GroupStrategy (gdx 1.12.1 API)

All Known Implementing Classes:

CameraGroupStrategy, PluggableGroupStrategy, SimpleOrthoGroupStrategy
```
public interface GroupStrategy
```
This class provides hooks which are invoked by DecalBatch to evaluate the group a sprite falls into, as well as to adjust settings before and after rendering a group.

A group is identified by an integer. The beforeGroup() method provides the strategy with a list of all the decals, which are contained in the group itself, and will be rendered before the associated call to afterGroup(int).
A call to beforeGroup() is always followed by a call to afterGroup().
Groups are always invoked based on their ascending int values. Group -10 will be rendered before group -5, group -5 before group 0, group 0 before group 6 and so on.
The call order for a single flush is always beforeGroups(), beforeGroup1(), afterGroup1(), ... beforeGroupN(), afterGroupN(), afterGroups().

The contents of the beforeGroup() call can be modified at will to realize view frustum culling, material & depth sorting, ... all based on the requirements of the current group. The batch itself does not change OpenGL settings except for whichever changes are entailed DecalMaterial.set(). If the group requires a special shader, blending, getGroupShader(int) should return it so that DecalBatch can apply it while rendering the group.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`afterGroup(int group)`	Invoked directly after rendering of a group has completed
`void`	`afterGroups()`	Invoked after having rendered all groups
`void`	`beforeGroup(int group, Array<Decal> contents)`	Invoked directly before rendering the contents of a group
`void`	`beforeGroups()`	Invoked before rendering any group
`int`	`decideGroup(Decal decal)`	Assigns a group to a decal
`ShaderProgram`	`getGroupShader(int group)`	Returns the shader to be used for the group.

- Method Detail
  - getGroupShader
```
ShaderProgram getGroupShader(int group)
```
    Returns the shader to be used for the group. Can be null in which case the GroupStrategy doesn't support GLES 2.0
    
    Parameters:
    
    group - the group
    
    Returns:
    
    the ShaderProgram
  - decideGroup
```
int decideGroup(Decal decal)
```
    Assigns a group to a decal
    
    Parameters:
    
    decal - Decal to assign group to
    
    Returns:
    
    group assigned
  - beforeGroup
```
void beforeGroup(int group,
                 Array<Decal> contents)
```
    Invoked directly before rendering the contents of a group
    
    Parameters:
    
    group - Group that will be rendered
    
    contents - Array of entries of arrays containing all the decals in the group
  - afterGroup
```
void afterGroup(int group)
```
    Invoked directly after rendering of a group has completed
    
    Parameters:
    
    group - Group which completed rendering
  - beforeGroups
```
void beforeGroups()
```
    Invoked before rendering any group
  - afterGroups
```
void afterGroups()
```
    Invoked after having rendered all groups