这里记录下自己学习的小总结吧,前段时间常常看见有人问怎么为一个物体的每一面贴不同的纹理图,我这里给出为一个为金字塔形状四面贴不同纹理图的例子,有需要的朋友可以看看。下面上代码:
第一步: Main.java,在入口Activity中定义一个内部类,用于获取Bitmap用的。
class BitGL {
public static Bitmap bitmap;
public static void init(Resources resources) {
bitmap = BitmapFactory.decodeResource(resources, R.drawable.walla);
}
}
第二步:在MySurfaceView.java中的onSurfaceCreated()方法中初始化金字塔类,并赋相应的值。
py = new Pyramid(gl,15.0f, 2.6f, 5.0f, 0, mContext); // 初始化金子塔
绘制金字塔的时候在onDrawFrame()方法中调用py.drawSlef(gl); 画金字塔
第三步:然后就是画金字塔并贴图了,注意,这是一个单独的类。
public class Pyramid {
Context mContext = null;
private int one = 0x10000;
public float mAngleX;
public float mAngleY;
private IntBuffer mVertexBuffer;
private FloatBuffer mTexBuffer;
FloatBuffer lightDiffuse = FloatBuffer.wrap(new float[] { 0.5f, 0.5f, 0.5f, 1.0f });
FloatBuffer specularParams = FloatBuffer.wrap(new float[] { 0.5f, 1.0f, 0.5f, 1.0f });
FloatBuffer lightPosition = FloatBuffer.wrap(new float[] { 0.3f, 0.0f, 2.0f, 1.0f });
int vertices[] = { 0, one, 0, -one, -one, one, one, -one, one,
0, one, 0, one, -one, one, one, -one, -one,
0, one, 0, one, -one, -one, -one, -one, -one,
0, one, 0, -one, -one, -one, -one, -one, one };
// 纹理点
private int[] texCoords = { 0, one, one, one, 0, 0, one, 0 };
float x, y, z;
boolean isY = true;
private Bitmap bitmap;
private int[] textureids = null;
private IntBuffer texBuffer;
private Bitmap[] bit = new Bitmap[4];
public Pyramid(GL10 gl, float x, float y, float z, float rot, Context context) {
this.mContext = context;
this.x = x;
this.y = y;
this.z = z;
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
vbb.order(ByteOrder.nativeOrder());
mVertexBuffer = vbb.asIntBuffer();
mVertexBuffer.put(vertices);
mVertexBuffer.position(0);
// 初始化
textureids = new int[4];
bit[0] = BitmapFactory.decodeResource(mContext.getResources(),
R.drawable.walla);
bit[1] = BitmapFactory.decodeResource(mContext.getResources(),
R.drawable.wallb);
bit[2] = BitmapFactory.decodeResource(mContext.getResources(),
R.drawable.walld);
bit[3] = BitmapFactory.decodeResource(mContext.getResources(),
R.drawable.wallf);
// 实例化bitmap
bitmap = BitGL.bitmap;
ByteBuffer tbbs = ByteBuffer.allocateDirect(texCoords.length * 3 * 4);
tbbs.order(ByteOrder.nativeOrder());
texBuffer = tbbs.asIntBuffer();
// 为每一个面贴上纹理
for (int i = 0; i < 3; i++) {
texBuffer.put(texCoords);
}
texBuffer.position(0);
/********* 贴图开始 ********/
// 打开纹理
gl.glEnable(GL10.GL_TEXTURE_2D);
IntBuffer ib = IntBuffer.allocate(4);
gl.glGenTextures(4, ib);
textureids = ib.array();
// gl.glGenTextures(4, textureids, 0); //4个纹理个数,用于四面
// 绑定要使用的纹理
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[0]);
// 生成纹理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bit[0], 0);
// 线性滤波
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[1]);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bit[1], 0);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[2]);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bit[2], 0);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[3]);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bit[3], 0);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
/********* 贴图结束 ********/
}
public void drawSlef(GL10 gl) {
gl.glPushMatrix();
gl.glTranslatef(x, y, z); // 绘制对象的位置
// gl.glRotatef(mAngleX, 0, 1, 0); // 对象的X旋转角度
// gl.glRotatef(mAngleY, 1, 0, 0); // 对象的Y旋转角度
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);// 使用纹理数组
gl.glVertexPointer(3, gl.GL_FIXED, 0, mVertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, texBuffer); // Define
for (int i = 0; i < 4; i++) { // 创建纹理
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[i]);
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, i * 3, 3);
}
gl.glDisable(GL10.GL_TEXTURE_2D);// 关闭纹理
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glLoadIdentity();
mAngleX++;
if (isY) {
mAngleY = mAngleY + 0.01f;
if (mAngleY > 1.8) {
isY = false;
}
} else {
mAngleY = mAngleY - 0.01f;
if (mAngleY < -2.5) {
isY = true;
}
}
gl.glPopMatrix();
}
}