FindOpenGL¶
FindModule for OpenGL and OpenGL Utility Library (GLU).
Optional COMPONENTS¶
This module respects several optional COMPONENTS: EGL, GLX, and
OpenGL. There are corresponding import targets for each of these flags.
IMPORTED Targets¶
This module defines the IMPORTED targets:
OpenGL::GLDefined to the platform-specific OpenGL libraries if the system has OpenGL.
OpenGL::OpenGLDefined to libOpenGL if the system is GLVND-based.
OpenGL::GLUDefined if the system has OpenGL Utility Library (GLU).
OpenGL::GLXDefined if the system has OpenGL Extension to the X Window System (GLX).
OpenGL::EGLDefined if the system has EGL.
Result Variables¶
This module sets the following variables:
OPENGL_FOUNDTrue, if the system has OpenGL and all components are found.
OPENGL_XMESA_FOUNDTrue, if the system has XMESA.
OPENGL_GLU_FOUNDTrue, if the system has GLU.
OpenGL_OpenGL_FOUNDTrue, if the system has an OpenGL library.
OpenGL_GLX_FOUNDTrue, if the system has GLX.
OpenGL_EGL_FOUNDTrue, if the system has EGL.
OPENGL_INCLUDE_DIRPath to the OpenGL include directory.
OPENGL_EGL_INCLUDE_DIRSPath to the EGL include directory.
OPENGL_LIBRARIESPaths to the OpenGL library, windowing system libraries, and GLU libraries. On Linux, this assumes GLX and is never correct for EGL-based targets. Clients are encouraged to use the
OpenGL::*import targets instead.
Cache variables¶
The following cache variables may also be set:
OPENGL_egl_LIBRARYPath to the EGL library.
OPENGL_glu_LIBRARYPath to the GLU library.
OPENGL_glx_LIBRARYPath to the GLVND ‘GLX’ library.
OPENGL_opengl_LIBRARYPath to the GLVND ‘OpenGL’ library
OPENGL_gl_LIBRARYPath to the OpenGL library. New code should prefer the
OpenGL::*import targets.
Linux-specific¶
Some Linux systems utilize GLVND as a new ABI for OpenGL. GLVND separates
context libraries from OpenGL itself; OpenGL lives in “libOpenGL”, and
contexts are defined in “libGLX” or “libEGL”. GLVND is currently the only way
to get OpenGL 3+ functionality via EGL in a manner portable across vendors.
Projects may use GLVND explicitly with target OpenGL::OpenGL and either
OpenGL::GLX or OpenGL::EGL.
Projects may use the OpenGL::GL target (or OPENGL_LIBRARIES variable)
to use legacy GL interfaces. These will use the legacy GL library located
by OPENGL_gl_LIBRARY, if available. If OPENGL_gl_LIBRARY is empty or
not found and GLVND is available, the OpenGL::GL target will use GLVND
OpenGL::OpenGL and OpenGL::GLX (and the OPENGL_LIBRARIES
variable will use the corresponding libraries). Thus, for non-EGL-based
Linux targets, the OpenGL::GL target is most portable.
A OpenGL_GL_PREFERENCE variable may be set to specify the preferred way
to provide legacy GL interfaces in case multiple choices are available.
The value may be one of:
GLVNDIf the GLVND OpenGL and GLX libraries are available, prefer them. This forces
OPENGL_gl_LIBRARYto be empty. This is the default if components were requested (since components correspond to GLVND libraries) or if policyCMP0072is set toNEW.LEGACYPrefer to use the legacy libGL library, if available. This is the default if no components were requested and policy
CMP0072is not set toNEW.
For EGL targets the client must rely on GLVND support on the user’s system.
Linking should use the OpenGL::OpenGL OpenGL::EGL targets. Using GLES*
libraries is theoretically possible in place of OpenGL::OpenGL, but this
module does not currently support that; contributions welcome.
OPENGL_egl_LIBRARY and OPENGL_EGL_INCLUDE_DIRS are defined in the case of
GLVND. For non-GLVND Linux and other systems these are left undefined.
macOS-Specific¶
On OSX FindOpenGL defaults to using the framework version of OpenGL. People will have to change the cache values of OPENGL_glu_LIBRARY and OPENGL_gl_LIBRARY to use OpenGL with X11 on OSX.