Nigtronix
Cheater
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Joined: 18 May 2007
Posts: 45
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 Posted: Wed May 23, 2007 2:11 am Post subject: 2D Line Rotation |
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Hey, I'm trying to make something like the second hand on an analog wall clock. I want a solid line to rotate from the center of the screen, 360 degrees.
Below is my attempt(SIMPLIFIED): (But it isn't working correctly)
| Code: |
/*************************************************************************************
RADAR_ME - An almost pointless program that tries to emulate a real radar or sonar
screen.
This version is conceptional version, that draws the radar to Device Context(0), or
the current global screen(desktop).
Author: NigTronIX
Date concepted: May 23, 2007 @ 12:07AM, Thanks rewt for the project idea ^^
Last Modified: May 23, 2007 @ 2:07AM
TODO: Threading optimizations, Transparent window, lighting effects or something
- Move all Function declarations in header file after coding window code
I don't know, but I think my line drawing functions need optimized also ;P
Thanks to my math book for rotating line formula!
Compiled using Microsoft Visual C++ 6.0 under Windows XP Home SP1
***************************************************************************************/
#include <windows.h>
#include <conio.h> //debugging
#include <math.h>
#include <stdlib.h>
#include <stdio.h> //debugging
#include <time.h>
/* Global Constants */
#define DCON 0 // Device context to use
#define DegToRad 0.017453293f
/* Prototypes ^^ */
int Draw_line(); // returns 0 on failure, USED LATER
int Get_Center_Of_Screen(int *x, int *y); // returns 0 on failure, USED LATER
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )
{
/* Get Center of Screen */
int cx = GetSystemMetrics(SM_CXSCREEN);
int cy = GetSystemMetrics(SM_CYSCREEN);
int pos1= cx / 2;
int pos2= cy / 2;
HDC hwnd = GetDC(DCON);
int T = 1;
while(1)
{
for(; T <= 60; T++) {
SetPixel(hwnd,(cos(T) * pos1) - (sin(T) * pos2), (sin(T) * pos1) + (cos(T) * pos2) ,RGB(255,0,0));
Sleep(1);
}
T = 1; // reset
}
return 0;
}
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UPDATE: I now have it operating ALMOST the way I want it: but I want it to show only one line not multiple lines
| Code: |
/* Get Center of Screen */
int cx = GetSystemMetrics(SM_CXSCREEN);
int cy = GetSystemMetrics(SM_CYSCREEN);
int pos1= cx / 2;
int pos2= cy / 2;
HDC hwnd = GetDC(DCON);
// General forumula: X = X_Origin + cos(angle) * radius
// Radius is the line length
// Y = Y_Origin + sin(angle) * radius
SaveDC(hwnd);
while(1)
{
for(int T = 1; T <= (10); T++) {
MoveToEx(hwnd, pos1, pos2, NULL); // update current brush to origin
LineTo(hwnd,pos1 + cos(T) * 200, pos2 + sin(T) * 200);
RestoreDC(hwnd,1);
Sleep(5);
SaveDC(hwnd);
}
}
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I'm trying to use SaveDC() and RestoreDC() to erase the lines before the new line is redrawn o.o
It's not working 
Any help will be appreicated thanks  , also anybody know how to specify line color,width, and length?
thanks
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