org.lwjgl.opengles

Class KHRRobustness

java.lang.Object

org.lwjgl.opengles.KHRRobustness

public class KHRRobustness
extends java.lang.Object

Native bindings to the KHR_robustness extension.

Several recent trends in how OpenGL ES integrates into modern computer systems have created new requirements for robustness and security for GL rendering contexts.

Additionally GPU architectures now support hardware fault detection; for example, video memory supporting ECC (error correcting codes) and error detection. GL contexts should be capable of recovering from hardware faults such as uncorrectable memory errors. Along with recovery from such hardware faults, the recovery mechanism can also allow recovery from video memory access exceptions and system software failures. System software failures can be due to device changes or driver failures.

GL queries that return (write) some number of bytes to a buffer indicated by a pointer parameter introduce risk of buffer overflows that might be exploitable by malware. To address this, queries with return value sizes that are not expressed directly by the parameters to the query itself are given additional API functions with an additional parameter that specifies the number of bytes in the buffer and never writing bytes beyond that limit. This is particularly useful for multi-threaded usage of GL contexts in a "share group" where one context can change objects in ways that can cause buffer overflows for another context's GL queries.

The original ARB_vertex_buffer_object extension includes an issue that explicitly states program termination is allowed when out-of-bounds vertex buffer object fetches occur. Modern graphics hardware is capable of well-defined behavior in the case of out-of- bounds vertex buffer object fetches. Older hardware may require extra checks to enforce well-defined (and termination free) behavior, but this expense is warranted when processing potentially untrusted content.

The intent of this extension is to address some specific robustness goals:

• For all existing GL queries, provide additional "safe" APIs that limit data written to user pointers to a buffer size in bytes that is an explicit additional parameter of the query.
• Provide a mechanism for a GL application to learn about graphics resets that affect the context. When a graphics reset occurs, the GL context becomes unusable and the application must create a new context to continue operation. Detecting a graphics reset happens through an inexpensive query.
• Define behavior of OpenGL calls made after a graphics reset.
• Provide an enable to guarantee that out-of-bounds buffer object accesses by the GPU will have deterministic behavior and preclude application instability or termination due to an incorrect buffer access. Such accesses include vertex buffer fetches of attributes and indices, and indexed reads of uniforms or parameters from buffers.

Requires GLES 2.0.

Field Summary

Fields

Modifier and Type	Field and Description
static int	GL_CONTEXT_LOST_KHR Returned by GetError.
static int	GL_CONTEXT_ROBUST_ACCESS_KHR Accepted by the value parameter of GetBooleanv, GetIntegerv, and GetFloatv.
static int	GL_GUILTY_CONTEXT_RESET_KHR Returned by GetGraphicsResetStatusKHR.
static int	GL_INNOCENT_CONTEXT_RESET_KHR Returned by GetGraphicsResetStatusKHR.
static int	GL_LOSE_CONTEXT_ON_RESET_KHR Returned by GetIntegerv and related simple queries when value is RESET_NOTIFICATION_STRATEGY_KHR.
static int	GL_NO_RESET_NOTIFICATION_KHR Returned by GetIntegerv and related simple queries when value is RESET_NOTIFICATION_STRATEGY_KHR.
static int	GL_RESET_NOTIFICATION_STRATEGY_KHR Accepted by the value parameter of GetBooleanv, GetIntegerv, and GetFloatv.
static int	GL_UNKNOWN_CONTEXT_RESET_KHR Returned by GetGraphicsResetStatusKHR.

Method Summary

Modifier and Type	Method and Description
static int	glGetGraphicsResetStatusKHR() Indicates if the GL context has been in a reset state at any point since the last call to GetGraphicsResetStatus: NO_ERROR indicates that the GL context has not been in a reset state since the last call. GUILTY_CONTEXT_RESET_KHR indicates that a reset has been detected that is attributable to the current GL context. INNOCENT_CONTEXT_RESET_KHR indicates a reset has been detected that is not attributable to the current GL context. UNKNOWN_CONTEXT_RESET_KHR indicates a detected graphics reset whose cause is unknown.
static float	glGetnUniformfKHR(int program, int location) Returns the value or values of a uniform of the default uniform block.
static void	glGetnUniformfvKHR(int program, int location, float[] params) Array version of: GetnUniformfvKHR
static void	glGetnUniformfvKHR(int program, int location, java.nio.FloatBuffer params) Returns the value or values of a uniform of the default uniform block.
static float	glGetnUniformiKHR(int program, int location) Integer version of GetnUniformfvKHR.
static void	glGetnUniformivKHR(int program, int location, float[] params) Array version of: GetnUniformivKHR
static void	glGetnUniformivKHR(int program, int location, java.nio.FloatBuffer params) Integer version of GetnUniformfvKHR.
static float	glGetnUniformuiKHR(int program, int location) Unsigned version of GetnUniformivKHR.
static void	glGetnUniformuivKHR(int program, int location, float[] params) Array version of: GetnUniformuivKHR
static void	glGetnUniformuivKHR(int program, int location, java.nio.FloatBuffer params) Unsigned version of GetnUniformivKHR.
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, java.nio.ByteBuffer pixels) Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, float[] pixels) Array version of: ReadnPixelsKHR
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, java.nio.FloatBuffer pixels) Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, int[] pixels) Array version of: ReadnPixelsKHR
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, java.nio.IntBuffer pixels) Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, int bufSize, long pixels) Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, short[] pixels) Array version of: ReadnPixelsKHR
static void	glReadnPixelsKHR(int x, int y, int width, int height, int format, int type, java.nio.ShortBuffer pixels) Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data
static void	nglGetnUniformfvKHR(int program, int location, int bufSize, long params) Unsafe version of: GetnUniformfvKHR
static void	nglGetnUniformivKHR(int program, int location, int bufSize, long params) Unsafe version of: GetnUniformivKHR
static void	nglGetnUniformuivKHR(int program, int location, int bufSize, long params) Unsafe version of: GetnUniformuivKHR
static void	nglReadnPixelsKHR(int x, int y, int width, int height, int format, int type, int bufSize, long pixels) Unsafe version of: ReadnPixelsKHR

