bindbc-opengl 1.1.1

BindBC-OpenGL

This project provides dynamic bindings to the OpenGL library. It supports OpenGL versions up to and including 4.6, along with numerous extensions (if an extension you need is not yet supported, please submit a PR or open an issue). BindBC-OpenGL is compatible with @nogc and nothrow and can be compiled with BetterC compatibility. This package is intended as a replacement of DerelictGL3, which does not provide the same level of compatibility.

NOTE: BindBC-OpenGL does not support static binding due to the nature of the OpenGL API.

NOTE: This documentation describes how to use BindBC-OpenGL. As the maintainer of this library, I do not provide instructions on using the OpenGL library. However, since this is a direct binding to the OpenGL API, existing OpenGL documentation and tutorials can be adapted to D with few modifications (those being minor differences in the language, such as array declaration syntax). The tutorial at learnopengl.com is a particularly good introduction to OpenGL for those who have little or no experience with the API. For documentation, I prefer the layout of docs.gl over that of the Khronos site.

Add BindBC-OpenGL to your project

By default, BindBC-OpenGL is configured to compile with BetterC compatibility disabled and with support only for up to OpenGL 2.1 core. To use BindBC-OpenGL in this default mode, simply add the package as a dependency in your dub.json or dub.sdl recipe.

Example: dub.json

"dependencies": {
	"bindbc-opengl": "~>1.1.0"
}

Example: dub.sdl

dependency "bindbc-opengl" version="~>1.1.0"

Enable BetterC support

If you are using BetterC, add the dynamicBC sub-configuration to your package recipe.

Example: dub.json

"subConfigurations": {
	"bindbc-opengl": "dynamicBC"
},

Example: dub.sdl

subConfiguration "bindbc-opengl" "dynamicBC"

Enable support for OpenGL 3.0 and higher

Support for OpenGL versions can be configured at compile time by adding the appropriate version to a versions directive in your package configuration file (or on the command line if you are building with a tool other than dub).

BindBC-OpenGL supports a D version identifier for each OpenGL version. The following table lists each identifier and the OpenGL versions they enable.

OpenGL versions	Version identifier
1.0–2.1	Default
1.0–3.0	GL_30
1.0–3.1	GL_31
1.0–3.2	GL_32
1.0–3.3	GL_33
1.0–4.0	GL_40
1.0–4.1	GL_41
1.0–4.2	GL_42
1.0–4.3	GL_43
1.0–4.4	GL_44
1.0–4.5	GL_45
1.0–4.6	GL_46

[!NOTE]\ If you use versions higher than OpenGL 4.1, then your application will not work on macOS; due to OpenGL being deprecated on macOS.

Adding one of these version identifiers to your package recipe will do two things:

• symbols for the core types and functions in the supported OpenGL versions will be declared and available in user code
• the loadOpenGL function will attempt to load all OpenGL versions for which support is enabled and which is supported by the OpenGL context at run time.

To load all functions and enable all constants from "classic" OpenGL versions, including those that have been deprecated, set the version identifier GL_AllowDeprecated in your build system. Note that doing so means you may need to take special steps to configure your OpenGL context to ensure the deprecated functions are made available by the driver. Check the documentation of the API you are using for OpenGL context creation.

The following examples are configured to load the core functions from all OpenGL versions up to OpenGL 4.1:

dub.json

"dependencies": {
	"bindbc-opengl": "~>1.1.0"
}
"versions": [
	"GL_41"
],

dub.sdl

dependency "bindbc-opengl" version="~>1.1.0"
versions "GL_41"

With this configuration, client code can make use of all core OpenGL types and functions up to OpenGL 4.1. At run time, if the context supports OpenGL 4.1 or higher, the loader will attempt to load up to OpenGL 4.1. If the highest OpenGL version the context supports is lower than 4.1, the loader will attempt to load up to that version.

To enable the loading of deprecated functions in the same configuration:

dub.json

"dependencies": {
	"bindbc-opengl": "~>1.1.0"
}
"versions": [
	"GL_41", "GL_AllowDeprecated"
],

dub.sdl

dependency "bindbc-opengl" version="~>1.1.0"
versions "GL_41" "GL_AllowDeprecated"

With this, all OpenGL functions, both core and deprecated, will be loaded if the context has been configured appropriately and they are supported by the driver. Some deprecated features were removed from the specification in later versions of OpenGL.

