我在Atari Breakout的基础上做学校项目。我使用ALLEGRO 5库在c ++中完成。我不知道如何避免一个问题。当我编译我的程序时，我的程序上有闪烁的图像，并且球太慢了。我试图改变FPS，但它仍然无法正常工作。
主循环收集关于鼠标（桨）的位置，球和砖的位置的信息。比它应该在屏幕上顺利打印。你有什么想法，我做错了吗？
这是我的代码：
#include <allegro5/allegro.h>
#include <allegro5\allegro_native_dialog.h>
#include <allegro5/allegro_primitives.h>
#include <allegro5/allegro_font.h>
#include <allegro5/allegro_ttf.h>
#define BRICKS_HORIZONTALLY 10
#define BRICKS_VERTICALLY 5
#define BRICK_WIDTH 102
#define BRICK_HEIGHT 50
#define BRICK_GAP 2
#define PADDLE_WIDTH 100
#define PADDLE_HEIGHT 20
#define PADDLE_POSITION_Y (768-50)
ALLEGRO_DISPLAY *display = NULL;
ALLEGRO_EVENT_QUEUE *event_queue = NULL;
struct ball_typ {
int xv, yv;
int x, y;
};
int playerPaddleEdgeX;
ball_typ ball;
int bricks[BRICKS_VERTICALLY][BRICKS_HORIZONTALLY];
void makeScreenBlack() { //clead screen to black
al_clear_to_color(al_map_rgb(0, 0, 0));
al_flip_display();
}
void resetBricks() {
for (int i = 0; i<BRICKS_VERTICALLY; i++) {
for (int ii = 0; ii<BRICKS_HORIZONTALLY; ii++) {
bricks[i][ii] = 1;
}
}
}
int numberOfBricksRemaining() {
int numberOfBricksRemaining;
numberOfBricksRemaining = 0;
for (int i = 0; i<BRICKS_VERTICALLY; i++) {
for (int ii = 0; ii<BRICKS_HORIZONTALLY; ii++) {
if (bricks[i][ii] != 0) {
numberOfBricksRemaining++;
}
}
}
return numberOfBricksRemaining;
}
void drawingThings() {
makeScreenBlack();
// draw the bricks
for (int i = 0; i<BRICKS_VERTICALLY; i++) {
for (int ii = 0; ii<BRICKS_HORIZONTALLY; ii++) {
if (bricks[i][ii] != 0) {
al_draw_filled_rectangle(ii*BRICK_WIDTH, i*BRICK_HEIGHT,(ii + 1)*BRICK_WIDTH - BRICK_GAP, (i + 1)*BRICK_HEIGHT - BRICK_GAP, al_map_rgb(255, 0, 0));
}
}
}
// draw the ball
al_draw_filled_circle(ball.x, ball.y, 8, al_map_rgb(255, 255, 255));
// draw the player
al_draw_filled_rectangle(playerPaddleEdgeX, PADDLE_POSITION_Y,playerPaddleEdgeX + PADDLE_WIDTH, PADDLE_POSITION_Y + PADDLE_HEIGHT, al_map_rgb(255, 255, 255));
ALLEGRO_FONT *font = al_create_builtin_font();
al_draw_textf(font, al_map_rgb(0, 0, 0), 10, 10, 0, "Player Position (playerPaddleEdgeX is %i)", playerPaddleEdgeX);
al_draw_textf(font, al_map_rgb(0, 0, 0), 10, 20, 0, "ball (x,y) position is (%i, %i)", ball.x, ball.y);
}
void resetBall() {
ball.x = 1024 / 2;
ball.y = 768 / 2;
ball.xv = 4;
ball.yv = 2;
}
int doesOverlap(int objectX, int objectY,
int areaLeft, int areaTop,
int areaRight, int areaBottom) {
if (ball.x > areaLeft &&
ball.x < areaRight &&
ball.y > areaTop &&
ball.y < areaBottom) {
return 1; // 1 here means yes
}
return 0; // 0 here means no
}
void moveBall() {
// update the ball's position for the next frame
ball.x += ball.xv;
ball.y += ball.yv;
// if the ball is overlapping the rectangle
if (ball.yv > 0) { // only if the ball is moving down
if (doesOverlap(ball.x, ball.y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.0),
PADDLE_POSITION_Y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.25),
PADDLE_POSITION_Y + PADDLE_HEIGHT) == 1) {
ball.xv = -5;