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GL_GUILTY_CONTEXT_RESET_KHR

public static final int GL_GUILTY_CONTEXT_RESET_KHR

Returned by GetGraphicsResetStatusKHR.

See Also:

Constant Field Values

GL_INNOCENT_CONTEXT_RESET_KHR

public static final int GL_INNOCENT_CONTEXT_RESET_KHR

Returned by GetGraphicsResetStatusKHR.

See Also:

Constant Field Values

GL_UNKNOWN_CONTEXT_RESET_KHR

public static final int GL_UNKNOWN_CONTEXT_RESET_KHR

Returned by GetGraphicsResetStatusKHR.

See Also:

Constant Field Values

GL_CONTEXT_ROBUST_ACCESS_KHR

public static final int GL_CONTEXT_ROBUST_ACCESS_KHR

Accepted by the value parameter of GetBooleanv, GetIntegerv, and GetFloatv.

See Also:

Constant Field Values

GL_RESET_NOTIFICATION_STRATEGY_KHR

public static final int GL_RESET_NOTIFICATION_STRATEGY_KHR

Accepted by the value parameter of GetBooleanv, GetIntegerv, and GetFloatv.

See Also:

Constant Field Values

GL_LOSE_CONTEXT_ON_RESET_KHR

public static final int GL_LOSE_CONTEXT_ON_RESET_KHR

Returned by GetIntegerv and related simple queries when value is RESET_NOTIFICATION_STRATEGY_KHR.

See Also:

Constant Field Values

GL_NO_RESET_NOTIFICATION_KHR

public static final int GL_NO_RESET_NOTIFICATION_KHR

Returned by GetIntegerv and related simple queries when value is RESET_NOTIFICATION_STRATEGY_KHR.

See Also:

Constant Field Values

GL_CONTEXT_LOST_KHR

public static final int GL_CONTEXT_LOST_KHR

Returned by GetError.

See Also:

Constant Field Values

Method Detail

glGetGraphicsResetStatusKHR

public static int glGetGraphicsResetStatusKHR()

Indicates if the GL context has been in a reset state at any point since the last call to GetGraphicsResetStatus:

• NO_ERROR indicates that the GL context has not been in a reset state since the last call.
• GUILTY_CONTEXT_RESET_KHR indicates that a reset has been detected that is attributable to the current GL context.
• INNOCENT_CONTEXT_RESET_KHR indicates a reset has been detected that is not attributable to the current GL context.
• UNKNOWN_CONTEXT_RESET_KHR indicates a detected graphics reset whose cause is unknown.

If a reset status other than NO_ERROR is returned and subsequent calls return NO_ERROR, the context reset was encountered and completed. If a reset status is repeatedly returned, the context may be in the process of resetting.

Reset notification behavior is determined at context creation time, and may be queried by calling GetIntegerv with the symbolic constant RESET_NOTIFICATION_STRATEGY_KHR.

If the reset notification behavior is NO_RESET_NOTIFICATION_KHR, then the implementation will never deliver notification of reset events, and GetGraphicsResetStatus will always return NO_ERROR.

If the behavior is LOSE_CONTEXT_ON_RESET_KHR, a graphics reset will result in a lost context and require creating a new context as described above. In this case GetGraphicsResetStatus will return an appropriate value from those described above.

If a graphics reset notification occurs in a context, a notification must also occur in all other contexts which share objects with that context.

