Conway 的生命游戏：当程序 运行 只有 blank/dead 个单元格 (C/SDL2) 时打印无关单元格
Conway's Game of Life: extraneous cells being printed when program run with only blank/dead cells (C/SDL2)
简而言之：当 运行 启动我的生命游戏程序时，它从一个空的死细胞板开始。如果我 运行 模拟一个周期，它应该保持为空，因为没有活细胞可供它处理。但是，当我 运行 我的程序时，一些小的死细胞在右下角变成 'alive' 。我不确定这是为什么，但我相信这要么是因为我检查活细胞邻居的方式，要么是因为我如何显示细胞。这是我的意思的图片：
#include <SDL.h>
#include <stdio.h>
#include <stdbool.h>
#define CELL_SIZE 10
#define GRID_WIDTH 100
#define GRID_HEIGHT 100
#define SCREEN_WIDTH (GRID_WIDTH * CELL_SIZE)
#define SCREEN_HEIGHT (GRID_HEIGHT * CELL_SIZE)
typedef enum {ALIVE, DEAD} State;
typedef struct{
int x;
int y;
State state;
} Cell;
// SDL related functions
SDL_Window *createWindow(char *title);
SDL_Renderer *createRenderer(SDL_Window *window);
void drawGrid(SDL_Renderer *r);
void drawCells(SDL_Renderer *r, int a[][GRID_WIDTH]);
// Game of Life functions
void updateCells(int a[][GRID_WIDTH]); // takes cells array as input
int countLivingNeighbours(int a[][GRID_WIDTH], int x, int y);
int main(int argc, char *argv[]){
// Initialise SDL
SDL_Init(SDL_INIT_VIDEO);
// Create window and renderer
SDL_Window *window = createWindow("Game of Life");
SDL_Renderer *renderer = createRenderer(window);
// Setup event handling + mouse co-ordinate handling
SDL_Event event;
int mouseX, mouseY;
bool mouse_left_down = false;
bool mouse_right_down = false;
// Set all cells to initial state of dead
int cells[GRID_HEIGHT][GRID_WIDTH];
int cx, cy;
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
cells[cy][cx] = DEAD;
}
}
// MAIN LOOP //
while(1){
// Handle events/input
while(SDL_PollEvent(&event) != 0){
switch(event.type){
case SDL_QUIT: // Check if user has quit
return 1;
// Check if user is HOLDING left or right mouse button
case SDL_MOUSEBUTTONDOWN: case SDL_MOUSEBUTTONUP:
switch(event.button.button){
case SDL_BUTTON_LEFT: mouse_left_down = !mouse_left_down; break;
case SDL_BUTTON_RIGHT: mouse_right_down = !mouse_right_down; break;
}
// If user presses space, simulate a single change
case SDL_KEYDOWN:
if(event.key.keysym.sym == SDLK_SPACE)
updateCells(cells);
}
}
// Get user mouse button input - left click gives life to cell at current co-ords, right click kills
SDL_GetMouseState(&mouseX, &mouseY);
if(mouse_left_down == true)
cells[mouseY / CELL_SIZE][mouseX / CELL_SIZE] = ALIVE;
else if(mouse_right_down == true)
cells[mouseY / CELL_SIZE][mouseX / CELL_SIZE] = DEAD;
// Set screen colour to white
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
// Render white to screen (clear screen)
SDL_RenderClear(renderer);
// Draw the grid and living cells
drawGrid(renderer);
drawCells(renderer, cells);
// Update screen
SDL_RenderPresent(renderer);
}
// Exit SDL and SDL_image
SDL_Quit();
return 0;
}
/*
1. Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
2. Any live cell with two or three live neighbours lives on to the next generation.
3. Any live cell with more than three live neighbours dies, as if by overpopulation.
4. Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
*/
void updateCells(int a[][GRID_WIDTH]){
int new[GRID_HEIGHT][GRID_WIDTH];
int cy, cx; // vertical count, horizontal count
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
// Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
if(a[cy][cx] == ALIVE && countLivingNeighbours(a, cx, cy) < 2)
new[cy][cx] = DEAD;
// Any live cell with two or three live neighbours lives on to the next generation.
else if(a[cy][cx] == ALIVE && (countLivingNeighbours(a, cx, cy) == 2 || countLivingNeighbours(a, cx, cy) == 3))
new[cy][cx] = ALIVE;
// Any live cell with more than three live neighbours dies, as if by overpopulation.
