Android 2.3 - cant compile openGL 2.0 ES fragment shader

Question

I have a very strange problem with my problem on android 2.3.3 - I try to compile a basic fragment shader, but the compiler gives back a 0 as compileStatus.

Here is my shader compile snippet:

    if (fragmentShaderHandle != 0) {

        // Pass in the shader source.
        GLES20.glShaderSource(fragmentShaderHandle, fragmentShader);

        // Compile the shader.
        GLES20.glCompileShader(fragmentShaderHandle);

        // Get the compilation status.
        final int[] compileStatus = new int[1];
        GLES20.glGetShaderiv(fragmentShaderHandle, GLES20.GL_COMPILE_STATUS, compileStatus, 0);

        // If the compilation failed, delete the shader.
        if (compileStatus[0] == 0) {

            ErrorLog = GLES20.glGetShaderInfoLog(fragmentShaderHandle);

            GLES20.glDeleteShader(fragmentShaderHandle); 
            fragmentShaderHandle = 0;
        }           
    }

    if (fragmentShaderHandle == 0) {

        throw new RuntimeException("Error creating fragment shader. Error: " + ErrorLog);
    }

The strangest thing, that the glGetShaderInfoLog gives back an empty string as an error - I dont get any information, other then "Error creating fragment shader." which is my error message. If I skip that line, then the program binding will give an error, as the fragment shader is not existing.

I tried every shader (if there is the error) but even the simplest shader dont run (simplest shader: void main { gl_FragmentColor = vec4(1.0f, 1.0f, 1.0f, 1.0f) } this give the same error without any error message).

But: this code will run flawlesly on android 4.0 (my friend tried it, and its work in the emulator as well). I asked some other friend with android 2.3 - but everyone got the same error with no error message.

The telephone support OpenGL 2.0 ES - if I dont load shader, just clear the screen, it works just fine.

Anybody have any idea where should I start looking? Without error message, its pretty hard to hunt down where I messed up :|

Thank you!

EDIT:

1) It sucessfully compile the vertexShader, and, if I dont load any shader, I can clear the screen using the GLES20.glClear(...) command, and it run succesfully on any tested device.

2) I added a check to see if the device compatible with the openGL 2.0 - each tested device said everything is ok:

boolean supportsEs2 = configurationInfo.reqGlEsVersion >= 0x20000;

3) I tried out the int glError = GLES20.glGetError(); - it returns a zero, like the was no error (as I get no error message either) - my shader still cant compile :(

How do you know that your device supports OpenGL ES 2.0 as that was optional in Android 2.3. Check the value of fragmentShaderHandler after every call. — Morrison Chang
Oops didn't see the outer fragementShaderHandler conditional. — Morrison Chang
Have you tried calling glGetError()? I wonder if something might be so messed up that it doesn't even try to compile your shader. For example, fragmentShaderHandle being invalid for some reason. — Reto Koradi
I updated my question - the device support openGL ES 2.0. And the glGEtError() return 0. I have no freaking idea whats wrong :( — Gabriel Butcher

Reto Koradi Reto Koradi · Accepted Answer · 2014-09-28T01:59:17

Not sure why you're not getting an error string from glGetShaderInfoLog(), but your "simplest fragment shader" contains multiple errors:

void main { gl_FragmentColor = vec4(1.0f, 1.0f, 1.0f, 1.0f) }

Needs precision qualifier for floats.
Needs empty parentheses after main.
The predefined output variable is gl_FragColor, not gl_FragmentColor.
1.0f is not a valid constant in ES 2.0. Must be 1.0.
Semicolon missing after statement.

The correct version would be:

precision mediump float;
void main() { gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0); }

Android 2.3 - cant compile openGL 2.0 ES fragment shader

1 Answers