Archive for February, 2009

Updated Functions

Posted by Anthony_B on February 27, 2009 at 22:00

Thanks to a certain mathematically adept someone, I’ve now updated some of the code examples in my last blog entry, namely the function used for wheelset rotation which is now better in terms of performance and ease of use, and also the code which “plugs” the doors into the bodyside when they’re closed, making the visual effect better as the doors don’t “jump” into position any more. The updated functions are now highlighted in yellow in my 26th February entry…

Animated Exterior Car Objects

Posted by Anthony_B on February 26, 2009 at 22:00

openBVE / X-City South screenshot - see video belowAs most of you will likely know already, » openBVE « now enables developers to use animated exterior car objects. I was pleasantly surprised by all the positive feedback and comments regarding my last video which I uploaded to YouTube (thank you!), but one criticism which was pointed out several times was the disparity between the quality of the scenic visuals, and the rather simplistic objects used to represent the class 323 EMU–the objects were fine for BVE’s passing trains, but less so when you can move the camera up close and look at the details, or lack thereof. I didn’t think it was worth spending much time on this latter aspect until animation could be applied to the exterior car objects, but now this is possible, I’ve been working on some far better 3D models for the class 323. I had hoped to get this task finished sooner, but it’s taken longer than I originally expected unfortunately–the main difficulty was getting the rounded cab looking right, and texturing it correctly. However, I’m now happy with the appearance, and so I present the work-in-progress fully 3D exterior car objects for openBVE and Cross-City South v1.4. Incidentally, as with all my openBVE/BVE objects, these models are entirely hand coded, with no “help” from 3D modelling software.

Currently the objects are rather more complex than I originally intended (so far, the entire three coach EMU contains around 8200 vertices/4900 faces), and there is a performance penalty that comes with using them; on a fairly typical BVE route, framerates should be okay, but when paired with a very highly detailed and intensively animated route such as Cross-City South v1.4, a fast PC will likely be required to enjoy both extensively detailed animated scenery and detailed external car objects with reasonable framerates. What I intend to do, for those of you with slower hardware, is release alternative versions of the exterior car objects with lower polygon counts, and because of the way I’ve created the textures, the end result should still look good despite less complex geometry. Even these lower detail versions will be rather better than the previous objects though. Emoticon Smile So ultimately, if framerates are a problem, you can simply choose either richly detailed scenery, or richly detailed train objects, depending on which is more important to you.

Currently, the models include the following standard animated features:

  • Rotating wheelsets including wheelslip effects (with provision for animated suspension, and bogie rotation should such functionality be possible in future)
  • Bi-parting, sliding plug doors (some issues with door open/close sound synchronisation–see below)
  • Moving window reflections (twin-layered with transparency, to create a parallax effect)

The models also include the following animated features linked to plugin (UKMUt.dll) variables:

  • Windscreen wipers (left/right sweep, plus arc motion; the wipers aren’t perfect–see below)
  • Head and tail lights (both ends of train)
  • Interior lights (on or off via pantograph up/down button)
  • LED destination display with flicker (on or off via pantograph up/down button)
  • Working pantograph (all illuminated features also extinguish when pantograph is lowered)

I’ve also prepared another video to show these features. Please note, the 3D objects aren’t finished yet; some textures need updating, and I’ve yet to add interior fittings. Developers might want to continue reading on, as I’ll explain how some of these animations have been implemented, and share some sample code from the .ANIMATED objects.

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Video: Demonstration of class 323 animated exterior car objects (work-in-progress)

» Link to YouTube page (HD – best quality) «
» Link to YouTube page (High Quality) «

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I also thought you might like to see a high resolution image of Cross-City South v1.4 and the new high detail class 323; in this screenshot, I’m running openBVE fullscreen at a resolution of 1280×1024, with 8x anti-aliasing and 16x anisotropic filtering enabled (on a Radeon HD 2600 Pro graphics card). Bilinear interpolation was enabled in openBVE’s settings, with the Transparency mode set to Sharp. I was getting around 16-19 fps at the time; the framerates in the next version of openBVE will hopefully be a little higher due to performance optimisations where animated object normals are concerned, although this gain may be offset by the addition of more animated scenery objects to the route:


openBVE/Cross-City South v1.4 screenshot--click to enlarge

openBVE / Cross-City South v1.4 plus 323 screenshot–click to enlarge

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Rotating Wheelsets
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openBVE / Class 323 screenshot - please see video above

