- Qt 6.8
- Qt 3D
- C++ Classes
- Qt3DExtras
- QGoochMaterial
- Qt 6.8.0 Reference Documentation

# QGoochMaterial Class

class Qt3DExtras::QGoochMaterial

The QGoochMaterial provides a material that implements the Gooch shading model, popular in CAD and CAM applications. More...

Header: | #include <QGoochMaterial>
CMake: | find_package(Qt6 REQUIRED COMPONENTS 3dextras) target_link_libraries(mytarget PRIVATE Qt6::3dextras)
qmake: | QT += 3dextras
Inherits: | Qt3DRender::QMaterial

- List of all members, including inherited members

## Properties

alpha : float beta : float cool : QColor diffuse : QColor | shininess : float specular : QColor warm : QColor

## Public Functions

| QGoochMaterial(Qt3DCore::QNode *parent = nullptr)
float | alpha() const
float | beta() const
QColor | cool() const
QColor | diffuse() const
float | shininess() const
QColor | specular() const
QColor | warm() const

## Public Slots

void | setAlpha(float alpha)
void | setBeta(float beta)
void | setCool(const QColor &cool)
void | setDiffuse(const QColor &diffuse)
void | setShininess(float shininess)
void | setSpecular(const QColor &specular)
void | setWarm(const QColor &warm)

## Signals

void | alphaChanged(float alpha)
void | betaChanged(float beta)
void | coolChanged(const QColor &cool)
void | diffuseChanged(const QColor &diffuse)
void | shininessChanged(float shininess)
void | specularChanged(const QColor &specular)
void | warmChanged(const QColor &warm)

## Detailed Description

The Gooch lighting model uses both color and brightness to help show the curvature of 3D surfaces. This is often better than models such as Phong that rely purely upon changes in brightness. In situations such as in CAD and CAM applications where photorealism is not a goal, the Gooch shading model in conjunction with some kind of silhouette edge inking is a popular solution.

The Gooch lighting model is explained fully in the original Gooch paper. The Gooch model mixes a diffuse object color with a user-provided cool color and warm color to produce the end points of a color ramp that is used to shade the object based upon the cosine of the angle between the vector from the fragment to the light source and the fragment's normal vector. Optionally, a specular highlight can be added on top. The relative contributions to the cool and warm colors by the diffuse color are controlled by the alpha and beta properties respecitvely.

This material uses an effect with a single render pass approach and performs per fragment lighting. Techniques are provided for OpenGL 2, OpenGL 3 or above as well as OpenGL ES 2.

## Property Documentation

### alpha : float

Holds the current alpha value. The start point of the color ramp used by the Gooch shader is calculated as {c = cool + alpha * diffuse}.

Access functions:

float | alpha() const
void | setAlpha(float alpha)

Notifier signal:

void | alphaChanged(float alpha)

### beta : float

Holds the current beta value. The start point of the color ramp used by the Gooch shader is calculated as {c = warm + beta * diffuse}.

Access functions:

float | beta() const
void | setBeta(float beta)

Notifier signal:

void | betaChanged(float beta)

### cool : QColor

Holds the current cool color.

Access functions:

QColor | cool() const
void | setCool(const QColor &cool)

Notifier signal:

void | coolChanged(const QColor &cool)

### diffuse : QColor

Holds the current diffuse color.

Access functions:

QColor | diffuse() const
void | setDiffuse(const QColor &diffuse)

Notifier signal:

void | diffuseChanged(const QColor &diffuse)

### shininess : float

Holds the current shininess value. Higher values of shininess result in a smaller and brighter highlight.

Access functions:

float | shininess() const
void | setShininess(float shininess)

Notifier signal:

void | shininessChanged(float shininess)

### specular : QColor

Holds the current specular color.

Access functions:

QColor | specular() const
void | setSpecular(const QColor &specular)

Notifier signal:

void | specularChanged(const QColor &specular)

### warm : QColor

Holds the current warm color.

Access functions:

QColor | warm() const
void | setWarm(const QColor &warm)

Notifier signal:

void | warmChanged(const QColor &warm)

## Member Function Documentation

### `[explicit]` QGoochMaterial::QGoochMaterial(Qt3DCore::QNode *parent = nullptr)

Constructs a new QGoochMaterial instance with parent object parent.