Pixel Collision - GameCreators Forum

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Madscientist

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Location: Between a rock and a hard place

Posted: 4th Aug 2010 16:02 Edited at: 4th Aug 2010 16:05

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Hi, I'm working on pixel collision and I do this by hiding all other sprites other than the ones that I'm checking. Then I used the point command to return if any pixel values changed on the boarder of my sprite. However the point command isn't returning any other color other than black. Does the point command even work on sprites or will I have to use the get image command and then check.

Hears my collision function.
The sprite collisionblank is used to cover up all other sprites.

Function PixelCollision(spr1,spr2)
	col$=""
	cls
	sprite Spr.CollisionBlank,0,0,Img.CollisionBlank	
	show sprite Spr.CollisionBlank
	
	set sprite priority spr2,3	
	set sprite priority spr1,2
	set sprite priority Spr.CollisionBlank,1
	
	if sprite visible(spr1)=0
		show sprite spr1
		v1=1
	endif
	
	if sprite visible(spr2)=0
		show sprite spr2
		v2=1
	endif

PointB=rgb(255,0,255)
	
	PointTR=point(sprite x(spr1)+1,sprite y(spr1)-1)
	PointTL=point(sprite x(spr1)+sprite width(spr1)-1,sprite y(spr1)-1)
	
	PointBR=point(sprite x(spr1)+1,sprite y(spr1)+sprite height(spr1)+1)
	PointBL=point(sprite x(spr1)+sprite width(spr1)-1,sprite y(spr1)+sprite height(spr1)+1)
	
	PointLT=point(sprite x(spr1)-1,sprite y(spr1)+1)
	PointLB=point(sprite x(spr1)-1,sprite y(spr1)+sprite height(spr1)-1)

PointRT=point(sprite x(spr1)+sprite width(spr1)+1,sprite y(spr1)+1)
	PointRB=point(sprite x(spr1)+sprite width(spr1)+1,sprite y(spr1)+sprite height(spr1)-1)	
	
	if PointTR<>PointB and PointTL<>PointB then Col$=Col$+"TOP"
	if PointBR<>PointB and PointBL<>PointB then Col$=Col$+"BOT"
	if PointLT<>PointB and PointLB<>PointB then Col$=Col$+"Lef"
	if PointRT<>PointB and PointRB<>PointB then Col$=Col$+"RIG"
		
	`red=rgbr(PointTR)
	`green=rgbg(PointTR)
	`blue=rgbb(PointTR)
	
	`sync 
	`wait key	
	
	ink Rgb(255,255,255),Rgb(0,0,0)

hide sprite Spr.CollisionBlank
	set sprite priority spr1,0
	set sprite priority spr2,0
	
	if v1=1 then hide sprite spr1
	if v2=1 then hide sprite spr2		
Endfunction col$

+ Code Snippet

Function PixelCollision(spr1,spr2)
	col$=""
	cls
	sprite Spr.CollisionBlank,0,0,Img.CollisionBlank	
	show sprite Spr.CollisionBlank
	
	set sprite priority spr2,3	
	set sprite priority spr1,2
	set sprite priority Spr.CollisionBlank,1
	
	if sprite visible(spr1)=0
		show sprite spr1
		v1=1
	endif
	
	if sprite visible(spr2)=0
		show sprite spr2
		v2=1
	endif	

	
	PointB=rgb(255,0,255)
	
	PointTR=point(sprite x(spr1)+1,sprite y(spr1)-1)
	PointTL=point(sprite x(spr1)+sprite width(spr1)-1,sprite y(spr1)-1)
	
	PointBR=point(sprite x(spr1)+1,sprite y(spr1)+sprite height(spr1)+1)
	PointBL=point(sprite x(spr1)+sprite width(spr1)-1,sprite y(spr1)+sprite height(spr1)+1)
	
	PointLT=point(sprite x(spr1)-1,sprite y(spr1)+1)
	PointLB=point(sprite x(spr1)-1,sprite y(spr1)+sprite height(spr1)-1)

