OpenGL::Image (OGI) objects provide optimized interfaces to imaging modules, such as PerlMagick.

OGI's use OpenGL::Array (OGA) objects as wrappers around image buffers. These buffers are are stored as typed C arrays, and allows sharing image data between imaging libraries and the GPU.

This facilitates loading/modifying/saving textures, FBOs and VBOs - and allows both OpenGL and the imaging libraries to access/modify the same buffers.

The result is performance comparable to C and significantly faster than other OpenGL language bindings.

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my $engines = OpenGL::Image::GetEngines();

Returns a hashref of available imaging engines. The hash keys are engine names; hash values are their version.

my $ok = OpenGL::Image::HasEngine('Magick','6.3.5');

Tests whether a particular engine (and optionally minimum version) is available.

my $tex = new OpenGL::Image(engine=>'Magick',source=>$image_file);

Create an OGI and load it with an image (engine defaults to the 'Targa' driver if not specified).

my($ifmt,$fmt,$type) = $tex->Get('gl_internalformat','gl_format','gl_type');
my($w,$h) = $tex->Get('width','height');

Retrieve image info.

if (!$tex->IsPowerOf2()) return;

Determine if image dimensions are powers of 2.

my $size = $tex->GetPowerOf2();

Return largest power of 2 dimension that fits within image's boundary.

glTexImage2D_c(GL_TEXTURE_2D, 0, $ifmt, $w, $h, 0, $fmt, $type, $tex->Ptr());

$tex->Ptr() returns a C pointer to the image buffer.

my $frame = new OpenGL::Image(engine=>'Magick', width=>$w, height=>$h);
my($fmt,$size) = $frame->Get('gl_format','gl_type');

Instantiate an OGI; get GL info.

glReadPixels_c(0, 0, $w, $h, $fmt, $size, $frame->Ptr());
$frame->Sync();

Read pixels from GPU to image buffer, then sync the buffer. Unless the image needs to be paged into cache, Sync is generally a NOP.

$frame->Native->Blur(radius=>2,sigma=>2);

Get the imaging lib's native handle to process the image.

glRasterPos2f(0,0);
glDrawPixels_c($w, $h, $fmt, $size, $frame->Ptr());

Write the pixels back to the GPU.

my $frame = new OpenGL::Image(width=>$w, height=>$h);
my($fmt,$size) = $frame->Get('gl_format','gl_type');
glReadPixels_c(0, 0, $w, $h, $fmt, $size, $frame->Ptr());
$frame->Save('MyImage.tga');

my($r,$g,$b,$a) = $img->GetPixel($x,$y);

$img->SetPixel($x,$y, 1.0, 0.5, 0.0, 1.0);

$frame->Sync();

This interface assumes RGBA and that all values are normalized to 1.0; Sync is generally a NOP.

my $oga = $img->GetArray();

Allows OGA operations on an image buffer.