blob: 2577dbfa9263d481d81728010156c42e44c17cab [file] [log] [blame]
 // Copyright 2014 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package f32 import "fmt" // A Mat3 is a 3x3 matrix of float32 values. // Elements are indexed first by row then column, i.e. m[row][column]. type Mat3 [3]Vec3 func (m Mat3) String() string { return fmt.Sprintf(`Mat3[% 0.3f, % 0.3f, % 0.3f, % 0.3f, % 0.3f, % 0.3f, % 0.3f, % 0.3f, % 0.3f]`, m[0][0], m[0][1], m[0][2], m[1][0], m[1][1], m[1][2], m[2][0], m[2][1], m[2][2]) } func (m *Mat3) Identity() { *m = Mat3{ {1, 0, 0}, {0, 1, 0}, {0, 0, 1}, } } func (m *Mat3) Eq(n *Mat3, epsilon float32) bool { for i := range m { for j := range m[i] { diff := m[i][j] - n[i][j] if diff < -epsilon || +epsilon < diff { return false } } } return true } // Mul stores a × b in m. func (m *Mat3) Mul(a, b *Mat3) { // Store the result in local variables, in case m == a || m == b. m00 := a[0][0]*b[0][0] + a[0][1]*b[1][0] + a[0][2]*b[2][0] m01 := a[0][0]*b[0][1] + a[0][1]*b[1][1] + a[0][2]*b[2][1] m02 := a[0][0]*b[0][2] + a[0][1]*b[1][2] + a[0][2]*b[2][2] m10 := a[1][0]*b[0][0] + a[1][1]*b[1][0] + a[1][2]*b[2][0] m11 := a[1][0]*b[0][1] + a[1][1]*b[1][1] + a[1][2]*b[2][1] m12 := a[1][0]*b[0][2] + a[1][1]*b[1][2] + a[1][2]*b[2][2] m20 := a[2][0]*b[0][0] + a[2][1]*b[1][0] + a[2][2]*b[2][0] m21 := a[2][0]*b[0][1] + a[2][1]*b[1][1] + a[2][2]*b[2][1] m22 := a[2][0]*b[0][2] + a[2][1]*b[1][2] + a[2][2]*b[2][2] m[0][0] = m00 m[0][1] = m01 m[0][2] = m02 m[1][0] = m10 m[1][1] = m11 m[1][2] = m12 m[2][0] = m20 m[2][1] = m21 m[2][2] = m22 }