c - 需要帮助处理 C 中的二维结构数组

Question

我正在用 C 语言开发俄罗斯方 block 游戏，我试图将落在二维数组中的 block 存储起来，然后将它们绘制在屏幕上并随后使用它们。我正在尝试创建一个函数来通过引用将 block 添加到数组中。具体来说，我想知道如何将 block 存储在数组中，以便之后可以在它们上使用 draw(Block* block, SDL_Renderer* renderer) 等。我创建了一个指针矩阵，并尝试在游戏 block 落地后将其添加到其中。现在，在 block 掉落后，它只是停留在那里，即使我对其调用 initGameBlock 也是如此。我不太清楚发生了什么事，请帮忙。我添加 block 并重新初始化“activeBlock”的部分位于 updateGameBlock 中。我怎样才能使这个矩阵发挥作用？

#include <stdio.h>
#include <math.h>
#include <SDL2/SDL.h>
#include <SDL_image.h>

//Initialize the constants for the screen width, height and block width
const int width = 600;
const int height = 800;
const int bwidth = 40;

//Enum for storing the types of blocks
typedef enum {BLOCK, LINE, CHAIR, TABLE, BED} Type; 

//This variable is used in the update function in order to make timing work
float prevTicks = 0;

//Function that returns ceiling of a number
int mceil(double num){
    return (int)num + 1;
}

//Struct ofr position/velocity
typedef struct{
    float x, y;
} Vector2;

//Function to keep a value between some constrains
void limit(int* value, int min, int max){
    if(*value > max){
        *value = max;
    }
    if(*value < min){
        *value = min;
    }
}

//The blocks in the game
typedef struct Block{
    Vector2 position;
    SDL_Texture* texture;
    SDL_Rect rect;
} Block;

//"Consturctor" for the block
void initBlock(Block* block, float x, float y, SDL_Texture* texture){
    block->position.x = x;
    block->position.y = y;
    block->rect.x = (int) x - bwidth / 2;
    block->rect.y = (int) y - bwidth / 2;
    block->rect.w = bwidth;
    block->rect.h = bwidth;
    block->texture = texture;
}

//The gameblock consisting of 4 blocks
typedef struct GameBlock{
    Vector2 position;
    Vector2 velocity;
    int falling;
    Type type;
    Block blocks[4];
    SDL_Texture* texture;
} GameBlock;

//"Constructor" for the falling blocks
void initGameBlock(GameBlock* gameBlock, float x, float y, float xvel, float yvel, Type type, SDL_Texture* texture){
    gameBlock->falling = 1; //Variable which tells whether the block is falling
    gameBlock->position.x = x;  
    gameBlock->position.y = y;
    gameBlock->velocity.x = xvel;   
    gameBlock->velocity.y = yvel;
    gameBlock->type = type;
    gameBlock->texture = texture;
    switch(gameBlock->type){
        //Depending on the type of the gameBlock, arranges the blocks in a certain way
        case BLOCK: {
            initBlock(&(gameBlock->blocks[0]), gameBlock->position.x - bwidth / 2, gameBlock->position.y - bwidth/2, texture);
            initBlock(&(gameBlock->blocks[1]), gameBlock->position.x + bwidth / 2, gameBlock->position.y - bwidth/2, texture);
            initBlock(&(gameBlock->blocks[2]), gameBlock->position.x + bwidth / 2, gameBlock->position.y + bwidth/2, texture);
            initBlock(&(gameBlock->blocks[3]), gameBlock->position.x - bwidth / 2, gameBlock->position.y + bwidth/2, texture);
            break;
        }
        case LINE: {
            initBlock(&(gameBlock->blocks[0]), gameBlock->position.x - bwidth / 2 - bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[1]), gameBlock->position.x + bwidth / 2 + bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[2]), gameBlock->position.x + bwidth / 2, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[3]), gameBlock->position.x - bwidth / 2, gameBlock->position.y, texture);
            break;
        }
        case CHAIR: {
            initBlock(&(gameBlock->blocks[0]), gameBlock->position.x, gameBlock->position.y - bwidth, texture);
            initBlock(&(gameBlock->blocks[1]), gameBlock->position.x + bwidth, gameBlock->position.y - bwidth, texture);
            initBlock(&(gameBlock->blocks[2]), gameBlock->position.x - bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[3]), gameBlock->position.x, gameBlock->position.y, texture);
            break;
        }
        case TABLE: {
            initBlock(&(gameBlock->blocks[0]), gameBlock->position.x, gameBlock->position.y - bwidth, texture);
            initBlock(&(gameBlock->blocks[1]), gameBlock->position.x + bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[2]), gameBlock->position.x - bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[3]), gameBlock->position.x, gameBlock->position.y, texture);
            break;
        }
        case BED: {
            initBlock(&(gameBlock->blocks[0]), gameBlock->position.x, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[1]), gameBlock->position.x + bwidth, gameBlock->position.y - bwidth, texture);
            initBlock(&(gameBlock->blocks[2]), gameBlock->position.x - bwidth, gameBlock->position.y, texture);
            initBlock(&(gameBlock->blocks[3]), gameBlock->position.x + bwidth, gameBlock->position.y, texture);
            break;
        }
    }   
}

