User:Zeracles/Background/Code/Stars - Revision history

Zeracles: SCDB move

2009-09-17T03:42:43Z

SCDB move

← Older revision		Revision as of 03:42, 17 September 2009
Line 2:		Line 2:
	%background.m		%background.m
	%by Anthony Smith (Zeracles); astroant@hotmail.com, asmith@physics.usyd.edu.au, http://www.physics.usyd.edu.au/~asmith/, http://wiki.uqm.stack.nl/User:Zeracles		%by Anthony Smith (Zeracles); astroant@hotmail.com, asmith@physics.usyd.edu.au, http://www.physics.usyd.edu.au/~asmith/, http://wiki.uqm.stack.nl/User:Zeracles
	%see http://~~starcontrol~~.~~classicgaming.gamespy~~.com/forum/index.php?topic=1660.0		%see http://www.star-control.com/forum/index.php/topic,1660.0.html
	%nice stellar geometry can be obtained with anglemagnificationbase=0.5;anglemagnificationindex=5;anglecutoffradiusfactor=1;		%nice stellar geometry can be obtained with anglemagnificationbase=0.5;anglemagnificationindex=5;anglecutoffradiusfactor=1;

Zeracles: oops

2009-05-13T23:42:18Z

oops

← Older revision		Revision as of 23:42, 13 May 2009
Line 30:		Line 30:
	plotimage=1;		plotimage=1;

	xposns=xmin+(xmax-~~ymin~~)*rand(n,1);		xposns=xmin+(xmax-xmin)*rand(n,1);
	yposns=ymin+(ymax-ymin)*rand(n,1);		yposns=ymin+(ymax-ymin)*rand(n,1);

Zeracles: fixing tab alignment

2009-03-05T11:43:58Z

fixing tab alignment

← Older revision		Revision as of 11:43, 5 March 2009
Line 44:		Line 44:

	for i=linspace(1,n,n)		for i=linspace(1,n,n)
	i		i

	xposn=xposns(i);		xposn=xposns(i);
	yposn=yposns(i);		yposn=yposns(i);

	radius=((exp(rand(1)))*14-0.01)/2;		radius=((exp(rand(1)))*14-0.01)/2;
	intensity=2*rand(1);		intensity=2*rand(1);

	redness=rand(1);		redness=rand(1);
	greenness=rand(1);		greenness=rand(1);
	blueness=rand(1);		blueness=rand(1);

	spokeprobability=rand(1);		spokeprobability=rand(1);

	spokeswitch=spokeprobability>spokethreshold;		spokeswitch=spokeprobability>spokethreshold;

	spokeangleoffset=pi/4;		spokeangleoffset=pi/4;

	ygaussiancontribution=[];		ygaussiancontribution=[];
Line 67:		Line 67:
	xgaussiancontribution=[];		xgaussiancontribution=[];
	for gridypixel=linspace(1,numypix,numypix)		for gridypixel=linspace(1,numypix,numypix)
	gridyposn=ymin+(gridypixel-1)*(yextent)/(numypix-1);		gridyposn=ymin+(gridypixel-1)*(yextent)/(numypix-1);

	xdiff=xposn-gridxposn;		xdiff=xposn-gridxposn;
	ydiff=yposn-gridyposn;		ydiff=yposn-gridyposn;

	distance=((xdiff)^2+(ydiff)^2)^(1/2);		distance=((xdiff)^2+(ydiff)^2)^(1/2);
	distancefactor=distance/radius;		distancefactor=distance/radius;
	if distancefactor>cutoffradiusfactor		if distancefactor>cutoffradiusfactor
Line 92:		Line 92:
	end		end
	end		end
	xgaussiancontribution=[xgaussiancontribution;littlexgaussiancontribution];		xgaussiancontribution=[xgaussiancontribution;littlexgaussiancontribution];
	end		end
	ygaussiancontribution=[ygaussiancontribution,xgaussiancontribution];		ygaussiancontribution=[ygaussiancontribution,xgaussiancontribution];
Line 98:		Line 98:
	gaussiancontribution=intensity*ygaussiancontribution;		gaussiancontribution=intensity*ygaussiancontribution;

	redmap=redmap+gaussiancontribution*redness;		redmap=redmap+gaussiancontribution*redness;
	greenmap=greenmap+gaussiancontribution*greenness;		greenmap=greenmap+gaussiancontribution*greenness;
	bluemap=bluemap+gaussiancontribution*blueness;		bluemap=bluemap+gaussiancontribution*blueness;

