OpenGL学习3

颜色和旋转

1.平滑着色

glColorPointer (int size, int type, int stride, Buffer pointer)

给每个点定义颜色值，各点之间平滑着色

需要gl.glEnableClientState(GL10.GL_COLOR_ARRAY);启动该功能，使用完需要gl.glDisableClientState(GL10.GL_COLOR_ARRAY);关闭平滑着色功能

 

2.单调着色

glColor4f (float red, float green, float blue, float alpha) 参数值在0.0-1.0之间

glColor4x (int red, int green, int blue, int alpha) int的高16位代表整数，低16为代表小数，因此，（0x10000,0,0,0x10000）表示红色不透明

 

3.旋转

 glRotatex (int angle, int x, int y, int z)

第一个参数表示旋转的角度，（x,y,z）和（0,0,0）组成的直线代表旋转的轴

4.demo

package com.lanhuidong.opengl;

import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLSurfaceView.Renderer;

import com.lanhuidong.opengl.util.BufferToNativeOrder;

/**
 * @author lan
 * @since 2011-6-27
 * @version
 */
public class OpenGLRender implements Renderer {

    private static int x = 0x10000 / 4;
    private static float f = 0.5f;
    private static float[] array = new float[] { -f, 0, 0, 0, (float) (f * Math.sqrt(3) / 2), 0, f, 0, 0 };
    private static int[] array2 = new int[] { x, x, 0, x, -x, 0, -x, x, 0, -x, -x, 0 };
    private static int[] array3 = new int[] { x, x, 0, -x, x, 0, -2 * x, 0, 0, -x, -x, 0, x, -x, 0, 2 * x, 0, 0 };
    private static float[] colorarray = new float[] { 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1 };
    private static float rotateTri = 0f;
    private static int rotateQuad = 0x10000;

    /**
     * 调用此方法绘制当前窗口
     */
    @Override
    public void onDrawFrame(GL10 gl) {
        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
        gl.glLoadIdentity();
        gl.glTranslatef(-0.5f, 0.5f, -1.0f);
        // 画三角行
        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
        FloatBuffer triangleBuffer = BufferToNativeOrder.getNativeOrderFloatBuffer(array);
        gl.glRotatef(rotateTri, 0f, 1f, 0f);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, triangleBuffer);
        gl.glColorPointer(4, GL10.GL_FIXED, 0, BufferToNativeOrder.getNativeOrderFloatBuffer(colorarray));
        gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
        rotateTri += 0.5;
        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);

        gl.glLoadIdentity();
        gl.glTranslatef(0.5f, 0.5f, -1.0f);
        // 画矩形
        IntBuffer quadrangleBuffer = BufferToNativeOrder.getNativeOrderIntBuffer(array2);
        gl.glVertexPointer(3, GL10.GL_FIXED, 0, quadrangleBuffer);
        gl.glColor4f(1f, 0f, 0f, 1f);
        gl.glRotatex(rotateQuad, 1, 0, 0);
        rotateQuad -= 0x10000;
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);

        gl.glLoadIdentity();
        gl.glTranslatef(-0.5f, -0.5f, -1.0f);
        // 画矩形
        gl.glVertexPointer(3, GL10.GL_FIXED, 0, BufferToNativeOrder.getNativeOrderIntBuffer(array3));
        gl.glColor4x(0x10000, 0, 0x10000, 0x10000);
        gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 6);

        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    }

    /**
     * 窗口被创建或者窗口大小改变时被调用
     */
    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {
        gl.glViewport(0, 0, width, height);

        float ratio = (float) width / height;
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
    }

    /**
     * 窗口被创建或者被重新创建时调用，做初始化工作
     */
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        gl.glClearColor(0, 0, 1.0f, 0.5f);
    }

}

 

5.效果