Fragment Shader Input

Built-in Input Variables

Many parameters have been passed from Vertex Shader to Fragment Shader, listed below.

Fragment Shader Input	Type	Needed Macros	Meaning
FSInput_worldPos	vec3	N/A	World Position
FSInput_worldNormal	vec3	N/A	World Normal
FSInput_faceSideSign	float	N/A	Two Side Sign be used for double-sided materials
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
FSInput_clipPos	vec4	CC_SURFACES_TRANSFER_CLIP_POS	Clip Position

Macro Switch

When you need to use input parameters with macro switches, you need to enable the corresponding macros in the macro-remapping code section. Here's an example.

CCProgram macro-remapping %{
    ...
    //Enable FSInput_localPos
    #define CC_SURFACES_TRANSFER_LOCAL_POS 1
    //Enable FSInput_clipPos
    #define CC_SURFACES_TRANSFER_CLIP_POS 1
    ...
}

How to use

Directly call them in your shader code.

Customize Varying Variables

When creating some special effects, the Vertex Shader must pass more information to the Fragment Shader. At this time, we need to add new varying variables.

Adding a new custom varying variable is quite simple. We will use the example of adding a new variable called testVec3.

First, declare a variable with an out tag in the Vertex Shader, as shown in the following example.

CCProgram surface-vertex %{
    ...
    out vec3 testVec3;
    ...
}

Then declare a corresponding variable with an in tag in the Fragment Shader, as shown below.

CCProgram surface-fragment %{
    ...
    in vec3 testVec3;
    ...
}

After that, you can use testVec3 in the code of the Fragment Shader.