	PointRT=point(sprite x(spr1)+sprite width(spr1)+1,sprite y(spr1)+1)
	PointRB=point(sprite x(spr1)+sprite width(spr1)+1,sprite y(spr1)+sprite height(spr1)-1)	
	
	if PointTR<>PointB and PointTL<>PointB then Col$=Col$+"TOP"
	if PointBR<>PointB and PointBL<>PointB then Col$=Col$+"BOT"
	if PointLT<>PointB and PointLB<>PointB then Col$=Col$+"Lef"
	if PointRT<>PointB and PointRB<>PointB then Col$=Col$+"RIG"
		
	`red=rgbr(PointTR)
	`green=rgbg(PointTR)
	`blue=rgbb(PointTR)
	
	`sync 
	`wait key	
	
	ink Rgb(255,255,255),Rgb(0,0,0)

	hide sprite Spr.CollisionBlank
	set sprite priority spr1,0
	set sprite priority spr2,0
	
	if v1=1 then hide sprite spr1
	if v2=1 then hide sprite spr2		
Endfunction col$

If it hasn't exploded yet, I haven't touched it.

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Diggsey

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Posted: 4th Aug 2010 16:06

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That won't work because sprites don't update as you hide/show them, they only update in the 'sync', so hiding and then showing a sprite will have no affect on the pixels in the backbuffer.

Also, point is very slow so don't bother using it.

[b]

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Madscientist

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Posted: 4th Aug 2010 16:10 Edited at: 6th Aug 2010 18:11

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Oh darn. I was basing that collision off something I wrote in C++. Because in C++ using SDL library doesn't need the images to be rendered to check pixel color.
Anyways, how could I get pixel collision fast without using any plugins?

EDIT:
Well I decided to use memblocks and being that I've never used them before, I have a good understanding of them. However my code doesn't detect colors in the image which is quite odd.

Function PixelCollision(spr1,spr2,spr2Img)
	col$=""

Make memblock from image 1,Spr2Img	
	memWidth=Sprite Width(spr2)
	memHeight=Sprite Height(spr2)
	memSize=Get memblock size(1)

Col$=GetPixels(spr1,spr2,memSize,MemWidth)

delete memblock 1
Endfunction col$

Function GetPixels(spr1,spr2,memSize,MemWidth)
	col$=""
	
	Xpos=sprite x(spr1)
	Ypos=sprite y(spr1)
	Width=Sprite width(spr1)
	Height=Sprite height(spr1)
	
	dim PointLoc(2,4,3)
	
	Pos=(3+Xpos+1+(Ypos-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,1,1)=memblock byte(1,Pos)
		PointLoc(1,1,2)=memblock byte(1,Pos+1)
		PointLoc(1,1,3)=memblock byte(1,Pos+2)
		text 0,0,"Pos: "+str$(Xpos+1)+", "+str$(Ypos-1)+" ->"+str$(Pos)
		text 0,10,"Blue: "+str$(PointLoc(1,1,1))
		text 0,20,"Green: "+str$(PointLoc(1,1,2))
		text 0,30,"Red: "+str$(PointLoc(1,1,3))		
	endif
	
	Pos=((3+Xpos+Width-1)+(Ypos-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,1,1)=memblock byte(1,Pos)
		PointLoc(2,1,2)=memblock byte(1,Pos+1)
		PointLoc(2,1,3)=memblock byte(1,Pos+2)
	endif
		
	Pos=(3+Xpos+1+(Ypos+Height+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,4,1)=memblock byte(1,Pos)
		PointLoc(1,4,2)=memblock byte(1,Pos+1)
		PointLoc(1,4,3)=memblock byte(1,Pos+2)	
	endif
	
	Pos=(3+Xpos+Width-1+(Ypos+Height+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,4,1)=memblock byte(1,Pos)
		PointLoc(2,4,2)=memblock byte(1,Pos+1)
		PointLoc(2,4,3)=memblock byte(1,Pos+2)
	endif

