Vuo  1.2.5
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Properties Friends Macros Groups Pages
Classes | Typedefs | Functions

Description

An image residing in GPU memory (GL Texture Object).

Classes

struct  _VuoImage
 An image residing in GPU memory (GL Texture Object), with an optional CPU copy. More...
 

Typedefs

typedef struct _VuoImageVuoImage
 An image residing in GPU memory (GL Texture Object).
 
typedef void(* VuoImage_freeCallback )(VuoImage imageToFree)
 A callback to be implemented if non-Vuo code needs to retain ownership of the GL texture (instead of the default behavior where VuoImage takes ownership of the texture).
 

Functions

VuoImage VuoImage_get (const char *imageURL)
 Retrieves the image at the specified imageURL, and creates a VuoImage from it.
 
void VuoImage_free (void *texture)
 Decrements the retain count of the OpenGL Texture Object associated with the specified VuoImage, and frees the texture VuoImage struct.
 
VuoImage VuoImage_make (unsigned int glTextureName, unsigned int glInternalFormat, unsigned long int pixelsWide, unsigned long int pixelsHigh)
 Returns a new VuoImage structure representing the specified glTextureName.
 
VuoImage VuoImage_makeClientOwned (unsigned int glTextureName, unsigned int glInternalFormat, unsigned long int pixelsWide, unsigned long int pixelsHigh, VuoImage_freeCallback freeCallback, void *freeCallbackContext)
 Returns a new VuoImage structure representing the specified glTextureName.
 
VuoImage VuoImage_makeClientOwnedGlTextureRectangle (unsigned int glTextureName, unsigned int glInternalFormat, unsigned long int pixelsWide, unsigned long int pixelsHigh, VuoImage_freeCallback freeCallback, void *freeCallbackContext)
 Returns a new VuoImage structure representing the specified glTextureName.
 
VuoImage VuoImage_makeFromBuffer (const void *pixels, unsigned int format, unsigned int pixelsWide, unsigned int pixelsHigh, VuoImageColorDepth colorDepth, void(^freeCallback)(void *pixels))
 Uploads the specified pixel data to the GPU and returns a new VuoImage referencing it.
 
VuoImage VuoImage_makeFromJson (json_object *js)
 Decodes the JSON object js to create a new value.
 
json_objectVuoImage_getJson (const VuoImage value)
 Encodes value as a JSON object.
 
json_objectVuoImage_getInterprocessJson (const VuoImage value)
 Returns a JSON object containing an interprocess handle for the specified texture.
 
char * VuoImage_getSummary (const VuoImage value)
 A brief summary of the contents of this texture.
 
VuoImage VuoImage_makeFromBufferWithStride (const void *pixels, unsigned int format, unsigned int pixelsWide, unsigned int pixelsHigh, unsigned int bytesPerRow, VuoImageColorDepth colorDepth, void(^freeCallback)(void *pixels)) __attribute__((nonnull(1)))
 Same as VuoImage_makeFromBuffer, but accepts a nonstandard stride (bytesPerRow).
 
VuoImage VuoImage_makeColorImage (VuoColor color, unsigned int pixelsWide, unsigned int pixelsHigh)
 Makes a solid-color image.
 
VuoImage VuoImage_makeCopy (VuoImage image, bool flip)
 Returns a new texture copy of the passed image.
 
VuoImage VuoImage_makeGlTextureRectangleCopy (VuoImage image)
 Copies image to a new GL_TEXTURE_RECTANGLE_ARB texture.
 
const unsigned char * VuoImage_getBuffer (VuoImage image, unsigned int requestedFormat)
 Downloads the specified image's pixel data from the GPU to the CPU (or returns it from a cache), and returns the CPU memory buffer.
 
VuoImageWrapMode VuoImage_getWrapMode (VuoImage image)
 Returns the image's wrap mode.
 
void VuoImage_setWrapMode (VuoImage image, VuoImageWrapMode wrapMode)
 Changes the image's wrap mode.
 
VuoImage VuoImage_mapColors (VuoImage image, VuoList_VuoColor colors, VuoReal filterOpacity)
 Returns a color-mapped copy of image.
 
bool VuoImage_areEqual (const VuoImage a, const VuoImage b)
 Returns true if both images have the same dimensions and the same RGBA pixel data.
 
bool VuoImage_areEqualWithinTolerance (const VuoImage a, const VuoImage b, const unsigned char tolerance)
 Like VuoImage_areEqual(), but permits color channel values to differ by up to tolerance.
 
bool VuoImage_isEmpty (const VuoImage image)
 
bool VuoImage_isPopulated (const VuoImage image)
 
VuoRectangle VuoImage_getRectangle (const VuoImage image)
 Returns a rectangle (in Vuo Coordinates) at the origin, with width 2 and height matching the image's aspect ratio.
 