Zeracles at 10:25, 5 March 2009

2009-03-05T10:25:15Z

← Older revision		Revision as of 10:25, 5 March 2009
Line 1:		Line 1:
			See also [http://www.physics.usyd.edu.au/~asmith/files/background.m this quick download]
	%background.m		%background.m
	%by Anthony Smith (Zeracles); astroant@hotmail.com, asmith@physics.usyd.edu.au, http://www.physics.usyd.edu.au/~asmith/, http://wiki.uqm.stack.nl/User:Zeracles		%by Anthony Smith (Zeracles); astroant@hotmail.com, asmith@physics.usyd.edu.au, http://www.physics.usyd.edu.au/~asmith/, http://wiki.uqm.stack.nl/User:Zeracles

Zeracles: stellar background code

2009-03-05T10:21:52Z

stellar background code

New page

%background.m
%by Anthony Smith (Zeracles); astroant@hotmail.com, asmith@physics.usyd.edu.au, http://www.physics.usyd.edu.au/~asmith/, http://wiki.uqm.stack.nl/User:Zeracles
%see http://starcontrol.classicgaming.gamespy.com/forum/index.php?topic=1660.0
%nice stellar geometry can be obtained with anglemagnificationbase=0.5;anglemagnificationindex=5;anglecutoffradiusfactor=1;

n=800;
resolution=1;

xmin=0;
xmax=1600;
ymin=0;
ymax=1200;

xextent=xmax-xmin;
yextent=ymax-ymin;

numxpix=round((xextent)/resolution);
numypix=round((yextent)/resolution);

spokethreshold=0;
spokes=4;
anglemagnificationbase=0.5;
anglemagnificationindex=5;

cutoffradiusfactor=4;
anglecutoffradiusfactor=1;

plotposns=1;
plotimage=1;

xposns=xmin+(xmax-ymin)*rand(n,1);
yposns=ymin+(ymax-ymin)*rand(n,1);

if plotposns==1
figure
box on
plot(xposns,yposns,'k.')
end

redmap=zeros(numypix,numxpix);
greenmap=zeros(numypix,numxpix);
bluemap=zeros(numypix,numxpix);

for i=linspace(1,n,n)
i

xposn=xposns(i);
yposn=yposns(i);

radius=((exp(rand(1)))*14-0.01)/2;
intensity=2*rand(1);

redness=rand(1);
greenness=rand(1);
blueness=rand(1);

spokeprobability=rand(1);

spokeswitch=spokeprobability>spokethreshold;

spokeangleoffset=pi/4;

ygaussiancontribution=[];
for gridxpixel=linspace(1,numxpix,numxpix)
gridxposn=xmin+(gridxpixel-1)*(xextent)/(numxpix-1);
xgaussiancontribution=[];
for gridypixel=linspace(1,numypix,numypix)
gridyposn=ymin+(gridypixel-1)*(yextent)/(numypix-1);

xdiff=xposn-gridxposn;
ydiff=yposn-gridyposn;

distance=((xdiff)^2+(ydiff)^2)^(1/2);
distancefactor=distance/radius;
if distancefactor>cutoffradiusfactor
littlexgaussiancontribution=0;
end
if distancefactor<=cutoffradiusfactor
littlexgaussiancontribution=exp(-1*(distance^2)/(2*radius^2));
if spokeswitch==1
anglesweep=2*pi/spokes;
angle=atan(ydiff/xdiff);
correctedangle=angle-spokeangleoffset;
angledisplacementnumber=round((correctedangle)/(anglesweep));
angledisplacement=abs((correctedangle)-angledisplacementnumber*(anglesweep));
anglemagnification=anglemagnificationbase+(1-anglemagnificationbase)*((1-anglecutoffradiusfactor*distancefactor*(angledisplacement*(anglesweep/2))))^anglemagnificationindex;
if anglemagnification<0
anglemagnification=0;
end
littlexgaussiancontribution=littlexgaussiancontribution*anglemagnification;
end
end
xgaussiancontribution=[xgaussiancontribution;littlexgaussiancontribution];
end
ygaussiancontribution=[ygaussiancontribution,xgaussiancontribution];
end
gaussiancontribution=intensity*ygaussiancontribution;

redmap=redmap+gaussiancontribution*redness;
greenmap=greenmap+gaussiancontribution*greenness;
bluemap=bluemap+gaussiancontribution*blueness;
end

excessmask=redmap>1;
redmap=redmap-excessmask.*(redmap-1);

excessmask=greenmap>1;
greenmap=greenmap-excessmask.*(greenmap-1);

excessmask=bluemap>1;
bluemap=bluemap-excessmask.*(bluemap-1);

backgroundmap=cat(3,redmap,greenmap,bluemap);

if plotimage==1
figure
box on
image(backgroundmap)
end