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Genesis-Plus-GX/source/render.c

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restored from bountysource
2008-08-07 14:26:07 +02:00
/***************************************************************************************
* Genesis Plus 1.2a
* Video Display Processor (Rendering)
*
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Charles Mac Donald (original code)
* modified by Eke-Eke (compatibility fixes & additional code), GC/Wii port
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
****************************************************************************************/
#include "shared.h"
/* Look-up pixel table information */
#define LUT_MAX (5)
#define LUT_SIZE (0x10000)
/* Clip structure */
typedef struct
{
uint8 left;
uint8 right;
uint8 enable;
}clip_t;
/* Function prototypes */
void render_obj(int line, uint8 *buf, uint8 *table);
void render_obj_im2(int line, uint8 *buf, uint8 *table, uint8 odd);
void render_ntw(int line, uint8 *buf);
void render_ntw_im2(int line, uint8 *buf, uint8 odd);
void render_ntx(int which, int line, uint8 *buf);
void render_ntx_im2(int which, int line, uint8 *buf, uint8 odd);
void render_ntx_vs(int which, int line, uint8 *buf);
void update_bg_pattern_cache(void);
void get_hscroll(int line, int shift, uint16 *scroll);
void window_clip(int line);
int make_lut_bg(int bx, int ax);
int make_lut_obj(int bx, int sx);
int make_lut_bg_ste(int bx, int ax);
int make_lut_obj_ste(int bx, int sx);
int make_lut_bgobj_ste(int bx, int sx);
void merge(uint8 *srca, uint8 *srcb, uint8 *dst, uint8 *table, int width);
void make_name_lut(void);
void (*color_update)(int index, uint16 data);
void remap_16(uint8 *src, uint16 *dst, uint16 *table, int length);
#ifndef NGC
void remap_8(uint8 *src, uint8 *dst, uint8 *table, int length);
void remap_32(uint8 *src, uint32 *dst, uint32 *table, int length);
#endif
#ifndef LSB_FIRST
static uint32 ATTR_MSB;
#endif
#ifdef ALIGN_LONG
/* Or change the names if you depend on these from elsewhere.. */
#undef READ_LONG
#undef WRITE_LONG
static __inline__ uint32 READ_LONG(void *address)
{
if ((uint32)address & 3)
{
#ifdef LSB_FIRST /* little endian version */
return ( *((uint8 *)address) +
(*((uint8 *)address+1) << 8) +
(*((uint8 *)address+2) << 16) +
(*((uint8 *)address+3) << 24) );
#else /* big endian version */
return ( *((uint8 *)address+3) +
(*((uint8 *)address+2) << 8) +
(*((uint8 *)address+1) << 16) +
(*((uint8 *)address) << 24) );
#endif /* LSB_FIRST */
}
else return *(uint32 *)address;
}
static __inline__ void WRITE_LONG(void *address, uint32 data)
{
if ((uint32)address & 3)
{
#ifdef LSB_FIRST
*((uint8 *)address) = data;
*((uint8 *)address+1) = (data >> 8);
*((uint8 *)address+2) = (data >> 16);
*((uint8 *)address+3) = (data >> 24);
#else
*((uint8 *)address+3) = data;
*((uint8 *)address+2) = (data >> 8);
*((uint8 *)address+1) = (data >> 16);
*((uint8 *)address) = (data >> 24);
#endif /* LSB_FIRST */
return;
}
else *(uint32 *)address = data;
}
#endif /* ALIGN_LONG */
/*
Two Pattern Attributes are written in VRAM as two 16bits WORD:
P = priority bit
C = color palette (2 bits)
V = Vertical Flip bit
H = Horizontal Flip bit
N = Pattern Number (11 bits)
MSB PCCVHNNN NNNNNNNN LSB PCCVHNNN NNNNNNNN LSB
PATTERN1 PATTERN2
Pattern attributes are read from VRAM as 32bits WORD like this:
LIT_ENDIAN: ATTR is MSB PCCVHNNN NNNNNNNN PCCVHNNN NNNNNNNN LSB
PATTERN2 PATTERN1
BIG_ENDIAN: ATTR is MSB PCCVHNNN NNNNNNNN PCCVHNNN NNNNNNNN LSB
PATTERN1 PATTERN2
Each Line Buffer written byte describe one pixel data like this:
msb SPppcccc lsb
with:
S = sprite data indicator (not written here)
P = priority bit (from Pattern Attribute)
p = color palette (from Pattern Attribute)
c = color data (from Pattern Cache)
A column is 2 patterns wide
A pattern is 8 pixels wide = 8 bytes = two 32 bits write
*/
/* Draw a single 8-pixel column */
/*
pattern cache is addressed like this: 00000VHN NNNNNNNN NNYYYXXX
with : Y = pattern row (1-8 lines)
X = pattern column (1-8 pixels)
V = Vertical Flip bit
H = Horizontal Flip bit
N = Pattern Number (1-2048)
*/
#ifdef ALIGN_LONG
#ifdef LSB_FIRST
#define DRAW_COLUMN(ATTR, LINE) \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
ATTR >>= 16; \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++;
#else
#define DRAW_COLUMN(ATTR, LINE) \
ATTR_MSB = ATTR >> 16; \
