DrawContext (NASA WorldWind Android)

java.lang.Object
- gov.nasa.worldwind.draw.DrawContext

public class DrawContext
extends java.lang.Object

Field Summary

Fields
Modifier and Type	Field and Description
`DrawableQueue`	`drawableQueue`
`DrawableQueue`	`drawableTerrain`
`Vec3`	`eyePoint`
`Matrix4`	`infiniteProjection`
`Matrix4`	`modelview`
`Matrix4`	`modelviewProjection`
`PickedObjectList`	`pickedObjects`
`boolean`	`pickMode`
`Vec2`	`pickPoint`
`Viewport`	`pickViewport`
`Matrix4`	`projection`
`Matrix4`	`screenProjection`
`Viewport`	`viewport`

Constructor Summary

Constructors
Constructor and Description

DrawContext()

Constructors
Constructor and Description
`DrawContext()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`activeTextureUnit(int textureUnit)` Specifies the OpenGL multitexture unit to make active.
`void`	`bindBuffer(int target, int bufferId)` Makes an OpenGL buffer object bound to a specified target buffer.
`void`	`bindFramebuffer(int framebufferId)` Makes an OpenGL framebuffer object active.
`void`	`bindTexture(int textureId)` Makes an OpenGL texture 2D object bound to the current multitexture unit.
`void`	`contextLost()`
`int`	`currentBuffer(int target)` Returns the name of the OpenGL buffer object bound to the specified target buffer.
`int`	`currentFramebuffer()` Returns the name of the OpenGL framebuffer object that is currently active.
`int`	`currentProgram()` Returns the name of the OpenGL program object that is currently active.
`int`	`currentTexture()` Returns the name of the OpenGL texture 2D object currently bound to the active multitexture unit.
`int`	`currentTexture(int textureUnit)` Returns the name of the OpenGL texture 2D object currently bound to the specified multitexture unit.
`int`	`currentTextureUnit()` Returns the OpenGL multitexture unit that is currently active.
`DrawableTerrain`	`getDrawableTerrain(int index)`
`int`	`getDrawableTerrainCount()`
`Drawable`	`peekDrawable()`
`Drawable`	`pollDrawable()`
`Color`	`readPixelColor(int x, int y, Color result)` Reads the fragment color at a screen point in the currently active OpenGL frame buffer.
`java.util.Set<Color>`	`readPixelColors(int x, int y, int width, int height)` Reads the unique fragment colors within a screen rectangle in the currently active OpenGL frame buffer.
`void`	`reset()`
`void`	`rewindDrawables()`
`java.nio.ByteBuffer`	`scratchBuffer(int capacity)` Returns a scratch NIO buffer suitable for use during drawing.
`Framebuffer`	`scratchFramebuffer()` Returns an OpenGL framebuffer object suitable for offscreen drawing.
`java.util.ArrayList<java.lang.Object>`	`scratchList()` Returns a scratch list suitable for accumulating entries during drawing.
`BufferObject`	`unitSquareBuffer()` Returns an OpenGL buffer object containing a unit square expressed as four vertices at (0, 1), (0, 0), (1, 1) and (1, 0).
`void`	`useProgram(int programId)` Makes an OpenGL program object active as part of current rendering state.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - eyePoint
```
public Vec3 eyePoint
```
  - viewport
```
public Viewport viewport
```
  - projection
```
public Matrix4 projection
```
  - modelview
```
public Matrix4 modelview
```
  - modelviewProjection
```
public Matrix4 modelviewProjection
```
  - infiniteProjection
```
public Matrix4 infiniteProjection
```
  - screenProjection
```
public Matrix4 screenProjection
```
  - drawableQueue
```
public DrawableQueue drawableQueue
```
  - drawableTerrain
```
public DrawableQueue drawableTerrain
```
  - pickedObjects
```
public PickedObjectList pickedObjects
```
  - pickViewport
```
public Viewport pickViewport
```
  - pickPoint
```
public Vec2 pickPoint
```
  - pickMode
```
public boolean pickMode
```
- Constructor Detail
  - DrawContext
```
public DrawContext()
```
- Method Detail
  - reset
```
public void reset()
```
  - contextLost
```
public void contextLost()
```
  - peekDrawable
```
public Drawable peekDrawable()
```
  - pollDrawable
```
public Drawable pollDrawable()
```
  - rewindDrawables
```
public void rewindDrawables()
```
  - getDrawableTerrainCount
```
public int getDrawableTerrainCount()
```
  - getDrawableTerrain
```
public DrawableTerrain getDrawableTerrain(int index)
```
  - currentFramebuffer
```
public int currentFramebuffer()
```
    Returns the name of the OpenGL framebuffer object that is currently active.
    