The first things I tried to animate were the wheelsets. Initially I had difficulty getting this to work as anticipated, and observed unexpected results while using the Speedometer variable, i.e. the resulting wheelset rotation appeared as though it were based upon acceleration rate rather than an actual velocity value (and » Ron « found the same when he first tried to animate wheelsets, it would seem). I usually like to try and figure out solutions to such problems myself, but sadly I’m not the reincarnation of Pierre de Fermat, and as such, my mathematical knowledge was insufficient. Fortunately, a way forward could be found over at the » openBVE Japanese « site, which includes some helpful material covering animated objects and functions. The following function can be used to rotate each wheelset:

RotateXFunction = value + mod [(speedometer * delta), 2.765] / 2.765 * 3.14 * 2

Incidentally, 2.765 is the circumference of the wheel. The above formula works perfectly, but initially I wondered if it was more complicated than it needed to be, so I attempted to find a more simple alternative, and somehow arrived at the following formula, where the value 0.05949986086344 results from (pi / 0.88) / 60, where 0.88 is the diameter of the wheel:

Not goodRotateXFunction = value + speedometer * 0.05949986086344

Initially this seemed to work well, but on closer examination, the end result wasn’t as good as the more complex formula because the rate of rotation varies with the framerate, and I observed no difference in performance between the two anyway.

CorrectUpdate

Thanks to a certain mathematically adept someone, I now have a new formula which is better in terms of performance and ease of use:

CorrectRotateXFunction = value + delta * speedometer / WHEEL_RADIUS_IN_METRES
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Animated Doors
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openBVE / Class 323 screenshot - please see video above

The bi-parting sliding plug doors are comprised of a pair of 3D door objects, which slide forwards and backwards via a translation along the Z axis, with values supplied via the left/rightdoors[i] variables, e.g:

Right door animation (Updated):

[Object]
Position = 0.002, 0, -5.552
States = Class323_Door_2_R_Dark.csv, Class323_Door_2_R.csv
TranslateZFunction = rightdoors[0] + 0.864
TranslateXFunction = min[power[10 * (rightdoors[0] – 0.1), 3] + 1, 1] * 0.05
StateFunction = pluginstate[31]

[Object]
Position = 0.002, 0, -6.417
States = Class323_Door_2a_R_Dark.csv, Class323_Door_2a_R.csv
TranslateZFunction = -rightdoors[0] + 0.864
TranslateXFunction = min[power[10 * (rightdoors[0] – 0.1), 3] + 1, 1] * 0.05
StateFunction = pluginstate[31]

Left door animation:

[Object]
Position = -0.002, 0, -5.552
States = Class323_Door_2_L_Dark.csv, Class323_Door_2_L.csv
TranslateZFunction = leftdoors[0] + 0.864
TranslateXFunction = -min[power[10 * (leftdoors[0] – 0.1), 3] + 1, 1] * 0.05
StateFunction = pluginstate[31]

[Object]
Position = -0.002, 0, -6.417
States = Class323_Door_2a_L_Dark.csv, Class323_Door_2a_L.csv
TranslateZFunction = -leftdoors[0] + 0.864
TranslateXFunction = -min[power[10 * (leftdoors[0] – 0.1), 3] + 1, 1] * 0.05
StateFunction = pluginstate[31]

The StateFunction command is there to switch between illuminated and non-illuminated versions of the door objects, and pluginstate[31] is equivalent to the ats31 subject in the class 323’s panel2.cfg file (when used with Simon Gathercole’s UKMUt.dll), i.e. the Line Light indicator (so the lights appear to go out when the pantograph is lowered). The objects are also translated along the X axis so they “plug” into the bodyside when fully closed. Unfortunately the door open and close sounds aren’t fully synchronised with the door motion; with UK trains, warning beeps are heard before the doors actually start to close, but the beeps are contained within the door closing audio file, and of course the visible doors start to close as soon as the beeping starts. The duration of the door opening motion is also shorter than the duration of the door opening audio files. I haven’t tried having door animation controlled via plugin variables yet; when I have time I’ll look into this further.

