SimpleEGLConfigChooser.java

package com.glview.hwui;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLDisplay;

import android.opengl.EGL14;
import android.opengl.EGLExt;

public class SimpleEGLConfigChooser implements EGLConfigChooser {
	
	protected int[] mConfigSpec;
	
	private int[] mValue = new int[1];
    // Subclasses can adjust these values:
    protected int mRedSize;
    protected int mGreenSize;
    protected int mBlueSize;
    protected int mAlphaSize;
    protected int mDepthSize;
    protected int mStencilSize;
    protected final int mEGLContextClientVersion;
    
    public SimpleEGLConfigChooser(int[] configSpec, int glVersion) {
    	mEGLContextClientVersion = glVersion;
    	mConfigSpec = filterConfigSpec(configSpec);
    }
    
    public SimpleEGLConfigChooser(int redSize, int greenSize, int blueSize,
            int alphaSize, int depthSize, int stencilSize, int glVersion) {
    	this(new int[] {
                EGL10.EGL_RED_SIZE, redSize,
                EGL10.EGL_GREEN_SIZE, greenSize,
                EGL10.EGL_BLUE_SIZE, blueSize,
                EGL10.EGL_ALPHA_SIZE, alphaSize,
                EGL10.EGL_DEPTH_SIZE, depthSize,
                EGL10.EGL_STENCIL_SIZE, stencilSize,
                EGL10.EGL_NONE}, glVersion);
        mRedSize = redSize;
        mGreenSize = greenSize;
        mBlueSize = blueSize;
        mAlphaSize = alphaSize;
        mDepthSize = depthSize;
        mStencilSize = stencilSize;
	}
    
    private int[] filterConfigSpec(int[] configSpec) {
        if (mEGLContextClientVersion != 2 && mEGLContextClientVersion != 3) {
            return configSpec;
        }
        /* We know none of the subclasses define EGL_RENDERABLE_TYPE.
         * And we know the configSpec is well formed.
         */
        int len = configSpec.length;
        int[] newConfigSpec = new int[len + 2];
        System.arraycopy(configSpec, 0, newConfigSpec, 0, len-1);
        newConfigSpec[len-1] = EGL10.EGL_RENDERABLE_TYPE;
        if (mEGLContextClientVersion == 2) {
            newConfigSpec[len] = EGL14.EGL_OPENGL_ES2_BIT;  /* EGL_OPENGL_ES2_BIT */
        } else {
            newConfigSpec[len] = EGLExt.EGL_OPENGL_ES3_BIT_KHR; /* EGL_OPENGL_ES3_BIT_KHR */
        }
        newConfigSpec[len+1] = EGL10.EGL_NONE;
        return newConfigSpec;
    }

	@Override
	public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
		int[] num_config = new int[1];
        if (!egl.eglChooseConfig(display, mConfigSpec, null, 0,
                num_config)) {
            throw new IllegalArgumentException("eglChooseConfig failed");
        }

        int numConfigs = num_config[0];

        if (numConfigs <= 0) {
            throw new IllegalArgumentException(
                    "No configs match configSpec");
        }

        EGLConfig[] configs = new EGLConfig[numConfigs];
        if (!egl.eglChooseConfig(display, mConfigSpec, configs, numConfigs,
                num_config)) {
            throw new IllegalArgumentException("eglChooseConfig#2 failed");
        }
        EGLConfig config = chooseConfig(egl, display, configs);
        if (config == null) {
            throw new IllegalArgumentException("No config chosen");
        }
        return config;
	}
	
    public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display,
            EGLConfig[] configs) {
        for (EGLConfig config : configs) {
            int d = findConfigAttrib(egl, display, config,
                    EGL10.EGL_DEPTH_SIZE, 0);
            int s = findConfigAttrib(egl, display, config,
                    EGL10.EGL_STENCIL_SIZE, 0);
            if ((d >= mDepthSize) && (s >= mStencilSize)) {
                int r = findConfigAttrib(egl, display, config,
                        EGL10.EGL_RED_SIZE, 0);
                int g = findConfigAttrib(egl, display, config,
                         EGL10.EGL_GREEN_SIZE, 0);
                int b = findConfigAttrib(egl, display, config,
                          EGL10.EGL_BLUE_SIZE, 0);
                int a = findConfigAttrib(egl, display, config,
                        EGL10.EGL_ALPHA_SIZE, 0);
                if ((r == mRedSize) && (g == mGreenSize)
                        && (b == mBlueSize) && (a == mAlphaSize)) {
                    return config;
                }
            }
        }
        return null;
    }

    protected int findConfigAttrib(EGL10 egl, EGLDisplay display,
            EGLConfig config, int attribute, int defaultValue) {

    	if (egl.eglGetConfigAttrib(display, config, attribute, mValue)) {
			return mValue[0];
		}
		return defaultValue;
    }
}