Android OpenGL10 基本图形绘制

原創 喝醉了的熊猫 2020-06-14 22:44

下面程序的opengl的图形是根据Opengl1.0版本API进行的.

<a> : 首先绘制点:

<1> : 新建一个android studio工程,这个工程参考前一篇座标系的.工程名:PumpKinBasicGL10,主类如下:

package org.durian.pumpkinbasicgl10;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;

import org.durian.pumpkinbasicgl10.draw2d.PumpKinRenderer;
import org.durian.pumpkinbasicgl10.draw2d.dot.PumpkinDotRenderer;
import org.durian.pumpkinbasicgl10.draw2d.line.PumpKinLineRenderer;
import org.durian.pumpkinbasicgl10.draw2d.triangle.PumpKinTriangleRenderer;
import org.durian.pumpkinbasicgl10.draw3d.cube.PumpKinCubeRenderer;
import org.durian.pumpkinbasicgl10.draw3d.shapes.PumpKinPyramidRenderer;

public class MainActivity extends Activity {

    private GLSurfaceView mSurfaceView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mSurfaceView=new GLSurfaceView(this);
        mSurfaceView.setRenderer(/*new PumpKinRenderer()*/new PumpkinDotRenderer()/*new PumpKinLineRenderer(this)*//*new PumpKinTriangleRenderer()*//*new PumpKinPyramidRenderer()*//*new PumpKinCubeRenderer()*/);
        setContentView(mSurfaceView/*R.layout.activity_main*/);
    }

    @Override
    protected void onResume() {
        super.onResume();
        mSurfaceView.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mSurfaceView.onPause();
    }
}


<2> : 画点类程序如下:

package org.durian.pumpkinbasicgl10.draw2d.dot;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/26.
 */
public class PumpKinDot {

    private FloatBuffer vertexsBuffer;

    private FloatBuffer colorsBuffer;

    //x,y,z
    private float[] vertexs=new float[]{
            1.0f,0.0f,0.0f,
            0.0f,1.0f,0.0f,
            -1.0f,0.0f,0.0f,
            0.0f,-1.0f,0.0f,
            0.5f,0.0f,0.0f,
            0.0f,0.5f,0.0f,
            -0.5f,0.0f,0.0f,
            0.0f,-0.5f,0.0f,
            0.0f,0.0f,0.0f,
            0.0f,0.0f,1.0f,
            0.0f,0.0f,-1.0f,
            0.0f,0.0f,0.5f,
            0.0f,0.0f,-0.5f,
            0.0f,0.0f,0.0f

    };

    //r,g,b,a
    private float[] colors={
            0.0f,1.0f,0.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            1.0f,1.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
            1.0f,1.0f,1.0f,1.0f,
    };

    public PumpKinDot(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertexs);
        vertexsBuffer.position(0);

        ByteBuffer cbb=ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        colorsBuffer=cbb.asFloatBuffer();
        colorsBuffer.put(colors);
        colorsBuffer.position(0);

    }

    public void draw(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);
        gl.glDrawArrays(GL10.GL_POINTS,0,vertexs.length/3);
        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

}
上面程序主要是注意

gl.glDrawArrays(GL10.GL_POINTS,0,vertexs.length/3);

第一个参数为设置绘制图形类型.第一篇博客已有说明.

程序在x,y,z轴上面绘制画出多个点.

渲染的类:

package org.durian.pumpkinbasicgl10.draw2d.dot;

import android.opengl.GLSurfaceView;
import android.opengl.GLU;

import org.durian.pumpkinbasicgl10.draw2d.PumpKin;

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

/**
 * Created by Administrator on 2016/4/26.
 */
public class PumpkinDotRenderer implements GLSurfaceView.Renderer {

    private PumpKinDot pumpKinDot;
    private PumpKin pumpKin;

    public PumpkinDotRenderer() {

        pumpKinDot = new PumpKinDot();
        pumpKin=new PumpKin();
    }

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if (height == 0) {
            height = 1;
        }
        float aspect = (float) width / height;

        gl.glViewport(0, 0, width, height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f, 0.0f, -6.0f);
        gl.glRotatef(45,1.0f,1.0f,1.0f);
        //pumpKin.draw(gl);
        pumpKinDot.draw(gl);


    }
}

上面对于的座标线:

//pumpKin.draw(gl);

被注释了,这个绘制的座标线不是必须的,只是让人可以更好定位三维空间位置,能够看得见.

