Surface Shader

Rendering tends to become more processing-heavy as development criteria rise. We introduce the Surface Shader framework in v3.5.1 to provide a more efficient and structured process for creating shaders.

Developers can find the corresponding shaders and shader fragments in Assets -> internal -> effect -> surfaces and Assets -> internal -> chunk -> surfaces.

Surface Shader aims to facilitate fast and streamlined shader creation with simple codes in unified structures and processes. Users may easily define lighting and shading attributes, access public properties such as global lighting and debug viewing with the additional benefit of low maintenance, better readability and higher compatibility.

With Surface Shader integrated, Material system in Cocos Creator will continue to expand in future versions including visual coding for shaders. However, it will also prohibit ad-hoc modifications such as custom lighting and shading calculations. In the event of such development scenario rises, please revert to the legacy shader system.

Surface Shader is built on the Cocos Effect system, of which the syntax and properties are fully compatible.

Related Concepts

The following sections illustrate new terminologies introduced by the Surface Shader framework.

1. Rendering Usage

Render Target specifies the destinations for the pixels rendered by the shader.

A shader typically incorporates multiple passes to render to various data outlets, such as to the screen for displaying, to the shadow maps to create shadows, to the reflection map to create reflections, etc.

Relevant functionalities can be found in the folder Assets -> internal -> chunk -> shading-entries -> main-functions.

Common Rendering Uses	File Locations	Notes
render-to-scene (default)	render-to-scene
render-to-shadowmap	render-to-shadowmap
render-to-environment	render-to-reflectmap	engine reserved
render-to-cartoon stroke	render-silhouette-edge
render sky	misc/sky
post-processing or general-purpose computation Pass	misc/quad	engine reserved

2. Lighting Model

Lighting model refers to the manner in which the material’s microscopic structures interact with lights and the visual outcomes thereof, such as specular, diffusion, reflection, etc.

Illumination Model Name	Description
standard	PBR lighting, support GGX BRDF distribution of isotropic and anisotropic lighting, support convolutional ambient lighting
toon	simple cartoon lighting, step lighting effect

3. Surface Material Model

Surface model refers to the material’s surface attributes such as IOR and roughness.

Surface models typically work in conjunction with lighting models. New models are to be introduced in future updates.

Material Model Name	Description
standard	Standard PBR material with roughness and metallic description, similar to material nodes in SP, Blender, Maya, etc.
toon	A simple cartoon material with multiple shade color treatments.

4. Shader Stage

Shader stage refers to the different stages in the render process, which includes:

Shader Stage	Identifier
Vertex Shader	vs
Fragment Shader	fs
Compute Shader	cs

Framework

Similar to legacy shaders, Surface Shader code also consists of Cocos Effect’s properties, techniques and UBOs but excludes macro definitions, in/out parameters, instancing, coordinate transformations and other calculations found in the legacy shaders.

A typical Surface Shader is comprised of three parts:

• Macro Remapping: Map declared parameters and macros in the Effect header to private macros
• Surface Functions: Declare functions in the Surface Shader
• Shader Assembly: Assemble the vertex shader and the fragment shader in the Surface Shader.

Using the default shader surfaces/standard.effect as an example, A Surface Shader include code such as:

Macro Remapping

When a certain functionality of the Surface Shader is required, users may choose to expose said functionality by defining a Marco in the Macro Mapping section of the Surface Shader. Doing so allows users to expose said functionalities in the Properties Panel with a name of the user’s choosing without interfering with the shading calculation involved.

These macros start with CC_SURFACES_ and the following is the complete list of macros.

Macro Name	Type	Meaning
CC_SURFACES_USE_VERTEX_COLOR	BOOL	Whether to use vertex color
CC_SURFACES_USE_SECOND_UV	BOOL	Whether to use 2uv
CC_SURFACES_USE_TWO_SIDED	BOOL	Whether to use double-sided normals
CC_SURFACES_USE_TANGENT_SPACE	BOOL	Whether to use tangent space (must be on when using normal map or anisotropy)
CC_SURFACES_TRANSFER_LOCAL_POS	BOOL	Whether to access model space coordinates in FS
CC_SURFACES_LIGHTING_ANISOTROPIC	BOOL	Whether to enable anisotropic materials
CC_SURFACES_LIGHTING_ANISOTROPIC_ENVCONVOLUTION_COUNT	UINT	The number of anisotropic ambient light convolution samples, 0 means convolution calculation is off, only valid when anisotropy is on
CC_SURFACES_LIGHTING_ANISOTROPIC_ENVCONVOLUTION_COUNT
CC_SURFACES_USE_REFLECTION_DENOISE	BOOL	Whether to turn on ambient reflection denoising
CC_SURFACES_USE_LEGACY_COMPATIBLE_LIGHTING	BOOL	Whether or not to enable legacy-compatible lighting mode, which makes the rendering effect identical to legacy/standard.effect and facilitates upgrades

NOTE: These macros can be left undefined and are automatically defined internally to the default value of 0; they can also be defined directly to 0 or some other value, indicating that they are forced off or on in this Effect and user adjustment is disabled.

