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Simple Rectangle Drawing Program Causes Major Issues http://forum.planetchili.net/viewtopic.php?f=3&t=4003 |
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Author: | BugSquisher [ April 19th, 2017, 11:32 pm ] |

Post subject: | Simple Rectangle Drawing Program Causes Major Issues |

Hi, I recently came back to the tutorial series and decided to make a small program through the framework in VS 2017 to get back into things. It simply draws a new rectangle every time I click the mouse. However, sometimes when I click the mouse, I lose the signal from my DVI port and have to reboot the computer to get back to normal. I don't think this is expected behavior from the framework, even if some variable is writing out of bounds. Could anyone chime in maybe if there have been similar issues? Thanks. |

Author: | albinopapa [ April 19th, 2017, 11:57 pm ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

Never heard of the losing video signal accept for changing screen resolutions to one that isn't supported by your monitor. |

Author: | chili [ April 20th, 2017, 2:31 pm ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

That is a super weird one that I've not heard before either. |

Author: | BugSquisher [ April 20th, 2017, 6:06 pm ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

Okay guys, I uninstalled and reinstalled Visual Studio and my graphics drivers. Problem appears fixed. I can only assume it was some corrupted driver or file somewhere. |

Author: | albinopapa [ April 20th, 2017, 8:22 pm ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

Well, hopefully that was the issue. Welcome to the forums btw. |

Author: | krautersuppe [ April 22nd, 2017, 3:40 am ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

BugSquisher wrote: It simply draws a new rectangle every time I click the mouse. . Yes I also thought that drawing a rectangle is a simple matter. In my case it didn't cause issues for my computer but it did cause issues for my head I tried to make a function to draw a rectangle of given height and width at given angle. I used chili's DrawLine function (old series tutorial 10): Code:void Graphics::DrawLine(int x1, int y1, int x2, int y2, int r, int g, int bl)// for elaborate explanation see old beginner series lesson 10 { int dx = x2 - x1; int dy = y2 - y1; if (abs(dy)>abs(dx)) { // calculates the x values relative to y - its an mirror function of the y = f(x) if (y1>y2) { int temp = y2;//swaps the values of y1 and y2 so that drawing loop gets executed for this condition y2 = y1; y1 = temp; temp = x2;//swaps the values of x2 and x1 x2 = x1; x1 = temp; } float m = (float)dx / (float)dy; // calculates the steepness of the line float b = x1 - m*y1; // calculates the y-intercept for (int y = y1; y <= y2; y++) { int x = m*y + b+ 0.5f; // 0.5f corrects the rounding effect of compiler(see video) PutPixel(x, y, r, g, bl); } } else { if (x1>x2) { int temp = y2;//swaps the values of y1 and y2 so that drawing loop gets executed for this condition(see video) y2 = y1; y1 = temp; temp = x2;//swaps the values of x2 and x1 x2 = x1; x1 = temp; } float m = (float)dy / (float)dx; // calculates the steepness of the line float b = y1 - m*x1; // calculates the y-intercept for (int x = x1; x <= x2; x++) { int y = m*x + b + 0.5f; PutPixel(x, y, r, g, bl); } } } but i was unable to draw a rectangle with single loop - some holes and gaps get drawn because of breaking lines . I use the second loop to fill them out: Code:void Graphics::DrawRectangle(int cx, int cy, int height, int width, int angle, int r, int g, int b) { const float PI = 3.14159; const float ra = angle* PI / 180.0;//angle in radians const int hw = width / 2; //half of width const int hh = height / 2; //half of height const int Ax = cx - hw*cos(ra) - hh*sin(ra); const int Ay = cy - hw*sin(ra) + hh*cos(ra); const int Bx = cx + hw*cos(ra) - hh*sin(ra); const int By = cy + hw*sin(ra) + hh*cos(ra); const int Cx = cx - hw*cos(ra) + hh*sin(ra); const int Cy = cy - hw*sin(ra) - hh*cos(ra); float y1 = Ay, x2 = Cx, y2 = Cy, x1=Ax; for ( x1 = x1; x1 <= Bx; x1 = x1+ cos(ra)) { DrawLine(x1, y1, x2, y2, r, g, b); x2 = x2 + cos(ra); y1 = y1 + sin(ra); y2 = y2 + sin(ra); } x1 = Ax, x2 = Bx, y2 = By; for ( y1 = Ay; y1 >= Cy; y1 = y1 - cos(ra)) { // this loop shouldn't be necessary - it's just meant to fill out holes DrawLine(x1, y1, x2, y2, r, g, b); x1= x1 + sin(ra); x2 = x2 + sin(ra); y2 = y2 - cos(ra); } I know that there are built-in functions for rotation and i try to reinvent the wheel here but maybe someone here finds this interesting and has some tips. Besides that it doesn't function properly if height>width or if angle>90 degrees because fucking sine is odd and cosine even. Attachment: rect1.png [ 4.93 KiB | Viewed 314 times ] |

Author: | albinopapa [ April 22nd, 2017, 11:55 pm ] |

Post subject: | Re: Simple Rectangle Drawing Program Causes Major Issues |

If you want to draw rects that rotate, check out chili's old Advanced tuts or his new 3D fundamentals tuts. He covers that very topic. |

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