    Returns:
    
    the currently active framebuffer object, or 0 if no framebuffer object is active
  - bindFramebuffer
```
public void bindFramebuffer(int framebufferId)
```
    Makes an OpenGL framebuffer object active. The active framebuffer becomes the target of all OpenGL commands that render to the framebuffer or read from the framebuffer. This has no effect if the specified framebuffer object is already active. The default is framebuffer 0, indicating that the default framebuffer provided by the windowing system is active.
    
    Parameters:
    
    framebufferId - the name of the OpenGL framebuffer object to make active, or 0 to make the default framebuffer provided by the windowing system active
  - scratchFramebuffer
```
public Framebuffer scratchFramebuffer()
```
    Returns an OpenGL framebuffer object suitable for offscreen drawing. The framebuffer has a 32-bit color buffer and a 32-bit depth buffer, both attached as OpenGL texture 2D objects.
    The framebuffer may be used by any drawable and for any purpose. However, the draw context makes no guarantees about the framebuffer's contents. Drawables must clear the framebuffer before use, and must assume its contents may be modified by another drawable, either during the current frame or in a subsequent frame.
    The OpenGL framebuffer object is created on first use and cached. Subsequent calls to this method return the cached buffer object.
    
    Returns:
    
    the draw context's scratch OpenGL framebuffer object
  - currentProgram
```
public int currentProgram()
```
    Returns the name of the OpenGL program object that is currently active.
    
    Returns:
    
    the currently active program object, or 0 if no program object is active
  - useProgram
```
public void useProgram(int programId)
```
    Makes an OpenGL program object active as part of current rendering state. This has no effect if the specified program object is already active. The default is program 0, indicating that no program is active.
    
    Parameters:
    
    programId - the name of the OpenGL program object to make active, or 0 to make no program active
  - currentTextureUnit
```
public int currentTextureUnit()
```
    Returns the OpenGL multitexture unit that is currently active. Returns a value from the GL_TEXTUREi enumeration, where i ranges from 0 to 32.
    
    Returns:
    
    the currently active multitexture unit.
  - activeTextureUnit
```
public void activeTextureUnit(int textureUnit)
```
    Specifies the OpenGL multitexture unit to make active. This has no effect if the specified multitexture unit is already active. The default is GL_TEXTURE0.
    
    Parameters:
    
    textureUnit - the multitexture unit, one of GL_TEXTUREi, where i ranges from 0 to 32.
  - currentTexture
```
public int currentTexture()
```
    Returns the name of the OpenGL texture 2D object currently bound to the active multitexture unit. The active multitexture unit may be determined by calling currentTextureUnit.
    
    Returns:
    
    the currently bound texture 2D object, or 0 if no texture object is bound
  - currentTexture
```
public int currentTexture(int textureUnit)
```
    Returns the name of the OpenGL texture 2D object currently bound to the specified multitexture unit.
    
    Parameters:
    
    textureUnit - the multitexture unit, one of GL_TEXTUREi, where i ranges from 0 to 32.
    
    Returns:
    
    the currently bound texture 2D object, or 0 if no texture object is bound
  - bindTexture
```
public void bindTexture(int textureId)
```
    Makes an OpenGL texture 2D object bound to the current multitexture unit. This has no effect if the specified texture object is already bound. The default is texture 0, indicating that no texture is bound.
    