atex = atex_table[(ATTR_MSB >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR_MSB & 0x1FFF) << 6 | (LINE)]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++;
#endif
#else /* NOT ALIGNED */
#ifdef LSB_FIRST
#define DRAW_COLUMN(ATTR, LINE) \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex); \
ATTR >>= 16; \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex);
#else
#define DRAW_COLUMN(ATTR, LINE) \
ATTR_MSB = ATTR >> 16; \
atex = atex_table[(ATTR_MSB >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR_MSB & 0x1FFF) << 6 | (LINE)]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex); \
atex = atex_table[(ATTR >> 13) & 7]; \
src = (uint32 *)&bg_pattern_cache[(ATTR & 0x1FFF) << 6 | (LINE)]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex);
#endif
#endif /* ALIGN_LONG */
/* Draw a single 16-pixel column */
/*
pattern cache is addressed like this: 00000VHN NNNNNNNN NYYYYXXX
with : Y = pattern row (1-16 lines)
X = pattern column (1-8 pixels)
V = Vertical Flip bit
H = Horizontal Flip bit
N = Pattern Number (1-1024)
one pattern line is 8 pixels = 8 bytes = 2 * 32 bits
*/
#ifdef ALIGN_LONG
#ifdef LSB_FIRST
#define DRAW_COLUMN_IM2(ATTR, LINE) \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
ATTR >>= 16; \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++;
#else
#define DRAW_COLUMN_IM2(ATTR, LINE) \
ATTR_MSB = ATTR >> 16; \
atex = atex_table[(ATTR_MSB >> 13) & 7]; \
offs = (ATTR_MSB & 0x03FF) << 7 | (ATTR_MSB & 0x1800) << 6 | (LINE); \
if(ATTR_MSB & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++; \
WRITE_LONG(dst, READ_LONG(src) | atex); \
dst++; \
src++;
#endif
#else /* NOT ALIGNED */
#ifdef LSB_FIRST
#define DRAW_COLUMN_IM2(ATTR, LINE) \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex); \
ATTR >>= 16; \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex);
#else
#define DRAW_COLUMN_IM2(ATTR, LINE) \
ATTR_MSB = ATTR >> 16; \
atex = atex_table[(ATTR_MSB >> 13) & 7]; \
offs = (ATTR_MSB & 0x03FF) << 7 | (ATTR_MSB & 0x1800) << 6 | (LINE); \
if(ATTR_MSB & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex); \
atex = atex_table[(ATTR >> 13) & 7]; \
offs = (ATTR & 0x03FF) << 7 | (ATTR & 0x1800) << 6 | (LINE); \
if(ATTR & 0x1000) offs ^= 0x40; \
src = (uint32 *)&bg_pattern_cache[offs]; \
*dst++ = (*src++ | atex); \
*dst++ = (*src++ | atex);
#endif
#endif /* ALIGN_LONG */
/*
gcc complains about this:
*lb++ = table[(*lb << 8) |(*src++ | palette)];
.. claiming the result on lb is undefined.
So we manually advance lb and use constant offsets into the line buffer.
*/
/* added sprite collision detection:
check if non-transparent sprite data has been previously drawn
*/
#define DRAW_SPRITE_TILE \
for(i=0; i<8; i++) \
{ \
if ((lb[i] & 0x80) && ((lb[i] | src[i]) & 0x0F)) status |= 0x20; \
lb[i] = table[(lb[i] << 8) |(src[i] | palette)]; \
}
/* Pixel creation macros, input is four bits each */
#ifndef NGC
/* 8:8:8 RGB */
#define MAKE_PIXEL_32(r,g,b) ((r) << 20 | (g) << 12 | (b) << 4)
/* 5:5:5 RGB */
#define MAKE_PIXEL_15(r,g,b) ((r) << 11 | (g) << 6 | (b) << 1)
/* 3:3:2 RGB */
#define MAKE_PIXEL_8(r,g,b) ((r) << 5 | (g) << 2 | ((b) >> 1))
#endif
/* 5:6:5 RGB */
#define MAKE_PIXEL_16(r,g,b) ((r) << 11 | (g) << 5 | (b))
/* Clip data */
static clip_t clip[2];
/* Attribute expansion table */
static const uint32 atex_table[] = {
0x00000000, 0x10101010, 0x20202020, 0x30303030,
0x40404040, 0x50505050, 0x60606060, 0x70707070
};
/* Sprite name look-up table */
static uint8 name_lut[0x400];
struct
{
uint16 ypos;
uint16 xpos;
uint16 attr;
uint8 size;
uint8 index;
} object_info[20];
/* Pixel look-up tables and table base address */
static uint8 *lut[5];
static uint8 *lut_base = NULL;
#ifndef NGC
/* 8-bit pixel remapping data */
static uint8 pixel_8[0x100];
static uint8 pixel_8_lut[3][0x200];
/* 15-bit pixel remapping data */
static uint16 pixel_15[0x100];
static uint16 pixel_15_lut[3][0x200];
/* 32-bit pixel remapping data */
static uint32 pixel_32[0x100];
static uint32 pixel_32_lut[3][0x200];
#endif
/* 16-bit pixel remapping data */
static uint16 pixel_16[0x100];
static uint16 pixel_16_lut[3][0x200];
/* Line buffers */
static uint8 tmp_buf[0x400]; /* Temporary buffer */
static uint8 bg_buf[0x400]; /* Merged background buffer */
static uint8 nta_buf[0x400]; /* Plane A / Window line buffer */
static uint8 ntb_buf[0x400]; /* Plane B line buffer */
static uint8 obj_buf[0x400]; /* Object layer line buffer */
/* Sprite line buffer data */