Pos=(3+Xpos-1+(Ypos+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,2,1)=memblock byte(1,Pos)
		PointLoc(1,2,2)=memblock byte(1,Pos+1)
		PointLoc(1,2,3)=memblock byte(1,Pos+2)
	endif
		
	Pos=(3+Xpos-1+(Ypos+Height-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,3,1)=memblock byte(1,Pos)
		PointLoc(1,3,2)=memblock byte(1,Pos+1)
		PointLoc(1,3,3)=memblock byte(1,Pos+2)
	endif
	
	Pos=(3+Xpos+Width+1+(Ypos+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,2,1)=memblock byte(1,Pos)
		PointLoc(2,2,2)=memblock byte(1,Pos+1)
		PointLoc(2,2,3)=memblock byte(1,Pos+2)
	endif
	
	Pos=(3+Xpos+Width+1+(Ypos+Height-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,3,1)=memblock byte(1,Pos)
		PointLoc(2,3,2)=memblock byte(1,Pos+1)
		PointLoc(2,3,3)=memblock byte(1,Pos+2)
	endif
	
	local black as byte
	Bground=0
	
	black=3
	x=1:y=1	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"TopL"

black=3
	x=2:y=1	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"TopR"
	
	black=3
	x=1:y=4	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"BotL"
	
	black=3
	x=2:y=4	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"BotR"
	
	black=3
	x=1:y=2	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"LefT"

black=3
	x=1:y=3	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"LefB"

black=3
	x=2:y=2	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"RigT"
		
	black=3
	x=2:y=3	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"RigB"	
Endfunction col$

+ Code Snippet

Function PixelCollision(spr1,spr2,spr2Img)
	col$=""

	Make memblock from image 1,Spr2Img	
	memWidth=Sprite Width(spr2)
	memHeight=Sprite Height(spr2)
	memSize=Get memblock size(1)

	Col$=GetPixels(spr1,spr2,memSize,MemWidth)

	delete memblock 1
Endfunction col$

Function GetPixels(spr1,spr2,memSize,MemWidth)
	col$=""
	
	Xpos=sprite x(spr1)
	Ypos=sprite y(spr1)
	Width=Sprite width(spr1)
	Height=Sprite height(spr1)
	
	dim PointLoc(2,4,3)
	
	Pos=(3+Xpos+1+(Ypos-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,1,1)=memblock byte(1,Pos)
		PointLoc(1,1,2)=memblock byte(1,Pos+1)
		PointLoc(1,1,3)=memblock byte(1,Pos+2)
		text 0,0,"Pos: "+str$(Xpos+1)+", "+str$(Ypos-1)+" ->"+str$(Pos)
		text 0,10,"Blue: "+str$(PointLoc(1,1,1))
		text 0,20,"Green: "+str$(PointLoc(1,1,2))
		text 0,30,"Red: "+str$(PointLoc(1,1,3))		
	endif
	
	Pos=((3+Xpos+Width-1)+(Ypos-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,1,1)=memblock byte(1,Pos)
		PointLoc(2,1,2)=memblock byte(1,Pos+1)
		PointLoc(2,1,3)=memblock byte(1,Pos+2)
	endif
		
	Pos=(3+Xpos+1+(Ypos+Height+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,4,1)=memblock byte(1,Pos)
		PointLoc(1,4,2)=memblock byte(1,Pos+1)
		PointLoc(1,4,3)=memblock byte(1,Pos+2)	
	endif
	
	Pos=(3+Xpos+Width-1+(Ypos+Height+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,4,1)=memblock byte(1,Pos)
		PointLoc(2,4,2)=memblock byte(1,Pos+1)
		PointLoc(2,4,3)=memblock byte(1,Pos+2)
	endif

	Pos=(3+Xpos-1+(Ypos+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,2,1)=memblock byte(1,Pos)
		PointLoc(1,2,2)=memblock byte(1,Pos+1)
		PointLoc(1,2,3)=memblock byte(1,Pos+2)
	endif
		
