作成日: 2023-07-21 (金)

初心者によるC++入門 #34 ブロックの基礎になるクラスを作る

#include <SDL2/SDL.h>
#include <iostream>

#include "board.h"
#include "gfxaux.h"

int main(int argc, char **argv) {
    int const ScreenWidth = 600;  // px
    int const ScreenHeight = 550; // px
    
    BoardInfo board {
        10, 20,
        24, 24,
        SDL_Point{10, 10}
    };

    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        std::cerr << "Error: init SDL\n";
        std::exit(1);
    }
    
    SDL_Window *window = SDL_CreateWindow(
            "HelloSDL window",
            SDL_WINDOWPOS_CENTERED,
            SDL_WINDOWPOS_CENTERED,
            ScreenWidth,
            ScreenHeight,
            0);
    if (window == nullptr) {
        std::cerr << "Error: create window\n";
        std::exit(1);
    }
    
    SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
    if (renderer == nullptr) {
        std::cerr << "Error: create renderer\n";
        std::exit(1);
    }
    
    // setup game
    Fence fence = setup_fence(board, Gray, White);

    // game loop
    bool running = true;
    while (running) {
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT) {
                running = false;
            }
        }
        
        SDL_SetRenderDrawColor(renderer, 100, 100, 255, 255);
        SDL_RenderClear(renderer);

        draw_fence(renderer, fence);
        
        SDL_RenderPresent(renderer);
        
        SDL_Delay(1);
    }
    
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);

    return 0;
}

#ifndef GFXAUX_H
#define GFXAUX_H

#include <SDL2/SDL.h>

SDL_Color const Gray{128, 128, 128, 255};
SDL_Color const White{255, 255, 255, 255};

void draw_rectangle(SDL_Renderer *renderer, SDL_Rect const &rect, SDL_Color const &fc, SDL_Color const &oc);

#endif

#include "gfxaux.h"

void draw_rectangle(SDL_Renderer *renderer, SDL_Rect const &rect, SDL_Color const &fc, SDL_Color const &oc) {
    SDL_SetRenderDrawColor(renderer, fc.r, fc.g, fc.b, fc.a);
    SDL_RenderFillRect(renderer, &rect);
    SDL_SetRenderDrawColor(renderer, oc.r, oc.g, oc.b, oc.a);
    SDL_RenderDrawRect(renderer, &rect);
}

#ifndef BOARD_H
#define BOARD_H

#include "cell.h"
#include <SDL2/SDL.h>
#include <vector>

struct BoardInfo {
    int arena_width;
    int arena_height;
    int cell_width;
    int cell_height;
    SDL_Point position;
};

using Fence = std::vector<Cell>;

Fence setup_fence(BoardInfo const &board,
                  SDL_Color const &fill_color,
                  SDL_Color const &outline_color);

void draw_fence(SDL_Renderer *renderer, Fence const &fence);

#endif

#include "board.h"

#include "gfxaux.h"
#include "cell.h"

Fence setup_fence(BoardInfo const &board,
                  SDL_Color const &fill_color,
                  SDL_Color const &outline_color) {
    Fence fence;
    
    // left wall
    for (int i{}; i < board.arena_height; ++i) {
        SDL_Point pt{0, i * board.cell_height};
        fence.emplace_back(&board, board.position, pt, fill_color, outline_color);
    }

    // right wall
    for (int i{}; i < board.arena_height; ++i) {
        SDL_Point pt{(board.arena_width + 1) * board.cell_width, i * board.cell_height};
        fence.emplace_back(&board, board.position, pt, fill_color, outline_color);
    }

    // floor
    for (int i{}; i < board.arena_width + 2; ++i) {
        SDL_Point pt{i * board.cell_width, board.arena_height * board.cell_height};
        fence.emplace_back(&board, board.position, pt, fill_color, outline_color);
    }

    return fence;
}

void draw_fence(SDL_Renderer *renderer, Fence const &fence) {
    for (Cell const &cell : fence) {
        cell.draw(renderer);
    }
}

#ifndef CELL_H
#define CELL_H

#include <SDL2/SDL.h>

struct BoardInfo;

class Cell {
public:
    Cell(BoardInfo const *board,
         SDL_Point const &origin,
         SDL_Point const &position,
         SDL_Color const &fill_color,
         SDL_Color const &outline_color);
    ~Cell() = default;
    
    SDL_Point global_position() const;
    SDL_Point local_position() const;
    
    void draw(SDL_Renderer *renderer) const;

private:
    BoardInfo const *board_;
    SDL_Point origin_;
    SDL_Point position_;
    SDL_Color fill_color_;
    SDL_Color outline_color_;
};

#endif

#include "cell.h"

#include "gfxaux.h"
#include "board.h"

Cell::Cell(BoardInfo const *board,
           SDL_Point const &origin,
           SDL_Point const &position,
           SDL_Color const &fill_color,
           SDL_Color const &outline_color)
        : board_{board}
        , origin_{origin}
        , position_{position}
        , fill_color_{fill_color}
        , outline_color_{outline_color} {
}

SDL_Point Cell::global_position() const {
    return {origin_.x + position_.x, origin_.y + position_.y};
}

SDL_Point Cell::local_position() const {
    return position_;
}

void Cell::draw(SDL_Renderer *renderer) const {
    auto [x, y] = global_position();
    SDL_Rect rect{x, y, board_->cell_width, board_->cell_height};
    draw_rectangle(renderer, rect, fill_color_, outline_color_);
}

SRCS = \
	main.cpp \
	board.cpp \
	gfxaux.cpp \
	cell.cpp
OBJS = ${SRCS:%.cpp=%.o}
DEPS = ${SRCS:%.cpp=%.d}
EXECUTABLE = tetris.exe
CXXFLAGS = -IC:\SDL2\include
LDFLAGS = -LC:\SDL2\lib
LDLIBS = -lmingw32 -lSDL2main -lSDL2

.PHONY: all
all: ${EXECUTABLE}

${EXECUTABLE}: ${OBJS}
	${CXX} -o $@ $^ ${LDFLAGS} ${LDLIBS}

%.o: %.cpp
	${CXX} -c -o $@ $< -MMD -MP ${CXXFLAGS}

.PHONY: clean
clean:
	${RM} ${EXECUTABLE} ${OBJS} ${DEPS}

-include ${DEPS}

C:\SDL2の部分は、SDLをインストールした場所を指定します。