else if(a[cy][cx] == ALIVE && countLivingNeighbours(a, cx, cy) > 3)
new[cy][cx] = DEAD;
// Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
else if(a[cy][cx] == DEAD && countLivingNeighbours(a, cx, cy) == 3)
new[cy][cx] = ALIVE;
else
new[cy][cx] = DEAD;
}
}
// Update all cells into new states
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
a[cy][cx] = new[cy][cx];
}
}
}
// THERE'S NO ERROR CHECKING HERE WHICH IS BAD
// Should ideally check if a cell even exists before checking its state
int countLivingNeighbours(int a[][GRID_WIDTH], int x, int y){
int count = 0, cx, cy;
for(cy = y - 1; cy <= y + 1; cy++){
for(cx = x - 1; cx <= x + 1; cx++){
// Ensure neighbouring cell is not out of bounds
if(!(cy < 0 || cx < 0 || cy > GRID_HEIGHT || cx > GRID_WIDTH)){
// If there is a living neighbouring cell, add to count
if(a[cy][cx] == ALIVE)
count++;
// disregard current cell as it is not a neighbour
if(a[cy][cx] == ALIVE && cx == x && cy == y)
count--;
}
}
}
return count;
}
void drawGrid(SDL_Renderer *r){
// Draw vertical grid lines
for(int v = CELL_SIZE; v < SCREEN_WIDTH; v += CELL_SIZE){
// Set draw colour to grey
SDL_SetRenderDrawColor(r, 110, 110, 110, 110);
// Draw vertical line
SDL_RenderDrawLine(r, v, 0, v, SCREEN_HEIGHT);
}
// Draw horizontal grid lines
for(int h = CELL_SIZE; h < SCREEN_HEIGHT; h += CELL_SIZE){
// Set draw colour to grey
SDL_SetRenderDrawColor(r, 110, 110, 110, 110);
// Draw horizontal line
SDL_RenderDrawLine(r, 0, h, SCREEN_WIDTH, h);
}
}
void drawCells(SDL_Renderer *r, int a[][GRID_WIDTH]){
// Define cell width/height
SDL_Rect cellRect;
cellRect.w = CELL_SIZE + 1; // Same size as one cell +1 so it covers the grid line fully
cellRect.h = CELL_SIZE + 1; // Same size as one cell +1 so it covers the grid line fully
// Draw living cells
int cx, cy;
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
if(a[cy][cx] == ALIVE){
// Set cell x/y pos
cellRect.x = cx * CELL_SIZE;
cellRect.y = cy * CELL_SIZE;
SDL_SetRenderDrawColor(r, 0, 0, 0, 0);
SDL_RenderFillRect(r, &cellRect);
}
}
}
}
SDL_Window *createWindow(char *title){
SDL_Window *window = SDL_CreateWindow(
title, // Title
SDL_WINDOWPOS_CENTERED, // Initial window x position
SDL_WINDOWPOS_CENTERED, // Initial window y position
SCREEN_WIDTH, // Window Width
SCREEN_HEIGHT, // Window Height
0 // Flags
);
if(window == NULL){
printf("Failed to create window. %s\n", SDL_GetError());
exit(EXIT_FAILURE);
}
return window;
}
SDL_Renderer *createRenderer(SDL_Window *window){
SDL_Renderer *renderer = SDL_CreateRenderer(
window, // Window
-1, // Monitor index (-1 for first available)
SDL_RENDERER_ACCELERATED // Flags
);
if(renderer == NULL){
printf("Failed to create renderer. %s\n", SDL_GetError());
exit(EXIT_FAILURE);
}
return renderer;
}
奇怪的是，这似乎只发生在 GRID_WIDTH 和 GRID_HEIGHT 设置为较高值时。当两者都是 100 时会发生这种情况，如果 GRID_WIDTH 设置为 150，程序只是 hangs/crashes，但将它们都设置为较低的值（我用 30 测试过）并且一切正常。
非常感谢任何帮助:)
// Ensure neighbouring cell is not out of bounds
if(!(cy < 0 || cx < 0 || cy > GRID_HEIGHT || cx > GRID_WIDTH)){
这个检查是错误的。如果 cy 等于 GRID_HEIGHT 或 cx 等于 GRID_WIDTH 它仍然是越界的。这是因为右下角的单元格坐标为 GRID_HEIGHT-1 和 GRID_WIDTH-1.