运行结果:


如果将座标系直线显示出来:


上面的在程序中,做了座标变换:对座标做了旋转变换.

gl.glRotatef(45,1.0f,1.0f,1.0f);

座标线条程序和前一篇一模一样:

package org.durian.pumpkinbasicgl10.draw2d;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/28.
 */
public class PumpKin {

    private FloatBuffer vertexsBuffer;
    private FloatBuffer colorsBuffer;

    private ByteBuffer indicesBuffer;

    private float vertexs[]={
            -3.0f,0.0f,0.0f,
            3.0f,0.0f,0.0f,
            0.0f,-3.0f,0.0f,
            0.0f,3.0f,0.0f,
            0.0f,0.0f,-3.0f,
            0.0f,0.0f,3.0f
    };

    private float colors[]={
            1.0f,0.0f,0.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            0.0f,0.0f,1.0f,1.0f,
            0.0f,0.0f,1.0f,1.0f
    };

    private byte indices[]={0,1,2};

    public PumpKin(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertexs);
        vertexsBuffer.position(0);

        ByteBuffer cbb=ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        colorsBuffer=cbb.asFloatBuffer();
        colorsBuffer.put(colors);
        colorsBuffer.position(0);

    }

    public void draw(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);

        gl.glDrawArrays(GL10.GL_LINES,0,vertexs.length/3);

        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

}

package org.durian.pumpkinbasicgl10.draw2d;

import android.opengl.GLSurfaceView;
import android.opengl.GLU;

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

/**
 * Created by Administrator on 2016/4/28.
 */
public class PumpKinRenderer implements GLSurfaceView.Renderer {

    private PumpKin pumpKin;

    public PumpKinRenderer(){
        pumpKin=new PumpKin();
    }
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f,0.0f,-2f);
        gl.glRotatef(45,1.0f,1.0f,1.0f);
        pumpKin.draw(gl);

    }
}

上面即是绘制点.


<b> : 下面介绍绘制直线,其实绘制直线前面已经有了,比如绘制座标直线.只需要在上面工程添加绘制line的类和渲染类

package org.durian.pumpkinbasicgl10.draw2d.line;

import android.util.Log;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/26.
 */
public class PumpKinLine {

    private FloatBuffer vertexsBuffer;
    private FloatBuffer colorsBuffer;
    private ByteBuffer indicesBuffer;

    private float[] vertexss={
            -1.0f,-1.0f,0.0f,
            1.0f,-1.0f,0.0f,
            -1.0f,1.0f,0.0f,
            1.0f,1.0f,0.0f
    };
    //x,y,z
    private float[] vertexs={
            0.0f,0.0f,0.0f,
            1.0f,0.0f,0.0f,
            0.0f,0.0f,0.0f,
            0.0f,1.0f,0.0f
    };
    //r,g,b,a
    private float[] colors={
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f
    };

    private byte[] indices={
            0,1,2
    };

    public PumpKinLine(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertexs);
        vertexsBuffer.position(0);


        ByteBuffer cbb=ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        colorsBuffer=cbb.asFloatBuffer();
        colorsBuffer.put(colors);
        colorsBuffer.position(0);

        indicesBuffer=ByteBuffer.allocateDirect(indices.length);
        indicesBuffer.put(indices);
        indicesBuffer.position(0);

    }

    public void draw(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);

        gl.glColor4f(1.0f,0.0f,0.0f,1.0f);
        gl.glDrawArrays(GL10.GL_LINES,0,vertexs.length/3);

        //gl.glDrawElements(GL10.GL_TRIANGLES,indices.length,GL10.GL_UNSIGNED_BYTE,indicesBuffer);
        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

}

绘制也可以通过:

gl.glDrawElements(GL10.GL_TRIANGLES,indices.length,GL10.GL_UNSIGNED_BYTE,indicesBuffer);

进行,只是这个方法需要提供绘制序列点indices数组.

