#include "ppu.h" /* Copyright (c) 2021 Devine Lu Linvega Copyright (c) 2021 Andrew Alderwick Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE. */ /* byte: p0-bg | p0-fg | p1-bg | p1-fg */ static Uint8 blending[5][16] = { {0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 0, 2, 3, 3, 3, 0}, {0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3}, {1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1}, {2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2}, {1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0}}; static Uint8 font[][8] = { {0x00, 0x7c, 0x82, 0x82, 0x82, 0x82, 0x82, 0x7c}, {0x00, 0x30, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10}, {0x00, 0x7c, 0x82, 0x02, 0x7c, 0x80, 0x80, 0xfe}, {0x00, 0x7c, 0x82, 0x02, 0x1c, 0x02, 0x82, 0x7c}, {0x00, 0x0c, 0x14, 0x24, 0x44, 0x84, 0xfe, 0x04}, {0x00, 0xfe, 0x80, 0x80, 0x7c, 0x02, 0x82, 0x7c}, {0x00, 0x7c, 0x82, 0x80, 0xfc, 0x82, 0x82, 0x7c}, {0x00, 0x7c, 0x82, 0x02, 0x1e, 0x02, 0x02, 0x02}, {0x00, 0x7c, 0x82, 0x82, 0x7c, 0x82, 0x82, 0x7c}, {0x00, 0x7c, 0x82, 0x82, 0x7e, 0x02, 0x82, 0x7c}, {0x00, 0x7c, 0x82, 0x02, 0x7e, 0x82, 0x82, 0x7e}, {0x00, 0xfc, 0x82, 0x82, 0xfc, 0x82, 0x82, 0xfc}, {0x00, 0x7c, 0x82, 0x80, 0x80, 0x80, 0x82, 0x7c}, {0x00, 0xfc, 0x82, 0x82, 0x82, 0x82, 0x82, 0xfc}, {0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x82, 0x7c}, {0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x80, 0x80}}; void ppu_resize(Ppu *p, Uint16 width, Uint16 height) { Uint8 *pixels; if(!(pixels = realloc(p->pixels, width * height / 2))) return; p->pixels = pixels; p->width = width; p->height = height; ppu_clear(p, CLEAR_BOTH); } void ppu_clear(Ppu *p, Uint8 mask) { Uint32 i, size = p->width * p->height / 2; for(i = 0; i < size; ++i) p->pixels[i] &= mask; } Uint8 ppu_read(Ppu *p, Uint16 x, Uint16 y) { if(x < p->width && y < p->height) { Uint32 row = (x + y * p->width) >> 1; Uint8 shift = (x & 0x1) << 2; Uint8 pix = p->pixels[row] >> shift; if(pix & 0x0c) pix >>= 2; return pix & 0x3; } return 0x0; } void ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color) { if(x < p->width && y < p->height) { Uint32 row = (x + y * p->width) >> 1; Uint8 shift = ((x & 0x1) << 2) + (layer << 1); Uint8 pix = p->pixels[row]; Uint8 mask = ~(0x3 << shift); Uint8 pixnew = (pix & mask) + (color << shift); if(pix != pixnew) { p->pixels[row] = pixnew; p->reqdraw = 1; } } } void ppu_1bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy) { Uint16 v, h; for(v = 0; v < 8; ++v) for(h = 0; h < 8; ++h) { Uint8 ch1 = (sprite[v] >> (7 - h)) & 0x1; if(ch1 || blending[4][color]) ppu_write(p, layer, x + (flipx ? 7 - h : h), y + (flipy ? 7 - v : v), blending[ch1][color]); } } void ppu_2bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy) { Uint16 v, h; for(v = 0; v < 8; ++v) for(h = 0; h < 8; ++h) { Uint8 ch1 = ((sprite[v] >> (7 - h)) & 0x1); Uint8 ch2 = ((sprite[v + 8] >> (7 - h)) & 0x1); Uint8 ch = ch1 + ch2 * 2; if(ch || blending[4][color]) ppu_write(p, layer, x + (flipx ? 7 - h : h), y + (flipy ? 7 - v : v), blending[ch][color]); } } void ppu_debug(Ppu *p, Uint8 *stack, Uint8 wptr, Uint8 rptr, Uint8 *memory) { Uint8 i, x, y, b; for(i = 0; i < 0x20; ++i) { x = ((i % 8) * 3 + 1) * 8, y = (i / 8 + 1) * 8, b = stack[i]; /* working stack */ ppu_1bpp(p, 1, x, y, font[(b >> 4) & 0xf], 1 + (wptr == i) * 0x7, 0, 0); ppu_1bpp(p, 1, x + 8, y, font[b & 0xf], 1 + (wptr == i) * 0x7, 0, 0); y = 0x28 + (i / 8 + 1) * 8; b = memory[i]; /* return stack */ ppu_1bpp(p, 1, x, y, font[(b >> 4) & 0xf], 3, 0, 0); ppu_1bpp(p, 1, x + 8, y, font[b & 0xf], 3, 0, 0); } /* return pointer */ ppu_1bpp(p, 1, 0x8, y + 0x10, font[(rptr >> 4) & 0xf], 0x2, 0, 0); ppu_1bpp(p, 1, 0x10, y + 0x10, font[rptr & 0xf], 0x2, 0, 0); /* guides */ for(x = 0; x < 0x10; ++x) { ppu_write(p, 1, x, p->height / 2, 2); ppu_write(p, 1, p->width - x, p->height / 2, 2); ppu_write(p, 1, p->width / 2, p->height - x, 2); ppu_write(p, 1, p->width / 2, x, 2); ppu_write(p, 1, p->width / 2 - 0x10 / 2 + x, p->height / 2, 2); ppu_write(p, 1, p->width / 2, p->height / 2 - 0x10 / 2 + x, 2); } }