View Full Version : Controll the VGA pins output voltage using OpenGL

11-16-2009, 10:54 PM
I have X-Y oscilloscope which draws a point to its screen using the X Y ports. As you guys know that the standard VGA card outputs 0.7 voltage in each of 15 pins.I have a text file with the x,y and intenesisty of car model.

I want to draw the car on the screen of the oscilloscope via the first three pins of the VGA Card as follows:the X value of the point goes to the Red pin. The Y value of the point goes to the Blue pin. Finally, the intensity of the color of the point goes to the Green pin of the VGA.

My problem is how to convert the coordinates of each point of the car to those three pins

Please feel free to ask any questions if you do not understand my idea.

11-17-2009, 12:10 AM
I assume you want the refresh rate of the oscciloscope to be tied to the one of the VGA screen, lets assume 60 hz, as vblank is quite long and may be visible.
The XY oscilloscope will only have 256*256 resolution, limited by number of colors per channel.
So for each point in the test file will have to be rendered as a horizontal line can be long or short, it will depend on the number of points to display per frame, but should fit in horizontal screen width (to avoid hblank). Lets start with less that 1024 points, for a 1280*1024 GL screen, and assume that xy points coordinates are normalised to fit in [0,255] range.
so for each point :
x0,y0,col0 -> draw line 0,1024 : 1024,1024, RGB color is x0,col0,y0
xi,yi,coli -> draw line 0,1024-i : 1024,1024-i, RGB color is xi,coli,yi

Interesting but I fail to see what this have to do with "advanced opengl"...