Searching for the CCProgram macro-remapping paragraph, you can see that the content consists of the following three parts.

1. Macros Not Used In The Surface Function

// ui displayed macros not used in this effect file
#pragma define-meta HAS_SECOND_UV
#pragma define-meta USE_TWOSIDE
#pragma define-meta USE_REFLECTION_DENOISE
#pragma define-meta IS_ANISOTROPY
#pragma define-meta USE_COMPATIBLE_LIGHTING
    
#define CC_SURFACES_USE_SECOND_UV HAS_SECOND_UV
#define CC_SURFACES_USE_TWO_SIDED USE_TWOSIDE
#define CC_SURFACES_USE_REFLECTION_DENOISE USE_REFLECTION_DENOISE
#define CC_SURFACES_LIGHTING_ANISOTROPIC IS_ANISOTROPY
#define CC_SURFACES_USE_LEGACY_COMPATIBLE_LIGHTING USE_COMPATIBLE_LIGHTING

Surface Shader omits certain codes compared to legacy shaders such as #if HAS_SECOND_UV. To declare a macro of the same purpose, users may pre-defined the macro #pragma define-meta MACRONAME for it to be displayed in the Properties Panel first, then map the newly declared macro to one of Surface Shader’s functionalities as with standard GLSL: #define CC_SURFACES_MACRONAME MACRONAME.

2. Macros Used In The Surface Function

// ui displayed macros used in this effect file
#define CC_SURFACES_USE_VERTEX_COLOR USE_VERTEX_COLOR
#if IS_ANISOTROPY || USE_NORMAL_MAP
  #define CC_SURFACES_USE_TANGENT_SPACE 1
#endif

Macros being used in the Surface Functions can be declare in the format: #define CC_SURFACES_MACRONAME MACRONAME. In this particular case, normal mapping and anisotropy requires CC_SURFACES_USE_TANGENT_SPACE to be enabled.

3. Internal Functional Macros

// functionality for each effect
#define CC_SURFACES_LIGHTING_ANISOTROPIC_ENVCONVOLUTION_COUNT 31

Internal macros can be defined with its intended value attached.

Surface Function

The function of each material function is similar to the output of a material parameter to a specified material node in the material editor of DCC (Digital Content Creation) software. Similar to：

1. Definition

Surface functions can be declared in CCProgram code blocks or their separate .chunk files.

Note: For consistency’s sake, all vertex shader code should be encased in one block while all fragment shader code in another. Vertex shader and fragment shader should not use more than one code blocks each. Also, vertex shader and fragment shader should not share the same code block.

Surface Shader provides simple default functions internally, so these functions are not mandatory, if you want to overload a function, you need to predefine the macro corresponding to that function to do so. These functions are named with Surfaces + ShaderStage name followed by the function description. They can be found in editor/assets/chunks/surfaces/default-functions to see the specific definition and implementation of each Surface function in different material models, e.g.

#define CC_SURFACES_VERTEX_MODIFY_WORLD_POS
vec3 SurfacesVertexModifyWorldPos(in SurfacesStandardVertexIntermediate In)
{
  vec3 worldPos = In.worldPos;
  worldPos.x += sin(cc_time.x * worldPos.z);
  worldPos.y += cos(cc_time.x * worldPos.z);
  return worldPos;
}

Defining the macro CC_SURFACES_VERTEX_MODIFY_WORLD_POS allows its corresponding function to be overridden with the code in the current Surface Shader.

Note: Overriding functions can be assigned new names and parameters. Users may override functions according to their own design or call the default version of the same function. This allows easy extension for the shader capabilities and avoid conflicts with future updates.

2. VS Corresponding Functions List

Functions relevant to vertex shaders are listed as follows. All functions takes the SurfacesStandardVertexIntermediate structure as parameter. As vertex shader rarely see customizations, these functions require no overriding in most scenarios.

