[Solved] Building CEGUI 0.8.7 with OpenGLES

[ishara]

Does anyone knows how to build CEGUI 0.8.7 with OpenGLES for ARM devices on linux(Debian -- “jessie”) . During the configuration process it shows following message.

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-- Could NOT find OPENGLES (missing:  OPENGLES_LIB OPENGLES_H_PATH)


And how can I find below two includes because installing "libgles2-mesa-dev" or "libgles1-mesa-dev" will not provide includes under the folder name "GLES".(Available include folders are GL,GLES2,GLES3)

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#   include <GLES/gl.h>
#   include <GLES/glext.h>


which are in "GLES.h" (cegui/include/CEGUI/RendererModules/OpenGLES)

Any help is welcome.

[YaronCT]

@ishara: Are u trying to use cegui on Android?

The packages "libgles2-mesa-dev" and "libgles1-mesa-dev" r for using OpenGL ES on your build platform (Debian), not on your host platform (Android?). The OpenGL ES headers are part of the Android NDK.

Anyway, to build cegui with OpenGL ES (>= 2) support, you don't need the OpenGL ES headers at all. U do need, however, to use Epoxy (get it here, use branch "master" - not a release) rather than GLEW, as an OpenGL loading library. To do that, configure cegui with "-DCEGUI_USE_EPOXY=ON -DCEGUI_USE_GLEW=OFF".

[ishara]

My intention is to run some UI components on SDL2 with CEGUI on BeagleBone Black board which is running Debian -- “jessie”.

I built CEGUI on BeagleBone Black (not cross-compiling) with relevant dependencies (via installing apt-get install libepoxy-dev ect... not manually building from source) .

Then the issue comes up with building CEGUI. As you mentioned I added DCEGUI_USE_EPOXY=ON and -DCEGUI_USE_GLEW=OFF via cmake-gui. But it didn't create a libCEGUIOpenGLESRenderer-0.so in the build location.

Therefore I'm not able to create a renderer as

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CEGUI::OpenGLESRenderer::bootstrapSystem();

Thanks for the quick reply.

[YaronCT]

Oh, I see..

Yes, this is indeed confusing. You don't need the "CEGUIOpenGLESRenderer" - I think it's an old unfinished work that was supposed to support only OpenGL ES 1. However, "CEGUIOpenGLRenderer" supports both desktop OpenGL 3.2 and OpenGL ES 2 - that's the renderer u should use. It automatically identifies whether it's desktop OpenGL or OpenGL ES.

[YaronCT]

Note: The official Epoxy is currently no longer maintained. I recommend u to use my fork that I linked to above, which contains fixes and improvements. Otherwise it may limit my ability to help u in case of a problem.

[ishara]

I managed to solve the issue with your instructions.... I used

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CEGUI::OpenGLRenderer::bootstrapSystem();

and

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#include <GL/gl.h>
#include <GL/glu.h>


worked for me instead of epoxy.

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CEGUI::OpenGL3Renderer::bootstrapSystem();

didn't worked for me because GLSL version 1.5 is not supported.

Thanks for the great help provided...

[YaronCT]

@ishara: What's GLSL 1.5? here I c GLSL 1.0 and 3.0, not 1.5. What version of OpenGL ES do u use?

[Ident]

There is a glsl "version #150", which is the version corresponding to OpenGL 3.2. This OpenGL version is the first with a core profile and therefore the one used for the OpenGL 3.2+ Core Profile renderer. I don't think there is an #150 shader version for OpenGL ES though.

[YaronCT]

Oh, for some reason I had gotten the impression he wants to use OpenGL ES..

[YaronCT]

@ishara: "CEGUI::OpenGLRenderer" supports only desktop OpenGL (1.2), not OpenGL ES. Does that fit your needs? And if so, y at all were u looking at OpenGL ES and Epoxy?

[Ident]

My point was that if wanting OpenGL ES then #150 is not a thing there. OpenGL 3 core profile is very close to OpenGL ES 2.X, but OpenGLRenderer (which is more like OpenGL 2.X) is closer to OpenGL ES 1.X. If he wants to use OpenGL ES 2.X (most likely) than adapting OpenGL 3 Core profile is the way to go. Otherwise the OpenGLRenderer is closest but I can't help with that.

[krishan121]

I'm using you'r fork of epoxy (https://github.com/yaronct/libepoxy) to build cegui 0.8.7.
I'm using OpenGL3Renderer with my application.

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::CEGUI::OpenGL3Renderer::bootstrapSystem()

when i'm running my application, I'm getting a CEGUI::RendererException

the error message i'm getting is,

CEGUI::RendererException in function 'void CEGUI::OpenGL3Shader::outputShaderLog(GLuint)' (/home/ubuntu/Desktop/shared_location/Software/cegui-0.8.7/cegui/src/RendererModules/OpenGL/Shader.cpp:244) : OpenGL3Shader compilation has failed.
(1:0) : error : Expect 100 afer the #version.
(1:0) : error : Error in parsing.
error : syntax error

terminate called after throwing an instance of 'CEGUI::RendererException'
what(): CEGUI::RendererException in function 'void CEGUI::OpenGL3Shader::outputShaderLog(GLuint)' (/home/ubuntu/Desktop/shared_location/Software/cegui-0.8.7/cegui/src/RendererModules/OpenGL/Shader.cpp:244) : OpenGL3Shader compilation has failed.
(1:0) : error : Expect 100 afer the #version.
(1:0) : error : Error in parsing.
error : syntax error

[YaronCT]

@krishan121: What platform? What does "OpenGLInfo::getSingleton().type()" return to u if u call it just b4 the exception is thrown?

[krishan121]

I solved my issue.
I'm using SDL2 in my application.
I changed my code from

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SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

to

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SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);

and removed following code

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glClearColor(0.0, 0.0, 0.0, 1.0);
                    glMatrixMode(GL_PROJECTION);
                    glLoadIdentity();
                    glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 0.0);

[YaronCT]

@krishan121: I'm glad it has worked out. In the future, plz open a new thread if u have a new issue.