绘制的直线的:

0.0f,0.0f,0.0f,
            1.0f,0.0f,0.0f,

这两点连接的线

以及:

0.0f,0.0f,0.0f,
            0.0f,1.0f,0.0f

这两天链接的线.

即两条线分别沿x,y正方向.

对应的渲染类如下:

package org.durian.pumpkinbasicgl10.draw2d.line;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.opengl.GLU;

import org.durian.pumpkinbasicgl10.draw2d.PumpKin;

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

/**
 * Created by Administrator on 2016/4/26.
 */
public class PumpKinLineRenderer implements GLSurfaceView.Renderer {

    private PumpKinLine pumpKinLine;
    private PumpKin pumpKin;
    public PumpKinLineRenderer(){

        pumpKinLine=new PumpKinLine();
        pumpKin=new PumpKin();

    }

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        //gl.glTranslatef(0.0f,0.0f,0.0f);
        gl.glTranslatef(0.0f,0.0f,-0.1f);
        //gl.glTranslatef(-3.0f,0.0f,-6.0f);
        //gl.glTranslatef(3.0f,0.0f,1.0f);
//        pumpKin.draw(gl);
        pumpKinLine.draw(gl);


    }

}


如果想显示当前的座标线,可以将

//        pumpKin.draw(gl);

去掉注释.


<c> : 绘制多边形:代码如下

package org.durian.pumpkinbasicgl10.draw2d.triangle;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/27.
 */
public class PumpKinTriangle {

    private FloatBuffer vertexsBuffer;
    private FloatBuffer vertexsaBuffer;
    private FloatBuffer colorsBuffer;
    private FloatBuffer colorsaBuffer;

    private ByteBuffer indicesBuffer;
    private ByteBuffer indicesaBuffer;

    //x,y,z
    private float[] vertexs={
        1.0f,0.0f,0.0f,
            0.0f,1.0f,0.0f,
                0.0f,0.0f,1.0f
    };

    private float[] vertexsa={
            1.0f,0.0f,0.0f,
            0.0f,1.0f,0.0f,
            0.0f,0.0f,1.0f,
            1.0f,0.0f,1.0f,
            0.5f,1.0f,0.0f,
            0.5f,1.0f,1.0f
    };

    //r,g,b,a
    private float[] colors={
        1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            0.0f,0.0f,1.0f,1.0f
    };

    private float[] colorsa={
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            0.0f,0.0f,1.0f,1.0f,
            1.0f,0.0f,0.0f,1.0f,
            0.0f,1.0f,0.0f,1.0f,
            0.0f,0.0f,1.0f,1.0f
    };

    private byte[] indices={0,1,2};

    private byte[] indicesa={0,1,2,3,4,5};


    public PumpKinTriangle(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertexs);
        vertexsBuffer.position(0);

        ByteBuffer vbba=ByteBuffer.allocateDirect(vertexsa.length*4);
        vbba.order(ByteOrder.nativeOrder());
        vertexsaBuffer=vbba.asFloatBuffer();
        vertexsaBuffer.put(vertexsa);
        vertexsaBuffer.position(0);

        ByteBuffer cbb=ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        colorsBuffer=cbb.asFloatBuffer();
        colorsBuffer.put(colors);
        colorsBuffer.position(0);

