PART 2: Camera angles and frames

The number of images in any BIF, or frame, is always a multiple of 4. Why ? Well each action a figure is capable of performing (walk/run/die etc) is always represented by exactly 4 images on a frame.

Each figures actions can be represented on the MTW battlefield from any one of 8 angles, for each of the hires or lowres definitions. If you consider scanning a camera all around a figure (0 to 360 degrees) on the battlefield, the 4 images for each action represent 'camera angles' between 0 and 180 degrees (at 36, 72, 108 and 144 degrees - roughly speaking). There are no exact front or rear images. However, the MTW engine 'flips' these 4 images along their vertical axis to represent the 4 camera-angles on the other side (between 180 to 360 degrees), thus allowing 8 camera-angles from 4 images.

The different generic plates may well contain a different number of images - always in multiples of 4. However, the number of images in any generic unit plate will differ; you may see 24, 28, 32 or even more images per frame. Why ? For 2 reasons -

1) some specific units have more possible actions than others
2) these are generic-units, used for multiple specific units

Note that, in most case, a specific-unit does'nt use all the figure images defined (un the BIF's) for a generic-unit.

Each image in a frame (figure, weapon or shield) is a stand-alone image, and can be thought of as being encapsulated in its own invisible 'image rectangle'. These image-rectangles don't overlap and are important to consider when adding or changing unit images. Think of each frame in these BIF's as being comprised of multiple rectangles.

Each action associated with a figure has 4 'camera angle' images associated with it in the BIF's. Considering each image can be flipped on its horizontal axis, this provides a total of 8 camera angles, per action, in the animation).

Each of these 4 camera-angles has 12 frames that serve to represent the movement sequence for the action and camera-angle.

Now lets call any image (what you see if you pause the game and don't move the camera) a figure-image. Thus, any single figure-image is defined by 3 criteria -

1) the action the figure is performing (1 of 6/9 or more)
2) the camera-angle for that action (1 of 4)
3) the position of the figure in a movement-sequence (1 of 12), for the action and camera-angle

There is no other 'real' relationship between any of the images on any single frame, but there is a critical relationship between any image (defined by the image-rectangle) throughout all 12 frames.

The 12 frames in each BIF contain 1 of 12 'image cycles' for each figures image-rectangle (pertaining to a specific action/camera-angle. Each of these 12 image-cycles serve to define the next movement for the figure image, and if shown in frame order comprise a cyclic sequence of movements that (when looped continuously) ensure the smooth animation of any figures action. The image-rectangles for any figure image will be exactly the same across all 12 frames.

(TIP: Open one of the generic-unit BIF's and try using the "Timer(Go)" option in the Shogun 2.1 BIF editor - you'll see the relationship between all 12 frames very clearly)

Note that whilst there is no 'real' relationship (in animation terms) between any of the images on any one single frame, there is a critical relationship between any figure image (defined by the image-rectangle) throughout all 12 frames that comprise that figure images image-cycle.


Why are some of the images in the frames displayed horizontally instead of vertically ? Purely to get all required images within the confines of the high res and low res BIF frames, and within non-overlapping image-rectangles. The orientation of any image in the BIF's does'nt matter as the x/y coordinates of any image-rectangle will serve to inform the MTW engine whether or not re-orientation is required before use (think about it!).