	Pos=(3+Xpos-1+(Ypos+Height-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(1,3,1)=memblock byte(1,Pos)
		PointLoc(1,3,2)=memblock byte(1,Pos+1)
		PointLoc(1,3,3)=memblock byte(1,Pos+2)
	endif
	
	Pos=(3+Xpos+Width+1+(Ypos+1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,2,1)=memblock byte(1,Pos)
		PointLoc(2,2,2)=memblock byte(1,Pos+1)
		PointLoc(2,2,3)=memblock byte(1,Pos+2)
	endif
	
	Pos=(3+Xpos+Width+1+(Ypos+Height-1)*memWidth)*4
	if Pos<MemSize and Pos>11
		PointLoc(2,3,1)=memblock byte(1,Pos)
		PointLoc(2,3,2)=memblock byte(1,Pos+1)
		PointLoc(2,3,3)=memblock byte(1,Pos+2)
	endif
	
	local black as byte
	Bground=0
	
	black=3
	x=1:y=1	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"TopL"

	black=3
	x=2:y=1	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"TopR"
	
	black=3
	x=1:y=4	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"BotL"
	
	black=3
	x=2:y=4	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"BotR"
	
	black=3
	x=1:y=2	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"LefT"

	black=3
	x=1:y=3	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"LefB"

	black=3
	x=2:y=2	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"RigT"
		
	black=3
	x=2:y=3	
	for color=1 to 3
		if PointLoc(x,y,color)<>Bground then dec black
	next PointLoc
	if black<3 then Col$=Col$+"RigB"	
Endfunction col$

My computer can render anything no matter the complexity of it in real time.
The memory is enormous. My computer is unique to everyone else’s. What computer do I have?

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Madscientist

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Posted: 6th Aug 2010 18:11

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Anyone?
I really need this fixed for my platformer.

My computer can render anything no matter the complexity of it in real time.
The memory is enormous. My computer is unique to everyone else’s. What computer do I have?

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My Brain

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Diggsey

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Posted: 6th Aug 2010 19:06

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I think there is a pixel perfect collision example in the codebase, and you will certainly find one if you search the forum.

However, if you don't mind the extra setup, line based collision will give you much better performance and flexibility

To do line based collision, you describe each collision shape as a set of points. If you connected up these points in order with lines it would draw the outline of your collision shape.

When you want to test for collision between two objects, you test all of the lines in the first shape against all of the lines in the second. If a line from one intersects a line from the other there is a collision.

All you need to do this is a line intersection algorithm, and I imagine you can find one of those in the codebase.

[b]

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Madscientist

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Posted: 6th Aug 2010 19:20

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Well that won't work for what I'm doing. I have to check for collision for an entire image which my is level and see if my player is touching a wall or floor. The player is constantly inside the level image. So the easiest way would be to check eight points around the player on the level image and see if they equal anything other that the alpha background. Then I will have collision if it isn't alpha detected.

My computer can render anything no matter the complexity of it in real time.
The memory is enormous. My computer is unique to everyone else’s. What computer do I have?

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DVader

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Posted: 9th Aug 2010 05:28 Edited at: 9th Aug 2010 05:30

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Everyone says point is slow but I have used it to reasonable effect in stuff. Trick is not to overuse it. I make a mask of the sprites I want to check against and paste it to a hidden screen. I use that screen to check for my point collisions. You may be able to do something similar with memblocks, but not tried that myself. Oh, and no the point command doesn't work with sprites just images.

http://s6.bitefight.org/c.php?uid=103081

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Grog Grueslayer

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Playing: Green Hell

Posted: 9th Aug 2010 06:23

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Quote: "Everyone says point is slow but I have used it to reasonable effect in stuff. Trick is not to overuse it. "

I feel the same way about POINT.