GL_AllowDeprecated by itself enables support for deprecated functions and constants from OpenGL versions 1.0 - 2.1. When GL_AllowDeprecated is specified in conjunction with GL_30 or higher, support for deprecated constants from OpenGL version 3.0 will be enabled.

Enable support for extensions

Extension support is enabled on an as-needed basis. All supported ARB/KHR extensions can be enabled by adding the GL_ARB version identifier to your dub.json or dub.sdl. Supported NV (Nvidia) extensions are enabled via GL_NV.

For example, the following enables support for all core OpenGL functions up to and including GL 4.1, as well as all ARB/KHR extensions:

dub.json

"dependencies": {
	"bindbc-opengl": "~>1.1.0"
}
"versions": [
	"GL_41",
	"GL_ARB"
],

dub.sdl

dependency "bindbc-opengl" version="~>1.1.0"
versions "GL_41" "GL_ARB"

Extensions which were promoted to the core OpenGL API are loaded automatically along with the OpenGL version APIs to which they belong.

Specific extensions can be enabled using the extension's OpenGL name string as a version identifier. The name string for each extension is listed below. They the form of GL_ prefixed to the extension name.

Version added to core	OpenGL extension	Version identifier
N/A	ARBbindlesstexture	GL_ARB_bindless_texture
N/A	ARBclevent	GL_ARB_cl_event
N/A	ARBcomputevariablegroupsize	GL_ARB_compute_variable_group_size
N/A	ARBdebugoutput	GL_ARB_debug_output
N/A	ARBframebuffersRGB	GL_ARB_framebuffer_sRGB
N/A	ARBgeometryshader4	GL_ARB_geometry_shader4
N/A	ARBglspirv	GL_ARB_gl_spirv
N/A	ARBgpushader_int64	GL_ARB_gpu_shader_int64
N/A	ARBindirectparameters	GL_ARB_indirect_parameters
N/A	ARBinstancedarrays	GL_ARB_instanced_arrays
N/A	ARBpipelinestatistics_query	GL_ARB_pipeline_statistics_query
N/A	ARBrobustnessisolation	GL_ARB_robustness_isolation
N/A	ARBsampleshading	GL_ARB_sample_shading
N/A	ARBtexturebuffer_object	GL_ARB_texture_buffer_object
N/A	ARBtexturecompression_bptc	GL_ARB_texture_compression_bptc
N/A	ARBtexturecubemaparray	GL_ARB_texture_cube_map_array
N/A	ARBtexturegather	GL_ARB_texture_gather
N/A	ARBtransformfeedbackoverflowquery	GL_ARB_transform_feedback_overflow_query
N/A	ARBsparsetexture	GL_ARB_sparse_texture
N/A	ARBsparsetexture2	GL_ARB_sparse_texture2
N/A	ARBsparsetexture_clamp	GL_ARB_sparse_texture_clamp
3.0	ARBdepthbuffer_float	GL_ARB_depth_buffer_float
3.0	ARBhalffloat_vertex	GL_ARB_half_float_vertex
3.0	ARBtexturecompression_rgtc	GL_ARB_texture_compression_rgtc
3.0	ARBtexturerg	GL_ARB_texture_rg
3.0	ARBframebufferobject	GL_ARB_framebuffer_object
3.0	ARBmapbuffer_range	GL_ARB_map_buffer_range
3.0	ARBvertexarray_object	GL_ARB_vertex_array_object
3.1	ARBcopybuffer	GL_ARB_copy_buffer
3.1	ARBuniformbuffer_object	GL_ARB_uniform_buffer_object
3.2	ARBdepthclamp	GL_ARB_depth_clamp
3.2	ARBprovokingvertex	GL_ARB_provoking_vertex
3.2	ARBseamlesscube_map	GL_ARB_seamless_cube_map
3.2	ARBdrawelementsbasevertex	GL_ARB_draw_elements_base_vertex
3.2	ARB_sync	GL_ARB_sync
3.2	ARBtexturemultisample	GL_ARB_texture_multisample
3.3	ARBocclusionquery2	GL_ARB_occlusion_query2
3.3	ARBtexturergb10_a2ui	GL_ARB_texture_rgb10_a2ui
3.3	ARBtextureswizzle	GL_ARB_texture_swizzle
3.3	ARBblendfunc_extended	GL_ARB_blend_func_extended
3.3	ARBsamplerobjects	GL_ARB_sampler_objects
3.3	ARBtimerquery	GL_ARB_timer_query
