" = "Opaque"
"RenderPipeline" = "UniversalPipeline"
"IgnoreProjector" = "True"
}
Pass
{
HLSLPROGRAM
#pragma target 2.0
#pragma editor_sync_compilation
// -------------------------------------
// Shader Stages
#pragma vertex vert
#pragma fragment frag
// -------------------------------------
// Unity defined keywords
#pragma multi_compile _ STEREO_INSTANCING_ON STEREO_MULTIVIEW_ON
//--------------------------------------
// GPU Instancing
#include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"
// -------------------------------------
// Includes
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl"
struct appdata_t
{
float4 vertex : POSITION;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
struct v2f
{
float4 vertex : SV_POSITION;
UNITY_VERTEX_OUTPUT_STEREO
};
v2f vert (appdata_t v)
{
v2f o;
UNITY_SETUP_INSTANCE_ID(v);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
o.vertex = TransformObjectToHClip(v.vertex.xyz);
return o;
}
float4 frag (v2f i) : SV_Target
{
return float4(1,0,1,1);
}
ENDHLSL
}
}
Fallback "Hidden/Core/FallbackError"
}