Game Development Reference
In-Depth Information
#pragma surface
The
#pragma surface
directive is used as follows:
#pragma surface surfaceFunction lightModel [optionalparams]
The required parameters to use this directive are as follows:
•
surfaceFunction
: This is used to define which Cg function has the surface
shader code. The function should have the form of
void surf (Input IN,
inout SurfaceOutput o)
, where
Input
is a structure you have defined.
Input
should contain any texture coordinates and extra automatic variables
needed by surface function.
•
lightModel
: This is used to define a lighting model to be used. The built-in
models are
Lambert
(diffuse) and
BlinnPhong
(specular). You can also write your
own lighting model using the following custom lighting models:
◦
half4 LightingName (SurfaceOutput s, half3
lightDir, half atten);
: This is used in forward rendering the
path for light models that are not view-direction dependent (for example,
diffuse)
◦
half4 LightingName (SurfaceOutput s, half3
lightDir, half3 viewDir, half atten);
: This is used in
forward rendering path for light models that are view-direction dependent
◦
half4 LightingName_PrePass (SurfaceOutput s, half4
light);
: This is used in the deferred lighting path.
Tip
Note that you don't need to declare all functions. A lighting model either uses view direc-
tion or it does not. Similarly, if the lighting model does not work in deferred lighting, you
just do not declare the
_PrePass
function, and all shaders that use it will compile to for-
ward rendering only, such as the shader that we created in
Project 3
,
Shade Your Hero/
Heroine
. We don't need the
_PrePass
function because our shader needs the view direc-
tion (
viewDir
) and the light direction (
lightDir
) for our custom lighting function to
calculate the ramp effect for the cartoon style shader (toon shader / cel shader), which is
only available in forward rendering.
Optional parameters
[optionalparams]
to use
#pragma surface
are listed in the
following table:
