summaryrefslogtreecommitdiffstatshomepage
path: root/src/mame/video/segas18.cpp
blob: f6033172e24502cc3107736d9482b819593b0266 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************

    Sega System 18 hardware

***************************************************************************/

#include "emu.h"
#include "includes/segas18.h"



/*************************************
 *
 *  Debugging
 *
 *************************************/

#define DEBUG_VDP               (0)


/*************************************
 *
 *  Video startup
 *
 *************************************/

void segas18_state::video_start()
{
	m_temp_bitmap.allocate(m_screen->width(), m_screen->height());
	m_grayscale_enable = 0;
	m_vdp_enable = 0;
	m_vdp_mixing = 0;

	// initialize the tile/text layers
	m_segaic16vid->tilemap_init( 0, segaic16_video_device::TILEMAP_16B, 0x000, 0, 8);

	save_item(NAME(m_grayscale_enable));
	save_item(NAME(m_vdp_enable));
	save_item(NAME(m_vdp_mixing));
	save_item(NAME(m_temp_bitmap));
}



/*************************************
 *
 *  Miscellaneous setters
 *
 *************************************/

WRITE_LINE_MEMBER(segas18_state::set_grayscale)
{
	if (state != m_grayscale_enable)
	{
		m_screen->update_partial(m_screen->vpos());
		m_grayscale_enable = state;
//      osd_printf_debug("Grayscale = %02X\n", enable);
	}
}


WRITE_LINE_MEMBER(segas18_state::set_vdp_enable)
{
	if (state != m_vdp_enable)
	{
		m_screen->update_partial(m_screen->vpos());
		m_vdp_enable = state;
#if DEBUG_VDP
		osd_printf_debug("VDP enable = %02X\n", enable);
#endif
	}
}


void segas18_state::set_vdp_mixing(uint8_t mixing)
{
	if (mixing != m_vdp_mixing)
	{
		m_screen->update_partial(m_screen->vpos());
		m_vdp_mixing = mixing;
#if DEBUG_VDP
		osd_printf_debug("VDP mixing = %02X\n", mixing);
#endif
	}
}



/*************************************
 *
 *  VDP drawing
 *
 *************************************/

void segas18_state::draw_vdp(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect, int priority)
{
	bitmap_ind8 &priority_bitmap = screen.priority();
	for (int y = cliprect.min_y; y <= cliprect.max_y; y++)
	{
	//  uint16_t *src = vdp->m_render_line; // can't use this because we're not in RGB32, which we'll need to be if there are palette effects
	//  uint16_t *src2 = vdp->m_render_line_raw;

		uint16_t *dst = &bitmap.pix(y);
		uint8_t *pri = &priority_bitmap.pix(y);
		for (int x = cliprect.min_x; x <= cliprect.max_x; x++)
		{
			if (m_vdp->m_render_line_raw[x] & 0x100)
			{
				int pix = m_vdp->m_render_line_raw[x] & 0x3f;
				if (pix & 0xf)
				{
					switch (pix & 0xc0)
					{
						case 0x00:
							dst[x] = pix + 0x2000; /* 0x2040 - would be shadow? */
							break;
						case 0x40:
						case 0x80:
							dst[x] = pix + 0x2000;
							break;
						case 0xc0:
							dst[x] = pix + 0x2000; /* 0x2080 - would be higlight? */
							break;
					}
					pri[x] |= priority;
				}
			}
		}
	}
}

/*************************************
 *
 *  Video update
 *
 *************************************/

uint32_t segas18_state::screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
{
/*
    Current understanding of VDP mixing:

    mixing = 0x00:
        astorm: layer = 0, pri = 0x00 or 0x01
        lghost: layer = 0, pri = 0x00 or 0x01

    mixing = 0x01:
        ddcrew: layer = 0, pri = 0x00 or 0x01 or 0x02

    mixing = 0x02:
        never seen

    mixing = 0x03:
        ddcrew: layer = 1, pri = 0x00 or 0x01 or 0x02

    mixing = 0x04:
        astorm: layer = 2 or 3, pri = 0x00 or 0x01 or 0x02
        mwalk:  layer = 2 or 3, pri = 0x00 or 0x01 or 0x02

    mixing = 0x05:
        ddcrew: layer = 2, pri = 0x04
        wwally: layer = 2, pri = 0x04

    mixing = 0x06:
        never seen

    mixing = 0x07:
        cltchitr: layer = 1 or 2 or 3, pri = 0x02 or 0x04 or 0x08
        mwalk:    layer = 3, pri = 0x04 or 0x08
*/

	int vdplayer = (m_vdp_mixing >> 1) & 3;
	int vdppri = (m_vdp_mixing & 1) ? (1 << vdplayer) : 0;

