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Add translate, scale and fix inverse of mat3 used for 2d graphics.

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treeform 2020-11-21 20:09:40 -08:00
parent 210c3fa128
commit 09fac31169
1 changed files with 20 additions and 6 deletions
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26
src/vmath.nim
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@ -599,6 +599,18 @@ func scale*(a: Mat3, v: Vec3): Mat3 =
result[7] = v.z * a[7]
result[8] = v.z * a[8]
func translate*(v: Vec2): Mat3 =
result[0, 0] = 1
result[1, 1] = 1
result[2, 0] = v.x
result[2, 1] = v.y
result[2, 2] = 1
func scale*(v: Vec2): Mat3 =
result[0, 0] = v.x
result[1, 1] = v.y
result[2, 2] = 1
func rotationMat3*(angle: float32): Mat3 =
# Create a matrix from an angle.
let
@ -637,13 +649,15 @@ func inverse*(a: Mat3): Mat3 =
)
let invDet = 1 / determinant
result[0, 0] = (a[1, 1] * a[2, 2] - a[2, 1] * a[1, 2]) * invDet
result[1, 0] = -(a[0, 1] * a[2, 2] - a[0, 2] * a[2, 1]) * invDet
result[2, 0] = (a[0, 1] * a[1, 2] - a[0, 2] * a[1, 1]) * invDet
result[0, 1] = -(a[1, 0] * a[2, 2] - a[1, 2] * a[2, 0]) * invDet
result[0, 1] = -(a[0, 1] * a[2, 2] - a[0, 2] * a[2, 1]) * invDet
result[0, 2] = (a[0, 1] * a[1, 2] - a[0, 2] * a[1, 1]) * invDet
result[1, 0] = -(a[1, 0] * a[2, 2] - a[1, 2] * a[2, 0]) * invDet
result[1, 1] = (a[0, 0] * a[2, 2] - a[0, 2] * a[2, 0]) * invDet
result[2, 1] = -(a[0, 0] * a[1, 2] - a[1, 0] * a[0, 2]) * invDet
result[0, 2] = (a[1, 0] * a[2, 1] - a[2, 0] * a[1, 1]) * invDet
result[1, 2] = -(a[0, 0] * a[2, 1] - a[2, 0] * a[0, 1]) * invDet
result[1, 2] = -(a[0, 0] * a[1, 2] - a[1, 0] * a[0, 2]) * invDet
result[2, 0] = (a[1, 0] * a[2, 1] - a[2, 0] * a[1, 1]) * invDet
result[2, 1] = -(a[0, 0] * a[2, 1] - a[2, 0] * a[0, 1]) * invDet
result[2, 2] = (a[0, 0] * a[1, 1] - a[1, 0] * a[0, 1]) * invDet
type Mat4* = array[16, float32] ## 4x4 Matrix - OpenGL row order