package com.xscm.moduleutil.widget;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import android.opengl.GLES20;
import android.util.Log;

public class ShaderUtils {

    private static final String TAG = "ShaderUtils";

    // 创建并编译着色器
    public static int loadShader(int type, String shaderCode) {
        int shader = GLES20.glCreateShader(type);
        GLES20.glShaderSource(shader, shaderCode);
        GLES20.glCompileShader(shader);

        int[] compiled = new int[1];
        GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
        if (compiled[0] == 0) {
            Log.e(TAG, "Could NOT compile shader: " + GLES20.glGetShaderInfoLog(shader));
            GLES20.glDeleteShader(shader);
            return 0;
        }

        return shader;
    }

    // 创建 FloatBuffer
    public static FloatBuffer createFloatBuffer(float[] array) {
        ByteBuffer bb = ByteBuffer.allocateDirect(array.length * 4);
        bb.order(ByteOrder.nativeOrder());
        FloatBuffer buffer = bb.asFloatBuffer();
        buffer.put(array);
        buffer.position(0);
        return buffer;
    }
}