        ByteBuffer cbba=ByteBuffer.allocateDirect(colorsa.length*4);
        cbba.order(ByteOrder.nativeOrder());
        colorsaBuffer=cbba.asFloatBuffer();
        colorsaBuffer.put(colorsa);
        colorsaBuffer.position(0);

        indicesBuffer=ByteBuffer.allocateDirect(indices.length);
        indicesBuffer.order(ByteOrder.nativeOrder());
        indicesBuffer.put(indices);
        indicesBuffer.position(0);

        indicesaBuffer=ByteBuffer.allocateDirect(indicesa.length);
        indicesaBuffer.order(ByteOrder.nativeOrder());
        indicesaBuffer.put(indicesa);
        indicesaBuffer.position(0);

    }

    // type :GL10.GL_TRIANGLES
    public void draw(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);

        gl.glDrawArrays(GL10.GL_TRIANGLES,0,vertexs.length/3);

        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

    public void drawE(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);
        gl.glDrawElements(GL10.GL_TRIANGLES,indices.length,GL10.GL_UNSIGNED_BYTE,indicesBuffer);

        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

    public void drawNc(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

        gl.glColor4f(0.0f,1.0f,0.0f,1.0f);
        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);

        gl.glDrawArrays(GL10.GL_TRIANGLES,0,vertexs.length/3);

    }

    //type : GL10.GL_TRIANGLE_STRIP
    public void draw1(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsaBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsaBuffer);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,vertexsa.length/3);

        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

    //type : GL10.GL_TRIANGLE_FAN
    public void draw1E(GL10 gl){

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsaBuffer);
        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsaBuffer);

        gl.glDrawElements(GL10.GL_TRIANGLE_FAN,indicesa.length,GL10.GL_UNSIGNED_BYTE,indicesaBuffer);

        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

}


程序采用了两种绘制图像的方法:

gl.glDrawArrays

和:

gl.glDrawElements

这两种绘制在前面大致说过了.

这里主要介绍这两个方法的第一个参数:分别是GL_TRIANGLES、GL_TRIANGLE_STRIP和GL_TRIANGLE_FAN

图片出处:http://blog.csdn.net/xiajun07061225/article/details/7455283,参考具体说明:

GL_TRIANGLES是以每三个顶点绘制一个三角形。第一个三角形使用顶点v0,v1,v2,第二个使用v3,v4,v5,以此类推。如果顶点的个数n不是3的倍数，那么最后的1个或者2个顶点会被忽略。

GL_TRIANGLE_STRIP则稍微有点复杂。
其规律是：
构建当前三角形的顶点的连接顺序依赖于要和前面已经出现过的2个顶点组成三角形的当前顶点的序号的奇偶性（如果从0开始）：
如果当前顶点是奇数：
组成三角形的顶点排列顺序：T = [n-1 n-2 n].
如果当前顶点是偶数：
组成三角形的顶点排列顺序：T = [n-2 n-21 n].
以上图为例，第一个三角形，顶点v2序号是2，是偶数，则顶点排列顺序是v0,v1,v2。第二个三角形，顶点v3序号是3，是奇数，则顶点排列顺序是v2,v1,v3,第三个三角形，顶点v4序号是4，是偶数，则顶点排列顺序是v2,v3,v4,以此类推。
这个顺序是为了保证所有的三角形都是按照相同的方向绘制的，使这个三角形串能够正确形成表面的一部分。对于某些操作，维持方向是很重要的，比如剔除。
注意：顶点个数n至少要大于3，否则不能绘制任何三角形。

GL_TRIANGLE_FAN与GL_TRIANGLE_STRIP类似，不过它的三角形的顶点排列顺序是T = [n-1 n-2 n].各三角形形成一个扇形序列

还有一个更加具体的可以参考,非常好:

http://blog.csdn.net/gisxs/article/details/16897229

对应渲染类:

package org.durian.pumpkinbasicgl10.draw2d.triangle;

import android.opengl.GLSurfaceView;
import android.opengl.GLU;

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

/**
 * Created by Administrator on 2016/4/27.
 */
public class PumpKinTriangleRenderer implements GLSurfaceView.Renderer {

    private PumpKinTriangle pumpKinTriangle;
    public PumpKinTriangleRenderer(){

        pumpKinTriangle=new PumpKinTriangle();

    }

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f,0.0f,-6.0f);

        pumpKinTriangle.draw1(gl);

    }
}

如果调用draw1方法,运行结果如下:


如果将渲染类中程序修改:

//        pumpKinTriangle.draw1(gl);
        pumpKinTriangle.draw1E(gl);


运行结果:



上面大致介绍了基本二维图形的绘制.

