Commit Graph

3 Commits

Author SHA1 Message Date
Benoit Bolsee
149d231d69 VideoTexture: new ImageMirror class for easy mirror (and portal) creation
The new class VideoTexture.ImageMirror() is available to perform
automatic mirror rendering.

Constructor:

  VideoTexture.ImageMirror(scene,observer,mirror,material)
    scene:    reference to the scene that will be rendered.
              Both observer and mirror must be part of that scene.
    observer: reference to a game object used as view point for
              mirror rendering: the scene will be rendered through
              the mirror as if the active camera was at the observer 
              location. Usually the observer is the active camera
              but you can use any game obejct.
    mirror:   reference to the mesh object holding the mirror.
    material: material ID of the mirror texture as returned by 
              VideoTexture.materialID(). The mirror is formed by 
              the polygons mapped to that material.

There are no specific methods or attributes. ImageMirror inherits 
all methods and attributes from ImageRender. You must refresh the
parent VideoTexture.Texture object regularly to update the mirror 
rendering.

Guidelines on how to create a working mirror:
- Use a texture that is specific to the mirror so that the mirror 
  rendering only appears on the mirror.
- The mirror must be planar; the algorithm works well only for planar
  or quasi planar mirror. For spherical mirror, you will get better
  results with ImageRender and a camera at the center of the mirror. 
  ImageMirror automatically computes the mirror orientation and 
  position. The mirror doesn't need to be rectangular, it can be 
  circular or take any form provided it is planar.
- The mirror up direction must be along the Z axis in local mesh
  coordinates. If the mirror is not vertical, ImageMirror will 
  compute the up direction as being the projection of the Z axis
  on the mirror plane.
- UV mapping must be set right to get correct mirror rendering:
  - make a planar projection of the mirror polygons (Unwrap or projection from view)
  - eventually rotate the projection so that UV up direction corresponds to the mesh Z axis
  - scale the projection so that the extreme points touch the border of the texture
  - flip the UV projection horizontally (scale -1 on X axis). This is needed
    because the mirror texture is rendered from the back of the mirror and
    thus is reversed from the view point of the observer. Horizontal flip 
    in the UV map restores the correct orientation.

Besides these simple rules, the mirror rendering is completely automatic. 
In particular, you don't need to allocate a camera for the rendering, 
ImageMirror creates dynamically a camera for that. The reflection is correct
even on large angles. The mirror can be a dynamic and moving object, the 
algorithm always computes the correct camera position based on observer 
relative position. You don't have to worry about mirror position in the scene: 
the algorithm automatically computes the camera frustum so that any object 
behind the mirror is not rendered.

Warnings:
- observer and mirror are references to game objects. ImageMirror keeps
  a pointer to them but does not increment the reference count. You must ensure 
  that these game objects are not deleted as long as you refresh() the ImageMirror
  object. You must release the ImageMirror object before you delete the game
  objects. To release the ImageMirror object (normally stored in GameLogic),
  just assign it to None.
- Mirror rendering is automatically skipped when the observer is behind the mirror
  but it is not disabled when the mirror is out of sight of the observer.
  You should only refresh the mirror when you know that the observer is likely to see it.
  For example, no need to refresh a car inner mirror when the player is not in the car.

Example:

  contr = GameLogic.getCurrentController()
  # object holding the mirror
  mirror = contr.getOwner()
  scene = GameLogic.getCurrentScene()
  # observer will be the active camere
  camera = scene.getObjectList()['OBCamera']
  matID = VideoTexture.materialID(mirror, 'IMmirror.png')
  GameLogic.mirror = VideoTexture.Texture(mirror, matID)
  GameLogic.mirror.source = VideoTexture.ImageMirror(scene,camera,mirror,matID)
  # to render the mirror, just call GameLogic.mirror.refresh(True) on each frame.

You can download a demo game (with a video file) here:

  http://home.scarlet.be/~tsi46445/blender/VideoTextureDemo.zip

For those who have already downloaded the demo, you can just update the blend file:

  http://home.scarlet.be/~tsi46445/blender/MirrorTextureDemo.blend
2008-12-04 16:07:46 +00:00
Benoit Bolsee
54401d36aa BGE Video Texture: fix constant initializer problem with Exception description. Uniformized the line ending. 2008-11-01 12:48:46 +00:00
Benoit Bolsee
a8c4eef326 VideoTexture module.
The only compilation system that works for sure is the MSVC project files. I've tried my best to
update the other compilation system but I count on the community to check and fix them.
 