Predefined macros	Corresponding function definitions	Corresponding material models	Function descriptions
CC_SURFACES_VERTEX_MODIFY_LOCAL_POS	vec3 SurfacesVertexModifyLocalPos	Common	Returns the modified model space coordinates
CC_SURFACES_VERTEX_MODIFY_WORLD_POS	vec3 SurfacesVertexModifyWorldPos	Common	Returns the modified world space coordinates (world space animation)
CC_SURFACES_VERTEX_MODIFY_CLIP_POS	vec4 SurfacesVertexModifyClipPos	Common	Returns the modified clipping (NDC) space coordinates (usually used to modify depth)
CC_SURFACES_VERTEX_MODIFY_UV	void SurfacesVertexModifyUV	Common	Modifies UV0 and UV1 within the structure (using tiling, etc.)
CC_SURFACES_VERTEX_MODIFY_WORLD_NORMAL	vec3 SurfacesVertexModifyWorldNormal	Common	Returns the modified world space normals (world space animation)

3. FS Corresponding Functions List

Functions relevant to fragment shaders are listed as follows. Most functions involve in modifying the value of one particular property while some modify more than one. In such cases, the respective functions can take multiple parameters.

Predefined macros	Corresponding function definitions	Corresponding material models	Function descriptions
CC_SURFACES_FRAGMENT_MODIFY_ BASECOLOR_AND_TRANSPARENCY	vec4 SurfacesFragmentModify BaseColorAndTransparency	Common	Returns the modified base color (rgb channel) and transparency values (a channel)
CC_SURFACES_FRAGMENT_MODIFY_ WORLD_NORMAL	vec3 SurfacesFragmentModify WorldNormal	Common	Returns the modified pixel normals (usually normal mapping)
CC_SURFACES_FRAGMENT_MODIFY_ SHARED_DATA	void SurfacesFragmentModify SharedData	Common	If some mapping and calculations need to be used in multiple material nodes, they can be done in this function, directly modifying the Surface structure This function can be used to modify the parameters in the surface structure directly, reducing performance costs.
CC_SURFACES_FRAGMENT_MODIFY_ WORLD_TANGENT_AND_BINORMAL	void SurfacesFragmentModify WorldTangentAndBinormal	Standard PBR	Modify Surface structure The world tangent space vector in the body
CC_SURFACES_FRAGMENT_MODIFY_ EMISSIVE	vec3 SurfacesFragmentModify Emissive	Standard PBR	Returns the modified self-illumination color
CC_SURFACES_FRAGMENT_MODIFY_ PBRPARAMS	vec4 SurfacesFragmentModify PBRParams	Standard PBR	Returns the modified PBR parameters (ao, roughness, metallic. specularIntensity)
CC_SURFACES_FRAGMENT_MODIFY_ ANISOTROPY_PARAMS	vec4 SurfacesFragmentModify AnisotropyParams	Standard PBR	Returns modified anisotropy parameters (rotation, shape. unused, unused)
CC_SURFACES_FRAGMENT_MODIFY_ BASECOLOR_AND_TOONSHADE	void SurfacesFragmentModify BaseColorAndToonShade	Toon	Modify Toon Render Base Color
CC_SURFACES_FRAGMENT_MODIFY_ TOON_STEP_AND_FEATHER	vec4 SurfacesFragmentModify ToonStepAndFeather	Toon	Returns the modified parameters
CC_SURFACES_FRAGMENT_MODIFY_ TOON_SHADOW_COVER	vec4 SurfacesFragmentModify ToonShadowCover	Toon	Returns the modified parameters
CC_SURFACES_FRAGMENT_MODIFY_ TOON_SPECULAR	vec4 SurfacesFragmentModify ToonSpecular	Toon	Returns the modified parameters

4. VS Input Value Acquisition

Input values of the vertex shader, which is stored in the format of a SurfacesStandardVertexIntermediate structure, include members as follows:

Vertex Shader Inputs	Type	Requires macro to be turned on when using	Meaning
position	vec4	N/A	Local Position
normal	vec3	N/A	Local Normal
tangent	vec4	CC_SURFACES_USE_TANGENT_SPACE	Local Tangent and Mirror Normal Sign
color	vec4	CC_SURFACES_USE_VERTEX_COLOR	Vertex Color
texCoord	vec2	N/A	UV0
texCoord1	vec2	CC_SURFACES_USE_SECOND_UV	UV1
clipPos	vec4	N/A	Clip(NDC) Position
worldPos	vec3	N/A	World Position
worldNormal	vec4	N/A	World Normal and Two Side Sign
worldTangent	vec3	CC_SURFACES_USE_TANGENT_SPACE	World Tangent
worldBinormal	vec3	CC_SURFACES_USE_TANGENT_SPACE	World Binormal

5. FS Input Value Acquisition

Input values of the fragment are listed as follows. Most can be accessed without macro condition evaluations.

