【Android】OpenGL ES---绘制3D图形、应用纹理贴图
绘制3D图形
glDrawElements(int mode,int count,int type Buffer indices):
- 根据indices指定的索引点来绘制三角形
- 第一个参数mode指定绘制的图形类型，可设置为GL10.GL_TRIANGLES或GL10.GL_TRIANGLE_STRIPE;
- 第二个参数指定一共包含多少个顶点。
- indices参数最重要，它包装了一个长度为3N的数组，比如让该参数包装（0，2，3，
1， 4，5 ）数组，这意味着告诉OpenGL ES 要绘制两个三角形，第一个三角形的三个顶点为0、2、3顶点，第二个三角形的三个顶点为1、4、5顶点。
MyRenderer.java
public class MyRenderer implements GLSurfaceView.Renderer {
float[] taperVertices = new float[]{
0.0f,0.5f,0.0f,//0
-0.5f,-0.5f,-0.2f,//1
0.5f,-0.5f,-0.2f,//2
0.0f,-0.6f,0.2f//3
};
int [] taperColors = new int[]{
65535,0,0,0,
0,65535,0,0,
0,0,65535,0,
65535,65535,0
};
byte[] taperFaces = new byte[]{
0,1,2,
0,1,3,
1,2,3,
0,2,3
};
FloatBuffer taperVerticesBuffer;
IntBuffer taperColorsBuffer;
ByteBuffer taperFacesBuffer;
private float angle = 1.0f;
public MyRenderer(){
taperVerticesBuffer = Utils.getFloatBuffer(taperVertices);
taperColorsBuffer = Utils.getIntBuffer(taperColors);
taperFacesBuffer = Utils.getByteBuffer(taperFaces);
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
gl.glClearColor(0.1f,0.1f,0.1f,0.0f);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
float ratio = (float) width/height;
gl.glFrustumf(-ratio,ratio,-1,1,1,10);
}
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
gl.glClear(GL10.GL_DEPTH_BUFFER_BIT);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
//所有的旋转和缩放都是在ModelView下进行的
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glTranslatef(0.0f,0.0f,-1.5f);
gl.glRotatef(angle,0f,0.2f,0f);
gl.glVertexPointer(3,GL10.GL_FLOAT,0,taperVerticesBuffer);
gl.glColorPointer(4,GL10.GL_FIXED,0,taperColorsBuffer);
gl.glDrawElements(GL10.GL_TRIANGLE_STRIP,taperFacesBuffer.remaining(),
GL10.GL_UNSIGNED_BYTE,taperFacesBuffer);
gl.glFinish();
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
angle++;
}
}
Utils.java
public class Utils {
public static FloatBuffer getFloatBuffer(float[] floats){
FloatBuffer floatBuffer;
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(floats.length*4);
byteBuffer.order(ByteOrder.nativeOrder());
floatBuffer = byteBuffer.asFloatBuffer();
floatBuffer.put(floats);
floatBuffer.position(0);
return floatBuffer;
}
public static IntBuffer getIntBuffer(int[] arrays){
IntBuffer intBuffer;
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(arrays.length*4);
byteBuffer.order(ByteOrder.nativeOrder());
intBuffer = byteBuffer.asIntBuffer();
intBuffer.put(arrays);
intBuffer.position(0);
return intBuffer;
}
public static ByteBuffer getByteBuffer(byte[] arrays){
ByteBuffer byteBuffer;
byteBuffer = ByteBuffer.allocateDirect(arrays.length*4);
byteBuffer.order(ByteOrder.nativeOrder());
byteBuffer.put(arrays);
byteBuffer.position(0);
return byteBuffer;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GLSurfaceView surfaceView = new GLSurfaceView(this);
surfaceView.setRenderer(new MyRenderer());
setContentView(surfaceView);
}
}
绘制立方体
MyRenderer.java
public class MyRenderer implements GLSurfaceView.Renderer {