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Animated Window Reflections
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openBVE / Class 323 screenshot - please see video above

The window reflections are made from two semi-transparent surfaces, which have texture shifting functions applied, based upon the current speed of the train, e.g:

Window reflection animation:

[Object]
Position = 0, 0, 0
States = ..\Class323_DMSO_1_WindowReflections.csv
TextureShiftXFunction = value + speed * 0.001

[Object]
Position = 0, 0, 0
States = ..\Class323_DMSO_1_WindowReflections_bg.csv
TextureShiftXFunction = value + speed * 0.0001

There’s a foreground reflection texture with transparency, showing near-track bushes, and there’s also a background reflection texture, showing a low resolution version of the backdrop (ground and sky) texture, and this surface’s texture is shifted more slowly than the foreground texture, creating a rather nice parallax effect when the train is in motion. The overall effect looks rather good in my opinion, but of course, if the reflection textures depict a Summer scene, but the train is used on a Winter route with snow, it looks a little silly…

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Interior Illumination
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openBVE / Class 323 screenshot - please see video above

Interior lighting strips, along with interior fittings and additional semi-transparent yellow surfaces to lighten the windows when viewed from outside at night (allowing adequate night-lighting effects while still being able to have daytime window reflections), are displayed when the pantograph is raised, and swapped for non-emissive versions when the pan is lowered, so it’s possible to turn the carriage lights on and off. When the pantograph is lowered, all exterior lights are also state-changed or translated so they appear to extinguish, and won’t illuminate until the pantograph is raised again. This is achieved using if[pluginstate[31] ... ] commands, as demonstrated in the next section.

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Animated Pantograph
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openBVE / Class 323 screenshot - please see video above

The pantograph itself can be visibly raised and lowered, with the head having a Y axis translation applied, and the upper and lower arms having X axis rotation, along with Y and Z axis translation applied. The pantograph animation is conditional upon the state of the value of plugin variable 31, or the ats31 subject in the class 323’s panel2.cfg. The code I’ve written which enables this is as follows (since updated on the 5th July 2009, thanks to a post by michelle herself):

Pantograph animation (updated 5th July 2009):

[Object]
Position = 0, 4.24, 9.071
States = ..\Pantograph_BWHS_Head.csv
TranslateYFunction = if[pluginstate[31] == 0, if[value > -0.97, value – delta * 0.49, -0.97], if[value < 0, value + delta * 0.49, 0]]

[Object]
Position = 0, 4.24, 9.071
States = ..\Pantograph_BWHS_UpperArm.csv
TranslateYFunction = if[pluginstate[31] == 0, if[value > -0.45, value – delta * 0.225, -0.45], if[value < 0, value + delta * 0.225, 0]]
RotateXFunction =     if[pluginstate[31] == 0, if[value > -0.29, value – delta * 0.145, -0.29], if[value < 0, value + delta * 0.145, 0]]
TranslateZFunction = if[pluginstate[31] == 0, if[value < 0.06, value + delta * 0.03, 0.06], if[value > 0, value – delta * 0.03, 0]]

[Object]
Position = 0, 4.24, 9.071
States = ..\Pantograph_BWHS_LowerArm.csv
TranslateYFunction = if[pluginstate[31] == 0, if[value > -0.45, value – delta * 0.225, -0.45], if[value < 0, value + delta * 0.225, 0]]
RotateXFunction = if[pluginstate[31] == 0, if[value < 0.27, value + delta * 0.135, 0.27], if[value > 0, value – delta * 0.135, 0]]
TranslateZFunction = if[pluginstate[31] == 0, if[value < 0.06, value + delta * 0.03, 0.06], if[value > 0, value – delta * 0.03, 0]]

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Animated Wipers and Working Headlights
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openBVE / Class 323 screenshot - please see video above

The windscreen wipers aren’t as good as I’d like them to be yet; when the if[pluginstate[i] ... ] conditions are satisfied and the truevalue formulae are executed, the wipers can jump to a position mid-sweep rather than starting to move from their currently held position. The same problem can happen when switching the wipers off as well, although the way I’ve implemented it, the wipers will stop in whatever position they are in when the wipers are turned off. More work needed here… Each wiper is comprised of two arms, and a wiper blade. The code so far, is as follows:

Wiper animation (code for left wiper only; reverse the signs of each occurrence of ‘power[]’ for the right wiper, excluding the one in the last TranslateYFunction command):

[Object]
States = ..\Class323_DMSO_Wiper_L_1.csv
Position = -0.56, 2.27, 0
RotateZFunction = if[pluginstate[198] > 0, power[1 – abs[cos[time]], 0.5] * 1.3, value]