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DVader

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Posted: 10th Aug 2010 23:58

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Together with a fellow coder, I have been working on a shoot em up editor. To test it I have started recreating a few levels off R-Type. The engine uses point for all of its collision in the main, and works at a very nice speed. So I whole heartedly recommend POINT.

http://s6.bitefight.org/c.php?uid=103081

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Madscientist

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Posted: 15th Aug 2010 22:40

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But point command is a lot slower then using memblocks. See my example:

Rem Project: Dark Basic Pro Project
Rem Created: Thursday, August 05, 2010

Rem ***** Main Source File *****
sync on

Img1=1
Img2=2
xof=100
yof=200

set image colorkey 0,0,255
ink rgb(0,0,255),rgb(0,0,0)
box 0,0,screen width(),screen height()

ink rgb(255,0,0),rgb(0,0,0)
box 20,20,50,50
get image Img1,0,0,screen width(),screen height()
cls

ink rgb(0,255,0),rgb(0,0,0)
box 0,0,50,50
get image Img2,0,0,50,50
cls

make memblock from image 1,Img1
ImgWidth=Memblock dword(1,0)
ImgHeight=Memblock dword(1,4)
ImgSize=get Memblock size(1)

for y=0 to image height(img2)-1
		for x=0 to image width(img2)-1
			Pos=(3+x+xof+(y+yof)*image width(img1))*4
			write memblock byte 1,Pos,0
			write memblock byte 1,Pos+1,255
			write memblock byte 1,Pos+2,0
		next x
	next y
	
delete image img1
delete image img2

Make image from memblock Img1,1	
paste image Img1,0,0

do
cls

paste image Img1,0,0

if mouseclick()=1
	GetColor(Img1)
endif

if mouseclick()=2
	color=point(mousex(),mousey())
	text 0,40,"Point Red: "+str$(rgbr(color))
	text 0,50,"Point Green: "+str$(rgbg(color))	
	text 0,60,"Point Blue: "+str$(rgbb(color))
endif

center text screen width()/2,0,"FPS: "+str$(screen fps())
text 0,80,"Click the left mouse button to see"
text 0,90,"the fps using memblock color detection."
text 0,100,"Click the right mouse button to see"
text 0,110,"the fps using the point command color detection."
sync
loop
end

Function GetColor(Img1)

ImgSize=get Memblock size(1)
	
	pos=(3+mouseX()+(MouseY())*image width(img1))*4
	if Pos<ImgSize and Pos>11
		text 0,0,"Red: "+str$(memblock byte (1,Pos+2))
		text 0,10,"Green: "+str$(memblock byte (1,Pos+1))
		text 0,20,"Blue: "+str$(memblock byte (1,Pos))	
	endif

Endfunction

+ Code Snippet

Rem Project: Dark Basic Pro Project
Rem Created: Thursday, August 05, 2010

Rem ***** Main Source File *****
sync on

Img1=1
Img2=2
xof=100
yof=200

set image colorkey 0,0,255
ink rgb(0,0,255),rgb(0,0,0)
box 0,0,screen width(),screen height()

ink rgb(255,0,0),rgb(0,0,0)
box 20,20,50,50
get image Img1,0,0,screen width(),screen height()
cls

ink rgb(0,255,0),rgb(0,0,0)
box 0,0,50,50
get image Img2,0,0,50,50
cls

make memblock from image 1,Img1
ImgWidth=Memblock dword(1,0)
ImgHeight=Memblock dword(1,4)
ImgSize=get Memblock size(1)

	for y=0 to image height(img2)-1
		for x=0 to image width(img2)-1
			Pos=(3+x+xof+(y+yof)*image width(img1))*4
			write memblock byte 1,Pos,0
			write memblock byte 1,Pos+1,255
			write memblock byte 1,Pos+2,0
		next x
	next y
	
delete image img1
delete image img2

Make image from memblock Img1,1	
paste image Img1,0,0

do
cls

paste image Img1,0,0

if mouseclick()=1
	GetColor(Img1)
endif

if mouseclick()=2
	color=point(mousex(),mousey())
	text 0,40,"Point Red: "+str$(rgbr(color))
	text 0,50,"Point Green: "+str$(rgbg(color))	
	text 0,60,"Point Blue: "+str$(rgbb(color))
endif

center text screen width()/2,0,"FPS: "+str$(screen fps())
text 0,80,"Click the left mouse button to see"
text 0,90,"the fps using memblock color detection."
text 0,100,"Click the right mouse button to see"
text 0,110,"the fps using the point command color detection."
sync
loop
end

