/*************************************************************************** Jaleco Exerion ***************************************************************************/ #include "emu.h" #include "video/resnet.h" #include "includes/exerion.h" #define BACKGROUND_X_START 32 #define VISIBLE_X_MIN (12*8) #define VISIBLE_X_MAX (52*8) #define VISIBLE_Y_MIN (2*8) #define VISIBLE_Y_MAX (30*8) /*************************************************************************** Convert the color PROMs into a more useable format. The palette PROM is connected to the RGB output this way: bit 7 -- 220 ohm resistor -- BLUE -- 470 ohm resistor -- BLUE -- 220 ohm resistor -- GREEN -- 470 ohm resistor -- GREEN -- 1 kohm resistor -- GREEN -- 220 ohm resistor -- RED -- 470 ohm resistor -- RED bit 0 -- 1 kohm resistor -- RED ***************************************************************************/ PALETTE_INIT( exerion ) { static const int resistances_rg[3] = { 1000, 470, 220 }; static const int resistances_b [2] = { 470, 220 }; double rweights[3], gweights[3], bweights[2]; int i; /* compute the color output resistor weights */ compute_resistor_weights(0, 255, -1.0, 3, &resistances_rg[0], rweights, 0, 0, 3, &resistances_rg[0], gweights, 0, 0, 2, &resistances_b[0], bweights, 0, 0); /* allocate the colortable */ machine.colortable = colortable_alloc(machine, 0x20); /* create a lookup table for the palette */ for (i = 0; i < 0x20; i++) { int bit0, bit1, bit2; int r, g, b; /* red component */ bit0 = (color_prom[i] >> 0) & 0x01; bit1 = (color_prom[i] >> 1) & 0x01; bit2 = (color_prom[i] >> 2) & 0x01; r = combine_3_weights(rweights, bit0, bit1, bit2); /* green component */ bit0 = (color_prom[i] >> 3) & 0x01; bit1 = (color_prom[i] >> 4) & 0x01; bit2 = (color_prom[i] >> 5) & 0x01; g = combine_3_weights(gweights, bit0, bit1, bit2); /* blue component */ bit0 = (color_prom[i] >> 6) & 0x01; bit1 = (color_prom[i] >> 7) & 0x01; b = combine_2_weights(bweights, bit0, bit1); colortable_palette_set_color(machine.colortable, i, MAKE_RGB(r, g, b)); } /* color_prom now points to the beginning of the lookup table */ color_prom += 0x20; /* fg chars and sprites */ for (i = 0; i < 0x200; i++) { UINT8 ctabentry = 0x10 | (color_prom[(i & 0x1c0) | ((i & 3) << 4) | ((i >> 2) & 0x0f)] & 0x0f); colortable_entry_set_value(machine.colortable, i, ctabentry); } /* bg chars (this is not the full story... there are four layers mixed */ /* using another PROM */ for (i = 0x200; i < 0x300; i++) { UINT8 ctabentry = color_prom[i] & 0x0f; colortable_entry_set_value(machine.colortable, i, ctabentry); } } /************************************* * * Video system startup * *************************************/ VIDEO_START( exerion ) { exerion_state *state = machine.driver_data(); int i; UINT8 *gfx; /* get pointers to the mixing and lookup PROMs */ state->m_background_mixer = machine.region("proms")->base() + 0x320; /* allocate memory for the decoded background graphics */ state->m_background_gfx[0] = auto_alloc_array(machine, UINT16, 256 * 256 * 4); state->m_background_gfx[1] = state->m_background_gfx[0] + 256 * 256; state->m_background_gfx[2] = state->m_background_gfx[1] + 256 * 256; state->m_background_gfx[3] = state->m_background_gfx[2] + 256 * 256; state->save_pointer(NAME(state->m_background_gfx[0]), 256 * 256 * 4); /*--------------------------------- * Decode the background graphics * * We decode the 4 background layers separately, but shuffle the bits so that * we can OR all four layers together. Each layer has 2 bits per pixel. Each * layer is decoded into the following bit patterns: * * 000a 0000 00AA * 00b0 0000 BB00 * 0c00 00CC 0000 * d000 DD00 0000 * * Where AA,BB,CC,DD are the 2bpp data for the pixel,and a,b,c,d are the OR * of these two bits together. */ gfx = machine.region("gfx3")->base(); for (i = 0; i < 4; i++) { int y; UINT8 *src = gfx + i * 0x2000; UINT16 *dst = state->m_background_gfx[i]; for (y = 0; y < 0x100; y++) { int x; for (x = 0; x < 0x80; x += 4) { UINT8 data = *src++; UINT16 val; val = ((data >> 3) & 