static uint8 object_index_count;
/*
3:3:3 to 5:6:5 RGB pixel extrapolation tables
this is used to convert 3bits RGB values to 5bits (R,B) or 6bits (G) values
there is three color modes:
normal: RGB range is [0;MAX]
half: RGB range is [0;MAX/2] (shadow mode)
high: RGB range is [MAX/2;MAX] (highlight mode)
MAX is 31 (R,B) or 63 (G) for 5:6:5 pixels and 7 (R,G,B) for 3:3:3 pixels
MAX/2 is rounded to inferior value (15, 31 or 3)
the extrapolation is linear and calculated like this:
for (i=0; i<8; i++)
{
rgb565_norm[0][i] = round(((double)i * 31.0) / 7.0);
rgb565_norm[1][i] = round(((double)i * 63.0) / 7.0);
rgb565_half[0][i] = round(((double)i * 31.0) / 7.0 / 2.0);
rgb565_half[1][i] = round(((double)i * 63.0) / 7.0 / 2.0);
rgb565_high[0][i] = round(((double)i * 31.0) / 7.0 / 2.0 + 15.5);
rgb565_high[1][i] = round(((double)i * 63.0) / 7.0 / 2.0 + 31.5);
}
*/
uint8 rgb565_norm[2][8] = {{0 , 4, 9, 13, 18, 22, 27, 31},
{0 , 9, 18, 27, 36, 45, 54, 63}};
uint8 rgb565_half[2][8] = {{0 , 2, 4, 6, 9, 11, 13, 15},
{0 , 4, 9, 13, 18, 22, 27, 31}};
uint8 rgb565_high[2][8] = {{15, 17, 19, 21, 24, 26, 28, 31},
{31, 35, 40, 44, 49, 53, 58, 63}};
void palette_init(void)
{
int i;
for (i = 0; i < 0x200; i += 1)
{
int r, g, b;
r = (i >> 6) & 7;
g = (i >> 3) & 7;
b = (i >> 0) & 7;
#ifndef NGC
pixel_8_lut[0][i] = MAKE_PIXEL_8(r>>1,g>>1,b>>1);
pixel_8_lut[1][i] = MAKE_PIXEL_8(r,g,b);
pixel_8_lut[2][i] = MAKE_PIXEL_8((r>>1)|4,(g>>1)|4,(b>>1)|4);
pixel_15_lut[0][i] = MAKE_PIXEL_15(r,g,b);
pixel_15_lut[1][i] = MAKE_PIXEL_15(r<<1,g<<1,b<<1);
pixel_15_lut[2][i] = MAKE_PIXEL_15(r|8,g|8,b|8);
pixel_32_lut[0][i] = MAKE_PIXEL_32(r,g,b);
pixel_32_lut[1][i] = MAKE_PIXEL_32(r<<1,g<<1,b<<1);
pixel_32_lut[2][i] = MAKE_PIXEL_32(r|8,g|8,b|8);
#endif
/* RGB 565 format: we extrapolate each 3-bit value into a 5-bit (R,B) or 6-bit (G) value
this is needed to correctly cover full color range: [0-31] for R,B or [0-63] for G */
pixel_16_lut[0][i] = MAKE_PIXEL_16(rgb565_half[0][r],rgb565_half[1][g],rgb565_half[0][b]);
pixel_16_lut[1][i] = MAKE_PIXEL_16(rgb565_norm[0][r],rgb565_norm[1][g],rgb565_norm[0][b]);
pixel_16_lut[2][i] = MAKE_PIXEL_16(rgb565_high[0][r],rgb565_high[1][g],rgb565_high[0][b]);
}
}
/*--------------------------------------------------------------------------*/
/* Init, reset, shutdown routines */
/*--------------------------------------------------------------------------*/
int render_init (void)
{
int bx, ax, i;
/* Allocate and align pixel look-up tables */
if (lut_base == NULL) lut_base = malloc ((LUT_MAX * LUT_SIZE) + LUT_SIZE);
lut[0] = (uint8 *) (((uint32) lut_base + LUT_SIZE) & ~(LUT_SIZE - 1));
for (i = 1; i < LUT_MAX; i += 1) lut[i] = lut[0] + (i * LUT_SIZE);
/* Make pixel look-up table data */
for (bx = 0; bx < 0x100; bx += 1)
for (ax = 0; ax < 0x100; ax += 1)
{
uint16 index = (bx << 8) | (ax);
lut[0][index] = make_lut_bg (bx, ax);
lut[1][index] = make_lut_obj (bx, ax);
lut[2][index] = make_lut_bg_ste (bx, ax);
lut[3][index] = make_lut_obj_ste (bx, ax);
lut[4][index] = make_lut_bgobj_ste (bx, ax);
}
/* Make pixel data tables */
palette_init();
/* Set up color update function */
#ifndef NGC
switch(bitmap.depth)
{
case 8: color_update = color_update_8; break;
case 15: color_update = color_update_15; break;
case 16: color_update = color_update_16; break;
case 32: color_update = color_update_32; break;
}
#else
color_update = color_update_16;
#endif
/* Make sprite name look-up table */
make_name_lut();
return (1);
}
void make_name_lut(void)
{
int col, row;
int vcol, vrow;
int width, height;
int flipx, flipy;
int i, name;
memset (name_lut, 0, sizeof (name_lut));
for (i = 0; i < 0x400; i += 1)
{
vcol = col = i & 3;
vrow = row = (i >> 2) & 3;
height = (i >> 4) & 3;
width = (i >> 6) & 3;
flipx = (i >> 8) & 1;
flipy = (i >> 9) & 1;
if(flipx) vcol = (width - col);
if(flipy) vrow = (height - row);
name = vrow + (vcol * (height + 1));
if ((row > height) || col > width) name = -1;
name_lut[i] = name;
}
}
void render_reset(void)
{
/* Clear display bitmap */
memset(bitmap.data, 0, bitmap.pitch * bitmap.height);
memset(&clip, 0, sizeof(clip));
memset(bg_buf, 0, sizeof(bg_buf));
memset(tmp_buf, 0, sizeof(tmp_buf));
memset(nta_buf, 0, sizeof(nta_buf));
memset(ntb_buf, 0, sizeof(ntb_buf));
memset(obj_buf, 0, sizeof(obj_buf));
#ifndef NGC
memset(&pixel_8, 0, sizeof(pixel_8));
memset(&pixel_15, 0, sizeof(pixel_15));
memset(&pixel_32, 0, sizeof(pixel_32));
#endif
memset(&pixel_16, 0, sizeof(pixel_16));