Function GetColor(Img1)

	ImgSize=get Memblock size(1)
	
	pos=(3+mouseX()+(MouseY())*image width(img1))*4
	if Pos<ImgSize and Pos>11
		text 0,0,"Red: "+str$(memblock byte (1,Pos+2))
		text 0,10,"Green: "+str$(memblock byte (1,Pos+1))
		text 0,20,"Blue: "+str$(memblock byte (1,Pos))	
	endif

Endfunction

My computer can render anything no matter the complexity of it in real time.
The memory is enormous. My computer is unique to everyone else’s. What computer do I have?

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My Brain

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Grog Grueslayer

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Posted: 15th Aug 2010 22:54

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Yeah your right. You've converted me with your excellent example.

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DVader

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Posted: 17th Aug 2010 03:22

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Ok, lol that is faster, but to some may seem complicated. You are calling point every loop which is exactly what I said to avoid lol. For instance.

Rem Project: Dark Basic Pro Project
Rem Created: Tuesday, August 17, 2010

Rem ***** Main Source File *****
Rem Project: Dark Basic Pro Project
Rem Created: Thursday, August 05, 2010

Rem ***** Main Source File *****
sync on

Img1=1
Img2=2
xof=100
yof=200

set image colorkey 0,0,255
ink rgb(0,0,255),rgb(0,0,0)
box 0,0,screen width(),screen height()

ink rgb(255,0,0),rgb(0,0,0)
box 20,20,50,50
get image Img1,0,0,screen width(),screen height()
cls

ink rgb(0,255,0),rgb(0,0,0)
box 0,0,50,50
get image Img2,0,0,50,50
cls

make memblock from image 1,Img1
ImgWidth=Memblock dword(1,0)
ImgHeight=Memblock dword(1,4)
ImgSize=get Memblock size(1)

for y=0 to image height(img2)-1
        for x=0 to image width(img2)-1
            Pos=(3+x+xof+(y+yof)*image width(img1))*4
            write memblock byte 1,Pos,0
            write memblock byte 1,Pos+1,255
            write memblock byte 1,Pos+2,0
        next x
    next y
    
delete image img1
delete image img2

Make image from memblock Img1,1    
paste image Img1,0,0

do
cls

paste image Img1,0,0

if mouseclick()=1
    GetColor(Img1)
endif

if mouseclick()=2 and rep=0
    rep=1
    color=point(mousex(),mousey())
 endif
if rep=1
    text 0,40,"Point Red: "+str$(rgbr(color)) 
    text 0,50,"Point Green: "+str$(rgbg(color))    
    text 0,60,"Point Blue: "+str$(rgbb(color))
endif
if mouseclick()=0
    rep=0
ENDIF
center text screen width()/2,0,"FPS: "+str$(screen fps())
text 0,80,"Click the left mouse button to see"
text 0,90,"the fps using memblock color detection."
text 0,100,"Click the right mouse button to see"
text 0,110,"the fps using the point command color detection."
sync
loop
end

Function GetColor(Img1)

ImgSize=get Memblock size(1)
    
    pos=(3+mouseX()+(MouseY())*image width(img1))*4
    if Pos<ImgSize and Pos>11
        text 0,0,"Red: "+str$(memblock byte (1,Pos+2))
        text 0,10,"Green: "+str$(memblock byte (1,Pos+1))
        text 0,20,"Blue: "+str$(memblock byte (1,Pos))    
    endif