3.3	ARBvertextype2101010_rev	GL_ARB_vertex_type_2_10_10_10_rev
4.0	ARBgpushader5	GL_ARB_gpu_shader5
4.0	ARBdrawindirect	GL_ARB_draw_indirect
4.0	ARBgpushader_fp64	GL_ARB_gpu_shader_fp64
4.0	ARBshadersubroutine	GL_ARB_shader_subroutine
4.0	ARBtessellationshader	GL_ARB_tessellation_shader
4.0	ARBtransformfeedback2	GL_ARB_transform_feedback2
4.0	ARBtransformfeedback3	GL_ARB_transform_feedback3
4.1	ARBES2compatibility	GL_ARB_ES2_compatibility
4.1	ARBgetprogram_binary	GL_ARB_get_program_binary
4.1	ARBseparateshader_objects	GL_ARB_separate_shader_objects
4.1	ARBvertexattrib_64bit	GL_ARB_vertex_attrib_64bit
4.1	ARBviewportarray	GL_ARB_viewport_array
4.2	ARBbaseinstance	GL_ARB_base_instance
4.2	ARBcompressedtexturepixelstorage	GL_ARB_compressed_texture_pixel_storage
4.2	ARBinternalformatquery	GL_ARB_internalformat_query
4.2	ARBmapbuffer_alignment	GL_ARB_map_buffer_alignment
4.2	ARBshaderimageloadstore	GL_ARB_shader_image_load_store
4.2	ARBtexturestorage	GL_ARB_texture_storage
4.2	ARBtransformfeedback_instanced	GL_ARB_transform_feedback_instanced
4.3	ARBclearbuffer_object	GL_ARB_clear_buffer_object
4.3	ARBcomputeshader	GL_ARB_compute_shader
4.3	ARBcopyimage	GL_ARB_copy_image
4.3	ARBES3compatibility	GL_ARB_ES3_compatibility
4.3	ARBexplicituniform_location	GL_ARB_explicit_uniform_location
4.3	ARBframebufferno_attachments	GL_ARB_framebuffer_no_attachments
4.3	ARBinternalformatquery2	GL_ARB_internalformat_query2
4.3	ARBinvalidatesubdata	GL_ARB_invalidate_subdata
4.3	ARBmultidraw_indirect	GL_ARB_multi_draw_indirect
4.3	ARBprograminterface_query	GL_ARB_program_interface_query
4.3	ARBshaderstoragebufferobject	GL_ARB_shader_storage_buffer_object
4.3	ARBstenciltexturing	GL_ARB_stencil_texturing
4.3	ARBtexturebuffer_range	GL_ARB_texture_buffer_range
4.3	ARBtexturestorage_multisample	GL_ARB_texture_storage_multisample
4.3	ARBtextureview	GL_ARB_texture_view
4.3	ARBvertexattrib_binding	GL_ARB_vertex_attrib_binding
4.3	KHR_debug	GL_KHR_debug
4.4	ARBbufferstorage	GL_ARB_buffer_storage
4.4	ARBcleartexture	GL_ARB_clear_texture
4.4	ARBenhancedlayouts	GL_ARB_enhanced_layouts
4.4	ARBmultibind	GL_ARB_multi_bind
4.4	ARBquerybuffer_object	GL_ARB_query_buffer_object
4.4	ARBtexturemirrorclampto_edge	GL_ARB_texture_mirror_clamp_to_edge
4.5	ARBclipcontrol	GL_ARB_clip_control
4.5	ARBconditionalrender_inverted	GL_ARB_conditional_render_inverted
4.5	ARBculldistance	GL_ARB_cull_distance
4.5	ARBdirectstate_access	GL_ARB_direct_state_access
4.5	ARBES31_compatibility	GL_ARB_ES3_1_compatibility
4.5	ARBgettexturesubimage	GL_ARB_get_texture_sub_image
4.5	ARBtexturebarrier	GL_ARB_texture_barrier
4.5	KHRcontextflush_control	GL_KHR_context_flush_control
4.5	KHR_robustness	GL_KHR_robustness
4.6	ARBpolygonoffset_clamp	GL_ARB_polygon_offset_clamp
4.6	ARBtexturefilter_anisotropic	GL_ARB_texture_filter_anisotropic

For example, the following configurations enable support for OpenGL 4.1 and the extensions ARB_base_instance and ARB_compressed_texture_pixel_storage, both of which were promoted to core in OpenGL 4.2:

dub.json

"dependencies": {
	"bindbc-opengl": "~>1.1.0"
}
"versions": [
	"GL_41",
	"GL_ARB_base_instance",
	"GL_ARB_compressed_texture_pixel_storage"
],

dub.sdl

dependency "bindbc-opengl" version="~>1.1.0"
versions "GL_41" "GL_ARB_base_instance" "GL_ARB_compressed_texture_pixel_storage"

