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r19805 Tuesday 25th December, 2012 at 13:19:40 UTC by David Haywood
added proper x-scroll handling for the decocass background, and some notes for further cleanup work regarding the background 'tilemap' - this improves Manhattan and several others.
[src/mame/drivers]decocass.c
[src/mame/includes]decocass.h
[src/mame/video]decocass.c

trunk/src/mame/video/decocass.c
r19804r19805
22
33    DECO Cassette System video
44
5   The video system has clearly been designed for Highway Chase,
6   which unsurprisingly is the first game on the system.  The
7   background 'tilemap' is very much like the road layer on the
8   standalone Highway Chase with a concept of left/right edges
9   with semi-independent scrolling, and the ability to transition
10   between scrolling different sections.
11
12   Additionally it supports the headlight effect also needed for
13   a Highway Chase style game.
14
515 ***********************************************************************/
616
717#include "emu.h"
r19804r19805
460470   }
461471}
462472
473// we could still massively clean up the background tilemap handling, I have a feeling the
474// code to ignore tiles with 0x80 set on the left tilemap etc. is just a convenient hack
475// to stop garbage tiles appearing when scrolling due to the weird ram layout and clipping rules
463476
477// 0 is left edge, 1 is right edge
478void decocass_state::draw_edge(bitmap_ind16 &bitmap, const rectangle &cliprect, int which, bool opaque)
479{
480   rectangle clip;
481   bitmap_ind16* srcbitmap;
482
483   int scrolly_l = m_back_vl_shift;
484   int scrolly_r = 256 - m_back_vr_shift;
485
486   // bit 0x04 of the mode select effectively selects between two banks of data
487   if (0 == (m_mode_set & 0x04))
488      scrolly_r += 256;
489   else
490      scrolly_l += 256;
491
492   int scrollx = 256 - m_back_h_shift;
493   int scrolly;
494
495   if (which==0)
496   {
497      clip = m_bg_tilemap_l_clip;
498      clip &= cliprect;
499      scrolly = scrolly_l;
500      srcbitmap = &m_bg_tilemap_l->pixmap();
501   }
502   else
503   {
504      clip = m_bg_tilemap_r_clip;
505      clip &= cliprect;
506      scrolly = scrolly_r;
507      srcbitmap = &m_bg_tilemap_r->pixmap();
508   }
509
510   int y,x;
511
512//   printf("m_mode_set %d\n", m_mode_set & 0x3);
513
514   // technically our y drawing probably shouldn't wrap / mask, but simply draw the 128pixel high 'edge' at the requested position
515   //  see note above this funciton
516   for (y=clip.min_y; y<=clip.max_y;y++)
517   {
518      int srcline = (y + scrolly) & 0x1ff;
519      UINT16* src = &srcbitmap->pix16(srcline);
520      UINT16* dst = &bitmap.pix16(y);
521
522      for (x=clip.min_x; x<=clip.max_x;x++)
523      {
524         int srccol;
525         
526         // 2 bits control the x scroll mode, allowing it to wrap either half of the tilemap, or transition one way or the other between the two halves
527
528         switch (m_mode_set & 3)
529         {
530            case 0x00: srccol = ((x + scrollx) & 0xff); break; // hwy normal case
531            case 0x01: srccol = (x + scrollx + 0x100) & 0x1ff; break; // manhattan building top
532            case 0x02: srccol = ((x + scrollx) & 0xff) + 0x100; break; // manhattan normal case
533            case 0x03: srccol = (x + scrollx) & 0x1ff; break; // hwy, burnrub etc.
534         }
535
536         UINT16 pix = src[srccol];
537
538         if ((pix & 0x3) || opaque)
539         {
540            dst[x] = pix;
541         }
542      }
543   }
544
545}
546
547
464548void decocass_state::video_start()
465549{
466550   m_bg_tilemap_l = &machine().tilemap().create(tilemap_get_info_delegate(FUNC(decocass_state::get_bg_l_tile_info),this), tilemap_mapper_delegate(FUNC(decocass_state::bgvideoram_scan_cols),this), 16, 16, 32, 32);
r19804r19805
477561   m_bg_tilemap_r_clip = machine().primary_screen->visible_area();
478562   m_bg_tilemap_r_clip.min_y = 256 / 2;
479563
480   /* background videroam bits D0-D3 are shared with the tileram */
564   /* background videoram bits D0-D3 are shared with the tileram */
481565   m_bgvideoram = m_tileram;
482566   m_bgvideoram_size = 0x0400;   /* d000-d3ff */