float[] cubeVertices = new float[]{
//前面四个顶点
0.5f,0.5f,0.5f,//0
-0.5f,0.5f,0.5f,//1
-0.5f,-0.5f,0.5f,//2
0.5f,-0.5f,0.5f,//3
//后面四个顶点
0.5f,0.5f,-0.5f,//4
-0.5f,0.5f,-0.5f,//5
-0.5f,-0.5f,-0.5f,//6
0.5f,-0.5f,-0.5f//7
};
int [] cubeColors = new int[]{
65535,0,0,0,
0,65535,0,0,
0,0,65535,0,
65535,65535,0,
65535,0,0,0,
0,65535,0,0,
0,0,65535,0,
65535,65535,0
};
//正方体
byte[] cubeFaces = new byte[]{
//前后面
0,1,2,
0,2,3,
4,5,6,
4,6,7,
//左右面
1,2,5,
2,5,6,
0,3,4,
3,4,7,
//上下面
0,1,4,
1,4,5,
2,3,6,
3,6,7
};
FloatBuffer cubeVerticesBuffer;
IntBuffer cubeColorsBuffer;
ByteBuffer cubeFacesBuffer;
private float angle = 1.0f;
public MyRenderer(){
cubeVerticesBuffer = Utils.getFloatBuffer(cubeVertices);
cubeColorsBuffer = Utils.getIntBuffer(cubeColors);
cubeFacesBuffer = Utils.getByteBuffer(cubeFaces);
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
gl.glClearColor(0.1f,0.1f,0.1f,0.0f);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
float ratio = (float) width/height;
gl.glFrustumf(-ratio,ratio,-1,1,1,10);
}
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
gl.glClear(GL10.GL_DEPTH_BUFFER_BIT);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
//所有的旋转和缩放都是在ModelView下进行的
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glTranslatef(0.0f,0.0f,-2.5f);
gl.glRotatef(angle,0f,0.2f,0f);
gl.glRotatef(angle,0.2f,0f,0f);
gl.glVertexPointer(3,GL10.GL_FLOAT,0, cubeVerticesBuffer);
gl.glColorPointer(4,GL10.GL_FIXED,0, cubeColorsBuffer);
//gl.glColor4f(1,0,0,0);
gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, cubeFacesBuffer.remaining(),
GL10.GL_UNSIGNED_BYTE, cubeFacesBuffer);
gl.glFinish();
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
angle++;
}
}
应用纹理贴图
在onSurfaceCreated(GL10 gl, EGLConfig config)中启动纹理贴图
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GLSurfaceView surfaceView = new GLSurfaceView(this);
//surfaceView.setRenderer(new Texture2DRenderer(MainActivity.this));//正方形贴图
surfaceView.setRenderer(new PureColorCubeRenderer());//立方体不同面纯色
//surfaceView.setRenderer(new CubeGraduateRenderer());//正方体，纯色过度
//surfaceView.setRenderer(new Texture3DRenderer(this));//立方体贴图
//surfaceView.setRenderer(new Special3DFigureRenderer(this));
setContentView(surfaceView);
}
}
Texture3DRenderer.java
public class Texture3DRenderer implements GLSurfaceView.Renderer {
float[] cubeVertices = new float[]{
//前面四个顶点
// 0.5f,0.5f,0.5f,//0
// -0.5f,0.5f,0.5f,//1
// -0.5f,-0.5f,0.5f,//2
// 0.5f,-0.5f,0.5f,//3
// //后面四个顶点
// 0.5f,0.5f,-0.5f,//4
// -0.5f,0.5f,-0.5f,//5
// -0.5f,-0.5f,-0.5f,//6
// 0.5f,-0.5f,-0.5f,//7
0.5f,0.5f,0.5f,//0
-0.5f,0.5f,0.5f,//1
-0.5f,-0.5f,0.5f,//2
0.5f,0.5f,0.5f,//0
-0.5f,-0.5f,0.5f,//2
0.5f,-0.5f,0.5f,//3
0.5f,0.5f,-0.5f,//4
-0.5f,0.5f,-0.5f,//5
-0.5f,-0.5f,-0.5f,//6
0.5f,0.5f,-0.5f,//4
-0.5f,-0.5f,-0.5f,//6
0.5f,-0.5f,-0.5f,//7
-0.5f,0.5f,0.5f,//1
-0.5f,-0.5f,0.5f,//2
-0.5f,0.5f,-0.5f,//5
-0.5f,-0.5f,0.5f,//2
-0.5f,0.5f,-0.5f,//5
-0.5f,-0.5f,-0.5f,//6
0.5f,0.5f,0.5f,//0
0.5f,-0.5f,0.5f,//3