当然应该是：
if(!(cy < 0 || cx < 0 || cy >= GRID_HEIGHT || cx >= GRID_WIDTH)){
简而言之：当 运行 启动我的生命游戏程序时，它从一个空的死细胞板开始。如果我 运行 模拟一个周期，它应该保持为空，因为没有活细胞可供它处理。但是，当我 运行 我的程序时，一些小的死细胞在右下角变成 'alive' 。我不确定这是为什么，但我相信这要么是因为我检查活细胞邻居的方式，要么是因为我如何显示细胞。这是我的意思的图片：
#include <SDL.h>
#include <stdio.h>
#include <stdbool.h>
#define CELL_SIZE 10
#define GRID_WIDTH 100
#define GRID_HEIGHT 100
#define SCREEN_WIDTH (GRID_WIDTH * CELL_SIZE)
#define SCREEN_HEIGHT (GRID_HEIGHT * CELL_SIZE)
typedef enum {ALIVE, DEAD} State;
typedef struct{
int x;
int y;
State state;
} Cell;
// SDL related functions
SDL_Window *createWindow(char *title);
SDL_Renderer *createRenderer(SDL_Window *window);
void drawGrid(SDL_Renderer *r);
void drawCells(SDL_Renderer *r, int a[][GRID_WIDTH]);
// Game of Life functions
void updateCells(int a[][GRID_WIDTH]); // takes cells array as input
int countLivingNeighbours(int a[][GRID_WIDTH], int x, int y);
int main(int argc, char *argv[]){
// Initialise SDL
SDL_Init(SDL_INIT_VIDEO);
// Create window and renderer
SDL_Window *window = createWindow("Game of Life");
SDL_Renderer *renderer = createRenderer(window);
// Setup event handling + mouse co-ordinate handling
SDL_Event event;
int mouseX, mouseY;
bool mouse_left_down = false;
bool mouse_right_down = false;
// Set all cells to initial state of dead
int cells[GRID_HEIGHT][GRID_WIDTH];
int cx, cy;
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
cells[cy][cx] = DEAD;
}
}
// MAIN LOOP //
while(1){
// Handle events/input
while(SDL_PollEvent(&event) != 0){
switch(event.type){
case SDL_QUIT: // Check if user has quit
return 1;
// Check if user is HOLDING left or right mouse button
case SDL_MOUSEBUTTONDOWN: case SDL_MOUSEBUTTONUP:
switch(event.button.button){
case SDL_BUTTON_LEFT: mouse_left_down = !mouse_left_down; break;
case SDL_BUTTON_RIGHT: mouse_right_down = !mouse_right_down; break;
}
// If user presses space, simulate a single change
case SDL_KEYDOWN:
if(event.key.keysym.sym == SDLK_SPACE)
updateCells(cells);
}
}
// Get user mouse button input - left click gives life to cell at current co-ords, right click kills
SDL_GetMouseState(&mouseX, &mouseY);
if(mouse_left_down == true)
cells[mouseY / CELL_SIZE][mouseX / CELL_SIZE] = ALIVE;
else if(mouse_right_down == true)
cells[mouseY / CELL_SIZE][mouseX / CELL_SIZE] = DEAD;
// Set screen colour to white
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
// Render white to screen (clear screen)
SDL_RenderClear(renderer);
// Draw the grid and living cells
drawGrid(renderer);
drawCells(renderer, cells);
// Update screen
SDL_RenderPresent(renderer);
}
// Exit SDL and SDL_image
SDL_Quit();
return 0;
}
/*
1. Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
2. Any live cell with two or three live neighbours lives on to the next generation.
3. Any live cell with more than three live neighbours dies, as if by overpopulation.
4. Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
*/
void updateCells(int a[][GRID_WIDTH]){
int new[GRID_HEIGHT][GRID_WIDTH];
int cy, cx; // vertical count, horizontal count
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
// Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
if(a[cy][cx] == ALIVE && countLivingNeighbours(a, cx, cy) < 2)
new[cy][cx] = DEAD;
// Any live cell with two or three live neighbours lives on to the next generation.
else if(a[cy][cx] == ALIVE && (countLivingNeighbours(a, cx, cy) == 2 || countLivingNeighbours(a, cx, cy) == 3))
new[cy][cx] = ALIVE;
// Any live cell with more than three live neighbours dies, as if by overpopulation.
