// license:BSD-3-Clause // copyright-holders:Aaron Giles /************************************************************************* Exidy 6502 hardware *************************************************************************/ #include "emu.h" #include "includes/exidy.h" /************************************* * * Video configuration * *************************************/ void exidy_state::exidy_video_config(uint8_t _collision_mask, uint8_t _collision_invert, int _is_2bpp) { m_collision_mask = _collision_mask; m_collision_invert = _collision_invert; m_is_2bpp = _is_2bpp; } /************************************* * * Video startup * *************************************/ void exidy_state::video_start() { m_screen->register_screen_bitmap(m_background_bitmap); m_motion_object_1_vid.allocate(16, 16); m_motion_object_2_vid.allocate(16, 16); m_motion_object_2_clip.allocate(16, 16); save_item(NAME(m_collision_mask)); save_item(NAME(m_collision_invert)); save_item(NAME(m_is_2bpp)); save_item(NAME(m_int_condition)); save_item(NAME(m_background_bitmap)); save_item(NAME(m_motion_object_1_vid)); save_item(NAME(m_motion_object_2_vid)); save_item(NAME(m_motion_object_2_clip)); } /************************************* * * Interrupt generation * *************************************/ inline void exidy_state::latch_condition(int collision) { collision ^= m_collision_invert; m_int_condition = (ioport("INTSOURCE")->read() & ~0x1c) | (collision & m_collision_mask); } INTERRUPT_GEN_MEMBER(exidy_state::exidy_vblank_interrupt) { /* latch the current condition */ latch_condition(0); m_int_condition &= ~0x80; /* set the IRQ line */ device.execute().set_input_line(0, ASSERT_LINE); } READ8_MEMBER(exidy_state::exidy_interrupt_r) { /* clear any interrupts */ m_maincpu->set_input_line(0, CLEAR_LINE); /* return the latched condition */ return m_int_condition; } /************************************* * * Palette handling * *************************************/ inline void exidy_state::set_1_color(int index, int which) { m_palette->set_pen_color(index, pal1bit(m_color_latch[2] >> which), pal1bit(m_color_latch[1] >> which), pal1bit(m_color_latch[0] >> which)); } void exidy_state::set_colors() { /* motion object 1 */ set_1_color(0, 0); set_1_color(1, 7); /* motion object 2 */ set_1_color(2, 0); set_1_color(3, 6); /* characters */ set_1_color(4, 4); set_1_color(5, 3); set_1_color(6, 2); set_1_color(7, 1); } /************************************* * * Background update * *************************************/ void exidy_state::draw_background() { offs_t offs; pen_t off_pen = 0; for (offs = 0; offs < 0x400; offs++) { uint8_t cy; pen_t on_pen_1, on_pen_2; uint8_t y = offs >> 5 << 3; uint8_t code = m_videoram[offs]; if (m_is_2bpp) { on_pen_1 = 4 + ((code >> 6) & 0x02); on_pen_2 = 5 + ((code >> 6) & 0x02); } else { on_pen_1 = 4 + ((code >> 6) & 0x03); on_pen_2 = off_pen; /* unused */ } for (cy = 0; cy < 8; cy++) { int i; uint8_t x = offs << 3; if (m_is_2bpp) { uint8_t data1 = m_characterram[0x000 | (code << 3) | cy]; uint8_t data2 = m_characterram[0x800 | (code << 3) | cy]; for (i = 0; i < 8; i++) { if (data1 & 0x80) m_background_bitmap.pix16(y, x) = (data2 & 0x80) ? on_pen_2 : on_pen_1; else m_background_bitmap.pix16(y, x) = off_pen; x = x + 1; data1 = data1 << 1; data2 = data2 << 1; } } /* 1bpp */ else { uint8_t data = m_characterram[(code << 3) | cy]; for (i = 0; i < 8; i++) { m_background_bitmap.pix16(y, x) = (data & 0x80) ? on_pen_1 : off_pen; x = x + 1; data = data << 1; } } y = y + 1; } } } /************************************* * * Sprite hardware * *************************************/ inline int exidy_state::sprite_1_enabled() { /* if the collision_mask is 0x00, then we are on old hardware that always has */ /* sprite 1 enabled regardless */ return (!