}
void render_shutdown(void)
{
if(lut_base) free(lut_base);
}
/*--------------------------------------------------------------------------*/
/* Line render function */
/*--------------------------------------------------------------------------*/
void remap_buffer(int line, int width)
{
/* get line offset from framebuffer */
int offset = vdp_pal ? bitmap.viewport.y : (bitmap.viewport.y*11/8); // NTSC is 243 lines
int vline = (line + offset) % lines_per_frame;
/* illegal video mode (screen rolls up) */
if (!vdp_pal && (reg[1] & 8)) vline = (vline + frame_cnt)%240;
/* double resolution mode */
if (config.render && interlaced) vline = (vline * 2) + odd_frame;
void *out =((void *)&bitmap.data[(vline * bitmap.pitch)]);
#ifndef NGC
switch(bitmap.depth)
{
case 8:
remap_8(tmp_buf+0x20-bitmap.viewport.x, (uint8 *)out, pixel_8, width);
break;
case 15:
remap_16(tmp_buf+0x20-bitmap.viewport.x, (uint16 *)out, pixel_15, width);
break;
case 16:
remap_16(tmp_buf+0x20-bitmap.viewport.x, (uint16 *)out, pixel_16, width);
break;
case 32:
remap_32(tmp_buf+0x20-bitmap.viewport.x, (uint32 *)out, pixel_32, width);
break;
}
#else
remap_16(tmp_buf+0x20-bitmap.viewport.x, (uint16 *)out, pixel_16, width);
#endif
}
void render_line(int line, uint8 odd_frame)
{
/* check if we are inside display area (including vertical borders) */
int min = bitmap.viewport.h + bitmap.viewport.y;
int max = lines_per_frame - bitmap.viewport.y;
if ((line >= min) && (line < max)) return;
uint8 *lb = tmp_buf;
int width = bitmap.viewport.w;
/* vertical borders or display OFF */
if ((line >= bitmap.viewport.h) || (!(reg[1] & 0x40)))
{
memset(&lb[0x20], 0x40 | border, width);
}
else
{
update_bg_pattern_cache();
window_clip(line);
if(im2_flag)
{
if (clip[0].enable) render_ntx_im2(0, line, nta_buf, odd_frame);
render_ntx_im2(1, line, ntb_buf, odd_frame);
if (clip[1].enable) render_ntw_im2(line, nta_buf, odd_frame);
}
else
{
if(reg[11] & 4)
{
if (clip[0].enable) render_ntx_vs(0, line, nta_buf);
render_ntx_vs(1, line, ntb_buf);
}
else
{
if (clip[0].enable) render_ntx(0, line, nta_buf);
render_ntx(1, line, ntb_buf);
}
if (clip[1].enable) render_ntw(line, nta_buf);
}
if(reg[12] & 8)
{
merge(&nta_buf[0x20], &ntb_buf[0x20], &bg_buf[0x20], lut[2], width);
memset(&obj_buf[0x20], 0, width);
if(im2_flag) render_obj_im2(line, obj_buf, lut[3], odd_frame);
else render_obj(line, obj_buf, lut[3]);
merge(&obj_buf[0x20], &bg_buf[0x20], &lb[0x20], lut[4], width);
}
else
{
merge(&nta_buf[0x20], &ntb_buf[0x20], &lb[0x20], lut[0], width);
if(im2_flag) render_obj_im2(line, lb, lut[1], odd_frame);
else render_obj(line, lb, lut[1]);
}
/* Mode 4 feature only (unemulated, no games rely on this) */
/*if(!(reg[1] & 0x04) && (reg[0] & 0x20)) memset(&lb[0x20], 0x40 | border, 0x08);*/
}
/* horizontal borders */
if (config.overscan)
{
memset(&lb[0x20 - bitmap.viewport.x], 0x40 | border, bitmap.viewport.x);
memset(&lb[0x20 + bitmap.viewport.w], 0x40 | border, bitmap.viewport.x);
width += 2 * bitmap.viewport.x;
}
/* LightGun mark */
if ((input.dev[4] == DEVICE_LIGHTGUN) && (config.crosshair))
{
int dy = v_counter - input.analog[0][1];
if (abs(dy) < 6)
{
int i;
int start = input.analog[0][0] - 4;
int end = start + 8;
if (start < 0) start = 0;
if (end > bitmap.viewport.w) end = bitmap.viewport.w;
for (i=start; i<end; i++)
{
lb[0x20+i] = 0xff;
}
}
}
remap_buffer(line,width);
}
/*--------------------------------------------------------------------------*/
/* Window rendering */
/*--------------------------------------------------------------------------*/
void render_ntw(int line, uint8 *buf)
{
int column, v_line, width;
uint32 *nt, *src, *dst, atex, atbuf;
v_line = (line & 7) << 3;
width = (reg[12] & 1) ? 7 : 6;
nt = (uint32 *)&vram[ntwb | ((line >> 3) << width)];
dst = (uint32 *)&buf[0x20 + (clip[1].left << 4)];
for(column = clip[1].left; column < clip[1].right; column ++)
{
atbuf = nt[column];
DRAW_COLUMN(atbuf, v_line)
}
}
void render_ntw_im2(int line, uint8 *buf, uint8 odd)
{
int column, v_line, width;
uint32 *nt, *src, *dst, atex, atbuf, offs;
v_line = ((line & 7) << 1 | odd) << 3;
width = (reg[12] & 1) ? 7 : 6;
nt = (uint32 *)&vram[ntwb | ((line >> 3) << width)];
dst = (uint32 *)&buf[0x20 + (clip[1].left << 4)];
for(column = clip[1].left; column < clip[1].right; column ++)
{
atbuf = nt[column];
DRAW_COLUMN_IM2(atbuf, v_line)
}
}
/*--------------------------------------------------------------------------*/
