我正在使用Android上的OpenGLES学习基础知识。我在SurfaceView上渲染2D对象时遇到问题。我正在使用3个班级：
当我在设备上运行应用程序（三星i5700）时，我只能看到的是Graphic3DRenderer.onDrawFrame中指定的背景颜色。没有三角形。相机位置/方向正常（我认为..）。在调试模式下，调用Graphic2DTriangle的方法draw（），但屏幕上没有任何事情发生。
课程代码：
Graphic3D
public class Graphic3D extends Activity{
GLSurfaceView mySurface;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mySurface = new GLSurfaceView(this);
//mySurface.setRenderer(new Graphics3DRenderer());
mySurface.setRenderer(new Graphics3DRenderer());
setContentView(mySurface);
}
@Override
protected void onPause() {
super.onPause();
mySurface.onPause();
}
@Override
protected void onResume() {
super.onResume();
mySurface.onResume();
}
}
Graphic3DRenderer
public class Graphics3DRenderer implements Renderer{
private Graphic2DTriangle tri;
public Graphics3DRenderer()
{
tri = new Graphic2DTriangle();
}
public void onSurfaceCreated(GL10 gl, EGLConfig eglConfig) {
gl.glDisable(GL10.GL_DITHER);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
gl.glClearColor(.8f, 0f, .2f, 1f);
gl.glClearDepthf(1f);
}
public void onDrawFrame(GL10 gl) {
gl.glDisable(GL10.GL_DITHER);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
GLU.gluLookAt(gl, 0, 0, -5, 0, 0, 0, 0, 2f, 0); // camera position | looking direction
tri.draw(gl);
}
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
float ratio = (float) width/height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 25);
}
}
Graphic2DTriangle
public class Graphic2DTriangle {
private float vertices[] = {
0f, 1f, //p0
1f, -1f, //p1
-1f, -1f //p2
};
private FloatBuffer vertBuff;
private short[] pIndex = {0, 1, 2};
private ShortBuffer pBuff;
public Graphic2DTriangle()
{
ByteBuffer bBuff = ByteBuffer.allocateDirect(vertices.length * 4);
bBuff.order(ByteOrder.nativeOrder());
vertBuff = bBuff.asFloatBuffer();
vertBuff.put(vertices);
vertBuff.position(0);
ByteBuffer pbBuff = ByteBuffer.allocate(pIndex.length * 2);
pbBuff.order(ByteOrder.nativeOrder());
pBuff = pbBuff.asShortBuffer();
pBuff.put(pIndex);
pBuff.position(0);
}
public void draw(GL10 gl)
{
gl.glFrontFace(GL10.GL_CW);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertBuff);
gl.glDrawElements(GL10.GL_TRIANGLES, pIndex.length, GL10.GL_UNSIGNED_SHORT, pBuff);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
}
}
答案 0 :(得分：0)
我找到了解决问题的方法，但找不到区别。有线索吗？
<强> Graphic3D
public class Graphic3D extends Activity{
private GLSurfaceView glView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
glView = new GLSurfaceView(this); // Allocate a GLSurfaceView
glView.setRenderer(new Graphics3DRenderer(this)); // Use a custom renderer
this.setContentView(glView); // This activity sets to GLSurfaceView
}
// Call back when the activity is going into the background
@Override
protected void onPause() {
super.onPause();
glView.onPause();
}
// Call back after onPause()
@Override
protected void onResume() {
super.onResume();
glView.onResume();
}
}
<强> Graphic3DRenderer
public class Graphics3DRenderer implements Renderer {
Context context; // Application's context
Graphic2DTriangle triangle;
// Constructor with global application context
public Graphics3DRenderer(Context context) {
this.context = context;
triangle = new Graphic2DTriangle();
}
// Call back when the surface is first created or re-created
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set color's clear-value to black
gl.glClearDepthf(1.0f); // Set depth's clear-value to farthest
gl.glEnable(GL10.GL_DEPTH_TEST); // Enables depth-buffer for hidden surface removal
gl.glDepthFunc(GL10.GL_LEQUAL); // The type of depth testing to do
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); // nice perspective view
gl.glShadeModel(GL10.GL_SMOOTH); // Enable smooth shading of color
gl.glDisable(GL10.GL_DITHER); // Disable dithering for better performance
// You OpenGL|ES initialization code here
// ......
}
// Call back after onSurfaceCreated() or whenever the window's size changes
public void onSurfaceChanged(GL10 gl, int width, int height) {
if (height == 0) height = 1; // To prevent divide by zero
float aspect = (float)width / height;
// Set the viewport (display area) to cover the entire window
gl.glViewport(0, 0, width, height);
// Setup perspective projection, with aspect ratio matches viewport
gl.glMatrixMode(GL10.GL_PROJECTION); // Select projection matrix
gl.glLoadIdentity(); // Reset projection matrix
// Use perspective projection
GLU.gluPerspective(gl, 45, aspect, 0.5f, 100.f);
gl.glMatrixMode(GL10.GL_MODELVIEW); // Select model-view matrix
gl.glLoadIdentity(); // Reset
// You OpenGL|ES display re-sizing code here
// ......
}
// Call back to draw the current frame.
public void onDrawFrame(GL10 gl) {
// Clear color and depth buffers using clear-value set earlier
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity(); // Reset model-view matrix ( NEW )
GLU.gluLookAt(gl, 0, 0, -5, 0, 0, 0, 0, 2f, 0);
// gl.glTranslatef(-1.5f, 0.0f, -6.0f); // Translate left and into the screen ( NEW )
triangle.draw(gl); // Draw triangle ( NEW )
}
}
<强> Graphic2DTriangle
public class Graphic2DTriangle {
private FloatBuffer vertexBuffer; // Buffer for vertex-array
private ByteBuffer indexBuffer; // Buffer for index-array
private float[] vertices = { // Vertices of the triangle
0.0f, 1.0f, 0.0f, // 0. top
-1.0f, -1.0f, 0.0f, // 1. left-bottom
1.0f, -1.0f, 0.0f // 2. right-bottom
};
private byte[] indices = { 0, 1, 2 }; // Indices to above vertices (in CCW)
// Constructor - Setup the data-array buffers
public Graphic2DTriangle() {
// Setup vertex-array buffer. Vertices in float. A float has 4 bytes.
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
vbb.order(ByteOrder.nativeOrder()); // Use native byte order
vertexBuffer = vbb.asFloatBuffer(); // Convert byte buffer to float
vertexBuffer.put(vertices); // Copy data into buffer
vertexBuffer.position(0); // Rewind
// Setup index-array buffer. Indices in byte.
indexBuffer = ByteBuffer.allocateDirect(indices.length);
indexBuffer.put(indices);
indexBuffer.position(0);
}
// Render this shape
public void draw(GL10 gl) {
// Enable vertex-array and define the buffers
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
// Draw the primitives via index-array
gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
}
}