2) | ((data >> 0) & 1); if (val) val |= 0x100 >> i; *dst++ = val << (2 * i); val = ((data >> 4) & 2) | ((data >> 1) & 1); if (val) val |= 0x100 >> i; *dst++ = val << (2 * i); val = ((data >> 5) & 2) | ((data >> 2) & 1); if (val) val |= 0x100 >> i; *dst++ = val << (2 * i); val = ((data >> 6) & 2) | ((data >> 3) & 1); if (val) val |= 0x100 >> i; *dst++ = val << (2 * i); } for (; x < 0x100; x++) *dst++ = 0; } } } /************************************* * * Video register I/O * *************************************/ WRITE8_HANDLER( exerion_videoreg_w ) { exerion_state *state = space->machine().driver_data(); /* bit 0 = flip screen and joystick input multiplexer */ state->m_cocktail_flip = data & 1; /* bits 1-2 char lookup table bank */ state->m_char_palette = (data & 0x06) >> 1; /* bits 3 char bank */ state->m_char_bank = (data & 0x08) >> 3; /* bits 4-5 unused */ /* bits 6-7 sprite lookup table bank */ state->m_sprite_palette = (data & 0xc0) >> 6; } WRITE8_HANDLER( exerion_video_latch_w ) { exerion_state *state = space->machine().driver_data(); int scanline = space->machine().primary_screen->vpos(); if (scanline > 0) space->machine().primary_screen->update_partial(scanline - 1); state->m_background_latches[offset] = data; } READ8_HANDLER( exerion_video_timing_r ) { /* bit 0 is the SNMI signal, which is the negated value of H6, if H7=1 & H8=1 & VBLANK=0, otherwise 1 */ /* bit 1 is VBLANK */ UINT16 hcounter = space->machine().primary_screen->hpos() + EXERION_HCOUNT_START; UINT8 snmi = 1; if (((hcounter & 0x180) == 0x180) && !space->machine().primary_screen->vblank()) snmi = !((hcounter >> 6) & 0x01); return (space->machine().primary_screen->vblank() << 1) | snmi; } /************************************* * * Background rendering * *************************************/ static void draw_background( running_machine &machine, bitmap_t *bitmap, const rectangle *cliprect) { exerion_state *state = machine.driver_data(); int x, y; /* loop over all visible scanlines */ for (y = cliprect->min_y; y <= cliprect->max_y; y++) { UINT16 *src0 = &state->m_background_gfx[0][state->m_background_latches[1] * 256]; UINT16 *src1 = &state->m_background_gfx[1][state->m_background_latches[3] * 256]; UINT16 *src2 = &state->m_background_gfx[2][state->m_background_latches[5] * 256]; UINT16 *src3 = &state->m_background_gfx[3][state->m_background_latches[7] * 256]; int xoffs0 = state->m_background_latches[0]; int xoffs1 = state->m_background_latches[2]; int xoffs2 = state->m_background_latches[4]; int xoffs3 = state->m_background_latches[6]; int start0 = state->m_background_latches[8] & 0x0f; int start1 = state->m_background_latches[9] & 0x0f; int start2 = state->m_background_latches[10] & 0x0f; int start3 = state->m_background_latches[11] & 0x0f; int stop0 = state->m_background_latches[8] >> 4; int stop1 = state->m_background_latches[9] >> 4; int stop2 = state->m_background_latches[10] >> 4; int stop3 = state->m_background_latches[11] >> 4; UINT8 *mixer = &state->m_background_mixer[(state->m_background_latches[12] << 4) & 0xf0]; UINT16 scanline[VISIBLE_X_MAX]; pen_t pen_base = 0x200 + ((state->m_background_latches[12] >> 4) << 4); /* the cocktail flip flag controls whether we count up or down in X */ if (!state->m_cocktail_flip) { /* skip processing anything that's not visible */ for (x = BACKGROUND_X_START; x < cliprect->min_x; x++) { if (!(++xoffs0 & 0x1f)) start0++, stop0++; if (!(++xoffs1 & 0x1f)) start1++, stop1++; if (!(++xoffs2 & 0x1f)) start2++, stop2++; if (!(++xoffs3 & 0x1f)) start3++, stop3++; } /* draw the rest of the scanline fully */ for (x = cliprect->min_x; x <= cliprect->max_x; x++) { UINT16 combined = 0; UINT8 lookupval; /* the output enable is controlled by the carries on the start/stop counters */ /* they are only active when the start has carried but the stop hasn't */ if ((start0 ^ stop0) & 0x10) combined |= src0[xoffs0 & 0xff]; if ((start1 ^ stop1) & 0x10) combined |= src1[xoffs1 & 0xff]; if ((start2 ^ stop2) & 0x10) combined |= src2[xoffs2 & 0xff]; if ((start3 ^ stop3) & 0x10) combined |= src3[xoffs3 & 0xff]; /* bits 8-11 of the combined value contains the lookup for the mixer PROM */ lookupval = mixer[combined >> 8] & 3; /* the color index comes from the looked up value combined with the pixel data */ scanline[x] = pen_base | (lookupval << 2) | ((combined >> (2 * lookupval)) & 3); /* the start/stop counters are clocked when the low 5 bits of the X counter overflow */ if (!