Fragment Shader Input	Type	Requires macro to be enabled when using	Meaning
FSInput_worldPos	vec3	N/A	World Position
FSInput_worldNormal	vec3	N/A	World Normal
FSInput_faceSideSign	float	N/A	Two Side Sign
FSInput_texcoord	vec2	N/A	UV0
FSInput_texcoord1	vec2	N/A	UV1
FSInput_vertexColor	vec4	N/A	Vertex Color
FSInput_worldTangent	vec3	N/A	World Tangent
FSInput_mirrorNormal	float	N/A	Mirror Normal Sign
FSInput_localPos	vec4	CC_SURFACES_TRANSFER_LOCAL_POS	Local Position

Shader Assembly

Users may assemble multiple modules with the include keyword for each pass of the Surface Shader. For instance, the fragment shader of the default Surface Shader is assembled by 6 parts:

1. Macros

Macros are required to be mapped and defined in the Marco Mapping section of the surface shader, which is integrated in the form of CCProgram code blocks or .chunk files.

By including common-macros, users can integrate most macros to the Surface Shader.

Pass standard-fs:
#include <macro-remapping>
#include <surfaces/effect-macros/common-macros>

In scenarios where only part of the Surface Shader’s capabilities are used, users can also include specific macros involved in the shading process.

Pass shadow-caster-fs:
#include <surfaces/effect-macros/render-to-shadowmap>

2. Shader Generic Header File

Header files should be included with their Shader Stage specified, such as:

Vertex Shader：
#include <surfaces/includes/common-vs>
Fragement Shader：
#include <surfaces/includes/common-fs>

3. Surface Utility Functions

Surface functions that are created in their separate .chunk file need to be included accordingly. Surface functions require access to the shared memory allocation to function properly. For this reason, shared UBO also need to be included prior to the .chunk files in question.

#include <shared-ubos>
#include <surface-fragment>

4. Lighting Model

Lighting models are optional and can only be used in the fragment shader to render to screen.

When including lighting models, their corresponding names are also required to be specified.

Standard PBR Lighting：
#include <lighting-models/includes/standard>
Toon Lighting：
#include <lighting-models/includes/toon>

5. Surface Materials and Shading Models

Surface material models are optional and can only be used to render to screen.

When including lighting models, their corresponding names and render stages involved are also required to be specified.

Vertex Shader：
#include <surfaces/includes/standard-vs>
Fragement Shader：
#include <surfaces/includes/standard-fs>

6. Main Shader Function

When including main render loop functions, their corresponding render target and render stages involved are also required to be specified.

Pass standard-fs:
#include <shading-entries/main-functions/render-to-scene/fs>
Pass shadow-caster-fs:
#include <shading-entries/main-functions/render-to-shadowmap/fs>

Debug View

Starting from v3.6, users may enable Debug View to print out data outputs for quick debugging.

Advanced Usage

1. Manual inserting vertex shader outputs and fragment shader inputs: with the new varying property introduced in the Surface Shader framework, vertex shader outputs and fragment shader inputs can be accessed in particular Surface Functions.
2. Surface Shader and legacy shader codes can be used in the same render loop as long as the varying vertex data are kept consistent between the two.

Public function libraries

The library headers can be found under assets -> internal -> chunks -> common folder in different categories.

The functions in the library do not depend on any internal data (engine related uniform, mapping, etc.) and can be used directly as tool functions.

Surface already automatically contains common public function headers internally, which can be classified according to type as:

Folder Name	Function Usage
color	color-related functions (color space, tonemapping, etc.)
data	Data-related functions (compression and decompression, etc.)
debug	Debug View-related functions
effect	Scene effect-related functions (water, fog, etc.)
lighting	lighting-related features (brdf, bsdf, attenuation, baking, etc.)
math	math library (coordinate transformation, numerical determination and operation, etc.)
mesh	model-related functions (material conversion, model animation, etc.)
shadow	shadow-related functions (pcf, hcs, etc.)
texture	mapping-related functions (sampling, mip calculation, etc.)

[^1]: Custom GPU geometry instancing properties are not supported.