else if(a[cy][cx] == ALIVE && countLivingNeighbours(a, cx, cy) > 3)
new[cy][cx] = DEAD;
// Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
else if(a[cy][cx] == DEAD && countLivingNeighbours(a, cx, cy) == 3)
new[cy][cx] = ALIVE;
else
new[cy][cx] = DEAD;
}
}
// Update all cells into new states
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
a[cy][cx] = new[cy][cx];
}
}
}
// THERE'S NO ERROR CHECKING HERE WHICH IS BAD
// Should ideally check if a cell even exists before checking its state
int countLivingNeighbours(int a[][GRID_WIDTH], int x, int y){
int count = 0, cx, cy;
for(cy = y - 1; cy <= y + 1; cy++){
for(cx = x - 1; cx <= x + 1; cx++){
// Ensure neighbouring cell is not out of bounds
if(!(cy < 0 || cx < 0 || cy > GRID_HEIGHT || cx > GRID_WIDTH)){
// If there is a living neighbouring cell, add to count
if(a[cy][cx] == ALIVE)
count++;
// disregard current cell as it is not a neighbour
if(a[cy][cx] == ALIVE && cx == x && cy == y)
count--;
}
}
}
return count;
}
void drawGrid(SDL_Renderer *r){
// Draw vertical grid lines
for(int v = CELL_SIZE; v < SCREEN_WIDTH; v += CELL_SIZE){
// Set draw colour to grey
SDL_SetRenderDrawColor(r, 110, 110, 110, 110);
// Draw vertical line
SDL_RenderDrawLine(r, v, 0, v, SCREEN_HEIGHT);
}
// Draw horizontal grid lines
for(int h = CELL_SIZE; h < SCREEN_HEIGHT; h += CELL_SIZE){
// Set draw colour to grey
SDL_SetRenderDrawColor(r, 110, 110, 110, 110);
// Draw horizontal line
SDL_RenderDrawLine(r, 0, h, SCREEN_WIDTH, h);
}
}
void drawCells(SDL_Renderer *r, int a[][GRID_WIDTH]){
// Define cell width/height
SDL_Rect cellRect;
cellRect.w = CELL_SIZE + 1; // Same size as one cell +1 so it covers the grid line fully
cellRect.h = CELL_SIZE + 1; // Same size as one cell +1 so it covers the grid line fully
// Draw living cells
int cx, cy;
for(cy = 0; cy < GRID_HEIGHT; cy++){
for(cx = 0; cx < GRID_WIDTH; cx++){
if(a[cy][cx] == ALIVE){
// Set cell x/y pos
cellRect.x = cx * CELL_SIZE;
cellRect.y = cy * CELL_SIZE;
SDL_SetRenderDrawColor(r, 0, 0, 0, 0);
SDL_RenderFillRect(r, &cellRect);
}
}
}
}
SDL_Window *createWindow(char *title){
SDL_Window *window = SDL_CreateWindow(
title, // Title
SDL_WINDOWPOS_CENTERED, // Initial window x position
SDL_WINDOWPOS_CENTERED, // Initial window y position
SCREEN_WIDTH, // Window Width
SCREEN_HEIGHT, // Window Height
0 // Flags
);
if(window == NULL){
printf("Failed to create window. %s\n", SDL_GetError());
exit(EXIT_FAILURE);
}
return window;
}
SDL_Renderer *createRenderer(SDL_Window *window){
SDL_Renderer *renderer = SDL_CreateRenderer(
window, // Window
-1, // Monitor index (-1 for first available)
SDL_RENDERER_ACCELERATED // Flags
);
if(renderer == NULL){
printf("Failed to create renderer. %s\n", SDL_GetError());
exit(EXIT_FAILURE);
}
return renderer;
}
奇怪的是，这似乎只发生在 GRID_WIDTH 和 GRID_HEIGHT 设置为较高值时。当两者都是 100 时会发生这种情况，如果 GRID_WIDTH 设置为 150，程序只是 hangs/crashes，但将它们都设置为较低的值（我用 30 测试过）并且一切正常。
非常感谢任何帮助:)
// Ensure neighbouring cell is not out of bounds if(!(cy < 0 || cx < 0 || cy > GRID_HEIGHT || cx > GRID_WIDTH)){
这个检查是错误的。如果 cy 等于 GRID_HEIGHT 或 cx 等于 GRID_WIDTH 它仍然是越界的。这是因为右下角的单元格坐标为 GRID_HEIGHT-1 和 GRID_WIDTH-1.
当然应该是：
if(!(cy < 0 || cx < 0 || cy >= GRID_HEIGHT || cx >= GRID_WIDTH)){