//The matrix containing blocks on the ground
Block* blocks[20][15] = {NULL};

//Function to add a block in this matrix
void addBlock(Block* block, Block* blocks[][15]){
    int col = (int) (block->position.x / bwidth);
    int row = (int) (block->position.y / bwidth);
    blocks[row][col] = block;
}

//Function to add the blocks from a gameBlock in the matrix
void addBlocks(GameBlock* gameBlock){
    for(unsigned int i = 0; i < 4; i++){
        addBlock(&(gameBlock->blocks[i]), blocks);
    }
}

//The logic for the gameBlock
void updateGameBlock(GameBlock** gameBlock){
    //If the gameObject is already on the ground do this:
    if((*gameBlock)->position.y > height - bwidth && (*gameBlock)->falling == 1){
        //Tell that it's not falling
        (*gameBlock)->falling = 0;
        //Add the blocks from the gameBlock into the matrix
        addBlocks(*gameBlock);
        //Reset the pointer and create a new gameBlock at the top
        *gameBlock = NULL;
        *gameBlock = (GameBlock*) malloc(sizeof(GameBlock));
        initGameBlock(*gameBlock, width / 2, bwidth / 2, 1.f, 1.f, BED, (*gameBlock)->texture);
    }
    //If the game object is still in the air
    if((*gameBlock)->falling == 1){
        //This makes it so that the object falls in steps
        if(SDL_GetTicks() - prevTicks >= 100){      
            (*gameBlock)->position.y += (*gameBlock)->velocity.y*bwidth/2;
        }
        //Update the position of the blocks in the gameBlock(all at the same time)
        for(unsigned int i = 0; i < 4; i++){
            (*gameBlock)->blocks[i].rect.x += (*gameBlock)->velocity.x*bwidth;
            (*gameBlock)->blocks[i].position.x += (*gameBlock)->velocity.x*bwidth;
            if(SDL_GetTicks() - prevTicks >= 100){      
                (*gameBlock)->blocks[i].rect.y += (*gameBlock)->velocity.y*bwidth/2;
                (*gameBlock)->blocks[i].position.y += (*gameBlock)->velocity.y*bwidth/2;
                if(i == 3)
                    prevTicks = SDL_GetTicks();
            }
        }
    }
}

//Function for displaying the block on the screen
void drawBlock(Block* block, SDL_Renderer* renderer){
    SDL_RenderCopy(renderer, block->texture, NULL, &(block->rect));
}

//Function for displaying the whole gameBlock on the screen
void drawGameBlock(GameBlock* gameBlock, SDL_Renderer* renderer){
    for(unsigned int i = 0; i < 4; i++){
        drawBlock(&(gameBlock->blocks[i]), renderer);
    }
}

int main(){

    //Initialize SDL, create a window and a renderer
    SDL_Init(SDL_INIT_EVERYTHING);
    SDL_Window* window = SDL_CreateWindow("Tetris", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, 0);