This is Zdeno Miklas video texture plugin ported to trunk. 
The original plugin API is maintained (can be found here http://home.scarlet.be/~tsi46445/blender/blendVideoTex.html)
EXCEPT for the following:

The module name is changed to VideoTexture (instead of blendVideoTex).

A new (and only) video source is now available: VideoFFmpeg()
You must pass 1 to 4 arguments when you create it (you can use named arguments):

VideoFFmpeg(file) : play a video file
VideoFFmpeg(file, capture, rate, width, height) : start a live video capture

file:
In the first form, file is a video file name, relative to startup directory.
It can also be a URL, FFmpeg will happily stream a video from a network source.
In the second form, file is empty or is a hint for the format of the video capture.
In Windows, file is ignored and should be empty or not specified.
In Linux, ffmpeg supports two types of device: VideoForLinux and DV1394. 
The user specifies the type of device with the file parameter:
   [<device_type>][:<standard>]
   <device_type> : 'v4l' for VideoForLinux, 'dv1394' for DV1394; default to 'v4l'
   <standard>    : 'pal', 'secam' or 'ntsc', default to 'ntsc'
The driver name is constructed automatically from the device types:
   v4l   : /dev/video<capture>
   dv1394: /dev/dv1394/<capture>
If you have different driver name, you can specify the driver name explicitely 
instead of device type. Examples of valid file parameter:
   /dev/v4l/video0:pal
   /dev/ieee1394/1:ntsc
   dv1394:ntsc
   v4l:pal
   :secam

capture: 
Defines the index number of the capture source, starting from 0. The first capture device is always 0.
The VideoTexutre modules knows that you want to start a live video capture when you set this parameter to a number >= 0. Setting this parameter < 0 indicates a video file playback. Default value is -1.

rate: 
the capture frame rate, by default 25 frames/sec

width: 
height: 
Width and height of the video capture in pixel, default value 0.
In Windows you must specify these values and they must fit with the capture device capability. 
For example, if you have a webcam that can capture at 160x120, 320x240 or 640x480, 
you must specify one of these couple of values or the opening of the video source will fail.
In Linux, default values are provided by the VideoForLinux driver if you don't specify width and height.

Simple example
**************
1. Texture definition script:

import VideoTexture

contr = GameLogic.getCurrentController()
obj = contr.getOwner()
if not hasattr(GameLogic, 'video'):
	matID = VideoTexture.materialID(obj, 'MAVideoMat')
	GameLogic.video = VideoTexture.Texture(obj, matID)
	GameLogic.vidSrc = VideoTexture.VideoFFmpeg('trailer_400p.ogg')
	# Streaming is also possible:
	#GameLogic.vidSrc = VideoTexture.VideoFFmpeg('http://10.32.1.10/trailer_400p.ogg')
	GameLogic.vidSrc.repeat = -1
	# If the video dimensions are not a power of 2, scaling must be done before
	# sending the texture to the GPU. This is done by default with gluScaleImage()
	# but you can also use a faster, but less precise, scaling by setting scale
	# to True. Best approach is to convert the video offline and set the dimensions right.
	GameLogic.vidSrc.scale = True
	# FFmpeg always delivers the video image upside down, so flipping is enabled automatically
	#GameLogic.vidSrc.flip = True

if contr.getSensors()[0].isPositive():
	GameLogic.video.source = GameLogic.vidSrc
	GameLogic.vidSrc.play()


2. Texture refresh script:

obj = GameLogic.getCurrentController().getOwner()
if hasattr(GameLogic, 'video') != 0:
  GameLogic.video.refresh(True)

You can download this demo here: 
http://home.scarlet.be/~tsi46445/blender/VideoTextureDemo.blend
http://home.scarlet.be/~tsi46445/blender/trailer_400p.ogg
2008-10-31 22:35:52 +00:00