/* Background plane rendering */
/*--------------------------------------------------------------------------*/
void render_ntx(int which, int line, uint8 *buf)
{
int column;
int start, end;
int index;
int shift;
int v_line;
uint32 atex, atbuf, *src, *dst;
uint16 xscroll;
int y_scroll;
uint32 *nt;
uint32 *vs;
uint16 table[2] = {ntab,ntbb};
uint8 xshift[2] = {0,2};
#ifdef LSB_FIRST
uint8 vsr_shift[2] = {0,16};
#else
uint8 vsr_shift[2] = {16,0};
#endif
get_hscroll(line, xshift[which], &xscroll);
shift = (xscroll & 0x0F);
index = playfield_col_mask + 1 - ((xscroll >> 4) & playfield_col_mask);
if(which)
{
start = 0;
end = (reg[12] & 1) ? 20 : 16;
}
else
{
start = clip[0].left;
end = clip[0].right;
index = (index + clip[0].left) & playfield_col_mask;
}
vs = (uint32 *)&vsram[0];
y_scroll = (vs[0] >> vsr_shift[which]) & 0x3FF;
y_scroll = (line + y_scroll) & playfield_row_mask;
v_line = (y_scroll & 7) << 3;
nt = (uint32 *)&vram[table[which] + (((y_scroll >> 3) << playfield_shift) & y_mask)];
if(shift)
{
dst = (uint32 *)&buf[0x10 + shift + (start<<4)];
/* Window bug */
if (start) atbuf = nt[(index) & playfield_col_mask];
else atbuf = nt[(index-1) & playfield_col_mask];
DRAW_COLUMN(atbuf, v_line);
}
dst = (uint32 *)&buf[0x20 + shift + (start<<4)];
for(column = start; column < end; column ++, index ++)
{
atbuf = nt[index & playfield_col_mask];
DRAW_COLUMN(atbuf, v_line)
}
}
void render_ntx_im2(int which, int line, uint8 *buf, uint8 odd)
{
int column;
int start, end;
int index;
int shift;
int v_line;
uint32 atex, atbuf, *src, *dst;
uint16 xscroll;
int y_scroll;
uint32 *nt;
uint32 *vs;
uint32 offs;
uint16 table[2] = {ntab,ntbb};
uint8 xshift[2] = {0,2};
#ifdef LSB_FIRST
uint8 vsr_shift[2] = {1,17};
#else
uint8 vsr_shift[2] = {17,1};
#endif
get_hscroll(line, xshift[which], &xscroll);
shift = (xscroll & 0x0F);
index = playfield_col_mask + 1 - ((xscroll >> 4) & playfield_col_mask);
if(which)
{
start = 0;
end = (reg[12] & 1) ? 20 : 16;
}
else
{
start = clip[0].left;
end = clip[0].right;
index = (index + clip[0].left) & playfield_col_mask;
}
vs = (uint32 *)&vsram[0];
y_scroll = (vs[0] >> vsr_shift[which]) & 0x3FF;
y_scroll = (line + y_scroll) & playfield_row_mask;
v_line = (((y_scroll & 7) << 1) | odd) << 3;
nt = (uint32 *)&vram[table[which] + (((y_scroll >> 3) << playfield_shift) & y_mask)];
if(shift)
{
dst = (uint32 *)&buf[0x10 + shift + (start<<4)];
/* Window bug */
if (start) atbuf = nt[(index) & playfield_col_mask];
else atbuf = nt[(index-1) & playfield_col_mask];
DRAW_COLUMN_IM2(atbuf, v_line);
}
dst = (uint32 *)&buf[0x20 + shift + (start<<4)];
for(column = start; column < end; column ++, index ++)
{
atbuf = nt[index & playfield_col_mask];
DRAW_COLUMN_IM2(atbuf, v_line)
}
}
void render_ntx_vs(int which, int line, uint8 *buf)
{
int column;
int start, end;
int index;
int shift;
int v_line;
uint32 atex, atbuf, *src, *dst;
uint16 xscroll;
int y_scroll;
uint32 *nt;
uint32 *vs;
uint16 table[2] = {ntab,ntbb};
uint8 xshift[2] = {0,2};
#ifdef LSB_FIRST
uint8 vsr_shift[2] = {0,16};
#else
uint8 vsr_shift[2] = {16,0};
#endif
get_hscroll(line, xshift[which], &xscroll);
shift = (xscroll & 0x0F);
index = playfield_col_mask + 1 - ((xscroll >> 4) & playfield_col_mask);
if(which)
{
start = 0;
end = (reg[12] & 1) ? 20 : 16;
}
else
{
start = clip[0].left;
end = clip[0].right;
index = (index + clip[0].left) & playfield_col_mask;
}
vs = (uint32 *)&vsram[0];
if(shift)
{
dst = (uint32 *)&buf[0x10 + shift + (start<<4)];
y_scroll = (line & playfield_row_mask);
v_line = (y_scroll & 7) << 3;
nt = (uint32 *)&vram[table[which] + (((y_scroll >> 3) << playfield_shift) & y_mask)];
/* Window bug */
if (start) atbuf = nt[(index) & playfield_col_mask];
else atbuf = nt[(index-1) & playfield_col_mask];
DRAW_COLUMN(atbuf, v_line);
}
dst = (uint32 *)&buf[0x20 + shift + (start<<4)];
for(column = start; column < end; column ++, index ++)
{
y_scroll = (vs[column] >> vsr_shift[which]) & 0x3FF;
y_scroll = (line + y_scroll) & playfield_row_mask;
v_line = (y_scroll & 7) << 3;
nt = (uint32 *)&vram[table[which] + (((y_scroll >> 3) << playfield_shift) & y_mask)];
atbuf = nt[index & playfield_col_mask];
DRAW_COLUMN(atbuf, v_line)
}
}
/*--------------------------------------------------------------------------*/
/* Helper functions (cache update, hscroll, window clip) */
/*--------------------------------------------------------------------------*/
void update_bg_pattern_cache(void)
{
int i;
uint8 x, y, c;
uint16 name;
#ifdef LSB_FIRST
uint8 shift_table[8] = {12, 8, 4, 0, 28, 24, 20, 16};
#else
uint8 shift_table[8] = {28, 24, 20, 16, 12, 8, 4, 0};
#endif
if(!bg_list_index) return;
for(i = 0; i < bg_list_index; i ++)
{
name = bg_name_list[i];
bg_name_list[i] = 0;
for(y = 0; y < 8; y ++)
{
if(bg_name_dirty[name] & (1 << y))
{
uint8 *dst = &bg_pattern_cache[name << 6];
uint32 bp = *(uint32 *)&vram[(name << 5) | (y << 2)];
for(x = 0; x < 8; x ++)
{
c = (bp >> shift_table[x]) & 0x0F;
dst[0x00000 | (y << 3) | (x)] = (c); /* hf=0, vf=0: normal */
dst[0x20000 | (y << 3) | (x ^ 7)] = (c); /* hf=1, vf=0: horizontal flipped */
dst[0x40000 | ((y ^ 7) << 3) | (x)] = (c); /* hf=0, vf=1: vertical flipped */
dst[0x60000 | ((y ^ 7) << 3) | (x ^ 7)] = (c); /* hf=1, vf=1: horizontal & vertical flipped */
}
}
}
bg_name_dirty[name] = 0;
}
bg_list_index = 0;
}
void get_hscroll(int line, int shift, uint16 *scroll)
{
switch(reg[11] & 3)
{
case 0: /* Full-screen */
*scroll = *(uint16 *)&vram[hscb + shift];
break;
case 1: /* First 8 lines */
*scroll = *(uint16 *)&vram[hscb + ((line & 7) << 2) + shift];
break;
case 2: /* Every 8 lines */
*scroll = *(uint16 *)&vram[hscb + ((line & ~7) << 2) + shift];
break;
case 3: /* Every line */
*scroll = *(uint16 *)&vram[hscb + (line << 2) + shift];
break;
}
*scroll &= 0x03FF;
}
void window_clip(int line)
{
/* Window size and invert flags */
int hp = (reg[17] & 0x1F);
int hf = (reg[17] >> 7) & 1;
int vp = (reg[18] & 0x1F) << 3;
int vf = (reg[18] >> 7) & 1;
/* Display size */
int sw = (reg[12] & 1) ? 20 : 16;
/* Clear clipping data */
memset(&clip, 0, sizeof(clip));
/* Check if line falls within window range */
if(vf == (line >= vp))
{
/* Window takes up entire line */
clip[1].right = sw;
clip[1].enable = 1;
}
else
{
/* Perform horizontal clipping; the results are applied in reverse
if the horizontal inversion flag is set */
int a = hf;
int w = hf ^ 1;
if(hp)
{
if(hp > sw)
{
/* Plane W takes up entire line */
clip[w].right = sw;
clip[w].enable = 1;
}
else
{
/* Window takes left side, Plane A takes right side */
clip[w].right = hp;
clip[a].left = hp;
clip[a].right = sw;
clip[0].enable = clip[1].enable = 1;
}
}
else
{
/* Plane A takes up entire line */
clip[a].right = sw;
clip[a].enable = 1;
}
}
}
/*--------------------------------------------------------------------------*/
/* Look-up table functions (handles priority between layers pixels) */
/*--------------------------------------------------------------------------*/
/* Input (bx): d5-d0=color, d6=priority, d7=unused */
/* Input (ax): d5-d0=color, d6=priority, d7=unused */
/* Output: d5-d0=color, d6=priority, d7=unused */
int make_lut_bg(int bx, int ax)
{
int bf, bp, b;
int af, ap, a;
int x = 0;
int c;
bf = (bx & 0x7F);
bp = (bx >> 6) & 1;
b = (bx & 0x0F);
af = (ax & 0x7F);
ap = (ax >> 6) & 1;
a = (ax & 0x0F);
c = (ap ? (a ? af : (b ? bf : x)) : \
(bp ? (b ? bf : (a ? af : x)) : \
( (a ? af : (b ? bf : x)) )));
/* Strip palette bits from transparent pixels */
if((c & 0x0F) == 0x00) c &= 0xC0;
return (c);
}
/* Input (bx): d5-d0=color, d6=priority, d7=sprite pixel marker */
/* Input (sx): d5-d0=color, d6=priority, d7=unused */
/* Output: d5-d0=color, d6=zero, d7=sprite pixel marker */
int make_lut_obj(int bx, int sx)
{
int bf, bp, bs, b;
int sf, sp, s;
int c;
bf = (bx & 0x3F);
bs = (bx >> 7) & 1;
bp = (bx >> 6) & 1;
b = (bx & 0x0F);
sf = (sx & 0x3F);
sp = (sx >> 6) & 1;
s = (sx & 0x0F);
if(s == 0) return bx;
if(bs)
{
c = bf; /* previous sprite has higher priority */
}
else
{
c = (sp ? (s ? sf : bf) : \
(bp ? (b ? bf : (s ? sf : bf)) : \
(s ? sf : bf) ));
}
/* Strip palette bits from transparent pixels */
if((c & 0x0F) == 0x00) c &= 0xC0;
return (c | 0x80);
}
/* Input (bx): d5-d0=color, d6=priority, d7=unused */
/* Input (sx): d5-d0=color, d6=priority, d7=unused */
/* Output: d5-d0=color, d6=priority, d7=intensity select (half/normal) */
int make_lut_bg_ste(int bx, int ax)
{
int bf, bp, b;
int af, ap, a;
int gi;
int x = 0;
int c;
bf = (bx & 0x7F);
bp = (bx >> 6) & 1;
b = (bx & 0x0F);
af = (ax & 0x7F);
ap = (ax >> 6) & 1;
a = (ax & 0x0F);
gi = (ap | bp) ? 0x80 : 0x00;
c = (ap ? (a ? af : (b ? bf : x)) :
(bp ? (b ? bf : (a ? af : x)) : ((a ? af : (b ? bf : x)))));
c |= gi;
/* Strip palette bits from transparent pixels */
if((c & 0x0F) == 0x00) c &= 0xC0;
return (c);
}
/* Input (bx): d5-d0=color, d6=priority, d7=sprite pixel marker */
