int Pac_Man() {
// Just the main loop
// #define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)
if (KEYDOWN(VK_ESCAPE)) {
SendMessage(main_window_handle, WM_CLOSE, 0, 0); }
memset(&ddsd,0,sizeof(ddsd));
ddsd.dwSize = sizeof(ddsd);
if (FAILED(lpddsprimary->Lock(NULL, &ddsd, DDLOCK_SURFACEMEMORYPTR | DDLOCK_WAIT, NULL))) {
return(0); }
int mempitch = static_cast<int>(ddsd.lPitch);
UCHAR *video_buffer = static_cast<UCHAR *>(ddsd.lpSurface);
const int halfScreenx = SCREEN_WIDTH / 2;
const int halfScreeny = SCREEN_HEIGHT / 2;
const double PI = 3.14159;
const double degToRad = PI / 180;
static int tempVecLength = 1;
int vecLength = rand() % tempVecLength;
// plot pacman shape
for (int index = 0; index < 100; index++) {
// select random position and color
UCHAR color = 1;
double Angle = (rand() % 36000 * degToRad) / 100.0;
int x = static_cast<int>(halfScreenx + vecLength * cos(Angle));
int y = static_cast<int>(halfScreeny + vecLength * sin(Angle));
// plot the pixels
video_buffer[x+y*mempitch] = color; }
if(tempVecLength < halfScreeny) { // make sure circle doesn't get larger than smallest part of the screen
tempVecLength++; }
if (FAILED(lpddsprimary->Unlock(NULL))) {
return(0); }
return(0);
}
Accidental Pac-Man
Author
I was screwing around with pixel plotting and made a program which would fill in a growing circle with random pixels. What I basically did was make a vector, gave it a random angle, then computed the x,y coordinates. But for some reason I decided to use degrees and I only used rand() % 360, which wasn't accurate, and made a lot of straight lines.
Then I used rand() % 3600, converted to radians, then divided by 10.0, which was more accurate but there were still some holes left when I used solid color. So finally I did rand() % 36000, converted to radians, then divided by 100.0.
And I got Pac-man. It didn't take me long realize I either had math overflow or rand() didn't go that high. I'm pretty sure it's cause rand doesn't go that high.
Here's the loop I was using, modified a little for effect:
I'm sure there are dozens of ways I could have designed the code better, but, oh well, I was just goofing around.
[edited by - nobodynews on November 7, 2002 11:49:28 PM]
Moved to a more appropriate forum.
-Ryan "Run_The_Shadows"
-Run_The_Shadows@excite.com
-The Navidson Record! The best film you''ll never see!
-Ryan "Run_The_Shadows"
-Run_The_Shadows@excite.com
-The Navidson Record! The best film you''ll never see!
Hit us with a screenshot 
MatrixCubed
http://MatrixCubed.cjb.net
[edited by - MatrixCubed on November 7, 2002 12:47:28 AM]
MatrixCubed
http://MatrixCubed.cjb.net
[edited by - MatrixCubed on November 7, 2002 12:47:28 AM]
RAND_MAX is indeed 32767 (0x7FFF) in Microsoft''s implementation.
(and, yes, there are better ways to get better random numbers.
)
-scott
(and, yes, there are better ways to get better random numbers.
)-scott
Yes, Scaught is right. RAND_MAX is usually the same as an int. You can build a little program to check what the maximum value of your RAND_MAX is.
The RAND_MAX constant is stored in the cstdlib library. Hope this helps some of you. =)
//This will display value of RAND_MAX constant.#include <iostream>#include <cstdlib>using namespace std;int main(){ cout << "The value of RAND_MAX on my system is: " << RAND_MAX << endl; return 0;} The RAND_MAX constant is stored in the cstdlib library. Hope this helps some of you. =)
Yeah, rand() is limited to a 32k integer. 
What you could do is %16000 and /50.0, or 24000 and 75.0, etc.. (not too sure; my brain and math don''t mix when I haven''t had coffee for a while, but I''m sure you get the idea). It''d be more precise than %3600 /10, but much less understandable.
You could do...
MaxAngle = 16000;
DivideBy = 50.0;
MyValue = rand()%MaxAngle / DivideBy;
...which would be somewhat more understandable, though. Well, like I said, my mind is numbed due to a lack of caffeine in my blood, but I''m pretty sure you could get something more precise using that.
And yeah, rand() isn''t the best number generator you can get ;P
What you could do is %16000 and /50.0, or 24000 and 75.0, etc.. (not too sure; my brain and math don''t mix when I haven''t had coffee for a while, but I''m sure you get the idea). It''d be more precise than %3600 /10, but much less understandable.
You could do...
MaxAngle = 16000;
DivideBy = 50.0;
MyValue = rand()%MaxAngle / DivideBy;
...which would be somewhat more understandable, though. Well, like I said, my mind is numbed due to a lack of caffeine in my blood, but I''m pretty sure you could get something more precise using that.
And yeah, rand() isn''t the best number generator you can get ;P
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