Perl OpenGL

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Perl OpenGL

A screenshot illustrating FBO and Vertex/Fragment program extensions via POGL
Developed by Stan Melax, Kenneth Albanowski, Ilya Zakharevich, Jean-Louis Morel, Bob Free
Latest release 0.56_01 / September 11, 2007
OS Cross-platform
Genre 3D computer graphics software (library/API)
License Perl Artistic and GPL licenses
Website graphcomp.com/opengl

Perl OpenGL (POGL) is a portable, compiled wrapper library that allows OpenGL to be used in the Perl programming language.

POGL provides support for most OpenGL 2.0 extensions, abstracts OS-specific proc handlers, and supports GLUT, a simple cross-platform windowing interface.

POGL provides additional Perl-friendly APIs for passing/returning strings and arrays.

Contents

[edit] Platform Support

  • Windows: NT/XP/Vista
  • Mac OS X: v10.4/10.5
  • Linux: Fedora 6, Debian/Ubuntu (Etch/Dapper), Gentoo
  • FreeBSD
  • Solaris

Confirmed with

  • nVidia (Quadro-110M,6600,6800,7300,7800,7950,8800)
  • ATI (Radeon 9000/9200, FireGL)
  • Cygwin/X (Mesa)

[edit] Interoperability

[edit] ImageMagick - Image Loading/Modification/Saving

The POGL team has collaborated with the ImageMagick team to add PerlMagick APIs that allow GPUs and ImageMagick to share cache buffers via C pointers - optimizing performance for FBOs and VBOs - for use with loading/saving textures and GPGPU data transfer.

These APIs have been added to ImageMagick 6.3.5:

  • Get('Scene') - returns the number of scenes in an IM image.
  • Get('Quantum') - returns IM's cache depth.
  • GetImagePixels() - returns a C pointer to IM's image cache.
  • SyncImagePixels() - sync's IM's image cache after a write (for large/paged images).

Benchmarks demonstrate GetImagePixels is 188x faster than ImageToBlob or GetPixels.

[edit] FFmpeg - Video Frame Textures

CPAN's FFmpeg module may be used in conjunction with POGL and the above Image::Magick APIs to map video to OpenGL textures.

[edit] Performance

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Please see the discussion on the talk page.(May 2008)
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This section may contain original research or unverified claims.
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POGL provides OpenGL performance comparable to that of C, and consistently outperforms other Perl Bindings like SDL::OpenGL and other language bindings like Python.

[edit] Comparison With Other Language Bindings

 The neutrality of this section is disputed.
Please see the discussion on the talk page.(May 2008)
Please do not remove this message until the dispute is resolved.
This section may contain original research or unverified claims.
Please help Wikipedia by adding references. See the talk page for details.(May 2008)

[edit] Perl vs C

General Purpose GPU (GPGPU) processing is one area in which Perl compares with compiled languages in terms of performance.

GPU benchmarks show no significant performance differences between C and Perl (via POGL), when rendering a realtime 3D animated object with dynamically generated texturemaps.

GPGPU vertex shaders can execute complex c-like code on large arrays of data, rarely touching the CPU. The CPU is left doing event handling, system calls, disk I/O and UI - which contributes a minor portion of the overall processing time. The performance difference between C and Perl becomes statistically insignificant.

Since GPU performance depends on tight integration with an OS' windowing system (WGL/X11/etc), OpenGL APIs (particularly GPGPU extensions) are OS-dependent. POGL abstracts these dependencies, allowing portable code.

[edit] Perl vs Java

Perl tends to rely on more binary modules than Java, providing additional performance benefits[citation needed]. POGL is a compiled module, and may be used in conjunction with compiled imaging modules (such as ImageMagick) for loading/saving data arrays (textures).

As of this writing, the Java OpenGL (JOGL) binding does not support Framebuffers and other advanced GPGPU extensions[citation needed].

[edit] Perl vs Python

As of this writing, Python OpenGL bindings do not support Framebuffers and other advanced GPGPU extensions.[citation needed]

  • Benchmarks demonstrate that POGL performs over 20% faster than Python [1]. This includes a blog posting by PyOpenGL's author explaining why Python's OpenGL implementation is likely to be slower than POGL. These benchmarks are based on Trislam, an independent OpenGL benchmark; these results were independently reproduced by Trislam's author.

[edit] OpenGL Objects

POGL provides specialized objects that dramatically enhance Perl performance. POGL objects store data as typed C arrays, and pass data between APIs using C pointers - eliminating the need to copy/convert/cast when passing data between interfaces.

The result is maximized performance, with the added flexibility/portability of Perl.

[edit] OpenGL::Array (OGA)

OGAs store OpenGL data as typed C arrays. OGAs may be populated by C pointer, Perl packed arrays (strings) or Perl arrays.

OGAs may be bound/mapped to VBOs to share data between the GPU and Perl.