After a graphics reset has occurred on a context, subsequent GL commands on that context (or any context which shares with that context) will generate a CONTEXT_LOST_KHR error. Such commands will not have side effects (in particular, they will not modify memory passed by pointer for query results, and may not block indefinitely or cause termination of the application. Exceptions to this behavior include:

• GetError and GetGraphicsResetStatusKHR behave normally following a graphics reset, so that the application can determine a reset has occurred, and when it is safe to destroy and recreate the context.
• Any commands which might cause a polling application to block indefinitely will generate a CONTEXT_LOST_KHR error, but will also return a value indicating completion to the application.

nglReadnPixelsKHR

public static void nglReadnPixelsKHR(int x,
                                     int y,
                                     int width,
                                     int height,
                                     int format,
                                     int type,
                                     int bufSize,
                                     long pixels)

Unsafe version of: ReadnPixelsKHR

Parameters:

bufSize - the maximum number of bytes to write into data

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    int bufSize,
                                    long pixels)

Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data

Parameters:

x - the left pixel coordinate

y - the lower pixel coordinate

width - the number of pixels to read in the x-dimension

height - the number of pixels to read in the y-dimension

format - the pixel format

type - the pixel type

bufSize - the maximum number of bytes to write into data

pixels - a buffer in which to place the returned pixel data

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    java.nio.ByteBuffer pixels)

Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data

Parameters:

x - the left pixel coordinate

y - the lower pixel coordinate

width - the number of pixels to read in the x-dimension

height - the number of pixels to read in the y-dimension

format - the pixel format

type - the pixel type

pixels - a buffer in which to place the returned pixel data

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    java.nio.ShortBuffer pixels)

Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data

Parameters:

x - the left pixel coordinate

y - the lower pixel coordinate

width - the number of pixels to read in the x-dimension

height - the number of pixels to read in the y-dimension

format - the pixel format

type - the pixel type

pixels - a buffer in which to place the returned pixel data

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    java.nio.IntBuffer pixels)

Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data

Parameters:

x - the left pixel coordinate

y - the lower pixel coordinate

width - the number of pixels to read in the x-dimension

height - the number of pixels to read in the y-dimension

format - the pixel format

type - the pixel type

pixels - a buffer in which to place the returned pixel data

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    java.nio.FloatBuffer pixels)

Behaves identically to ReadPixels except that it does not write more than bufSize bytes into data

Parameters:

x - the left pixel coordinate

y - the lower pixel coordinate

width - the number of pixels to read in the x-dimension

height - the number of pixels to read in the y-dimension

format - the pixel format

type - the pixel type

pixels - a buffer in which to place the returned pixel data

nglGetnUniformfvKHR

public static void nglGetnUniformfvKHR(int program,
                                       int location,
                                       int bufSize,
                                       long params)

Unsafe version of: GetnUniformfvKHR

Parameters:

bufSize - the maximum number of bytes to write to params

glGetnUniformfvKHR

public static void glGetnUniformfvKHR(int program,
                                      int location,
                                      java.nio.FloatBuffer params)

Returns the value or values of a uniform of the default uniform block.

Parameters:

program - the program object

location - the uniform location

params - the buffer in which to place the returned data

glGetnUniformfKHR

public static float glGetnUniformfKHR(int program,
                                      int location)

Returns the value or values of a uniform of the default uniform block.

Parameters:

program - the program object

location - the uniform location

nglGetnUniformivKHR

public static void nglGetnUniformivKHR(int program,
                                       int location,
                                       int bufSize,
                                       long params)

Unsafe version of: GetnUniformivKHR

Parameters:

bufSize - the maximum number of bytes to write to params

glGetnUniformivKHR

public static void glGetnUniformivKHR(int program,
                                      int location,
                                      java.nio.FloatBuffer params)

Integer version of GetnUniformfvKHR.

Parameters:

program - the program object

location - the uniform location

params - the buffer in which to place the returned data

glGetnUniformiKHR

public static float glGetnUniformiKHR(int program,
                                      int location)

Integer version of GetnUniformfvKHR.

Parameters:

program - the program object

location - the uniform location

nglGetnUniformuivKHR

public static void nglGetnUniformuivKHR(int program,
                                        int location,
                                        int bufSize,
                                        long params)

Unsafe version of: GetnUniformuivKHR

Parameters:

bufSize - the maximum number of bytes to write to params

glGetnUniformuivKHR

public static void glGetnUniformuivKHR(int program,
                                       int location,
                                       java.nio.FloatBuffer params)

Unsigned version of GetnUniformivKHR.

Parameters:

program - the program object

location - the uniform location

params - the buffer in which to place the returned data

glGetnUniformuiKHR

public static float glGetnUniformuiKHR(int program,
                                       int location)

Unsigned version of GetnUniformivKHR.

Parameters:

program - the program object

location - the uniform location

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    short[] pixels)

Array version of: ReadnPixelsKHR

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    int[] pixels)

Array version of: ReadnPixelsKHR

glReadnPixelsKHR

public static void glReadnPixelsKHR(int x,
                                    int y,
                                    int width,
                                    int height,
                                    int format,
                                    int type,
                                    float[] pixels)

Array version of: ReadnPixelsKHR

glGetnUniformfvKHR

public static void glGetnUniformfvKHR(int program,
                                      int location,
                                      float[] params)

Array version of: GetnUniformfvKHR

glGetnUniformivKHR

public static void glGetnUniformivKHR(int program,
                                      int location,
                                      float[] params)

Array version of: GetnUniformivKHR

glGetnUniformuivKHR

public static void glGetnUniformuivKHR(int program,
                                       int location,
                                       float[] params)

Array version of: GetnUniformuivKHR