ball.yv = -3;
}
if (doesOverlap(ball.x, ball.y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.25),
PADDLE_POSITION_Y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.5),
PADDLE_POSITION_Y + PADDLE_HEIGHT) == 1) {
ball.xv = -3;
ball.yv = -5;
}
if (doesOverlap(ball.x, ball.y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.5),
PADDLE_POSITION_Y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.75),
PADDLE_POSITION_Y + PADDLE_HEIGHT) == 1) {
ball.xv = 3;
ball.yv = -5;
}
if (doesOverlap(ball.x, ball.y,
playerPaddleEdgeX + (PADDLE_WIDTH*0.75),
PADDLE_POSITION_Y,
playerPaddleEdgeX + (PADDLE_WIDTH*1.0),
PADDLE_POSITION_Y + PADDLE_HEIGHT) == 1) {
ball.xv = 5;
ball.yv = -3;
}
}
for (int i = 0; i<BRICKS_VERTICALLY; i++) {
for (int ii = 0; ii<BRICKS_HORIZONTALLY; ii++) {
if (bricks[i][ii] != 0) { // is the brick still here?
if (doesOverlap(ball.x, ball.y,
ii*BRICK_WIDTH, i*BRICK_HEIGHT,
(ii + 1)*BRICK_WIDTH - BRICK_GAP,
(i + 1)*BRICK_HEIGHT - BRICK_GAP) == 1) {
// reverse ball's vertical direction
ball.yv = -ball.yv;
bricks[i][ii] = 0; // erase the brick
}
}
}
}
// bounce off edges of screen
if (ball.x > 1024) {
ball.xv = -ball.xv;
}
if (ball.x < 0) {
ball.xv = -ball.xv;
}
if (ball.y < 0) {
ball.yv = -ball.yv;
}
// but reset ball if it goes off bottom of screen
if (ball.y > 768) {
// lose!
ALLEGRO_MOUSE_STATE state;
al_get_mouse_state(&state);
if (state.buttons & 1) { //reappear ball
resetBall();
}
}
}
void updatePaddlePosition() {
// for now, put the player's paddle where the mouse is
int pos_x = 1024 / 2;
ALLEGRO_MOUSE_STATE state;
al_get_mouse_state(&state);
pos_x = state.x;
playerPaddleEdgeX = pos_x;
}
void gameSetup() {
resetBricks();
resetBall();
// start with the ball off the bottom of the screen
ball.y = 768 + 50;
}
int main() {
ALLEGRO_TIMER * timer = NULL;
int FPS = 60;
al_init(); // allegro initializing
al_init_font_addon();
al_init_primitives_addon();
if (!al_init()){ //check
al_show_native_message_box(NULL, NULL, NULL,
"failed to initialize allegro!", NULL, NULL);
return -1;
}
timer = al_create_timer(1.0 / FPS);
al_install_keyboard();
al_install_mouse();
event_queue = al_create_event_queue();
al_register_event_source(event_queue, al_get_mouse_event_source());
al_register_event_source(event_queue, al_get_timer_event_source(timer));
al_set_new_window_position(20, 30);
display = al_create_display(1024, 768);
if (!display){ //check
al_show_native_message_box(NULL, NULL, NULL,
"failed to initialize display!", NULL, NULL);
return -1;
}
makeScreenBlack();
updatePaddlePosition();
gameSetup();
ALLEGRO_KEYBOARD_STATE key;
al_start_timer(timer);
while (al_key_down(&key, ALLEGRO_KEY_ESCAPE)){
updatePaddlePosition();
moveBall();
if (numberOfBricksRemaining() == 0) {
resetBricks();
}
drawingThings();
al_flip_display();
al_rest(0.01);
}
al_destroy_display(display);
return 0;
}
答案 0 :(得分：2)
您已拨打al_flip_display两次。您应该移除al_flip_display中makeScreenBlack()的号召，并保留另一个号码。