(*m_sprite_enable & 0x80) || (*m_sprite_enable & 0x10) || (m_collision_mask == 0x00)); } void exidy_state::draw_sprites(bitmap_ind16 &bitmap, const rectangle &cliprect) { /* draw sprite 2 first */ int sprite_set_2 = ((*m_sprite_enable & 0x40) != 0); int sx = 236 - *m_sprite2_xpos - 4; int sy = 244 - *m_sprite2_ypos - 4; m_gfxdecode->gfx(0)->transpen(bitmap,cliprect, ((*m_spriteno >> 4) & 0x0f) + 32 + 16 * sprite_set_2, 1, 0, 0, sx, sy, 0); /* draw sprite 1 next */ if (sprite_1_enabled()) { int sprite_set_1 = ((*m_sprite_enable & 0x20) != 0); sx = 236 - *m_sprite1_xpos - 4; sy = 244 - *m_sprite1_ypos - 4; if (sy < 0) sy = 0; m_gfxdecode->gfx(0)->transpen(bitmap,cliprect, (*m_spriteno & 0x0f) + 16 * sprite_set_1, 0, 0, 0, sx, sy, 0); } } /************************************* * * Collision detection * *************************************/ /*************************************************************************** Exidy hardware checks for two types of collisions based on the video signals. If the Motion Object 1 and Motion Object 2 signals are on at the same time, an M1M2 collision bit gets set. If the Motion Object 1 and Background Character signals are on at the same time, an M1CHAR collision bit gets set. So effectively, there's a pixel-by-pixel collision check comparing Motion Object 1 (the player) to the background and to the other Motion Object (typically a bad guy). ***************************************************************************/ void exidy_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { switch (id) { case TIMER_COLLISION_IRQ: /* latch the collision bits */ latch_condition(param); /* set the IRQ line */ m_maincpu->set_input_line(0, ASSERT_LINE); break; default: assert_always(false, "Unknown id in exidy_state::device_timer"); } } void exidy_state::check_collision() { uint8_t sprite_set_1 = ((*m_sprite_enable & 0x20) != 0); uint8_t sprite_set_2 = ((*m_sprite_enable & 0x40) != 0); const rectangle clip(0, 15, 0, 15); int org_1_x = 0, org_1_y = 0; int org_2_x = 0, org_2_y = 0; int sx, sy; int count = 0; /* if there is nothing to detect, bail */ if (m_collision_mask == 0) return; /* draw sprite 1 */ m_motion_object_1_vid.fill(0xff, clip); if (sprite_1_enabled()) { org_1_x = 236 - *m_sprite1_xpos - 4; org_1_y = 244 - *m_sprite1_ypos - 4; m_gfxdecode->gfx(0)->transpen(m_motion_object_1_vid,clip, (*m_spriteno & 0x0f) + 16 * sprite_set_1, 0, 0, 0, 0, 0, 0); } /* draw sprite 2 */ m_motion_object_2_vid.fill(0xff, clip); org_2_x = 236 - *m_sprite2_xpos - 4; org_2_y = 244 - *m_sprite2_ypos - 4; m_gfxdecode->gfx(0)->transpen(m_motion_object_2_vid,clip, ((*m_spriteno >> 4) & 0x0f) + 32 + 16 * sprite_set_2, 0, 0, 0, 0, 0, 0); /* draw sprite 2 clipped to sprite 1's location */ m_motion_object_2_clip.fill(0xff, clip); if (sprite_1_enabled()) { sx = org_2_x - org_1_x; sy = org_2_y - org_1_y; m_gfxdecode->gfx(0)->transpen(m_motion_object_2_clip,clip, ((*m_spriteno >> 4) & 0x0f) + 32 + 16 * sprite_set_2, 0, 0, 0, sx, sy, 0); } /* scan for collisions */ for (sy = 0; sy < 16; sy++) for (sx = 0; sx < 16; sx++) { if (m_motion_object_1_vid.pix16(sy, sx) != 0xff) { uint8_t current_collision_mask = 0; /* check for background collision (M1CHAR) */ if (m_background_bitmap.pix16(org_1_y + sy, org_1_x + sx) != 0) current_collision_mask |= 0x04; /* check for motion object collision (M1M2) */ if (m_motion_object_2_clip.pix16(sy, sx) != 0xff) current_collision_mask |= 0x10; /* if we got one, trigger an interrupt */ if ((current_collision_mask & m_collision_mask) && (count++ < 128)) timer_set(m_screen->time_until_pos(org_1_x + sx, org_1_y + sy), TIMER_COLLISION_IRQ, current_collision_mask); } if (m_motion_object_2_vid.pix16(sy, sx) != 0xff) { /* check for background collision (M2CHAR) */ if (m_background_bitmap.pix16(org_2_y + sy, org_2_x + sx) != 0) if ((m_collision_mask & 0x08) && (count++ < 128)) timer_set(m_screen->time_until_pos(org_2_x + sx, org_2_y + sy), TIMER_COLLISION_IRQ, 0x08); } } } /************************************* * * Standard screen refresh callback * *************************************/ uint32_t exidy_state::screen_update_exidy(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { /* refresh the colors from the palette (static or dynamic) */ set_colors(); /* update the background and draw it */ draw_background(); copybitmap(bitmap, m_background_bitmap, 0, 0, 0, 0, cliprect); /* draw the sprites */ draw_sprites(bitmap, cliprect); /* check for collision, this will set the appropriate bits in collision_mask */ check_collision(); return 0; }