Linux and OpenGL ES 2.0

[payload]

I tried to get Linux 64bit and OpenGL ES 2.0 working and did it in a hackish manner, because I just needed it fast. The steps to get it done:

• compile and include a libglfw3.a with GLFW_USE_EGL = true and GLFW_CLIENT_LIBRARY = glesv2

In ofAppRunner.cpp:

• include ofAppEGLWindow.h, so in cases were defined(TARGET_RASPBERRY_PI) add || defined(TARGET_OPENGLES)
• don't include "glu.h" in ofGraphics.cpp

In ofConstants.h:

• move the #ifdef TARGET_OPENGLES up such that only GLES and EGL is included, not X11

In config.linux.common.mk:

• I forced PLATFORM_DEFINES = TARGET_OPENGLES
• removed PLATFORM_CORE_EXCLUSIONS += $(OF_LIBS_PATH)/openFrameworks/app/ofAppEGLWindow.cpp
• forced PLATFORM_LIBRARIES = EGL Xinerama for correct libglfw3.a linking
• removed PLATFORM_LIBRARIES += glut for #ifneq ($(LINUX_ARM),1)

One has to make the makefiles and the ifdefs cleaner in differenciating between TARGET_LINUX, TARGET_ARM, TARGET_OPENGLES and such. There are many implicit assumptions tangled up in them.

[arturoc]

thanks! out of curiosity, in which platform are you using linux64 + opengles?

[payload]

Good question. I want to test a special OpenGL implementation I wrote based on ClusterGL. It only supports OpenGL ES 2.0 because it is the easiest to implement fully. But it is also notable that recent Mesa implements OpenGL ES and EGL for desktop. I use Ubuntu 14.04 with Mesa 10.1.3 on Intel Ivybridge Mobile i965.

Being able to write new applications against modern OpenGL without having a OpenGL version like 4.1 were everything got deprecated is really important I think, to use a somewhat decent OpenGL API. To much glBegin glEnd code out there.

[arturoc]

That looks great. Are you using ofAppEGLWindow or ofAppGLFWWindow? you shouldn't need both and from your description it seems you are compiling glfw with EGL support but then using ofAppEGLWindow?

[payload]

ah yes. yes one does only need ofAppEGLWindow cause ofAppRunner can go for it with the implicit assumption that TARGET_OPENGLES availability also means EGL availability. so no specially crafted libglfw3 is needed.

[arturoc]

i would try using glfw with EGL support instead it should be more stable than the EGL window which is a custom implementation we did specially for the raspberry pi. anyway, thanks for reporting the changes i'll check how can we remove all the assumptions that desktop linux is always not ES

[payload]

Is this issue still on your radar?

[arturoc]

it is but there's a ton of things to do before the release. next time i modify the makefiles i'll try to take a look at this. also if you want to send a PR that would be great