Question

我的精灵在我的游戏中通过循环遍历每个精灵来绘制它们，调用glPushMatrix，转换到位置，绘制四边形并调用glPopMatrix。

我希望这很好，但我得到一些奇怪的行为，屏幕上的其他一些对象（看似）随机翻译了一些。我认为精灵位置的变换会影响另一个绘图，但是在调用glPopMatrix之后怎么会发生？

我正在绘制精灵和积分，出于某种原因，当我只是画点时，没有任何东西可以得到这个随机翻译。当我开始绘制精灵时，是否有人可以帮助解决造成它的原因？

这是精灵的绘图程序：

gl.glPushMatrix();

//set the drawing position
gl.glTranslatef((float)positionDelta.getX(), (float)positionDelta.getY(), z);
gl.glRotatef((float) (180*angle/Math.PI), 0, 0, 1);

//draw 
getSprite().draw(gl);

//reset the drawing position
gl.glPopMatrix();

和quad的绘图功能：

public void draw(GL10 gl) {
  gl.glEnable(GL10.GL_TEXTURE_2D);

  //Bind our only previously generated texture in this case
  gl.glBindTexture(GL10.GL_TEXTURE_2D, texture.getGLID());

  //Point to our buffers
  gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
  gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

  //Set the face rotation
  gl.glFrontFace(GL10.GL_CCW);

  //Enable the vertex and texture state
  gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
  gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);

  //Set The Color To Blue
  gl.glColor4f(0.5f, 0.5f, 1.0f, 1.0f);   

  //Draw the vertices as triangles, based on the Index Buffer information
  gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer);      


  //Disable the client state before leaving
  gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
  gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}

这是一个似乎总是被翻译的东西的绘图，一个简单的观点：

gl.glDisable(GL10.GL_TEXTURE_2D);

//Point to our buffers
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

//Set the face rotation
gl.glFrontFace(GL10.GL_CCW);

//Enable the vertex and texture state
//gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);

gl.glPushMatrix();

//set the drawing position
gl.glTranslatef((float)positionDelta.getX(), (float)positionDelta.getY(), z);

gl.glPointSize(size);

gl.glColor4f(red, green, blue, alpha);

//Draw the vertices as triangles, based on the Index Buffer information
gl.glDrawElements(GL10.GL_POINTS, indexBuffer.capacity(), GL10.GL_UNSIGNED_BYTE, indexBuffer);

//Disable the client state before leaving
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

//reset the drawing position
gl.glPopMatrix();

（以下评论）OnSurfaceChange：

     @Override
  public void onSurfaceChanged(GL10 gl, int width, int height) {
    gl.glViewport(0, 0, width, height);
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    //GLU.gluPerspective(gl, 60.0f, (float)width / (float)height, 0.1f, 100.0f);
    GLU.gluOrtho2D(gl, -width, width , -height, height);

    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();

    //font loading stuff
    texFont = new TexFont(context, gl);
    try {
      getTexFont().LoadFont("Fonts/Palatino Linotype.bff", gl);
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

以下是OpenGL调用的一部分：

04-01 13:46:08.535: VERBOSE/GLSurfaceView(20649): glPushMatrix();
04-01 13:46:08.535: VERBOSE/GLSurfaceView(20649): glTranslatef(15.63553, 119.22188, 0.0);
04-01 13:46:08.540: VERBOSE/GLSurfaceView(20649): glRotatef(61.17992, 0.0, 0.0, 1.0);
04-01 13:46:08.540: VERBOSE/GLSurfaceView(20649): glEnable(GL_TEXTURE_2D);
04-01 13:46:08.540: VERBOSE/GLSurfaceView(20649): glBindTexture(GL_TEXTURE_2D, 1);
04-01 13:46:08.540: VERBOSE/GLSurfaceView(20649): glEnableClientState(GL_VERTEX_ARRAY);
04-01 13:46:08.540: VERBOSE/GLSurfaceView(20649): glEnableClientState(GL_TEXTURE_COORD_ARRAY);
04-01 13:46:08.545: VERBOSE/GLSurfaceView(20649): glFrontFace(2305);
04-01 13:46:08.545: VERBOSE/GLSurfaceView(20649): glVertexPointer(3, GL_FLOAT, 0, java.nio.FloatToByteBufferAdapter, status: capacity=12 position=0 limit=12);
04-01 13:46:08.545: VERBOSE/GLSurfaceView(20649): glTexCoordPointer(2, GL_FLOAT, 0, java.nio.FloatToByteBufferAdapter, status: capacity=8 position=0 limit=8);
04-01 13:46:08.565: VERBOSE/GLSurfaceView(20649): glColor4f(0.5, 0.5, 1.0, 1.0);
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649): glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [0 : 0] = v:{-40.0, -40.0, 0.0} t:{0.0, 0.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [1 : 1] = v:{40.0, -40.0, 0.0} t:{0.0, 1.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [2 : 3] = v:{40.0, 40.0, 0.0} t:{1.0, 1.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [3 : 0] = v:{-40.0, -40.0, 0.0} t:{0.0, 0.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [4 : 3] = v:{40.0, 40.0, 0.0} t:{1.0, 1.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649):  [5 : 2] = v:{-40.0, 40.0, 0.0} t:{1.0, 0.0}
04-01 13:46:08.580: VERBOSE/GLSurfaceView(20649): );
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glDisableClientState(GL_VERTEX_ARRAY);
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glDisableClientState(GL_TEXTURE_COORD_ARRAY);
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glPopMatrix();
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glDisable(GL_TEXTURE_2D);
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glEnableClientState(GL_VERTEX_ARRAY);
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glFrontFace(2305);
04-01 13:46:08.590: VERBOSE/GLSurfaceView(20649): glPushMatrix();
04-01 13:46:08.595: VERBOSE/GLSurfaceView(20649): glTranslatef(-14.2896805, 191.06998, 0.0);
04-01 13:46:08.595: VERBOSE/GLSurfaceView(20649): glPointSize(5.0);
04-01 13:46:08.595: VERBOSE/GLSurfaceView(20649): glColor4f(1.0, 0.0, 0.0, 0.5);
04-01 13:46:08.600: VERBOSE/GLSurfaceView(20649): glDrawElements(GL_POINTS, 1, GL_UNSIGNED_BYTE
04-01 13:46:08.600: VERBOSE/GLSurfaceView(20649):  [0 : 0] = v:{-40.0, -40.0, 0.0}
04-01 13:46:08.600: VERBOSE/GLSurfaceView(20649): );
04-01 13:46:08.600: VERBOSE/GLSurfaceView(20649): glDisableClientState(GL_VERTEX_ARRAY);
04-01 13:46:08.600: VERBOSE/GLSurfaceView(20649): glPopMatrix();

它绘制了一些点，然后是一个精灵，然后是一些点。一切都很好，除了我注意到点的顶点是-40，-40。我不认为这恰好与四边形的第一个顶点相同！这似乎是问题，而不是矩阵。

编辑找到它！

gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);

点缺少

，这意味着他们使用了最后一个绘制对象的第一个顶点，如果它是一个精灵是-40，-40！谢谢！

Answer 1

看起来没问题，只要这是切换完成的唯一位置。由于您使用的是GL10，请通过DEBUG_LOG_GL_CALLS设置setDebugFlags。这包装了GL10实例并使调用显示在LogCat中（脚注：我希望包含push / pop调用，这对GLES20不起作用）。将一些日志调用自身作为日志流中的标记。

Android OpenGL - 在glPopMatrix之后保留glTranslatef

1 个答案: