2021-05-12 21:28:45 -04:00
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#include "ppu.h"
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2021-04-07 20:32:18 -04:00
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/*
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Copyright (c) 2021 Devine Lu Linvega
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Copyright (c) 2021 Andrew Alderwick
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Permission to use, copy, modify, and distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE.
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*/
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2021-08-01 14:16:29 -04:00
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static Uint8 blending[5][16] = {
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{0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 0, 2, 3, 3, 3, 0},
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{0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3},
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{1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1},
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{2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2},
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{1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0}};
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2021-08-01 14:00:07 -04:00
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2021-09-21 13:39:00 -04:00
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void
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ppu_frame(Ppu *p)
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{
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2021-09-29 19:14:13 -04:00
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p->reqdraw = 0;
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2021-09-21 13:39:00 -04:00
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p->i0 = p->width / PPW + p->height * p->stride;
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p->i1 = 0;
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}
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2021-09-18 20:18:20 -04:00
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static void
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ppu_clear(Ppu *p)
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{
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2021-09-20 18:12:11 -04:00
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unsigned int i;
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2021-09-20 17:32:42 -04:00
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for(i = 0; i < p->stride * p->height; ++i)
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2021-09-19 19:04:40 -04:00
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p->dat[i] = 0;
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}
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2021-09-29 19:01:54 -04:00
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Uint8
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ppu_read(Ppu *p, Uint16 x, Uint16 y)
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{
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unsigned int i = x / PPW + y * p->stride, shift = x % PPW * 4;
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return (p->dat[i] >> shift) & 0xf;
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}
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2021-09-21 13:39:00 -04:00
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void
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ppu_write(Ppu *p, int fg, Uint16 x, Uint16 y, Uint8 color)
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{
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unsigned int v, i = x / PPW + y * p->stride, shift = x % PPW * 4;
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if(x >= p->width || y >= p->height)
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return;
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v = p->dat[i];
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if(fg) shift += 2;
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p->dat[i] &= ~(3 << shift);
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p->dat[i] |= color << shift;
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if((v ^ p->dat[i]) != 0) {
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p->reqdraw = 1;
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p->i0 = p->i0 < i ? p->i0 : i;
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p->i1 = p->i1 > i ? p->i1 : i;
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}
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2021-04-07 20:32:18 -04:00
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}
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void
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ppu_1bpp(Ppu *p, int fg, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
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{
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Uint16 v, h;
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for(v = 0; v < 8; v++)
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for(h = 0; h < 8; h++) {
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Uint8 ch1 = (sprite[v] >> (7 - h)) & 0x1;
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if(ch1 || blending[4][color])
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ppu_write(p,
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fg,
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x + (flipx ? 7 - h : h),
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y + (flipy ? 7 - v : v),
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blending[ch1][color]);
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}
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}
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2021-09-21 13:39:00 -04:00
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void
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ppu_2bpp(Ppu *p, int fg, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
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{
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Uint16 v, h;
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for(v = 0; v < 8; v++)
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for(h = 0; h < 8; h++) {
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Uint8 ch1 = ((sprite[v] >> (7 - h)) & 0x1);
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Uint8 ch2 = ((sprite[v + 8] >> (7 - h)) & 0x1);
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Uint8 ch = ch1 + ch2 * 2;
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if(ch || blending[4][color])
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ppu_write(p,
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fg,
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x + (flipx ? 7 - h : h),
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y + (flipy ? 7 - v : v),
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blending[ch][color]);
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}
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}
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2021-04-20 23:38:15 -04:00
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/* output */
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2021-04-07 20:42:30 -04:00
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int
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ppu_set_size(Ppu *p, Uint16 width, Uint16 height)
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{
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p->width = width;
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p->stride = (width + PPW - 1) / PPW;
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p->height = height;
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p->dat = realloc(p->dat, p->stride * p->height * sizeof(unsigned int));
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if(p->dat == NULL) return 0;
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2021-09-18 20:18:20 -04:00
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ppu_clear(p);
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ppu_frame(p);
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return 1;
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}
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