0.5f,0.5f,-0.5f,//4
0.5f,-0.5f,0.5f,//3
0.5f,0.5f,-0.5f,//4
0.5f,-0.5f,-0.5f,//7
0.5f,0.5f,0.5f,//0
-0.5f,0.5f,0.5f,//1
0.5f,0.5f,-0.5f,//4
-0.5f,0.5f,0.5f,//1
0.5f,0.5f,-0.5f,//4
-0.5f,0.5f,-0.5f,//5
-0.5f,-0.5f,0.5f,//2
0.5f,-0.5f,0.5f,//3
-0.5f,-0.5f,-0.5f,//6
0.5f,-0.5f,0.5f,//3
-0.5f,-0.5f,-0.5f,//6
0.5f,-0.5f,-0.5f,//7
};
//正方体
byte[] cubeFaces = new byte[]{
//前后面
0,1,2,
3,4,5,
6,7,8,
9,10,11,
//左右面
12,13,14,
15,16,17,
18,19,20,
21,22,23,
//上下面
24,25,26,
27,28,29,
30,31,32,
33,34,35
};
float[] texturesVertices = new float[]{
//前
1.0f,0.0f,
0.0f,0.0f,
0.0f,1.0f,
1.0f,0.0f,
0.0f,1.0f,
1.0f,1.0f,
//后
0.0f,0.0f,
1.0f,0.0f,
1.0f,1.0f,
0.0f,0.0f,
1.0f,1.0f,
0.0f,1.0f,
//左
1.0f,0.0f,
1.0f,1.0f,
0.0f,0.0f,
1.0f,1.0f,
0.0f,0.0f,
0.0f,1.0f,
//右
0.0f,0.0f,
0.0f,1.0f,
1.0f,0.0f,
0.0f,1.0f,
1.0f,0.0f,
1.0f,1.0f,
//上
1.0f,1.0f,
0.0f,1.0f,
1.0f,0.0f,
0.0f,1.0f,
1.0f,0.0f,
0.0f,0.0f,
//下
0.0f,0.0f,
1.0f,0.0f,
0.0f,1.0f,
1.0f,0.0f,
0.0f,1.0f,
1.0f,1.0f
};
FloatBuffer cubeVerticesBuffer;
ByteBuffer cubeFacesBuffer;
FloatBuffer texturesVerticesBuffer;
private Context context;
private int texture;
private float anglex = 1.0f;
private float angley = 1.0f;
public Texture3DRenderer(Context context){
this.context = context;
cubeVerticesBuffer = Utils.getFloatBuffer(cubeVertices);
cubeFacesBuffer = Utils.getByteBuffer(cubeFaces);
texturesVerticesBuffer = Utils.getFloatBuffer(texturesVertices);
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
gl.glClearColor(0.1f,0.1f,0.1f,0.0f);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
gl.glEnable(GL10.GL_TEXTURE_2D);
loadTexture(gl);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
float ratio = (float) width/height;
gl.glFrustumf(-ratio,ratio,-1,1,1,10);
}
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
gl.glClear(GL10.GL_DEPTH_BUFFER_BIT);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
//所有的旋转和缩放都是在ModelView下进行的
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glTranslatef(0.0f,0.0f,-2.5f);
gl.glRotatef(angley,0f,0.2f,0f);
gl.glRotatef(anglex,0.2f,0f,0f);
gl.glVertexPointer(3,GL10.GL_FLOAT,0, cubeVerticesBuffer);
gl.glTexCoordPointer(2,GL10.GL_FLOAT,0,texturesVerticesBuffer);
gl.glBindTexture(GL10.GL_TEXTURE_2D,texture);
gl.glDrawElements(GL10.GL_TRIANGLES, cubeFacesBuffer.remaining(),
GL10.GL_UNSIGNED_BYTE, cubeFacesBuffer);
gl.glFinish();
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
anglex++;
angley+=2;
}
private void loadTexture(GL10 gl) {
Bitmap bitmap = null;
bitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.a1111);
int[] textures = new int[4];
gl.glGenTextures(1,textures,0);
texture = textures[0];
gl.glBindTexture(GL10.GL_TEXTURE_2D,texture);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_WRAP_S,GL10.GL_REPEAT);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_WRAP_T,GL10.GL_REPEAT);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D,0,bitmap,0);
}
}
总结
在实现这个贴图的过程中当中，要注意纹理映射的顶点数组（textureVertices）中的值是要与顶点数组（cubeVertices）中的值一一对应的