[Object]
States = ..\Class323_DMSO_Wiper_L_1a.csv
Position = -0.5, 2.27, 0
RotateZFunction = if[pluginstate[198] > 0, power[1 – abs[cos[time]], 0.5] * 1.3, value]

[Object]
States = ..\Class323_DMSO_Wiper_L_1b.csv
Position = -0.55, 2.28, 0
TranslateXFunction = if[pluginstate[198] > 0, -power[1 – abs[cos[time]], 0.5] * 0.73, value]
TranslateYFunction = if[pluginstate[198] > 0, power[sin[time * 2], 2] * 0.13, value]

The last TranslateYFunction command moves the wiper blade up and down at the correct speed, which when combined with the X axis translation, creates the overall effect of an arc movement rather than a simple left-right motion.

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The head (and tail) lights are linked to the proving lights in the cab (the ats20 and ats21 subjects in the class 323’s panel2.cfg). Each headlight configuration has it’s own csv object. The headlights will only be illuminated when the pantograph is also raised (dependent on the state of plugin variable 31, or the ats31 subject in panel2.cfg). When the tail lights at one end of the train are on, they automatically turn off at the other end of the train. For the rear of the train, the headlights can only illuminate if the tail lights are also off. The code which enables all of this is as follows (please note, I’m presenting two alternative ways of implementing the lights on the leading vehicle, the reason why can be found below):

Head and tail lights:

Class323_DMSO_1.animated (lead vehicle) OPTION 1

[Object]
States = ..\null.csv, ..\Class323_Headlights_0.csv, ..\Class323_Headlights_1.csv, ..\Class323_Headlights_2.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
StateFunction = if[pluginstate[31] == 1, pluginstate[20], 0]

[Object]
States = ..\null.csv, ..\Class323_Taillights_1.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
StateFunction = if[pluginstate[31] == 1, pluginstate[21], 0]

Class323_DMSO_1.animated (lead vehicle) OPTION 2

[Object]
States = ..\Class323_Headlights_0.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
TranslateYFunction = if[pluginstate[31] == 1, if[pluginstate[20] == 1, 0, -600], -600]

[Object]
States = ..\Class323_Headlights_1.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
TranslateYFunction = if[pluginstate[31] == 1, if[pluginstate[20] == 2, 0, -600], -600]

[Object]
States = ..\Class323_Headlights_2.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
TranslateYFunction = if[pluginstate[31] == 1, if[pluginstate[20] == 3, 0, -600], -600]

[Object] States = ..\Class323_Taillights_1.csv
Position = 0, 0, 0
RotateYFunction = 3.1416
TranslateYFunction = if[pluginstate[31] == 1, if[pluginstate[21] == 1, 0, -600], -600]

Class323_DMSO_3.animated (rear vehicle)

[Object]
States = ..\null.csv, ..\Class323_Headlights_0.csv, ..\Class323_Headlights_1.csv, ..\Class323_Headlights_2.csv
Position = 0, 0, 0
StateFunction = if[pluginstate[31] == 1, if[pluginstate[21] == 1, pluginstate[20], 0], 0]

[Object]
States = ..\Class323_Taillights_1.csv, ..\null.csv
Position = 0, 0, 0
StateFunction = if[pluginstate[31] == 1, if[pluginstate[31] == 1, pluginstate[21], 0], 1]

In Option 1 above, the lead vehicle’s headlights are changed using StateFunction commands alone. This method works fine, but the first time each state is changed to, you’ll see the object’s texture isn’t loaded until a fraction of a second after the object is displayed, leading to a flash of colour which is a little distracting. Using Option 2 gets around this issue however, because the headlight objects and textures are always loaded upon swtiching to an external view, and are displayed by translating the relevant object along the Y axis instead, conditional upon the value read via the pluginstate[i] variable. As these textures are always loaded in an external view, StateFunction commands alone can be used in the rear vehicle.

Incidentally, the RotateYFunction = 3.1416 lines simply rotate the relevant objects 180° around the Y axis (the value is in radians, rather than degrees).

What I need to do next, is add interior fittings such as seats, luggage racks, LCD TV screens, and so-on. I might make some more progress with the route itself instead though, as to be honest I could do with a break from modelling the minutiae of train objects for a while. Emoticon Smile