Stonesense Rendering Optimization

void WorldSegment::drawAllBlocks()
{

    // x,y,z print pricess
    ALLEGRO_BITMAP * temp = al_get_target_bitmap();
    int32_t vsxmax = viewedSegment->sizex-1;
    int32_t vsymax = viewedSegment->sizey-1;
    int32_t vszmax = viewedSegment->sizez-1; // grabbing one tile +z more than we should for tile rules
    //al_hold_bitmap_drawing(true);
    int op, src, dst, alpha_op, alpha_src, alpha_dst;
    ALLEGRO_COLOR color;
    al_get_separate_blender(&op, &src, &dst, &alpha_op, &alpha_src, &alpha_dst);
    al_clear_to_color(al_map_rgb(config.fogr, config.fogg, config.fogb)); //Flicker Fix
    //al_flip_display(); //Anti Flicker for Slow Debug Drawing
    //al_clear_to_color(al_map_rgb(config.fogr, config.fogg, config.fogb)); // Same as above
    for(int32_t vsz=0; vsz < vszmax; vsz++)
    {
        if(config.showRenderStatus)
            SetTitle("Stonesense - Drawing Terrain, Level %d/%d", (vsz+1), vszmax);
        if(config.fogenable && config.foga)
        {
            if(!fog)
            {
                fog = al_create_bitmap(al_get_bitmap_width(temp), al_get_bitmap_height(temp));
                al_set_target_bitmap(fog);
                al_clear_to_color(al_map_rgb(config.fogr, config.fogg, config.fogb));
                al_set_target_bitmap(temp);
            }
            if(!((al_get_bitmap_width(fog) == al_get_bitmap_width(temp)) && (al_get_bitmap_height(fog) == al_get_bitmap_height(temp))))
            {
                al_destroy_bitmap(fog);
                fog = al_create_bitmap(al_get_bitmap_width(temp), al_get_bitmap_height(temp));
                al_set_target_bitmap(fog);
                al_clear_to_color(al_map_rgb(config.fogr, config.fogg, config.fogb));
                al_set_target_bitmap(temp);
            }
            al_draw_tinted_bitmap(fog, al_map_rgba(255, 255, 255, config.foga), 0, 0, 0);
        }
        if(vsz == vszmax-1)
        {
            if(config.show_osd) DrawCurrentLevelOutline(true);
        }
        if(config.dayNightCycle)
            al_hold_bitmap_drawing(true);
        for(int32_t vsx=1; vsx < vsxmax; vsx++)
        {
            for(int32_t vsy=1; vsy < vsymax; vsy++)
            {
                Block *b = getBlockLocal(vsx,vsy,vsz);
                if(b==NULL || (b->floorType == 0 && b->ramp.type == 0 && b->wallType == 0))
                {
                    Block* bLow = getBlockLocal(vsx,vsy,vsz-1);
                    if(bLow != NULL)
                    {
                        bLow->DrawRamptops();
                    }
                }
                if(b)
                {
                    Block *frontleft = getBlockLocal(vsx,vsy+1,vsz);
                    Block *frontright = getBlockLocal(vsx+1,vsy,vsz);
                    Block *top = getBlockLocal(vsx,vsy,vsz+1);
                    Block *topleft = getBlockLocal(vsx,vsy+1,vsz+1);
                    Block *topright = getBlockLocal(vsx+1,vsy,vsz+1);
                    Block *topfront = getBlockLocal(vsx+1,vsy+1,vsz+1);
                    bool drawtl=false;
                    bool drawtr=false;
                    bool drawtf=false;
                    bool drawt=false;
                    if(topleft!=NULL)
                        drawtl = topleft->wallType||topleft->floorType||topleft->ramp.type; // Is Top Left beeing drawn
                    if(topright!=NULL)
                        drawtr = topright->wallType||topright->floorType||topright->ramp.type; // Is Top Right beeing drawn
                    if(topfront!=NULL)
                        drawtf = topfront->wallType||topfront->floorType||topfront->ramp.type; // Is Top Front beeing drawn
                    if(top!=NULL)
                        drawt = top->wallType||top->floorType||top->ramp.type; // Is Top beeing drawn
                    if(vsx<vsxmax-1&&vsy<vsymax-1&&vsz<vszmax-1) // Draw empty blocks on map edge and on top
                    {
                        if(!(b->wallType||b->floorType||b->ramp.type||b->stairType)) // Nothing to draw, moving on
                            continue;
                        if(!(topleft==NULL||topright==NULL||top==NULL||topfront==NULL)&&(drawtl&&drawtr&&drawtf&&drawt)) //Block is totally covered from above, moving on
                            continue;
                        if(((frontleft!=NULL&&frontleft->wallType)&&(frontright!=NULL&&frontright->wallType)&&(top!=NULL&&(top->wallType||top->floorType)))) //Block is covered by sides and top, moving on
                            continue;
                    }

                    b->Draw();
                    /*al_flip_display();  // Slow Debug drawing: You can see every Block as its beeing drawn very useful =)
                    b->Draw();
                    al_flip_display();*/
                }
            }
        }
        al_hold_bitmap_drawing(false);
        al_hold_bitmap_drawing(true);
        for(int32_t vsx=1; vsx < vsxmax; vsx++)
        {
            for(int32_t vsy=1; vsy < vsymax; vsy++)
            {
                Block *b = getBlockLocal(vsx,vsy,vsz);
                if(b)
                {
                    b->Drawcreaturetext();
                    //while(!key[KEY_SPACE]) ;
                    //rest(100);
                }
            }
        }
        al_hold_bitmap_drawing(false);
    }
    if(config.showRenderStatus)
        SetTitle("Stonesense");
}