/* Input (sx): d5-d0=color, d6=priority, d7=unused */
/* Output: d5-d0=color, d6=priority, d7=sprite pixel marker */
int make_lut_obj_ste(int bx, int sx)
{
int bf, bs;
int sf;
int c;
bf = (bx & 0x7F);
bs = (bx >> 7) & 1;
sf = (sx & 0x7F);
if((sx & 0x0F) == 0) return bx;
c = (bs) ? bf : sf;
/* Strip palette bits from transparent pixels */
if((c & 0x0F) == 0x00) c &= 0xC0;
return (c | 0x80);
}
/* Input (bx): d5-d0=color, d6=priority, d7=intensity (half/normal) */
/* Input (sx): d5-d0=color, d6=priority, d7=sprite marker */
/* Output: d5-d0=color, d6=intensity (half/normal), d7=(double/invalid) */
int make_lut_bgobj_ste(int bx, int sx)
{
int c;
int bf = (bx & 0x3F);
int bp = (bx >> 6) & 1;
int bi = (bx & 0x80) ? 0x40 : 0x00;
int b = (bx & 0x0F);
int sf = (sx & 0x3F);
int sp = (sx >> 6) & 1;
int si = (sx & 0x40);
int s = (sx & 0x0F);
if(bi & 0x40) si |= 0x40;
if(sp)
{
if(s)
{
if((sf & 0x3E) == 0x3E)
{
if(sf & 1)
{
c = (bf | 0x00);
}
else
{
c = (bx & 0x80) ? (bf | 0x80) : (bf | 0x40);
}
}
else
{
if(sf == 0x0E || sf == 0x1E || sf == 0x2E)
{
c = (sf | 0x40);
}
else
{
c = (sf | si);
}
}
}
else
{
c = (bf | bi);
}
}
else
{
if(bp)
{
if(b)
{
c = (bf | bi);
}
else
{
if(s)
{
if((sf & 0x3E) == 0x3E)
{
if(sf & 1)
{
c = (bf | 0x00);
}
else
{
c = (bx & 0x80) ? (bf | 0x80) : (bf | 0x40);
}
}
else
{
if(sf == 0x0E || sf == 0x1E || sf == 0x2E)
{
c = (sf | 0x40);
}
else
{
c = (sf | si);
}
}
}
else
{
c = (bf | bi);
}
}
}
else
{
if(s)
{
if((sf & 0x3E) == 0x3E)
{
if(sf & 1)
{
c = (bf | 0x00);
}
else
{
c = (bx & 0x80) ? (bf | 0x80) : (bf | 0x40);
}
}
else
{
if(sf == 0x0E || sf == 0x1E || sf == 0x2E)
{
c = (sf | 0x40);
}
else
{
c = (sf | si);
}
}
}
else
{
c = (bf | bi);
}
}
}
if((c & 0x0f) == 0x00) c &= 0xC0;
return (c);
}
/*--------------------------------------------------------------------------*/
/* Remap functions */
/*--------------------------------------------------------------------------*/
#ifndef NGC
void remap_8(uint8 *src, uint8 *dst, uint8 *table, int length)
{
int count;
for(count = 0; count < length; count += 1)
{
*dst++ = table[*src++];
}
}
void remap_32(uint8 *src, uint32 *dst, uint32 *table, int length)
{
int count;
for(count = 0; count < length; count += 1)
{
*dst++ = table[*src++];
}
}
#endif
void remap_16(uint8 *src, uint16 *dst, uint16 *table, int length)
{
int count;
for(count = 0; count < length; count += 1)
{
*dst++ = table[*src++];
}
}
/*--------------------------------------------------------------------------*/
/* Merge functions */
/*--------------------------------------------------------------------------*/
void merge(uint8 *srca, uint8 *srcb, uint8 *dst, uint8 *table, int width)
{
int i;
for(i = 0; i < width; i += 1)
{
uint8 a = srca[i];
uint8 b = srcb[i];
uint8 c = table[(b << 8) | (a)];
dst[i] = c;
}
}
/*--------------------------------------------------------------------------*/
/* Color update functions */
/*--------------------------------------------------------------------------*/
#ifndef NGC
void color_update_8(int index, uint16 data)
{
if(reg[12] & 8)
{
pixel_8[0x00 | index] = pixel_8_lut[0][data];
pixel_8[0x40 | index] = pixel_8_lut[1][data];
pixel_8[0x80 | index] = pixel_8_lut[2][data];
}
else
{
uint8 temp = pixel_8_lut[1][data];
pixel_8[0x00 | index] = temp;
pixel_8[0x40 | index] = temp;
pixel_8[0x80 | index] = temp;
}
}
void color_update_15(int index, uint16 data)
{
if(reg[12] & 8)
{
pixel_15[0x00 | index] = pixel_15_lut[0][data];
pixel_15[0x40 | index] = pixel_15_lut[1][data];
pixel_15[0x80 | index] = pixel_15_lut[2][data];
}
else
{
uint16 temp = pixel_15_lut[1][data];
pixel_15[0x00 | index] = temp;
pixel_15[0x40 | index] = temp;
pixel_15[0x80 | index] = temp;
}
}
void color_update_32(int index, uint16 data)
{
if(reg[12] & 8)
{
pixel_32[0x00 | index] = pixel_32_lut[0][data];
pixel_32[0x40 | index] = pixel_32_lut[1][data];
pixel_32[0x80 | index] = pixel_32_lut[2][data];
}
else
{
uint32 temp = pixel_32_lut[1][data];
pixel_32[0x00 | index] = temp;
pixel_32[0x40 | index] = temp;
pixel_32[0x80 | index] = temp;
}
}
#endif
void color_update_16(int index, uint16 data)
{
if(reg[12] & 8)
{
pixel_16[0x00 | index] = pixel_16_lut[0][data];
pixel_16[0x40 | index] = pixel_16_lut[1][data];
pixel_16[0x80 | index] = pixel_16_lut[2][data];
}
else
{
uint16 temp = pixel_16_lut[1][data];
pixel_16[0x00 | index] = temp;
pixel_16[0x40 | index] = temp;
pixel_16[0x80 | index] = temp;
}
}
/*--------------------------------------------------------------------------*/