(++xoffs0 & 0x1f)) start0++, stop0++; if (!(++xoffs1 & 0x1f)) start1++, stop1++; if (!(++xoffs2 & 0x1f)) start2++, stop2++; if (!(++xoffs3 & 0x1f)) start3++, stop3++; } } else { /* skip processing anything that's not visible */ for (x = BACKGROUND_X_START; x < cliprect->min_x; x++) { if (!(xoffs0-- & 0x1f)) start0++, stop0++; if (!(xoffs1-- & 0x1f)) start1++, stop1++; if (!(xoffs2-- & 0x1f)) start2++, stop2++; if (!(xoffs3-- & 0x1f)) start3++, stop3++; } /* draw the rest of the scanline fully */ for (x = cliprect->min_x; x <= cliprect->max_x; x++) { UINT16 combined = 0; UINT8 lookupval; /* the output enable is controlled by the carries on the start/stop counters */ /* they are only active when the start has carried but the stop hasn't */ if ((start0 ^ stop0) & 0x10) combined |= src0[xoffs0 & 0xff]; if ((start1 ^ stop1) & 0x10) combined |= src1[xoffs1 & 0xff]; if ((start2 ^ stop2) & 0x10) combined |= src2[xoffs2 & 0xff]; if ((start3 ^ stop3) & 0x10) combined |= src3[xoffs3 & 0xff]; /* bits 8-11 of the combined value contains the lookup for the mixer PROM */ lookupval = mixer[combined >> 8] & 3; /* the color index comes from the looked up value combined with the pixel data */ scanline[x] = pen_base | (lookupval << 2) | ((combined >> (2 * lookupval)) & 3); /* the start/stop counters are clocked when the low 5 bits of the X counter overflow */ if (!(xoffs0-- & 0x1f)) start0++, stop0++; if (!(xoffs1-- & 0x1f)) start1++, stop1++; if (!(xoffs2-- & 0x1f)) start2++, stop2++; if (!(xoffs3-- & 0x1f)) start3++, stop3++; } } /* draw the scanline */ draw_scanline16(bitmap, cliprect->min_x, y, cliprect->max_x - cliprect->min_x + 1, &scanline[cliprect->min_x], NULL); } } /************************************* * * Core refresh routine * *************************************/ SCREEN_UPDATE( exerion ) { exerion_state *state = screen->machine().driver_data(); int sx, sy, offs, i; /* draw background */ draw_background(screen->machine(), bitmap, cliprect); /* draw sprites */ for (i = 0; i < state->m_spriteram_size; i += 4) { int flags = state->m_spriteram[i + 0]; int y = state->m_spriteram[i + 1] ^ 255; int code = state->m_spriteram[i + 2]; int x = state->m_spriteram[i + 3] * 2 + 72; int xflip = flags & 0x80; int yflip = flags & 0x40; int doubled = flags & 0x10; int wide = flags & 0x08; int code2 = code; int color = ((flags >> 1) & 0x03) | ((code >> 5) & 0x04) | (code & 0x08) | (state->m_sprite_palette * 16); const gfx_element *gfx = doubled ? screen->machine().gfx[2] : screen->machine().gfx[1]; if (state->m_cocktail_flip) { x = 64*8 - gfx->width - x; y = 32*8 - gfx->height - y; if (wide) y -= gfx->height; xflip = !xflip; yflip = !yflip; } if (wide) { if (yflip) code |= 0x10, code2 &= ~0x10; else code &= ~0x10, code2 |= 0x10; drawgfx_transmask(bitmap, cliprect, gfx, code2, color, xflip, yflip, x, y + gfx->height, colortable_get_transpen_mask(screen->machine().colortable, gfx, color, 0x10)); } drawgfx_transmask(bitmap, cliprect, gfx, code, color, xflip, yflip, x, y, colortable_get_transpen_mask(screen->machine().colortable, gfx, color, 0x10)); if (doubled) i += 4; } /* draw the visible text layer */ for (sy = cliprect->min_y/8; sy <= cliprect->max_y/8; sy++) for (sx = VISIBLE_X_MIN/8; sx < VISIBLE_X_MAX/8; sx++) { int x = state->m_cocktail_flip ? (63*8 - 8*sx) : 8*sx; int y = state->m_cocktail_flip ? (31*8 - 8*sy) : 8*sy; offs = sx + sy * 64; drawgfx_transpen(bitmap, cliprect, screen->machine().gfx[0], state->m_videoram[offs] + 256 * state->m_char_bank, ((state->m_videoram[offs] & 0xf0) >> 4) + state->m_char_palette * 16, state->m_cocktail_flip, state->m_cocktail_flip, x, y, 0); } return 0; }