D3DXTRANSITION_TYPE enumeration
Defines the transition style between values of a mesh animation.
Syntax
typedef enum D3DXTRANSITION_TYPE {
D3DXTRANSITION_LINEAR = 0x000,
D3DXTRANSITION_EASEINEASEOUT = 0x001,
D3DXTRANSITION_FORCE_DWORD = 0x7fffffff
} D3DXTRANSITION_TYPE, *LPD3DXTRANSITION_TYPE;
Constants
-
D3DXTRANSITION_LINEAR
-
Linear transition between values.
-
D3DXTRANSITION_EASEINEASEOUT
-
Ease-in, ease-out spline transition between values.
-
D3DXTRANSITION_FORCE_DWORD
-
Forces this enumeration to compile to 32 bits in size. Without this value, some compilers would allow this enumeration to compile to a size other than 32 bits. This value is not used.
Remarks
The calculation for the ramp from ease in to ease out is calculated as follows:
- Q(t) = 2(x - y)t³ + 3(y - x)t² + x
where the ramp is a function Q(t) with the following properties:
- Q(t) is a cubic spline.
- Q(t) interpolates between x and y as t ranges from 0 to 1.
- Q(t) is horizontal when t = 0 and t = 1.
Mathematically, this translates into:
- Q(t) = At³ + Bt² + Ct + D (and therefore, Q'(t) = 3At² + 2Bt + C)
2a) Q(0) = x
2b) Q(1) = y
3a) Q'(0) = 0
3b) Q'(1) = 0
Solving for A, B, C, D:
- D = x (from 2a)
C = 0 (from 3a)
3A + 2B = 0 (from 3b)
A + B = y - x (from 2b and D = x)
Therefore:
- A = 2(x - y), B = 3(y - x), C = 0, D = x
Requirements
| Requirement | Value |
|---|---|
| Header |
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See also