VuoImageColorDepth VuoImage_getColorDepth (const VuoImage image)
 Returns the color depth of the image.
 
GLuint VuoImage_resolveInterprocessJsonUsingTextureProvider (struct json_object *js, GLuint(^provider)(unsigned int pixelsWide, unsigned int pixelsHigh), unsigned int *outputPixelsWide, unsigned int *outputPixelsHigh, void *outputIOSurface)
 Decodes the JSON object js onto a host-provided OpenGL texture's GL_TEXTURE_RECTANGLE_ARB target.
 
VuoImage VuoImage_makeFromString (const char *str)
 Automatically generated function.
 
char * VuoImage_getString (const VuoImage value)
 Automatically generated function.
 
char * VuoImage_getInterprocessString (const VuoImage value)
 Automatically generated function.
 
void VuoImage_retain (VuoImage value)
 Automatically generated function.
 
void VuoImage_release (VuoImage value)
 Automatically generated function.
 

Class Documentation

struct _VuoImage
Class Members
struct json_object * cpuData Map of GL formats to their char * pixelbuffers and freeCallbacks.
dispatch_queue_t cpuQueue Serializes access to cpuData.
dispatch_once_t cpuQueueInitialized Has cpuQueue been initialized?
void * freeCallbackContext User data for freeCallback. See VuoImage_makeClientOwned.
unsigned int glInternalFormat The OpenGL internal texture format (as provided to glTexImage2D).
unsigned int glTextureName The unique OpenGL texture identifier.
unsigned long int glTextureTarget Always GL_TEXTURE_2D, unless converting from an IOSurface.
unsigned long int pixelsHigh The vertical size of the image, in pixels.
unsigned long int pixelsWide The horizontal size of the image, in pixels.
float scaleFactor Number of linear pixels per point in this image. scaleFactor=1 for @1x images, 2 for @2x (Retina) images.

Typedef Documentation

typedef struct _VuoImage* VuoImage

An image residing in GPU memory (GL Texture Object).

The struct is typedef'd to a pointer so that VuoImages are reference-counted, enabling us to automatically delete the GL Texture Object when the last reference is released.

typedef void(* VuoImage_freeCallback)(VuoImage imageToFree)

A callback to be implemented if non-Vuo code needs to retain ownership of the GL texture (instead of the default behavior where VuoImage takes ownership of the texture).

See Also
VuoImage_makeClientOwned

Function Documentation

bool VuoImage_areEqual ( const VuoImage  a,
const VuoImage  b 
)

Returns true if both images have the same dimensions and the same RGBA pixel data.

Other attributes (pixel format, target) are ignored.

Two NULL images are considered equal. A NULL image is never equal to a non-NULL image.

This operation is fairly expensive — it requires downloading both images from the GPU to the CPU. It's intended primarily for use in automated tests.

bool VuoImage_areEqualWithinTolerance ( const VuoImage  a,
const VuoImage  b,
const unsigned char  tolerance 
)

Like VuoImage_areEqual(), but permits color channel values to differ by up to tolerance.

void VuoImage_free ( void *  texture)

Decrements the retain count of the OpenGL Texture Object associated with the specified VuoImage, and frees the texture VuoImage struct.

This function may be called from any thread.

VuoImage VuoImage_get ( const char *  imageURL)

Retrieves the image at the specified imageURL, and creates a VuoImage from it.

This function may be called from any thread.

const unsigned char* VuoImage_getBuffer ( VuoImage  image,
unsigned int  requestedFormat 
)

Downloads the specified image's pixel data from the GPU to the CPU (or returns it from a cache), and returns the CPU memory buffer.

The return value is a pointer to a buffer of pixel data. 8 bits per channel. Row-major, starting at the bottom (flipped). Zero stride. Premultiplied alpha.

The returned buffer is owned by the VuoImage instance; the caller should not modify or free() it.

This function may be called from any thread.

Parameters
imageThe image to download.
requestedFormatAn OpenGL format constant. Supported formats include:
  • GL_RGBA (32 bits per pixel)
  • GL_BGRA (32 bits per pixel)
  • GL_RGBA16I_EXT (64 bits per pixel)
  • GL_RGBA16F_ARB (64 bits per pixel)
  • GL_RGBA32F_ARB (128 bits per pixel)
  • GL_R16 (16 bits per pixel)
  • GL_LUMINANCE (8 bits per pixel)
  • GL_LUMINANCE_ALPHA (16 bits per pixel)
  • GL_DEPTH_COMPONENT16 (16 bits per pixel)
VuoImageColorDepth VuoImage_getColorDepth ( const VuoImage  image)

Returns the color depth of the image.

struct json_object * VuoImage_getInterprocessJson ( const VuoImage  value)
read

Returns a JSON object containing an interprocess handle for the specified texture.

value may be either GL_TEXTURE_2D or GL_TEXTURE_RECTANGLE_ARB.