The loadOpenGL function (described in the next section) will attempt to load all extensions configured in this manner. No errors will be reported on failure. To determine if an extension was loaded, use the has* property for each extension, like so:

import bindbc.opengl;

// Create the OpenGL context and load OpenGl
...
// Check for required extensions
if(hasARBBaseInstance){
	// configure renderer for GL_ARB_base_instance support
}
if(hasARBCompressedTexturePixelStorage){
	// configure renderer for GL_ARB_compressed_texture_pixel_storage support
}

If you have a need for an extension that is not currently supported then please submit a pull request.

Loading OpenGL

The loadOpenGL function is used to load all supported OpenGL functions and extensions. In order for this function to succeed, an OpenGL context must be created before it is called. The return value of loadOpenGL can be used to determine which version of OpenGL actually loaded.

For example, assume you've configured BindBC-OpenGL to support up to OpenGL 4.1, but you've designed your renderer to work with both 4.1 and 3.3. You can create a 4.1 or 3.3 context in one part of your code, then load OpenGL in another part, and configure your renderer based upon the return value.

import bindbc.opengl;

// Create OpenGL context
...
// Load supported OpenGL version + supported extensions
GLSupport retVal = loadOpenGL();
if(retVal == GLSupport.gl41){
	// configure renderer for OpenGL 4.1
}else if(retVal == GLSupport.gl33){
	// configure renderer for OpenGL 3.3
}else{
	// Error
}

[!NOTE]\ loadOpenGL returns the highest version that was loaded. On some systems, deprecated OpenGL functions (e.g. from OpenGL 1.2) may be missing, so if you rely on these you should check that they were loaded using versionLoadedStatus:

if((versionLoadedStatus(GLSupport.gl12) & GLLoadStatus.loaded) == 0){
	//OpenGL 1.2 functions were not loaded!
}

On error, loadOpenGL will return one of the following:

• GLSupport.noLibrary - the OpenGL shared library failed to load
• GLSupport.badLibrary - one of the context-independent symbols (OpenGL 1.0 & 1.1) in the OpenGL shared library failed to load.
• GLSupport.noContext - an OpenGL context was not created before calling the function. When asserts are enabled, calling loadOpenGL before a context is created will trigger an assertion failure instead.

The following functions are provided for convenience:

• isOpenGLLoaded - returns true if any version of OpenGL has been successfully loaded and false otherwise.
• openGLContextVersion - returns a GLSupport member corresponding to the version supported by the OpenGL context against which the library was loaded.
• loadedOpenGLVersion - returns a GLSupport member corresponding to the version of OpenGL currently loaded (identical to the return value of loadOpenGL).

Note that when working with multiple contexts, it may be necessary to call loadOpenGL on every context switch. On Windows in particular, a context switch may cause context-dependent functions, i.e., core functions above 1.1 and all extensions, to become invalid in some circumstances.

The error reporting API in bindbc.loader can be used to facilitate logging error messages.

// Import the dependent package
import bindbc.opengl;

/*
 Import the sharedlib module for error handling. Assigning an alias ensures the function names do not conflict with
 other public APIs. This isn't strictly necessary, but the API names are common enough that they could appear in other
 packages.
*/
import loader = bindbc.loader.sharedlib;

// Create the OpenGL context before calling this function.
bool loadLib(){
	/*
	Compare the return value of loadGL with the global `glSupport` constant to determine if the version of GLFW
	configured at compile time is the version that was loaded.
	*/
	auto ret = loadOpenGL();
	if(ret != glSupport){
		// Log the error info
		foreach(info; loader.errors){
			/*
			A hypothetical logging function. Note that `info.error` and `info.message` are `const(char)*`, not
			`string`.
			*/
			logError(info.error, info.message);
		}
		
		// Optionally construct a user-friendly error message for the user
		string msg;
		if(ret == GLSupport.noLibrary){
			msg = "This application requires OpenGL.";
		}else if(ret == GLSupport.badLibrary){
			msg = "The version of OpenGL on your system is too low. Please upgrade."
		}else{
			// GLSupport.noContext
			msg = "This program has encountered a graphics configuration error. Please report it to the developers."
		}
		// A hypothetical message box function
		showMessageBox(msg);
		return false;
	}
	return true;
}