下面介绍三维图形,三维图形其实和二维在程序上面没什么区别,只是需要注意z轴了,座标方式差不多.三维图形基本也是由基本二维图形构成的.

<d> : 绘制金字塔模型:

package org.durian.pumpkinbasicgl10.draw3d.shapes;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/28.
 */
public class PumpKinPyramid {

    private FloatBuffer vertexsBuffer;
    private FloatBuffer colorsBuffer;

    private ByteBuffer indicesBuffer;

    // 5 vertices of the pyramid in (x,y,z)
    private float[] vertexs={
            -1.0f, -1.0f, -1.0f,  // 0. left-bottom-back
            1.0f, -1.0f, -1.0f,  // 1. right-bottom-back
            1.0f, -1.0f,  1.0f,  // 2. right-bottom-front
            -1.0f, -1.0f,  1.0f,  // 3. left-bottom-front
            0.0f,  1.0f,  0.0f   // 4. top
    };

    // Colors of the 5 vertices in RGBA
    private float[] colors={
            0.0f, 0.0f, 1.0f, 1.0f,  // 0. blue
            0.0f, 1.0f, 0.0f, 1.0f,  // 1. green
            0.0f, 0.0f, 1.0f, 1.0f,  // 2. blue
            0.0f, 1.0f, 0.0f, 1.0f,  // 3. green
            1.0f, 0.0f, 0.0f, 1.0f   // 4. red
    };

    private byte indices[]={
            2, 4, 3,   // front face (CCW)
            1, 4, 2,   // right face
            0, 4, 1,   // back face
            4, 0, 3    // left face
    };

    public PumpKinPyramid(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertexs);
        vertexsBuffer.position(0);

        ByteBuffer cbb=ByteBuffer.allocateDirect(colors.length*4);
        cbb.order(ByteOrder.nativeOrder());
        colorsBuffer=cbb.asFloatBuffer();
        colorsBuffer.put(colors);
        colorsBuffer.position(0);

        indicesBuffer=ByteBuffer.allocateDirect(indices.length);
        indicesBuffer.order(ByteOrder.nativeOrder());
        indicesBuffer.put(indices);
        indicesBuffer.position(0);

    }

    public void draw(GL10 gl){

        gl.glFrontFace(GL10.GL_CCW);

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl.glColorPointer(4,GL10.GL_FLOAT,0,colorsBuffer);
        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);

        gl.glDrawElements(GL10.GL_TRIANGLE_STRIP,indices.length,GL10.GL_UNSIGNED_BYTE,indicesBuffer);

        gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }


}

其中:

gl.glFrontFace(GL10.GL_CCW);

改程序设置:设置逆时针方向为正面.

上面的程序了vertexs顶点数组,可以很难搞清,等下在渲染器中添加座标,然后再来对应上面的座标点就了解了.
下面给出对应的渲染类:

package org.durian.pumpkinbasicgl10.draw3d.shapes;

import android.opengl.GLSurfaceView;
import android.opengl.GLU;

import org.durian.pumpkinbasicgl10.draw2d.PumpKin;

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

/**
 * Created by Administrator on 2016/4/28.
 */
public class PumpKinPyramidRenderer implements GLSurfaceView.Renderer {

    private PumpKinPyramid pumpKinPyramid;
    private PumpKin pumpKin;

    public PumpKinPyramidRenderer(){

        pumpKinPyramid=new PumpKinPyramid();
        pumpKin=new PumpKin();

    }
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f, 0.0f, -8.0f);
        gl.glRotatef(45,1.0f,1.0f,1.0f);
        pumpKinPyramid.draw(gl);
        pumpKin.draw(gl);

    }
}


运行结果:




一个金字塔形的立体需要4个面,一共需要5个顶点,主要是要定好座标原点,比如上面座标原点在金字塔中心位置.比如上面对着我们的绿色角,对应的顶点座标(-1.0f, -1.0f,  1.0f),红色顶点在y轴(红线是x轴,绿色y轴,蓝色z轴)位置(0.0f,  1.0f,  0.0f),刚好绿线(y轴)结果顶点,其他的一次类推.