This function may be called from any thread.

char* VuoImage_getInterprocessString ( const VuoImage  value)

Automatically generated function.

struct json_object * VuoImage_getJson ( const VuoImage  value)
read

Encodes value as a JSON object.

This function may be called from any thread.

VuoRectangle VuoImage_getRectangle ( const VuoImage  image)

Returns a rectangle (in Vuo Coordinates) at the origin, with width 2 and height matching the image's aspect ratio.

char* VuoImage_getString ( const VuoImage  value)

Automatically generated function.

char * VuoImage_getSummary ( const VuoImage  value)

A brief summary of the contents of this texture.

This function may be called from any thread.

Example:
GL Texture (ID 42)
640x480
VuoImageWrapMode VuoImage_getWrapMode ( VuoImage  image)

Returns the image's wrap mode.

bool VuoImage_isEmpty ( const VuoImage  image)
  • If either image dimension is 0, returns true.
  • If the image is fully transparent (all pixels have alpha value 0), returns true.
  • Otherwise returns false.
bool VuoImage_isPopulated ( const VuoImage  image)
  • If the image is null, returns false.
  • If either image dimension is 0, returns false.
  • Otherwise returns true.
VuoImage VuoImage_make ( unsigned int  glTextureName,
unsigned int  glInternalFormat,
unsigned long int  pixelsWide,
unsigned long int  pixelsHigh 
)

Returns a new VuoImage structure representing the specified glTextureName.

The texture must:

  • be of type GL_TEXTURE_2D.
  • use wrap mode GL_CLAMP_TO_EDGE on the S and T axes
  • use minifying and magnification filter GL_LINEAR

The VuoImage takes ownership of glTextureName, and will call glDeleteTextures() on it when it's no longer needed.

VuoImage is intended to be immutable — do not modify the contents of the glTextureName after passing it to this function.

This function may be called from any thread.

VuoImage VuoImage_makeClientOwned ( unsigned int  glTextureName,
unsigned int  glInternalFormat,
unsigned long int  pixelsWide,
unsigned long int  pixelsHigh,
VuoImage_freeCallback  freeCallback,
void *  freeCallbackContext 
)

Returns a new VuoImage structure representing the specified glTextureName.

The texture must:

  • be of type GL_TEXTURE_2D
  • use wrap mode GL_CLAMP_TO_EDGE on the S and T axes
  • use minifying and magnification filter GL_LINEAR

When the VuoImage is no longer needed, freeCallback is called. The freeCallback may then activate a GL context and delete the texture, or send it back to a texture pool. freeCallback must not be NULL.

freeCallbackContext is optional data passed to freeCallback via the VuoImage struct. Use NULL if you don't need to provide additional data to the callback.

VuoImage is intended to be immutable — do not modify the contents of the glTextureName between passing it to this function and when freeCallback is called.

This function may be called from any thread.

VuoImage VuoImage_makeClientOwnedGlTextureRectangle ( unsigned int  glTextureName,
unsigned int  glInternalFormat,
unsigned long int  pixelsWide,
unsigned long int  pixelsHigh,
VuoImage_freeCallback  freeCallback,
void *  freeCallbackContext 
)

Returns a new VuoImage structure representing the specified glTextureName.

The texture must:

  • be of type GL_TEXTURE_RECTANGLE_ARB
  • use wrap mode GL_CLAMP_TO_EDGE on the S and T axes
  • use minifying and magnification filter GL_LINEAR

When the VuoImage is no longer needed, freeCallback is called. The freeCallback may then activate a GL context and delete the texture, or send it back to a texture pool. freeCallback must not be NULL.

freeCallbackContext is optional data passed to freeCallback via the VuoImage struct. Use NULL if you don't need to provide additional data to the callback.

VuoImage is intended to be immutable — do not modify the contents of the glTextureName between passing it to this function and when freeCallback is called.

Note
Images returned by this function may only be passed to functions that explicitly mention support for GL_TEXTURE_RECTANGLE_ARB.

This function may be called from any thread.

VuoImage VuoImage_makeColorImage ( VuoColor  color,
unsigned int  pixelsWide,
unsigned int  pixelsHigh 
)

Makes a solid-color image.

