nesemu/gui/dbg_nametable.c

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//
// Created by william on 7/23/24.
//
#include "dbg_nametable.h"
#include "../include/ppu.h"
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#include "../include/system.h"
#include "../include/rom.h"
#define NAMETABLE_ROW_DRAW_WIDTH (NAMETABLE_ROW_WIDTH * PATTERN_DRAW_SIZE)
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DebugNameTable dbg_nametable;
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void dbg_nametable_init() {
dbg_nametable.vertical_mirroring = rom_get()->nametable_mirrored;
}
void dbg_nametable_build_bank(byte *nametable, DebugTile *bank) {
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for (int i = 0; i < NAMETABLE_BANK_SIZE; i++) {
DebugTile *tile = &bank[i];
tile->tile_id = nametable[i];
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address attr_addr = 0x3c0 | (i & 0xc00) | ((i >> 4) & 0x38) | ((i >> 2) & 0x7);
tile->attribute = nametable[attr_addr];
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}
}
void dbg_nametable_update() {
dbg_nametable_build_bank(ppu_get_state()->memory.nametable_0, dbg_nametable.bank_0);
dbg_nametable_build_bank(ppu_get_state()->memory.nametable_1, dbg_nametable.bank_1);
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}
static inline DebugTile *dbg_nametable_get_bank(int bank) {
if (dbg_nametable.vertical_mirroring) {
if (bank % 2 == 0) {
return dbg_nametable.bank_0;
}
return dbg_nametable.bank_1;
}
// Horizontal mirroring
if (bank < 2) {
return dbg_nametable.bank_0;
}
return dbg_nametable.bank_1;
}
void dbg_nametable_render_bank(int bank, pixel *buffer) {
DebugTile *table = dbg_nametable_get_bank(bank);
int pattern_bank = ppu_get_state()->bg_pattern_table_addr >> 12;
for (int i = 0; i < NAMETABLE_BANK_SIZE; i++) {
int pattern_id = table[i].tile_id;
// Tile Index:
// 0000 00RR RRRC CCCC
// || |||+ ++++-- Tile column
// ++ +++-------- Tile row
int row = (i & ~(NAMETABLE_ROW_WIDTH - 1)) >> 5;
int col = i & (NAMETABLE_ROW_WIDTH - 1);
int tile_pixel_addr =
(row * PATTERN_DRAW_SIZE * PATTERN_DRAW_SIZE * NAMETABLE_ROW_WIDTH) + (col * PATTERN_DRAW_SIZE);
pixel *tile_buffer = &buffer[tile_pixel_addr];
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// Attribute Data:
// 7654 3210
// |||| ||++- Color bits 3-2 for top left quadrant of this byte
// |||| ++--- Color bits 3-2 for top right quadrant of this byte
// ||++------ Color bits 3-2 for bottom left quadrant of this byte
// ++-------- Color bits 3-2 for bottom right quadrant of this byte
byte palette = table[i].attribute;
if (row % 4 >= 2) {
palette >>= 4;
}
if (col % 4 >= 2) {
palette >>= 2;
}
palette &= 0b11;
dbg_pattern_draw(pattern_id, pattern_bank, tile_buffer, NAMETABLE_ROW_DRAW_WIDTH, palette);
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}
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}