graphics rendering problem

nt DrawGLScene(GLvoid)									// Here's Where We Do All The Drawing{	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Clear The Screen And The Depth Buffer	glLoadIdentity();		glTranslatef(transX, transY, transZ);	// DRAW THE SKY //		// Bind the sky texture		glBindTexture(GL_TEXTURE_2D, texture[3]);		// Draw the sky dome		glPushMatrix();		glRotatef(-90,1,0,0);		glBegin(GL_TRIANGLE_STRIP);		for(int i = 0; i != NumVertices; i++)		{			glTexCoord2f(Vertices.u, Vertices.v);			glVertex3f(Vertices.x, Vertices.y, Vertices.z);		}			glEnd();		glPopMatrix();		// DRAW THE GROUND //		// Bind the grass texture	glBindTexture(GL_TEXTURE_2D, texture[0]);	/* Draw the ground */	glBegin(GL_QUADS);		for(int i = 0; i != MAX_FLOOR_TILES; i++)			floortileArray.createFloorTile();	glEnd();	// Bind texture used for boxes	glBindTexture(GL_TEXTURE_2D, texture[1]);		//  DRAW BOX CRATES  //		/* Draw Boxes on the ground */	glBegin(GL_QUADS);	// Draw 3 crates near side of ground	for(int i = 0; i != MAX_CRATES; i++)		nearCrate.CreateBox();	// Draw 3 crates far side of ground	for(int i = 0; i != MAX_CRATES; i++)		farCrate.CreateBox();	glEnd();	// DRAW THE TREES //		// Bind texture used for trees	glBindTexture(GL_TEXTURE_2D, texture[2]);		glBegin(GL_TRIANGLES);								// Start Drawing A Triangle	// Draw trees on the left hand side	for(int i = 0; i != MAX_TREES; i++)		leftTrees.generateFullTree();	// Draw right trees	for(int i = 0; i != MAX_TREES; i++)		rightTrees.generateFullTree();		glEnd();	 	// DRAW THE VAN //		glPushMatrix();	glTranslatef(vanTransX, vanTransY, vanTransZ);		glRotatef(vanXRot,1.0f,0.0f,0.0f);	glRotatef(vanYRot,0.0f,1.0f,0.0f);	glRotatef(vanZRot,0.0f,0.0f,1.0f);	glBegin(GL_QUADS);		myTransit.constructVan();	glEnd();	glPopMatrix();	glColor3f(1.0f, 1.0f, 1.0f);} // End of GLDrawScene function