Android OpenGL10 基本图形绘制
下面程序的opengl的图形是根据Opengl1.0版本API进行的.
<1> : 新建一个android studio工程,这个工程参考前一篇坐标系的.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);
}
}
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);
}
}
上面对于的坐标线:
//pumpKin.draw(gl);被注释了,这个绘制的坐标线不是必须的,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:
如果将坐标系直线显示出来:
上面的在程序中,做了坐标变换:对坐标做了旋转变换.
gl.glRotatef(45,1.0f,1.0f,1.0f);坐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.
: 下面介绍绘制直线,其实绘制直线前面已经有了,比如绘制坐标直线.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);
}
}
如果想显示当前的坐标线,可以将
// pumpKin.draw(gl);去掉注释.
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,坐标方式差不多.三维图形基本也是由基本二维图形构成的.
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坐标,然后再来对应上面的坐标点就了解了.
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,主要是要定好坐标原点,比如上面坐标原点在金字塔中心位置.比如上面对着我们的绿色角,对应的顶点坐标(-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.
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
* 三维坐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);gl.glCullFace(GL10.GL_BACK);gl.glFrontFace(GL10.GL_CCW);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.