Accessor methods provide a means to get/set array elements by C pointer, packed arrays or Perl arrays.

Documentation can be found on POGL's Developer Site

[edit] OpenGL::Image (OGI)

OGIs use OGAs to wrap image buffers from various imaging libraries. OGI simplifies loading/modifying/saving OpenGL textures, FBOs and VBOs.

OGI provides an extensible plug-in architecture to support new imaging libraries: OGI supports ImageMagick (v6.3.5 or newer), and by default Targa (uncompressed RGBA files).

OGI provides direct C pointer access to ImageMagick's image cache, resulting in dramatic performance in transferring images/data between the GPU and IM.

Documentation can be found on POGL's Developer Site

OGI is available on CPAN as a separate OpenGL-Image module [2].

[edit] OpenGL::Shader (OGS)

The OSG module abstracts OpenGL APIs for ARB (assembly), Cg and GLSL shading languages.

$shdr = new OpenGL::Shader();
my $ext = lc($shdr->GetType());
my $stat = $shdr->LoadFiles("fragment.$ext","vertex.$ext");

$shdr->Enable();
$Shader->SetVector('surfacecolor',1.0,0.5,0.0,1.0);
$Shader->SetMatrix('xform',$xform);

# Draw here

$shdr->Disable();

Documentation can be found on POGL's Developer Site

OGS is available on CPAN as a separate OpenGL-Shader module [3].

[edit] Sample Renderings

Snap shot of a realtime animated blacklight shader.

[edit] Status and Standardization

The latest CPAN release of the following POGL modules are

  • OpenGL v0.56
  • OpenGL-Image v1.02
  • OpenGL-Shader v1.00

Updates and binary distributions are available on Graphcomp's Perl OpenGL (POGL) site.

POGL supports the following OpenGL extensions:

  • GL_ARB_color_buffer_float
  • GL_ARB_depth_texture
  • GL_ARB_draw_buffers
  • GL_ARB_fragment_program
  • GL_ARB_fragment_program_shadow
  • GL_ARB_fragment_shader
  • GL_ARB_half_float_pixel
  • GL_ARB_multisample
  • GL_ARB_multitexture
  • GL_ARB_pixel_buffer_object
  • GL_ARB_point_parameters
  • GL_ARB_point_sprite
  • GL_ARB_shader_objects
  • GL_ARB_shading_language_100
  • GL_ARB_shadow
  • GL_ARB_texture_border_clamp
  • GL_ARB_texture_cube_map
  • GL_ARB_texture_env_add
  • GL_ARB_texture_env_combine
  • GL_ARB_texture_env_dot3
  • GL_ARB_texture_float
  • GL_ARB_texture_mirrored_repeat
  • GL_ARB_texture_non_power_of_two
  • GL_ARB_texture_rectangle
  • GL_ARB_vertex_buffer_object
  • GL_ARB_vertex_program
  • GL_ARB_vertex_shader
  • GL_ATI_texture_float
  • GL_ATI_texture_mirror_once
  • GL_EXT_Cg_shader
  • GL_EXT_abgr
  • GL_EXT_bgra
  • GL_EXT_blend_color
  • GL_EXT_blend_subtract
  • GL_EXT_framebuffer_object
  • GL_EXT_packed_pixels
  • GL_EXT_pixel_buffer_object
  • GL_EXT_rescale_normal
  • GL_EXT_separate_specular_color
  • GL_EXT_shadow_funcs
  • GL_EXT_stencil_wrap
  • GL_EXT_texture3D
  • GL_EXT_texture_cube_map
  • GL_EXT_texture_env_combine
  • GL_EXT_texture_env_dot3
  • GL_EXT_texture_filter_anisotropic
  • GL_EXT_texture_lod_bias
  • GL_EXT_texture_mirror_clamp
  • GL_EXT_vertex_array
  • GL_HP_occlusion_test
  • GL_IBM_rasterpos_clip
  • GL_NV_blend_square
  • GL_NV_copy_depth_to_color
  • GL_NV_depth_clamp
  • GL_NV_fog_distance
  • GL_NV_fragment_program2
  • GL_NV_fragment_program_option
  • GL_NV_light_max_exponent
  • GL_NV_packed_depth_stencil
  • GL_NV_texgen_reflection
  • GL_NV_texture_expand_normal
  • GL_NV_texture_rectangle
  • GL_NV_texture_shader
  • GL_NV_texture_shader2
  • GL_NV_texture_shader3
  • GL_NV_vertex_program2_option
  • GL_NV_vertex_program3
  • GL_S3_s3tc
  • GL_SGIS_generate_mipmap
  • GL_SGIS_texture_lod
  • GL_SGIX_depth_texture
  • GL_SGIX_shadow
  • GL_SUN_slice_accum

The primary author of this release is Bob Free of Graphcomp.

Bob Free was made primary owner of CPAN's Perl OpenGL module on April 13, 2007.

[edit] External links