#if DEBUG_VDP
	if (machine().input().code_pressed(KEYCODE_Q)) vdplayer = 0;
	if (machine().input().code_pressed(KEYCODE_W)) vdplayer = 1;
	if (machine().input().code_pressed(KEYCODE_E)) vdplayer = 2;
	if (machine().input().code_pressed(KEYCODE_R)) vdplayer = 3;
	if (machine().input().code_pressed(KEYCODE_A)) vdppri = 0x00;
	if (machine().input().code_pressed(KEYCODE_S)) vdppri = 0x01;
	if (machine().input().code_pressed(KEYCODE_D)) vdppri = 0x02;
	if (machine().input().code_pressed(KEYCODE_F)) vdppri = 0x04;
	if (machine().input().code_pressed(KEYCODE_G)) vdppri = 0x08;
#endif

	// if no drawing is happening, fill with black and get out
	if (!m_segaic16vid->m_display_enable)
	{
		bitmap.fill(m_palette->black_pen(), cliprect);
		return 0;
	}

	// start the sprites drawing
	m_sprites->draw_async(cliprect);

	// reset priorities
	screen.priority().fill(0, cliprect);

	// draw background opaquely first, not setting any priorities
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 0 | TILEMAP_DRAW_OPAQUE, 0x00);
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 1 | TILEMAP_DRAW_OPAQUE, 0x00);
	if (m_vdp_enable && vdplayer == 0) draw_vdp(screen, bitmap, cliprect, vdppri);

	// draw background again to draw non-transparent pixels over the VDP and set the priority
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 0, 0x01);
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_BACKGROUND, 1, 0x02);
	if (m_vdp_enable && vdplayer == 1) draw_vdp(screen, bitmap, cliprect, vdppri);

	// draw foreground
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_FOREGROUND, 0, 0x02);
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_FOREGROUND, 1, 0x04);
	if (m_vdp_enable && vdplayer == 2) draw_vdp(screen, bitmap, cliprect, vdppri);

	// text layer
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_TEXT, 0, 0x04);
	m_segaic16vid->tilemap_draw( screen, bitmap, cliprect, 0, segaic16_video_device::TILEMAP_TEXT, 1, 0x08);
	if (m_vdp_enable && vdplayer == 3) draw_vdp(screen, bitmap, cliprect, vdppri);

	// mix in sprites
	bitmap_ind16 &sprites = m_sprites->bitmap();
	for (const sparse_dirty_rect *rect = m_sprites->first_dirty_rect(cliprect); rect != nullptr; rect = rect->next())
	{
		for (int y = rect->min_y; y <= rect->max_y; y++)
		{
			uint16_t *dest = &bitmap.pix(y);
			uint16_t *src = &sprites.pix(y);
			uint8_t *pri = &screen.priority().pix(y);
			for (int x = rect->min_x; x <= rect->max_x; x++)
			{
				// only process written pixels
				uint16_t pix = src[x];
				if (pix != 0xffff)
				{
					// compare sprite priority against tilemap priority
					int priority = (pix >> 10) & 3;
					if ((1 << priority) > pri[x])
					{
						// if the color is set to maximum, shadow pixels underneath us
						if ((pix & 0x03f0) == 0x03f0)
							dest[x] += (m_paletteram[dest[x]] & 0x8000) ? m_palette_entries*2 : m_palette_entries;

						// otherwise, just add in sprite palette base
						else
							dest[x] = 0x400 | (pix & 0x3ff);
					}
				}
			}
		}
	}

#if DEBUG_VDP
	if (m_vdp_enable && machine().input().code_pressed(KEYCODE_V))
	{
		bitmap.fill(m_palette->black_pen(), cliprect);
		update_system18_vdp(bitmap, cliprect);
	}
	if (vdp_enable && machine().input().code_pressed(KEYCODE_B))
	{
		FILE *f = fopen("vdp.bin", "w");
		fwrite(m_temp_bitmap->base(), 1, m_temp_bitmap->rowpixels() * (m_temp_bitmap->bpp() / 8) * m_temp_bitmap->height(), f);
		fclose(f);
	}
#endif
	return 0;
}