    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
    SDL_SetRenderDrawColor(renderer, 34, 134, 134, 255);
    int running = 1;    

    GameBlock testBlock;
    SDL_Surface* testSurface = IMG_Load("./res/blueCube.png");
    SDL_Texture* testTexture = SDL_CreateTextureFromSurface(renderer, testSurface);
    SDL_FreeSurface(testSurface);
    testSurface == NULL;
    GameBlock* activeBlock = &testBlock;


    initGameBlock(&testBlock, width / 2, bwidth / 2, 1.f, 1.f, BED, testTexture);

    SDL_Event e;
    //These variables are for controlling the fps
    float df = 0.f;
    float past = SDL_GetTicks();
    float fps;
    float now;
    float dt;
    while(running){
        //Reset the x velocity of the block
        testBlock.velocity.x = 0.f;
        while(SDL_PollEvent(&e)){
            switch(e.type){
                case SDL_QUIT: running = 0;
                case SDL_KEYDOWN:
                    switch(e.key.keysym.scancode){
                        case SDL_SCANCODE_LEFT:
                            activeBlock->velocity.x += -1;
                            break;
                        case SDL_SCANCODE_RIGHT:
                            activeBlock->velocity.x += 1;
                            break;
                        case SDL_SCANCODE_ESCAPE:
                            running = 0;
                            break;
                    }
            }
        }
        //Clear the screen and draw the testBlock
        SDL_RenderClear(renderer);
        drawGameBlock(activeBlock, renderer);
        //Draw the blocks from the matrix
        for(int i = 0; i < 20; i++){
            for(int j = 0; j < 15; j++){
                if(blocks[i][j] != NULL){
                    drawBlock(blocks[i][j], renderer);
                    printf("x: %d y: %d\n", (int) blocks[i][j]->position.x, (int) blocks[i][j]->position.y);
                }
            }
        }
        updateGameBlock(&activeBlock);
        SDL_RenderPresent(renderer);

        //Limit the fps
        now = SDL_GetTicks();
        df++;
        dt = (now - past)/1000;
        fps = df / dt;
        if(fps > 60){
            SDL_Delay(mceil((1.f / 30.f - dt / df)*1000));
        }
        if(SDL_GetTicks() % 1000 == 0)
            printf("fps = %d\n", (int) fps);
    }

    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;

}

为了编译我使用:

gcc -o 俄罗斯方 block tetris.c $(pkg-config --cflags --libs sdl2) -lSDL2_image -lSDL2_ttf

Answer 1

免责声明:您的代码很难阅读和理解(没有注释，我无法运行它来查看发生了什么，某些地方的缩进很差)。我的回答更像是一个简短的评论和一些我在代码几分钟后得到的提示。如果您编辑代码/添加更多详细信息，我将相应地编辑我的答案。

在对应用程序进行编码时，要记住的一件事是将业务逻辑与视觉逻辑分开。这对于可视化发生的情况有很大帮助，因为界面代码往往非常冗长，如果将其与逻辑代码混合，调试很快就会变得一团糟。另外，您可以用瘦接口(interface)(仅限文本)替换接口(interface)代码，以调试逻辑部分。

另一个需要考虑的事情是数据不一致。当您将相同的数据存储在两个位置并且仅修改其中之一时，就会发生这种情况。由于将 block 放入矩阵中，但每个 block 都知道其位置，因此存在数据不一致的情况。您甚至不需要将位置存储在 block 结构内，只需将其放置在矩阵中即可。

话虽这么说，您需要提高代码的模块化程度。应该有一个函数接受 block 矩阵并打印它，这应该是与 View 库的唯一连接点。在业务逻辑中，您应该只关心游戏 block 。处理完它们后，您只需将它们的 block 放入矩阵中并绘制矩阵即可。一路上你可能会遇到一些困难(主要是关于碰撞)，但从这种心态开始。