483567
r19804r19805
493577
494578UINT32 decocass_state::screen_update_decocass(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
495579{
496   int scrollx, scrolly_l, scrolly_r;
497   rectangle clip;
580   /* THIS CODE SHOULD NOT BE IN SCREEN UPDATE !! */
498581
499582   if (0xc0 != (machine().root_device().ioport("IN2")->read() & 0xc0))  /* coin slots assert an NMI */
500583      m_maincpu->set_input_line(INPUT_LINE_NMI, ASSERT_LINE);
r19804r19805
504587   else if (m_watchdog_count-- > 0)
505588      machine().watchdog_reset();
506589
590   /* (end) THIS CODE SHOULD NOT BE IN SCREEN UPDATE !! */
591
592
507593#ifdef MAME_DEBUG
508594   {
509595      if (machine().input().code_pressed_once(KEYCODE_I))
r19804r19805
525611
526612   bitmap.fill(0, cliprect);
527613
528   scrolly_l = m_back_vl_shift;
529   scrolly_r = 256 - m_back_vr_shift;
530
531   scrollx = 256 - m_back_h_shift;
532   if (0 == (m_mode_set & 0x02))
533      scrollx += 256;
534
535#if 0
536/* this is wrong */
537   if (0 != m_back_h_shift && 0 == ((m_mode_set ^ (m_mode_set >> 1)) & 1))
538      scrollx += 256;
539#endif
540
541   if (0 == (m_mode_set & 0x04))
542      scrolly_r += 256;
543   else
544      scrolly_l += 256;
545
546   m_bg_tilemap_l->set_scrollx(0, scrollx);
547   m_bg_tilemap_l->set_scrolly(0, scrolly_l);
548
549   m_bg_tilemap_r->set_scrollx(0, scrollx);
550   m_bg_tilemap_r->set_scrolly(0, scrolly_r);
551
552614   if (m_mode_set & 0x08)   /* bkg_ena on ? */
553615   {
554      clip = m_bg_tilemap_l_clip;
555      clip &= cliprect;
556      m_bg_tilemap_l->draw(bitmap, clip, TILEMAP_DRAW_OPAQUE, 0);
557
558      clip = m_bg_tilemap_r_clip;
559      clip &= cliprect;
560      m_bg_tilemap_r->draw(bitmap, clip, TILEMAP_DRAW_OPAQUE, 0);
616      draw_edge(bitmap,cliprect,0,true);
617      draw_edge(bitmap,cliprect,1,true);
561618   }
562619
563620   if (m_mode_set & 0x20)
r19804r19805
571628      draw_center(bitmap, cliprect);
572629      if (m_mode_set & 0x08)   /* bkg_ena on ? */
573630      {
574         clip = m_bg_tilemap_l_clip;
575         clip &= cliprect;
576         m_bg_tilemap_l->draw(bitmap, clip, 0, 0);
577
578         clip = m_bg_tilemap_r_clip;
579         clip &= cliprect;
580         m_bg_tilemap_r->draw(bitmap, clip, 0, 0);
631         draw_edge(bitmap,cliprect,0,false);
632         draw_edge(bitmap,cliprect,1,false);
581633      }
582634   }
583635   m_fg_tilemap->draw(bitmap, cliprect, 0, 0);
trunk/src/mame/includes/decocass.h
r19804r19805
244244   DECLARE_READ8_MEMBER(decocass_nodong_r);
245245
246246   UINT8* m_type1_map;
247
247   void draw_edge(bitmap_ind16 &bitmap, const rectangle &cliprect, int which, bool opaque);
248248   void draw_object(bitmap_ind16 &bitmap, const rectangle &cliprect);
249249   void draw_center(bitmap_ind16 &bitmap, const rectangle &cliprect);
250250   void mark_bg_tile_dirty(offs_t offset);
trunk/src/mame/drivers/decocass.c
r19804r19805
110110   AM_RANGE(0xe400, 0xe400) AM_WRITE(decocass_reset_w)
111111
112112/* BIO-3 board */
113   AM_RANGE(0xe402, 0xe402) AM_WRITE(decocass_mode_set_w)
114   AM_RANGE(0xe403, 0xe403) AM_WRITE(decocass_back_h_shift_w)
115   AM_RANGE(0xe404, 0xe404) AM_WRITE(decocass_back_vl_shift_w)
116   AM_RANGE(0xe405, 0xe405) AM_WRITE(decocass_back_vr_shift_w)
117   AM_RANGE(0xe406, 0xe406) AM_WRITE(decocass_part_h_shift_w)
118   AM_RANGE(0xe407, 0xe407) AM_WRITE(decocass_part_v_shift_w)
113   AM_RANGE(0xe402, 0xe402) AM_WRITE(decocass_mode_set_w)      /* scroll mode regs + various enable regs */
114   AM_RANGE(0xe403, 0xe403) AM_WRITE(decocass_back_h_shift_w)  /* back (both)  tilemap x scroll */
115   AM_RANGE(0xe404, 0xe404) AM_WRITE(decocass_back_vl_shift_w) /* back (left)  (top@rot0) tilemap y scroll */
116   AM_RANGE(0xe405, 0xe405) AM_WRITE(decocass_back_vr_shift_w) /* back (right) (bot@rot0) tilemap y scroll */
117   AM_RANGE(0xe406, 0xe406) AM_WRITE(decocass_part_h_shift_w) /* headlight */
118   AM_RANGE(0xe407, 0xe407) AM_WRITE(decocass_part_v_shift_w) /* headlight */
119119
120120   AM_RANGE(0xe410, 0xe410) AM_WRITE(decocass_color_center_bot_w)
121121   AM_RANGE(0xe411, 0xe411) AM_WRITE(decocass_center_h_shift_space_w)

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