CVOpenGLTexture Reference

Derived from	CVImageBuffer Reference: CVBuffer Reference: CFType Reference
Framework	System/Library/Frameworks/QuartzCore.framework
Companion guide	Core Video Programming Guide
Declared in	CVOpenGLTexture.h

Overview

In Core Video, you manipulate OpenGL textures using the CVOpenGLTexture opaque type. This type serves as a wrapper around the standard OpenGL texture type. An OpenGL texture is stored in video memory. You output OpenGL textures to the screen in response to the display link callback. For more information on the display link callback, see CVDisplayLinkOutputCallback.

Functions

CVOpenGLTextureGetCleanTexCoords

Returns the texture coordinates for the part of the image that should be displayed.

void CVOpenGLTextureGetCleanTexCoords (
   CVOpenGLTextureRef image,
   GLfloat lowerLeft[2],
   GLfloat lowerRight[2],
   GLfloat upperRight[2],
   GLfloat upperLeft[2]
);

Parameters

image: The Core Video OpenGL texture whose clean tex coordinates you want to obtain.
lowerLeft: On output, the GLFloat array holds the s and t texture coordinates of the lower-left corner of the image.
lowerRight: On output, the GLFloat array holds the s and t texture coordinates of the lower-right corner of the image.
upperRight: On output, the GLFloat array holds the s and t texture coordinates of the upper-right corner of the image.
upperLeft: On output, the GLFloat array holds the s and t texture coordinates of the upper-left corner of the image.

Discussion

This function automatically takes into account whether or not the texture is flipped.

Availability

Available in OS X v10.4 and later.

Related Sample Code

QTCoreVideo301

Declared In

CVOpenGLTexture.h

CVOpenGLTextureGetName

Returns the texture target name of a CoreVideo OpenGL texture.

GLuint CVOpenGLTextureGetName (
   CVOpenGLTextureRef image
);

Parameters

image: The Core Video OpenGL texture whose texture target name you want to obtain.

Return Value

The target name of the texture.

Discussion

See the OpenGL specification for more information about texture targets.

Availability

Available in OS X v10.4 and later.

Related Sample Code

Declared In

CVOpenGLTexture.h

CVOpenGLTextureGetTarget

Returns the texture target (for example, GL_TEXTURE_2D) of an OpenGL texture.

GLenum CVOpenGLTextureGetTarget (
   CVOpenGLTextureRef image
);

Parameters

image: The Core Video OpenGL texture whose target you want to obtain.

Return Value

The OpenGL texture target.

Discussion

See the OpenGL specification for more information about texture targets.

Availability

Available in OS X v10.4 and later.

Related Sample Code

Declared In

CVOpenGLTexture.h

CVOpenGLTextureGetTypeID

Obtains the Core Foundation ID for the Core Video OpenGL texture type.

CFTypeID CVOpenGLTextureGetTypeID (
   void
);

Return Value

The Core Foundation ID for this type.

Availability

Available in OS X v10.4 and later.

Declared In

CVOpenGLTexture.h

CVOpenGLTextureIsFlipped

Determines whether an OpenGL texture is flipped vertically.

Boolean CVOpenGLTextureIsFlipped (
   CVOpenGLTextureRef image
);

Parameters

image: The Core Video OpenGL texture whose vertical orientation you want to determine.

Return Value

Returns true if (0,0) in the texture is in the upper-left corner, and false if (0,0) is in the lower-left corner.

Discussion

Quartz assumes a lower-left origin.

Availability

Available in OS X v10.4 and later.

Related Sample Code

Declared In

CVOpenGLTexture.h

CVOpenGLTextureRelease

Releases a Core Video OpenGL texture.

void CVOpenGLTextureRelease (
   CVOpenGLTextureRef texture
);

Parameters

texture: The Core Video OpenGL texture that you want to release.

Discussion

This function is equivalent to CFRelease, but is NULL safe.

Availability

Available in OS X v10.4 and later.

Related Sample Code

Declared In

CVOpenGLTexture.h

CVOpenGLTextureRetain

Retains a Core Video OpenGL texture.

CVOpenGLTextureRef CVOpenGLTextureRetain (
   CVOpenGLTextureRef texture
);

Parameters

texture: The Core Video OpenGL texture that you want to retain.

Return Value

For convenience, the Core Video OpenGL texture you want to retain.

Discussion

This function is equivalent to CFRetain, but is NULL safe.

Availability

Available in OS X v10.4 and later.

Related Sample Code

Declared In

CVOpenGLTexture.h

Data Types