GLSLCompat.glsllib doesn't compile on Android

[nickidebruyn]

While test jme3.7.0 with my android projects I found that the jme3-core/src/main/resources/Common/ShaderLib/GLSLCompat.glsllib
code contains ';' semicolons at the end of the first few lines and android is not happy with that.

Error I am experiencing:

ERROR: 0:11: ';' : Syntax error:  syntax error
INTERNAL ERROR: no main() function!
ERROR: 1 compilation errors.  No code generated.                                                                                                    
                                                                                                    	at com.jme3.renderer.opengl.GLRenderer.updateShaderSourceData(GLRenderer.java:1658)
                                                                                                    	at com.jme3.renderer.opengl.GLRenderer.updateShaderData(GLRenderer.java:1685)
                                                                                                    	at com.jme3.renderer.opengl.GLRenderer.setShader(GLRenderer.java:1750)

After some more investigation I found that the first part is the problem:

#ifdef GL_ES
  #ifdef FRAGMENT_SHADER
    precision highp float;
    precision highp int;
    precision highp sampler2DArray;
    precision highp sampler2DShadow;
    precision highp samplerCube;
    precision highp sampler3D;
    precision highp sampler2D;
    #if __VERSION__ >= 310
      precision highp sampler2DMS;
    #endif
  #endif
#endif

[stephengold]

Thanks for documenting the issue, @nickidebruyn!

[stephengold]

According to "git blame", the failing code was last modified by PR #2217, which was integrated between v3.7.0-alpha2 and v3.7.0-beta1.

@nickidebruyn Do your Android projects work with JME v3.7.0-alpha2 ?

[nickidebruyn]

I tested a few scenarios for this. I can confirm that none of the new version (v3.7.0-alpha2, v3.7.0-beta1, v3.7.0-stable) works.
I then tested again with v3.6.1 and it worked again.
After that I changed back to v3.7.0-stable and created my own local GLSLCompat.glsllib and changed the frag shader to point to that and it worked again. This is the code I removed from my local: GLSLCompat.glsllib

#ifdef GL_ES
  #ifdef FRAGMENT_SHADER
    precision highp float;
    precision highp int;
    precision highp sampler2DArray;
    precision highp sampler2DShadow;
    precision highp samplerCube;
    precision highp sampler3D;
    precision highp sampler2D;
    #if __VERSION__ >= 310
      precision highp sampler2DMS;
    #endif
  #endif
#endif

[stephengold]

Thank you for the investigation.
Based on your findings, I'm convinced PR #2061 caused the regression.
At the time (August 2023), Riccardo indicated 2061 would need to be tested on Android.
Apparently it never got such testing, and neither did JME 3.7!
I think this calls for a 3.7.1 release...

[nickidebruyn]

Agree, that is probably a good decision.
Most shaders uses that lib.