   problem about translucent and blend
 some translucent cloud have dark cap.here is the code:glClearColor((float)red / 255.0f, (float)green / 255.0f, (float)blue/255.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glClearDepth(1.0f); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glEnable(GL_TEXTURE_2D); glEnable(GL_LINE_SMOOTH); glEnable(GL_ALPHA_TEST); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glTexEnvf(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_REPLACE); glHint(GL_PERSPECTIVE_CORRECTION_Hint, GL_NICEST); glShadeModel(GL_SMOOTH);  glMatrixMode(openGL.GL_MODELVIEW); glLoadIdentity(); glPushMatrix(); glLoadIdentity(); glTranslatef(fMoveX, fMoveY, -2.5f); glRotatef(fAngleX, 1.0f, 0.0f, 0.0f); glRotatef(fAngleY, 0.0f, 1.0f, 0.0f); glRotatef(fAngleZ, 0.0f, 0.0f, 1.0f); glScalef(Scale, Scale, Scale); if (Width1 > 0 && Height1 > 0) {glBindTexture(GL_TEXTURE_2D, intexture[1]);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);glTexParameteri(openGL.GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_CLAMP);glTexParameteri(openGL.GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);gluBuild2DMipmaps(GL_TEXTURE_2D, 4, Width1, Height1, GL_BGRA_EXT, GL_UNSIGNED_byte, m_symbol);glEnable(GL_LIGHTING);glEnable(GL_LIGHT0);float[] light_position ={ 0.0f, 6.0f, 3.5f, 0.0f };float[] light_ambient ={ 1.0f, 1.0f, 1.0f, 1.0f };float[] mat_env ={ 0.75f, 0.75f, 0.75f, 0.0f };glLightfv(GL_LIGHT0, GL_POSITION, light_position);glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);glMaterialfv(GL_FRONT, GL_AMBIENT, mat_env);draw();glDisable(GL_LIGHTING); } glDisable(GL_TEXTURE_2D);