nesemu/gui/pattern_window.c

//
// Created by william on 6/14/24.
//

#include "pattern_window.h"

#define PW_TILE_SIZE 8
#define PW_TILE_BYTES (PW_TILE_SIZE * 2)
#define PW_BANK_SIZE 0x1000
#define PW_BANK_TILE_COUNT (PW_ROW_TILE_COUNT * PW_ROW_TILE_COUNT)

#define PW_TILE_BORDER_WIDTH 1
#define PW_TILE_BORDER_COLOR 0xff2223b2
#define PW_TILE_DRAW_SIZE (PW_TILE_SIZE + PW_TILE_BORDER_WIDTH)

#define PW_WIDTH (PW_ROW_TILE_COUNT * PW_TILE_DRAW_SIZE + PW_TILE_BORDER_WIDTH)
#define PW_HEIGHT (PW_ROW_TILE_COUNT * PW_TILE_DRAW_SIZE * 2 + PW_TILE_BORDER_WIDTH)
#define PW_SCALE 2

void pattern_window_init(NesPatternWindow *window) {
    window->sdl_context = window_init("Pattern Table", PW_WIDTH, PW_HEIGHT, PW_SCALE);

    window->texture = SDL_CreateTexture(window->sdl_context.renderer, SDL_PIXELFORMAT_ARGB8888,
                                        SDL_TEXTUREACCESS_STATIC, PW_WIDTH, PW_HEIGHT);
}

void pattern_window_uninit(NesPatternWindow *window) {
    window_uninit(window->sdl_context);
}

/*
 * d888888b d888888b db      d88888b .d8888.
 * `~~88~~'   `88'   88      88'     88'  YP
 *    88       88    88      88ooooo `8bo.
 *    88       88    88      88~~~~~   `Y8b.
 *    88      .88.   88booo. 88.     db   8D
 *    YP    Y888888P Y88888P Y88888P `8888Y'
 */
static PatternTile pattern_window_build_tile(int x, int y, byte *pattern_memory) {
    PatternTile tile;
    tile.x = x;
    tile.y = y;

    address tile_addr = (x + y * PW_ROW_TILE_COUNT) * PW_TILE_BYTES;
    memcpy(tile.data_low, &pattern_memory[tile_addr], 8);
    memcpy(tile.data_high, &pattern_memory[tile_addr + 8], 8);

    return tile;
}

static void pattern_window_build_bank(byte *pattern_memory, PatternTile *bank) {
    for (int y = 0; y < PW_ROW_TILE_COUNT; y++) {
        for (int x = 0; x < PW_ROW_TILE_COUNT; x++) {
            int tile_index = y * PW_ROW_TILE_COUNT + x;
            PatternTile *tile = &bank[tile_index];
            *tile = pattern_window_build_tile(x, y, pattern_memory);
        }
    }
}

void pattern_window_build_tiles(NesPatternWindow *window, byte *pattern_memory) {
    pattern_window_build_bank(pattern_memory, window->tiles_bank_0);
    pattern_window_build_bank(&pattern_memory[PW_BANK_SIZE], window->tiles_bank_1);
}

/*
 * d8888b. d88888b d8b   db d8888b. d88888b d8888b. d888888b d8b   db  d888b
 * 88  `8D 88'     888o  88 88  `8D 88'     88  `8D   `88'   888o  88 88' Y8b
 * 88oobY' 88ooooo 88V8o 88 88   88 88ooooo 88oobY'    88    88V8o 88 88
 * 88`8b   88~~~~~ 88 V8o88 88   88 88~~~~~ 88`8b      88    88 V8o88 88  ooo
 * 88 `88. 88.     88  V888 88  .8D 88.     88 `88.   .88.   88  V888 88. ~8~
 * 88   YD Y88888P VP   V8P Y8888D' Y88888P 88   YD Y888888P VP   V8P  Y888P
 */
static void pattern_window_draw_borders(unsigned int *buffer) {
    for (int x = 0; x < PW_WIDTH; x++) {
        buffer[x] = PW_TILE_BORDER_COLOR;
    }

    for (int y = 1; y < PW_HEIGHT; y++) {
        buffer[y * PW_WIDTH] = PW_TILE_BORDER_COLOR;
    }
}

static void pattern_window_draw_tile_borders(int tile_addr, unsigned int *buffer) {
    for (int by = 0; by < PW_TILE_DRAW_SIZE; by++) {
        int pixel_addr = tile_addr + (by * PW_WIDTH) + PW_TILE_DRAW_SIZE - 1;
        buffer[pixel_addr] = PW_TILE_BORDER_COLOR;
    }

    for (int bx = 0; bx < PW_TILE_DRAW_SIZE; bx++) {
        int pixel_addr = tile_addr + ((PW_TILE_DRAW_SIZE - 1) * PW_WIDTH) + bx;
        buffer[pixel_addr] = PW_TILE_BORDER_COLOR;
    }
}

static void pattern_window_draw_tile(PatternTile *tile, unsigned int *buffer) {
    int row_addr = (tile->y * PW_TILE_DRAW_SIZE + 1) * PW_WIDTH;
    int tile_buffer_addr = row_addr + (tile->x * PW_TILE_DRAW_SIZE + 1);

    for (int fine_y = 0; fine_y < PW_TILE_SIZE; fine_y++) {
        byte data_high = tile->data_high[fine_y];
        byte data_low = tile->data_low[fine_y];

        for (int fine_x = 0; fine_x < PW_TILE_SIZE; fine_x++) {
            byte bitmask = 1 << (PW_TILE_SIZE - fine_x - 1);
            byte bit_high = data_high & bitmask;
            byte bit_low = data_low & bitmask;

            int pixel_addr = tile_buffer_addr + fine_x + fine_y * PW_WIDTH;
            unsigned int *pixel_data = &buffer[pixel_addr];

            if (bit_high && bit_low) {
                *pixel_data = 0xffffffff;
            } else if (bit_low) {
                *pixel_data = 0xffff0000;
            } else if (bit_high) {
                *pixel_data = 0xff00ffff;
            } else {
                *pixel_data = 0xff000000;
            }
        }
    }

    pattern_window_draw_tile_borders(tile_buffer_addr, buffer);
}

void pattern_window_draw_bank(PatternTile *tiles, unsigned int *buffer) {
    for (int i = 0; i < PW_BANK_TILE_COUNT; i++) {
        PatternTile *tile = &tiles[i];
        pattern_window_draw_tile(tile, buffer);
    }
}

void pattern_window_draw_table(NesPatternWindow *window) {
    unsigned int tex_buffer[PW_WIDTH * PW_HEIGHT] = {0};
    pattern_window_draw_borders(tex_buffer);
    pattern_window_draw_bank(window->tiles_bank_0, tex_buffer);
    pattern_window_draw_bank(window->tiles_bank_1, &tex_buffer[PW_WIDTH * (PW_HEIGHT / 2)]);

    SDL_UpdateTexture(window->texture, NULL, tex_buffer, PW_WIDTH * sizeof(unsigned int));
}

void pattern_window_build_table(NesPatternWindow *window, byte *pattern_memory) {
    pattern_window_build_tiles(window, pattern_memory);
    pattern_window_draw_table(window);
}

void pattern_window_render(NesPatternWindow *window) {
    SDL_RenderClear(window->sdl_context.renderer);
    SDL_RenderCopy(window->sdl_context.renderer, window->texture, NULL, NULL);
}

void pattern_window_present(NesPatternWindow *window) {
    SDL_RenderPresent(window->sdl_context.renderer);
}