VuoImage VuoImage_makeCopy ( VuoImage  image,
bool  flip 
)

Returns a new texture copy of the passed image.

image may be either GL_TEXTURE_2D or GL_TEXTURE_RECTANGLE_ARB.

If flip is true, the copied image is flipped upside-down relative to the source image.

VuoImage VuoImage_makeFromBuffer ( const void *  pixels,
unsigned int  format,
unsigned int  pixelsWide,
unsigned int  pixelsHigh,
VuoImageColorDepth  colorDepth,
void(^)(void *pixels)  freeCallback 
)

Uploads the specified pixel data to the GPU and returns a new VuoImage referencing it.

This function may be called from any thread.

Parameters
pixelsPointer to a buffer of pixel data. Row-major, starting at the bottom (flipped). Zero stride. Premultiplied alpha. Vuo takes ownership of this data, and will invoke freeCallback when it's done using it.
formatAn OpenGL format constant. Supported formats include:
  • GL_RGB
  • GL_YCBCR_422_APPLE
  • GL_RGBA
  • GL_BGRA
  • GL_LUMINANCE
  • GL_LUMINANCE_ALPHA
pixelsWideWidth in pixels
pixelsHighHeight in pixels
colorDepthThe number of bits per channel. When 8bpc, pixels should be unsigned char *; when 16bpc, pixels should be float *.
freeCallback
VuoImage VuoImage_makeFromBufferWithStride ( const void *  pixels,
unsigned int  format,
unsigned int  pixelsWide,
unsigned int  pixelsHigh,
unsigned int  bytesPerRow,
VuoImageColorDepth  colorDepth,
void(^)(void *pixels)  freeCallback 
)

Same as VuoImage_makeFromBuffer, but accepts a nonstandard stride (bytesPerRow).

VuoImage VuoImage_makeFromJson ( json_object js)

Decodes the JSON object js to create a new value.

Automatically activates and deactivates a GL Context (if needed to dereference an IOSurface).

This function may be called from any thread.

Returns
If js contains valid data, returns a pointer to the VuoImage. If not, returns NULL.
Parameters
jsA JSON object containing one of the following schemas:
  • a pointer to a VuoImage:
    Example:
    {
    "pointer": ...
    }
  • an IOSurfaceID and the texture's width and height in pixels:
    Example:
    {
    "ioSurface": 42,
    "pixelsWide": 640,
    "pixelsHigh": 480
    }
  • a color and the texture's width and height in pixels:
    Example:
    {
    "color": {"r":0.5, "g":1, "b":0, "a":1},
    "pixelsWide": 640,
    "pixelsHigh": 480
    }
VuoImage VuoImage_makeFromString ( const char *  str)

Automatically generated function.

VuoImage VuoImage_makeGlTextureRectangleCopy ( VuoImage  image)

Copies image to a new GL_TEXTURE_RECTANGLE_ARB texture.

Note
This is intended for interfacing with host apps; Vuo should always use GL_TEXTURE_2D internally.
VuoImage VuoImage_mapColors ( VuoImage  image,
VuoList_VuoColor  colors,
VuoReal  filterOpacity 
)

Returns a color-mapped copy of image.

(Or, if colors is empty, returns image.)

void VuoImage_release ( VuoImage  value)

Automatically generated function.

GLuint VuoImage_resolveInterprocessJsonUsingTextureProvider ( struct json_object js,
GLuint(^)(unsigned int pixelsWide, unsigned int pixelsHigh)  provider,
unsigned int *  outputPixelsWide,
unsigned int *  outputPixelsHigh,
void *  outputIOSurface 
)

Decodes the JSON object js onto a host-provided OpenGL texture's GL_TEXTURE_RECTANGLE_ARB target.

Returns
If js contains valid data, returns the OpenGL texture name. If not, returns 0.
Parameters
jsAn interprocess JSON object containing an ioSurface.
providerA block that returns an OpenGL texture name with the requested width and height. The host app must not call glTexImage2D() on the texture, since this makes the texture incompatible with the IOSurface backing.
[out]outputPixelsWideUpon return, this contains the width of the output texture.
[out]outputPixelsHighUpon return, this contains the height of the output texture.
[out]outputIOSurfaceUpon return, this contains the IOSurface backing the output texture. When the host app is finished with the output texture, it must signal and release the IOSurface:
VuoIoSurfacePool_signal(outputIOSurface);
CFRelease(outputIOSurface);

This function may be called from any thread.

void VuoImage_retain ( VuoImage  value)

Automatically generated function.

void VuoImage_setWrapMode ( VuoImage  image,
VuoImageWrapMode  wrapMode 
)

Changes the image's wrap mode.