Post by thread:[PIC]: LCD Graphics Routines

Having looked at Steve Lawther's web page on the T6963 LCD controller PIC code I wondered if there was a web link anyone can give me that explains how to generate graphics procedures. (Thanks to Steve, I'm about to try it out on a 240*64 pixel Varitronix display) Things like drawing circles, rotating line vectors say for creating a virtual speedometer or rev counter? With all the games code out there I'm sure there must be a concise web location with mathematical methods/routines for doing quite complex graphic front ends. Oh... I realise Steve had some graphics routines in his PIC code but I'm after maybe a more generic source of material explaining the most efficient way to produce various graphical shapes and or vector/dot drawings Anyone help? Pete

part 0 1002 bytes -----Original Message----- From: Peter Betts [spam_OUTpeter.bettsTakeThisOuTNOKIA.COM] Sent: 07 June 2000 10:49 To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU Subject: [PIC]: LCD Graphics Routines Having looked at Steve Lawther's web page on the T6963 LCD controller PIC code I wondered if there was a web link anyone can give me that explains how to generate graphics procedures. (Thanks to Steve, I'm about to try it out on a 240*64 pixel Varitronix display) Things like drawing circles, rotating line vectors say for creating a virtual speedometer or rev counter? With all the games code out there I'm sure there must be a concise web location with mathematical methods/routines for doing quite complex graphic front ends. Oh... I realise Steve had some graphics routines in his PIC code but I'm after maybe a more generic source of material explaining the most efficient way to produce various graphical shapes and or vector/dot drawings Anyone help? Pete Attachment converted: creation:t6963.zip (pZIP/pZIP) (0001626C)

> Please let me know is you find anything. I've searched the web but can't find a concise list of equations or methods of 2D or even 3D drawings. Everything I find seems to relate to some form of software CAD package which is no good. > Are you using the fuel injection pulse to measure > RPM and fuel? Yes. I want to measure the duty cycle of the injector pulse and display this as either a bar (like a VU meter) or a rotating dial like a rev counter. Oh and also have the same for a rev counter. I could go back to basics and translate the duty cycle into a rotation angle and do some trigonometry but I don't want to do it the long winded way if there are easier ways of doing this kind of thing. Pete

{Quote hidden}> > > Please let me know is you find anything. > I've searched the web but can't find a concise list of equations or methods > of 2D or even 3D drawings. Everything I find seems to relate to some form of > software CAD package which is no good. > > > > Are you using the fuel injection pulse to measure > > RPM and fuel? > > Yes. I want to measure the duty cycle of the injector pulse and display this > as either a bar (like a VU meter) or a rotating dial like a rev counter. > Oh and also have the same for a rev counter. > > I could go back to basics and translate the duty cycle into a rotation angle > and do some trigonometry but I don't want to do it the long winded way if > there are easier ways of doing this kind of thing. > > Pete > The simplest way to do this (also turns out to be the most efficent in terms of processing power) is to have a list of all the points on your gage that will be effected by whatever it is you are trying to messure. Say you have a range between 0 and 99, divide your list into 100 sections. Section 0 contains all the points that will be in the on state at value 0, section 1 contains all the points that will be in the on state at value 0 and 1, section 2 contains all the points that will be in th on state at value 0 and 1 and 2. Now when your value moves from 0 to 5 you set all the pixels on that belong to section 5 when the value moves down (from 5) to 3 you set all the pixels off that belong to sections 5 and not section 3. when the value again goes up to 6 (from 3) you set all the pixels on that belong to section 6 and not section 3. If the range is 0 to 99 but the steps between each division are too big, multiply the range so that the steps become smaller (keep 100 divisions just increase the resolution). If the list of pixels is kept ordered (section 0, section 1, section 2 etc) then you can superimpose each section onto a common list and have pointers to the sections in the common list. With a little creative pointer aritmetic you end up with a list of points that must be turned on or off and an incredibly tight and efficient loop. This method allows you to have both a needle and flood fill gage with superimposed divisions, numbers etc. e.g. | | <- section 4 --| GOING UP | | | | | |-- All pixels that must | | <- section 3 | be turned on when value | | | moves from 2 to 4 | | | | | <- section 2 --| | | | | | | <- section 1 | | | | | | <- section 0 ^ | common list of pixels | | <- section 4 --| GOING DOWN | | | | | |-- All pixels that must | | <- section 3 --| be turned off when value | | moves from 4 to 3 | | | | <- section 2 | | | | | | <- section 1 | | | | | | <- section 0 ^ | common list of pixels This isn't taken from a game but a commercial product called XEBOT. This is the internal mechanism it uses to update user defined gages. The user describes a gage using two curves and XEBOT does the rest. Sorry XEBOT wont run on a PIC. Sergio Masci Sentient Real Time Systems Ltd http://www.xcprod.com/titan