[英]How to create box illusion in SDL?
I want to create a optical illusion for now just using rects and nothing else I am able to pull it off with 2 rects but I can't think of any way to keep generating rects after one another. 我现在想只使用rects来创造一种视觉上的错觉,我无法用2个rects来实现它,但我想不出任何办法来继续生成rects。 Right now the code I have only generates 2 rects but I want to know how I can change my code where it keep generating rects and do not stop until user presses exit. 现在,我仅有的代码只生成2个rect,但是我想知道如何在继续生成rect的地方更改我的代码,直到用户按下exit才停止。 Below is my code any help will be appreciated. 下面是我的代码,将不胜感激任何帮助。
#include <iostream>
#include <math.h>
#include "SDL.h"
using namespace std;
const int screen_width = 500;
const int screen_height = 500;
int main(int argc, char ** argv)
{
SDL_Init(SDL_INIT_VIDEO);
SDL_Window *window = SDL_CreateWindow("SDLDEMOSCENE", 50, 50, screen_width, screen_height, SDL_WINDOW_SHOWN);
SDL_Renderer *renderer = SDL_CreateRenderer(window, 0, SDL_RENDERER_ACCELERATED);
SDL_Rect rectangle, rectangle2;
double rect1_x = screen_width / 2;
double rect1_y = screen_height / 2;
double rect1_width = 5;
double rect1_height = 5;
double rect2_x = screen_width / 2;
double rect2_y = screen_height / 2;
double rect2_width = 5;
double rect2_height = 5;
bool quit = false;
while (quit == false)
{
SDL_Event event;
while (SDL_PollEvent(&event))
{
if (event.type == SDL_QUIT)
{
quit = true;
}
}
rectangle.x = rect1_x;
rectangle.y = rect1_y;
rectangle.h = rect1_height;
rectangle.w = rect1_width;
rectangle2.x = rect2_x;
rectangle2.y = rect2_y;
rectangle2.h = rect2_height;
rectangle2.w = rect2_width;
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderFillRect(renderer, &rectangle);
rect1_x -= 0.01;
rect1_y -= 0.01;
rect1_width += 0.02;
rect1_height += 0.02;
if (rect1_x < 200 || rect1_y < 200)
{
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderFillRect(renderer, &rectangle2);
rect2_x -= 0.01;
rect2_y -= 0.01;
rect2_width += 0.02;
rect2_height += 0.02;
}
if (rect2_x < 0 || rect2_y < 0)
{
rect2_height = 0;
rect2_width = 0;
rect2_x = 250;
rect2_y = 250;
rect1_height = 5;
rect1_width = 5;
rect1_x = 250;
rect1_y = 250;
}
SDL_RenderPresent(renderer);
}
SDL_Quit();
return 0;
}
With this edited code now 2 squares are coming and the program is running continuously but they are coming like pulses both rects are forming together now I just want the help to make the changes where there is no delay and the 2 rects should form continuously so it gives the feel of illusion. 有了这个经过编辑的代码,现在有2个方格出现,并且程序正在连续运行,但是它们就像脉冲一样出现了,两个矩形现在都在一起形成了,我只希望帮助做出无延迟的更改,并且2个矩形应该连续形成,所以给人一种幻觉。
Here's it: You forgot to reset rect1's properties after rect2 finishes it's turn. 就是这样:在rect2完成后,您忘记了重置rect1的属性。 Change the block if(rect2_x<0 || rect2_y<0)
to this: 将块if(rect2_x<0 || rect2_y<0)
更改为此:
if (rect2_x < 0 || rect2_y < 0)
{
rect2_height = 0;
rect2_width = 0;
rect2_x = 250;
rect2_y = 250;
rect1_height = 5;
rect1_width = 5;
rect1_x = 250;
rect1_y = 250;
}
Why does if(rect1_x<0 || rect1_y<0)
contain if(rect1_x<250 || rect1_y<250)
inside it? 为什么if(rect1_x<0 || rect1_y<0)
包含if(rect1_x<250 || rect1_y<250)
? rect_x<0
implies rect1_x<250
rect_x<0
表示rect1_x<250
So you can remove that extra nesting if-block and place it in the previous one. 因此,您可以删除多余的嵌套if块,并将其放在上一个中。
Not part of the answer, but heres what random things I did with your program: https://pastebin.com/zBBn7eBQ Call it inside any SDL_Window! 这不是答案的一部分,但是这是我对程序执行的随机操作: https ://pastebin.com/zBBn7eBQ在任何SDL_Window中调用它!
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