/* Object render functions */
/*--------------------------------------------------------------------------*/
void parse_satb(int line)
{
static uint8 sizetab[] = {8, 16, 24, 32};
uint8 link = 0;
uint16 *p, *q;
uint16 ypos;
uint8 size;
int count;
int height;
int limit = (reg[12] & 1) ? 20 : 16;
int total = (reg[12] & 1) ? 80 : 64;
object_index_count = 0;
for(count = 0; count < total; count += 1)
{
q = (uint16 *) &sat[link << 3];
ypos = q[0];
if(im2_flag) ypos = (ypos >> 1) & 0x1FF;
else ypos &= 0x1FF;
size = q[1] >> 8;
height = sizetab[size & 3];
if((line >= ypos) && (line < (ypos + height)))
{
/* sprite limit (max. 16 or 20 sprites displayed per line) */
if(object_index_count == limit)
{
if(vint_pending == 0) status |= 0x40;
return;
}
// using xpos from internal satb stops sprite x
// scrolling in bloodlin.bin,
// but this seems to go against the test prog
p = (uint16 *) &vram[satb + (link << 3)];
object_info[object_index_count].ypos = q[0];
object_info[object_index_count].xpos = p[3];
object_info[object_index_count].attr = p[2];
object_info[object_index_count].size = size;
object_info[object_index_count].index = count;
object_index_count += 1;
}
link = q[1] & 0x7F;
if(link == 0) break;
}
}
void render_obj(int line, uint8 *buf, uint8 *table)
{
uint16 ypos;
uint16 attr;
uint16 xpos;
uint8 sizetab[] = {8, 16, 24, 32};
uint8 size;
uint8 *src;
int count;
int pixelcount = 0;
int width;
int height;
int v_line;
int column;
int sol_flag = 0;
int left = 0x80;
int right = 0x80 + bitmap.viewport.w;
int i;
uint8 *s, *lb;
uint16 name, index;
uint8 palette;
int attr_mask, nt_row;
for(count = 0; count < object_index_count; count += 1)
{
xpos = object_info[count].xpos;
xpos &= 0x1ff;
/* sprite masking */
if(xpos != 0) sol_flag = 1;
else if(xpos == 0 && sol_flag) return;
size = object_info[count].size & 0x0f;
width = sizetab[(size >> 2) & 3];
/* update pixel count (off-screen sprites included) */
pixelcount += width;
if(((xpos + width) >= left) && (xpos < right))
{
ypos = object_info[count].ypos;
ypos &= 0x1ff;
attr = object_info[count].attr;
attr_mask = (attr & 0x1800);
height = sizetab[size & 3];
palette = (attr >> 9) & 0x70;
v_line = (line - ypos);
nt_row = (v_line >> 3) & 3;
v_line = (v_line & 7) << 3;
name = (attr & 0x07FF);
s = &name_lut[((attr >> 3) & 0x300) | (size << 4) | (nt_row << 2)];
lb = (uint8 *)&buf[0x20 + (xpos - 0x80)];
/* number of tiles to draw */
width >>= 3;
for(column = 0; column < width; column += 1, lb+=8)
{
index = attr_mask | ((name + s[column]) & 0x07FF);
src = &bg_pattern_cache[(index << 6) | (v_line)];
DRAW_SPRITE_TILE;
}
}
/* sprite limit (256 or 320 pixels) */
if (pixelcount >= bitmap.viewport.w) return;
}
}
void render_obj_im2(int line, uint8 *buf, uint8 *table, uint8 odd)
{
uint16 ypos;
uint16 attr;
uint16 xpos;
uint8 sizetab[] = {8, 16, 24, 32};
uint8 size;
uint8 *src;
int count;
int pixelcount = 0;
int width;
int height;
int v_line;
int column;
int sol_flag = 0;
int left = 0x80;
int right = 0x80 + bitmap.viewport.w;
int i;
uint8 *s, *lb;
uint16 name, index;
uint8 palette;
uint32 offs;
int attr_mask, nt_row;
for(count = 0; count < object_index_count; count += 1)
{
xpos = object_info[count].xpos;
xpos &= 0x1ff;
/* sprite masking */
if(xpos != 0) sol_flag = 1;
else if(xpos == 0 && sol_flag) return;
size = object_info[count].size & 0x0f;
width = sizetab[(size >> 2) & 3];
/* update pixel count (off-screen sprites included) */
pixelcount += width;
if(((xpos + width) >= left) && (xpos < right))
{
ypos = object_info[count].ypos;
ypos = (ypos >> 1) & 0x1ff;
attr = object_info[count].attr;
attr_mask = (attr & 0x1800);
height = sizetab[size & 3];
palette = (attr >> 9) & 0x70;
v_line = (line - ypos);
nt_row = (v_line >> 3) & 3;
v_line = (((v_line & 7) << 1) | odd) << 3;
name = (attr & 0x03FF);
s = &name_lut[((attr >> 3) & 0x300) | (size << 4) | (nt_row << 2)];
lb = (uint8 *)&buf[0x20 + (xpos - 0x80)];
/* number of tiles to draw */
/* adjusted for sprite limit */
if (pixelcount > bitmap.viewport.w) width -= (pixelcount - bitmap.viewport.w);
width >>= 3;
for(column = 0; column < width; column += 1, lb+=8)
{
index = (name + s[column]) & 0x3ff;
offs = index << 7 | attr_mask << 6 | v_line;
if(attr & 0x1000) offs ^= 0x40;
src = &bg_pattern_cache[offs];
DRAW_SPRITE_TILE;
}
}
/* sprite limit (256 or 320 pixels) */
if (pixelcount >= bitmap.viewport.w) return;
}
}
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