RendererException in PBRTerrain.frag

5th generation Mac Mini (Apple Silicon) OpenJDK 64-Bit Server VM Temurin-17.0.2+8 (build 17.0.2+8, mixed mode) JME v3.5 branch

The “HelloMav” application crashes with the message is “ERROR: ‘’ 0:1306: : syntax error: preprocessor command must not be preceded by any other statement in that line”. Googling that message led me to https://stackoverflow.com/questions/9574919/webgl-differs-from-opengl-preprocessor-on-same-graphics-stack

My conclusion: “PBRTerrain.frag” uses the ## operator in 20+ places, but that operator isn’t supported in some versions of GLSL.

GitHub won’t allow me to post the full console output. Here’s a redacted version:

Mar 18, 2022 3:11:41 PM com.jme3.renderer.opengl.GLRenderer updateShaderSourceData
WARNING: Bad compile of:
1       #version 110
2       #define SRGB 1
3       #define FRAGMENT_SHADER 1
4       #define TRI_PLANAR_MAPPING 1
5       #define ALBEDOMAP_0 1
6       #define ALBEDOMAP_1 1
7       #define ALBEDOMAP_2 1
8       #define ALBEDOMAP_3 1
9       #define ALBEDOMAP_4 1
10      #define ALBEDOMAP_5 1
11      #define ALBEDOMAP_6 1
12      #define ALPHAMAP 1
13      #define ALPHAMAP_1 1
14      #define ALBEDOMAP_0_SCALE 0.1
15      #define ALBEDOMAP_1_SCALE 0.05
16      #define ALBEDOMAP_2_SCALE 0.1
17      #define ALBEDOMAP_3_SCALE 0.1
18      #define ALBEDOMAP_4_SCALE 0.3
19      #define ALBEDOMAP_5_SCALE 0.1
20      #define ALBEDOMAP_6_SCALE 0.5
21      #define DEBUG_VALUES_MODE 0
22      #define SINGLE_PASS_LIGHTING 1
23      #define NB_LIGHTS 3
24      #define NB_PROBES 1
25      #define USE_AMBIENT_LIGHT 1
26      #extension GL_ARB_shader_texture_lod : enable
27      // -- begin import Common/ShaderLib/GLSLCompat.glsllib --
28      #if defined GL_ES

…

1301        #ifdef ALBEDOMAP_0   
1302                        //NOTE! the old (phong) terrain shaders do not have an "_0" for the first diffuse map, it is just "DiffuseMap"
1303            #ifdef NORMALMAP_0
1304                BLEND_NORMAL(_0,  alphaBlend.r)
1305            #else
1306                BLEND(_0,  alphaBlend.r)
1307            #endif
1308            
1309        #endif
1310        #ifdef ALBEDOMAP_1
1311            #ifdef NORMALMAP_1
1312                BLEND_NORMAL(_1,  alphaBlend.g)
1313            #else
1314                BLEND(_1,  alphaBlend.g)
1315            #endif

…

1934            
1935        #endif
1936        
1937        gl_FragColor.a = albedo.a;
1938    
1939    }

Mar 18, 2022 3:11:41 PM com.jme3.app.LegacyApplication handleError
SEVERE: Uncaught exception thrown in Thread[jME3 Main,5,main]
com.jme3.renderer.RendererException: compile error in: ShaderSource[name=Common/MatDefs/Terrain/PBRTerrain.frag, defines, type=Fragment, language=GLSL100]
ERROR: 0:1306: '' : syntax error: preprocessor command must not be preceded by any other statement in that line
ERROR: 0:1306: 'premature EOF' : syntax error syntax error

        at com.jme3.renderer.opengl.GLRenderer.updateShaderSourceData(GLRenderer.java:1539)
        at com.jme3.renderer.opengl.GLRenderer.updateShaderData(GLRenderer.java:1566)
        at com.jme3.renderer.opengl.GLRenderer.setShader(GLRenderer.java:1631)
        at com.jme3.material.logic.SinglePassAndImageBasedLightingLogic.render(SinglePassAndImageBasedLightingLogic.java:276)
        at com.jme3.material.Technique.render(Technique.java:167)
        at com.jme3.material.Material.render(Material.java:1052)
        at com.jme3.renderer.RenderManager.renderGeometry(RenderManager.java:651)
        at com.jme3.renderer.queue.RenderQueue.renderGeometryList(RenderQueue.java:273)
        at com.jme3.renderer.queue.RenderQueue.renderQueue(RenderQueue.java:312)
        at com.jme3.renderer.RenderManager.renderViewPortQueues(RenderManager.java:928)
        at com.jme3.renderer.RenderManager.flushQueue(RenderManager.java:823)
        at com.jme3.renderer.RenderManager.renderViewPort(RenderManager.java:1184)
        at com.jme3.renderer.RenderManager.render(RenderManager.java:1248)
        at com.jme3.app.SimpleApplication.update(SimpleApplication.java:278)
        at com.jme3.system.lwjgl.LwjglWindow.runLoop(LwjglWindow.java:580)
        at com.jme3.system.lwjgl.LwjglWindow.run(LwjglWindow.java:669)
        at com.jme3.system.lwjgl.LwjglWindow.create(LwjglWindow.java:493)
        at com.jme3.app.LegacyApplication.start(LegacyApplication.java:490)
        at com.jme3.app.LegacyApplication.start(LegacyApplication.java:442)
        at com.jme3.app.SimpleApplication.start(SimpleApplication.java:126)
        at com.jayfella.jme.vehicle.simpledemo.HelloMav.main(HelloMav.java:104)

[JME ERROR] Uncaught exception thrown in Thread[jME3 Main,5,main]
RendererException: compile error in: ShaderSource[name=Common/MatDefs/Terrain/PBRTerrain.frag, defines, type=Fragment, language=GLSL100]
ERROR: 0:1306: '' : syntax error: preprocessor command must not be preceded by any other statement in that line
ERROR: 0:1306: 'premature EOF' : syntax error syntax error

[stephengold]

I agree that if there’s ever a JMonkeyEngine 3.6 release, then PR #1758 and the fix for this issue should be included.

As long as the fix for this issue is integrated into “master” branch before the 3.6 code freeze, I don’t foresee any difficulty.

Currently there’s no 3.6 release scheduled, so I don’t know when code freeze will occur. My best guess would be summer of 2022.

[riccardobl]

Asking @stephengold since he is managing jme3.x releases