SFML/src/SFML/Graphics/GLExtensions.cpp at master · githubhy/SFML · GitHub

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////////////////////////////////////////////////////////////

// SFML - Simple and Fast Multimedia Library

// This software is provided 'as-is', without any express or implied warranty.

// In no event will the authors be held liable for any damages arising from the use of this software.

// Permission is granted to anyone to use this software for any purpose,

// including commercial applications, and to alter it and redistribute it freely,

// subject to the following restrictions:

// 1. The origin of this software must not be misrepresented;

// you must not claim that you wrote the original software.

// If you use this software in a product, an acknowledgment

// in the product documentation would be appreciated but is not required.

// 2. Altered source versions must be plainly marked as such,

// and must not be misrepresented as being the original software.

// 3. This notice may not be removed or altered from any source distribution.

////////////////////////////////////////////////////////////

// Headers

////////////////////////////////////////////////////////////

#include <SFML/Graphics/GLExtensions.hpp>

#include <SFML/Window/Context.hpp>

#include <SFML/System/Err.hpp>

// We check for this definition in order to avoid multiple definitions of GLAD

// entities during unity builds of SFML.

#ifndef SF_GLAD_GL_IMPLEMENTATION_INCLUDED

#define SF_GLAD_GL_IMPLEMENTATION_INCLUDED

#define SF_GLAD_GL_IMPLEMENTATION

#include <glad/gl.h>

#endif

#include <ostream>

#if !defined(GL_MAJOR_VERSION)

#define GL_MAJOR_VERSION 0x821B

#endif

#if !defined(GL_MINOR_VERSION)

#define GL_MINOR_VERSION 0x821C

#endif

namespace sf::priv

{

////////////////////////////////////////////////////////////

void extensionSanityCheck()

{

static const auto check = [](int& flag, auto... entryPoints)

{

// If a required entry point is missing, flag the whole extension as unavailable

if (!(entryPoints && ...))

flag = 0;

};

#ifdef SFML_OPENGL_ES

check(GLEXT_multitexture_dependencies);

check(GLEXT_vertex_buffer_object_dependencies);

check(GLEXT_OES_blend_subtract_dependencies);

check(GLEXT_blend_func_separate_dependencies);

check(GLEXT_blend_equation_separate_dependencies);

check(GLEXT_framebuffer_object_dependencies);

check(GLEXT_EXT_blend_minmax_dependencies);

#else

check(GLEXT_blend_minmax_dependencies);

check(GLEXT_multitexture_dependencies);

check(GLEXT_blend_func_separate_dependencies);

check(GLEXT_vertex_buffer_object_dependencies);

check(GLEXT_shader_objects_dependencies);

check(GLEXT_blend_equation_separate_dependencies);

check(GLEXT_framebuffer_object_dependencies);

check(GLEXT_framebuffer_blit_dependencies);

check(GLEXT_framebuffer_multisample_dependencies);

check(GLEXT_copy_buffer_dependencies);

#endif

}

////////////////////////////////////////////////////////////

void ensureExtensionsInit()

{

static bool initialized = false;

if (!initialized)

{

initialized = true;

#ifdef SFML_OPENGL_ES

gladLoadGLES1(Context::getFunction);

#else

gladLoadGL(Context::getFunction);

#endif

// Some GL implementations don't fully follow extension specifications

// and advertise support for extensions although not providing the

// entry points specified for the corresponding extension.

// In order to protect ourselves from such implementations, we perform

// a sanity check to ensure an extension is _really_ supported, even

// from an entry point perspective.

extensionSanityCheck();

// Retrieve the context version number

int majorVersion = 0;

int minorVersion = 0;

// Try the new way first

glGetIntegerv(GL_MAJOR_VERSION, &majorVersion);

glGetIntegerv(GL_MINOR_VERSION, &minorVersion);

if (glGetError() == GL_INVALID_ENUM)

{

// Try the old way

const GLubyte* version = glGetString(GL_VERSION);

if (version)

{

// The beginning of the returned string is "major.minor" (this is standard)

majorVersion = version[0] - '0';

minorVersion = version[2] - '0';

}

else

{

// Can't get the version number, assume 1.1

majorVersion = 1;

minorVersion = 1;

}

if ((majorVersion < 1) || ((majorVersion == 1) && (minorVersion < 1)))

{

err() << "sfml-graphics requires support for OpenGL 1.1 or greater" << '\n'

<< "Ensure that hardware acceleration is enabled if available" << std::endl;

}

} // namespace sf::priv

SFML/src/SFML/Graphics/GLExtensions.cpp at master · githubhy/SFML · GitHub

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