Endfunction

+ Code Snippet

Rem Project: Dark Basic Pro Project
Rem Created: Tuesday, August 17, 2010

Rem ***** Main Source File *****
Rem Project: Dark Basic Pro Project
Rem Created: Thursday, August 05, 2010

Rem ***** Main Source File *****
sync on

Img1=1
Img2=2
xof=100
yof=200

set image colorkey 0,0,255
ink rgb(0,0,255),rgb(0,0,0)
box 0,0,screen width(),screen height()

ink rgb(255,0,0),rgb(0,0,0)
box 20,20,50,50
get image Img1,0,0,screen width(),screen height()
cls

ink rgb(0,255,0),rgb(0,0,0)
box 0,0,50,50
get image Img2,0,0,50,50
cls

make memblock from image 1,Img1
ImgWidth=Memblock dword(1,0)
ImgHeight=Memblock dword(1,4)
ImgSize=get Memblock size(1)

    for y=0 to image height(img2)-1
        for x=0 to image width(img2)-1
            Pos=(3+x+xof+(y+yof)*image width(img1))*4
            write memblock byte 1,Pos,0
            write memblock byte 1,Pos+1,255
            write memblock byte 1,Pos+2,0
        next x
    next y
    
delete image img1
delete image img2

Make image from memblock Img1,1    
paste image Img1,0,0

do
cls

paste image Img1,0,0

if mouseclick()=1
    GetColor(Img1)
endif

if mouseclick()=2 and rep=0
    rep=1
    color=point(mousex(),mousey())
 endif
if rep=1
    text 0,40,"Point Red: "+str$(rgbr(color)) 
    text 0,50,"Point Green: "+str$(rgbg(color))    
    text 0,60,"Point Blue: "+str$(rgbb(color))
endif
if mouseclick()=0
    rep=0
ENDIF
center text screen width()/2,0,"FPS: "+str$(screen fps())
text 0,80,"Click the left mouse button to see"
text 0,90,"the fps using memblock color detection."
text 0,100,"Click the right mouse button to see"
text 0,110,"the fps using the point command color detection."
sync
loop
end

Function GetColor(Img1)

    ImgSize=get Memblock size(1)
    
    pos=(3+mouseX()+(MouseY())*image width(img1))*4
    if Pos<ImgSize and Pos>11
        text 0,0,"Red: "+str$(memblock byte (1,Pos+2))
        text 0,10,"Green: "+str$(memblock byte (1,Pos+1))
        text 0,20,"Blue: "+str$(memblock byte (1,Pos))    
    endif

Endfunction

Modifying your code so that it checks when you click and only when you click, makes the code pretty much the same as using memblocks. Dependant on what you need the collision for, it is perfectly acceptable to use the point command. But I do see that the memblock technique is ultimately the fastest method

http://s6.bitefight.org/c.php?uid=103081

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Madscientist

16

Years of Service

User Offline

Joined: 23rd Aug 2009

Location: Between a rock and a hard place

Posted: 17th Aug 2010 05:39

Link

Well I finally got memblocks to work for my collision but thanks for the help anyway.
The reason it wasn't working was because I forgot to set the transparecy flag for paste image to 1 and that was the image collision was checked against.

My computer can render anything no matter the complexity of it in real time.
The memory is enormous. My computer is unique to everyone else’s. What computer do I have?

+ Code Snippet

My Brain

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Phaelax

DBPro Master

23

Years of Service

User Offline

Joined: 16th Apr 2003

Location: Metropia

Posted: 18th Aug 2010 04:39

Link

There's an alternative to using point:

+ Code Snippet

start = get pixels pointer()
repeat_number = get pixels pitch()
bits_per_pixel = bitmap depth(num)/8
pointer = start + y*repeat_number + x*bits_per_pixel
color_value = *pointer

Might have the pointer symbol wrong, I can't remember for sure. No clue if it's any faster than using the point command.

"Any sufficiently advanced technology is indistinguishable from magic" ~ Arthur C. Clarke

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DarkBASIC Professional Discussion / Pixel Collision