<e> : 下面介绍立方体,基本上都是类似做法,立方体有八个座标,同上,原点(0,0,0)设置在立方体中心位置,程序如下:

package org.durian.pumpkinbasicgl10.draw3d.cube;

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

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by Administrator on 2016/4/29.
 */
public class PumpKinCube {

    private FloatBuffer vertexsBuffer;

    private FloatBuffer lvertexsBuffer;
    private FloatBuffer lcolorsBuffer;

    /*
    * eight vertex as following :
    * V0 : -1.0f, -1.0f,  1.0f
    * V1 : 1.0f, -1.0f,  1.0f
    * V2 : -1.0f,  1.0f,  1.0f
    * V3 : -1.0f, -1.0f, -1.0f
    * V4 : -1.0f, -1.0f, -1.0f
    * V5 : -1.0f,  1.0f, -1.0f
    * V6 : 1.0f, -1.0f, -1.0f
    * V7 : 1.0f,  1.0f, -1.0f
    * 三维座标系原点在这个立方体中心
    * */
    private float[] vertices = {  // Vertices of the 6 faces
            // FRONT
            -1.0f, -1.0f,  1.0f,  // 0. left-bottom-front
            1.0f, -1.0f,  1.0f,  // 1. right-bottom-front
            -1.0f,  1.0f,  1.0f,  // 2. left-top-front
            1.0f,  1.0f,  1.0f,  // 3. right-top-front
            // BACK
            1.0f, -1.0f, -1.0f,  // 6. right-bottom-back
            -1.0f, -1.0f, -1.0f,  // 4. left-bottom-back
            1.0f,  1.0f, -1.0f,  // 7. right-top-back
            -1.0f,  1.0f, -1.0f,  // 5. left-top-back
            // LEFT
            -1.0f, -1.0f, -1.0f,  // 4. left-bottom-back
            -1.0f, -1.0f,  1.0f,  // 0. left-bottom-front
            -1.0f,  1.0f, -1.0f,  // 5. left-top-back
            -1.0f,  1.0f,  1.0f,  // 2. left-top-front
            // RIGHT
            1.0f, -1.0f,  1.0f,  // 1. right-bottom-front
            1.0f, -1.0f, -1.0f,  // 6. right-bottom-back
            1.0f,  1.0f,  1.0f,  // 3. right-top-front
            1.0f,  1.0f, -1.0f,  // 7. right-top-back
            // TOP
            -1.0f,  1.0f,  1.0f,  // 2. left-top-front
            1.0f,  1.0f,  1.0f,  // 3. right-top-front
            -1.0f,  1.0f, -1.0f,  // 5. left-top-back
            1.0f,  1.0f, -1.0f,  // 7. right-top-back
            // BOTTOM
            -1.0f, -1.0f, -1.0f,  // 4. left-bottom-back
            1.0f, -1.0f, -1.0f,  // 6. right-bottom-back
            -1.0f, -1.0f,  1.0f,  // 0. left-bottom-front
            1.0f, -1.0f,  1.0f   // 1. right-bottom-front
    };

    private float[][] colors = {  // Colors of the 6 faces
            {1.0f, 0.5f, 0.0f, 1.0f},  // 0. orange
            {1.0f, 0.0f, 1.0f, 1.0f},  // 1. violet
            {0.0f, 1.0f, 0.0f, 1.0f},  // 2. green
            {0.0f, 0.0f, 1.0f, 1.0f},  // 3. blue
            {1.0f, 0.0f, 0.0f, 1.0f},  // 4. red
            {1.0f, 1.0f, 0.0f, 1.0f}   // 5. yellow
    };

    public PumpKinCube(){

        ByteBuffer vbb=ByteBuffer.allocateDirect(vertices.length*4);
        vbb.order(ByteOrder.nativeOrder());
        vertexsBuffer=vbb.asFloatBuffer();
        vertexsBuffer.put(vertices);
        vertexsBuffer.position(0);

