android 使用OPENGL ES繪製一個圓柱體-三維空間
阿新 • • 發佈：2019-02-04
package com.scout.eeeeeee; /** * Created by liuguodong on 2017/10/29. */ import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import java.util.ArrayList; import javax.microedition.khronos.opengles.GL10; public class zhuCH { private FloatBuffer dingBuffer;//頂點座標緩衝 private FloatBuffermyNormalBuffer;//向量緩衝 private FloatBuffer myTexture;//紋理緩衝 int textureId; int vCount;//頂點數量 float length;//圓柱長度 float circle_radius;//圓截環半徑 float degreespan; //圓截環每一份的度數大小 public float mAngleX; public float mAngleY; public float mAngleZ; public zhuCH(float length,float circle_radius,float degreespan,int textureId) { this.circle_radius=circle_radius; this.length=length; this.degreespan=degreespan; this.textureId=textureId; float collength=(float)length;//圓柱每塊所佔的長度 int spannum=(int)(360.0f/degreespan); ArrayList<Float> val=new ArrayList<Float>();//頂點存放列表 ArrayList<Float> ial=new ArrayList<Float>();//法向量存放列表 for(float circle_degree=180.0f;circle_degree>0.0f;circle_degree-=degreespan)//迴圈行 { float x1 =(float)(-length/2); float y1=(float) (circle_radius*Math.sin(Math.toRadians(circle_degree))); float z1=(float) (circle_radius*Math.cos(Math.toRadians(circle_degree))); float a1=0; float b1=y1; float c1=z1; float l1=getVectorLength(a1, b1, c1);//模長 a1=a1/l1;//法向量規格化 b1=b1/l1; c1=c1/l1; float x2 =(float)(-length/2); float y2=(float) (circle_radius*Math.sin(Math.toRadians(circle_degree-degreespan))); float z2=(float) (circle_radius*Math.cos(Math.toRadians(circle_degree-degreespan))); float a2=0; float b2=y2; float c2=z2; float l2=getVectorLength(a2, b2, c2);//模長 a2=a2/l2;//法向量規格化 b2=b2/l2; c2=c2/l2; float x3 =(float)(length/2); float y3=(float) (circle_radius*Math.sin(Math.toRadians(circle_degree-degreespan))); float z3=(float) (circle_radius*Math.cos(Math.toRadians(circle_degree-degreespan))); float a3=0; float b3=y3; float c3=z3; float l3=getVectorLength(a3, b3, c3);//模長 a3=a3/l3;//法向量規格化 b3=b3/l3; c3=c3/l3; float x4 =(float)(length/2); float y4=(float) (circle_radius*Math.sin(Math.toRadians(circle_degree))); float z4=(float) (circle_radius*Math.cos(Math.toRadians(circle_degree))); float a4=0; float b4=y4; float c4=z4; float l4=getVectorLength(a4, b4, c4);//模長 a4=a4/l4;//法向量規格化 b4=b4/l4; c4=c4/l4; val.add(x1);val.add(y1);val.add(z1);//兩個三角形，共6個頂點的座標 val.add(x2);val.add(y2);val.add(z2); val.add(x4);val.add(y4);val.add(z4); val.add(x2);val.add(y2);val.add(z2); val.add(x3);val.add(y3);val.add(z3); val.add(x4);val.add(y4);val.add(z4); ial.add(a1);ial.add(b1);ial.add(c1);//頂點對應的法向量 ial.add(a2);ial.add(b2);ial.add(c2); ial.add(a4);ial.add(b4);ial.add(c4); ial.add(a2);ial.add(b2);ial.add(c2); ial.add(a3);ial.add(b3);ial.add(c3); ial.add(a4);ial.add(b4);ial.add(c4); } vCount=val.size()/3;//確定頂點數量 //頂點 float[] vertexs=new float[vCount*3]; for(int i=0;i<vCount*3;i++) { vertexs[i]=val.get(i); } ByteBuffer vbb=ByteBuffer.allocateDirect(vertexs.length*4); vbb.order(ByteOrder.nativeOrder()); dingBuffer=vbb.asFloatBuffer(); dingBuffer.put(vertexs); dingBuffer.position(0); //法向量 float[] normals=new float[vCount*3]; for(int i=0;i<vCount*3;i++) { normals[i]=ial.get(i); } ByteBuffer ibb=ByteBuffer.allocateDirect(normals.length*4); ibb.order(ByteOrder.nativeOrder()); myNormalBuffer=ibb.asFloatBuffer(); myNormalBuffer.put(normals); myNormalBuffer.position(0); //紋理 float[] textures=generateTexCoor(spannum); ByteBuffer tbb=ByteBuffer.allocateDirect(textures.length*4); tbb.order(ByteOrder.nativeOrder()); myTexture=tbb.asFloatBuffer(); myTexture.put(textures); myTexture.position(0); } public void drawSelf(GL10 gl) { gl.glRotatef(mAngleX, 1, 0, 0);//旋轉 gl.glRotatef(mAngleY, 0, 1, 0); gl.glRotatef(mAngleZ, 0, 0, 1); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);//開啟頂點緩衝 gl.glVertexPointer(3, GL10.GL_FLOAT, 0, dingBuffer);//指定頂點緩衝 gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);//開啟法向量緩衝 gl.glNormalPointer(GL10.GL_FLOAT, 0, myNormalBuffer);//指定法向量緩衝 gl.glEnable(GL10.GL_TEXTURE_2D); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, myTexture); gl.glBindTexture(GL10.GL_TEXTURE_2D, textureId); gl.glDrawArrays(GL10.GL_TRIANGLES, 0, vCount);//繪製圖像 gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);//關閉緩衝 gl.glEnable(GL10.GL_TEXTURE_2D); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_NORMAL_ARRAY); } //法向量規格化，求模長度 public float getVectorLength(float x,float y,float z) { float pingfang=x*x+y*y+z*z; float length=(float) Math.sqrt(pingfang); return length; } //自動切分紋理產生紋理陣列的方法 public float[] generateTexCoor(int bh) { float[] result=new float[bh*6*2]; float REPEAT=2; float sizeh=1.0f/bh;//行數 int c=0; for(int i=0;i<bh;i++) { //每行列一個矩形，由兩個三角形構成，共六個點，12個紋理座標 float t=i*sizeh; result[c++]=0; result[c++]=t; result[c++]=0; result[c++]=t+sizeh; result[c++]=REPEAT; result[c++]=t; result[c++]=0; result[c++]=t+sizeh; result[c++]=REPEAT; result[c++]=t+sizeh; result[c++]=REPEAT; result[c++]=t; } return result; } }