    Parameters:
    
    textureId - the name of the OpenGL texture 2D object to make active, or 0 to make no texture active
  - currentBuffer
```
public int currentBuffer(int target)
```
    Returns the name of the OpenGL buffer object bound to the specified target buffer.
    
    Parameters:
    
    target - the target buffer, either GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER
    
    Returns:
    
    the currently bound buffer object, or 0 if no buffer object is bound
  - bindBuffer
```
public void bindBuffer(int target,
                       int bufferId)
```
    Makes an OpenGL buffer object bound to a specified target buffer. This has no effect if the specified buffer object is already bound. The default is buffer 0, indicating that no buffer object is bound.
    
    Parameters:
    
    target - the target buffer, either GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER
    
    bufferId - the name of the OpenGL buffer object to make active
  - unitSquareBuffer
```
public BufferObject unitSquareBuffer()
```
    Returns an OpenGL buffer object containing a unit square expressed as four vertices at (0, 1), (0, 0), (1, 1) and (1, 0). Each vertex is stored as two 32-bit floating point coordinates. The four vertices are in the order required by a triangle strip.
    The OpenGL buffer object is created on first use and cached. Subsequent calls to this method return the cached buffer object.
    
    Returns:
    
    the draw context's unit square OpenGL buffer object
  - readPixelColor
```
public Color readPixelColor(int x,
                            int y,
                            Color result)
```
    Reads the fragment color at a screen point in the currently active OpenGL frame buffer. The X and Y components indicate OpenGL screen coordinates, which originate in the frame buffer's lower left corner.
    
    Parameters:
    
    x - the screen point's X component
    
    y - the screen point's Y component
    
    result - an optional pre-allocated Color in which to return the fragment color, or null to return a new color
    
    Returns:
    
    the result argument set to the fragment color, or a new color if the result is null
  - readPixelColors
```
public java.util.Set<Color> readPixelColors(int x,
                                            int y,
                                            int width,
                                            int height)
```
    Reads the unique fragment colors within a screen rectangle in the currently active OpenGL frame buffer. The components indicate OpenGL screen coordinates, which originate in the frame buffer's lower left corner.
    
    Parameters:
    
    x - the screen rectangle's X component
    
    y - the screen rectangle's Y component
    
    width - the screen rectangle's width
    
    height - the screen rectangle's height
    
    Returns:
    
    a set containing the unique fragment colors
  - scratchBuffer
```
public java.nio.ByteBuffer scratchBuffer(int capacity)
```
    Returns a scratch NIO buffer suitable for use during drawing. The returned buffer has capacity at least equal to the specified capacity. The buffer is cleared before each frame, otherwise its contents, position, limit and mark are undefined.
    
    Parameters:
    
    capacity - the buffer's minimum capacity in bytes
    
    Returns:
    
    the draw context's scratch buffer
  - scratchList
```
public java.util.ArrayList<java.lang.Object> scratchList()
```
    Returns a scratch list suitable for accumulating entries during drawing. The list is cleared before each frame, otherwise its contents are undefined.
    
    Returns:
    
    the draw context's scratch list

Class DrawContext

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

eyePoint

viewport

projection

modelview

modelviewProjection

infiniteProjection

screenProjection

drawableQueue

drawableTerrain

pickedObjects

pickViewport

pickPoint

pickMode

Constructor Detail

DrawContext

Method Detail

reset

contextLost

peekDrawable

pollDrawable

rewindDrawables

getDrawableTerrainCount

getDrawableTerrain

currentFramebuffer

bindFramebuffer

scratchFramebuffer

currentProgram

useProgram

currentTextureUnit

activeTextureUnit

currentTexture

currentTexture

bindTexture

currentBuffer

bindBuffer

unitSquareBuffer

readPixelColor

readPixelColors

scratchBuffer

scratchList