    }

    public void draw(GL10 gl){

        gl.glFrontFace(GL10.GL_CCW);
        gl.glEnable(GL10.GL_CULL_FACE);
        gl.glCullFace(GL10.GL_BACK);

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

        gl.glVertexPointer(3,GL10.GL_FLOAT,0,vertexsBuffer);

        for(int i=0;i<6;i++){

            gl.glColor4f(colors[i][0],colors[i][1],colors[i][2],colors[i][3]);
            gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,i*4,4);

        }

        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glDisable(GL10.GL_CULL_FACE);

    }

}

特别说一下:

gl.glFrontFace(GL10.GL_CCW);
        gl.glEnable(GL10.GL_CULL_FACE);
        gl.glCullFace(GL10.GL_BACK);
gl.glEnable(GL10.GL_CULL_FACE);
设置openggl有剔除效果，就是看不到的面就不画，当然可以增加效率
gl.glCullFace(GL10.GL_BACK);
设置背面被剔除，不画.
gl.glFrontFace(GL10.GL_CCW);
设置逆时针方向为正面


对应渲染器类:

package org.durian.pumpkinbasicgl10.draw3d.cube;

import android.opengl.GLSurfaceView;
import android.opengl.GLU;

import org.durian.pumpkinbasicgl10.draw2d.PumpKin;

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

/**
 * Created by Administrator on 2016/4/29.
 */
public class PumpKinCubeRenderer implements GLSurfaceView.Renderer {

    private PumpKinCube pumpKinCube;
    private PumpKin pumpKin;

    private int cubeAngle=0;
    private int cubeSpeech=1;

    public PumpKinCubeRenderer(){
        pumpKinCube=new PumpKinCube();
        pumpKin=new PumpKin();
    }
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {

        gl.glClearColor(0.0f,0.0f,0.0f,1.0f);
        gl.glClearDepthf(1.0f);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glDepthFunc(GL10.GL_LEQUAL);
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,GL10.GL_NICEST);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glDisable(GL10.GL_DITHER);

    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {

        if(height==0){
            height=1;
        }
        float aspect=(float)width/height;

        gl.glViewport(0,0,width,height);

        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.0f);

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

    }

    @Override
    public void onDrawFrame(GL10 gl) {

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f,0.0f,-6.0f);
        gl.glRotatef(cubeAngle,1.0f,1.0f,1.0f);
        gl.glScalef(0.8f,0.8f,0.8f);
        pumpKinCube.draw(gl);
        pumpKin.draw(gl);

        cubeAngle+=cubeSpeech;
    }
}


运行如下:




至于纹理部分将在后面单独给出来简述.


















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喝醉了的熊猫 2020-06-14 22:45:07

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對於很多初學者,視圖投影之類非常的難理解,然而這個東西非常非常的重要,如果不是非常清楚,根本無法定位3D Object(空間座標)和觀察角度(觀察角度不一樣,效果就不一樣),自己閱博無數,發現了一篇非常棒的blog文章: http://b

喝醉了的熊猫 2020-06-14 22:45:07

Android OpenGL 座标系

計算機中任何繪圖都離不開座標系只是在每種繪圖中座標系形式有些差異,比如平時做android的View,在自定義View中繪製直線,那麼這個時候默認的是採用的是屏幕座標系,即座標原點在屏幕左上角,X軸向右,Y向下: 而在opengl中採用

喝醉了的熊猫 2020-06-14 22:45:07