Bug 425

According to the logic in ShaderProgram and ShaderState, glBindAttribLocation will always fail because it requires that the program be attached to the state but not linked, and attaching the program to the state (attachProgram) requires that the program be linked (because attachProgram calls ShaderProgram.glUseProgram, which requires the program be linked).

Perhaps glUseProgram could be modified so that if on is false, it shouldn't check whether the program is linked?

Here is a method which illustrates the contradiction:

   public ShaderState gltLoadShaderPairSrcWithAttributes(GL2 gl, String vertexSrc, String fragmentSrc, 
            HashMap<Integer, String> attributes) 
    { 
        ByteArrayOutputStream verboseOutBuffer = new ByteArrayOutputStream(); 
        PrintStream verboseOut = new PrintStream(verboseOutBuffer, true); 

         // Create ShaderCode objects 

        ShaderCode vertexShaderCode = new ShaderCode(GL2.GL_VERTEX_SHADER, 1, 
                new String[][]{ { vertexSrc } }); 
        ShaderCode fragmentShaderCode = new ShaderCode(GL2.GL_FRAGMENT_SHADER, 1, 
                new String[][]{ { fragmentSrc } }); 

        // Put them in a ShaderProgram 

        ShaderProgram program = new ShaderProgram(); 
        program.add(vertexShaderCode); 
        program.add(fragmentShaderCode); 

        // Create a new ShaderState 

        ShaderState shaderState = new ShaderState(); 

        // Link the programs here? 

        if (!program.link(gl, verboseOut)) 
            throw new GLException("Failed to compile and link shaders: " + verboseOutBuffer.toString()); 

        // Attach the program to the state. Requires that the program be linked. 

        shaderState.attachShaderProgram(gl, program); 

        // Set some attributes. Requires that the program be attached BUT NOT LINKED??? 

        Set<Entry<Integer, String>> attributeSet = attributes.entrySet(); 
        Iterator<Entry<Integer, String>> iterator = attributeSet.iterator(); 
        while (iterator.hasNext()) 
        { 
            Entry<Integer, String> entry = iterator.next(); 
            shaderState.glBindAttribLocation(gl, entry.getKey(), entry.getValue()); 
        } 

        return shaderState; 
}