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https://github.com/hajimehoshi/ebiten.git
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c22857ca89
Fixes #586
137 lines
3.4 KiB
Go
137 lines
3.4 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ebiten
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import (
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"fmt"
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"github.com/hajimehoshi/ebiten/internal/affine"
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)
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// GeoMDim is a dimension of a GeoM.
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const GeoMDim = affine.GeoMDim
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// A GeoM represents a matrix to transform geometry when rendering an image.
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//
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// The initial value is identity.
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type GeoM struct {
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impl *affine.GeoM
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}
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// String returns a string representation of GeoM.
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func (g *GeoM) String() string {
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a, b, c, d, tx, ty := g.impl.Elements()
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return fmt.Sprintf("[[%f, %f, %f], [%f, %f, %f]]", a, b, tx, c, d, ty)
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}
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// Reset resets the GeoM as identity.
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func (g *GeoM) Reset() {
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g.impl = nil
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}
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// Apply pre-multiplies a vector (x, y, 1) by the matrix.
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// In other words, Apply calculates GeoM * (x, y, 1)^T.
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// The return value is x and y values of the result vector.
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func (g *GeoM) Apply(x, y float64) (x2, y2 float64) {
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return g.impl.Apply(x, y)
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}
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// Element returns a value of a matrix at (i, j).
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func (g *GeoM) Element(i, j int) float64 {
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a, b, c, d, tx, ty := g.impl.Elements()
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switch {
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case i == 0 && j == 0:
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return a
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case i == 0 && j == 1:
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return b
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case i == 0 && j == 2:
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return tx
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case i == 1 && j == 0:
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return c
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case i == 1 && j == 1:
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return d
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case i == 1 && j == 2:
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return ty
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default:
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panic("ebiten: i or j is out of index")
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}
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}
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// Concat multiplies a geometry matrix with the other geometry matrix.
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// This is same as muptiplying the matrix other and the matrix g in this order.
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func (g *GeoM) Concat(other GeoM) {
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g.impl = g.impl.Concat(other.impl)
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}
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// Add is deprecated as of 1.5.0-alpha.
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// Note that this doesn't make sense as an operation for affine matrices.
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func (g *GeoM) Add(other GeoM) {
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g.impl = g.impl.Add(other.impl)
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}
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// Scale scales the matrix by (x, y).
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func (g *GeoM) Scale(x, y float64) {
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g.impl = g.impl.Scale(x, y)
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}
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// Translate translates the matrix by (tx, ty).
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func (g *GeoM) Translate(tx, ty float64) {
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g.impl = g.impl.Translate(tx, ty)
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}
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// IsInvertible returns a boolean value indicating
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// whether the matrix g is invertible or not.
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func (g *GeoM) IsInvertible() bool {
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return g.impl.IsInvertible()
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}
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// Invert inverts the matrix.
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// If g is not invertible, Invert panics.
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func (g *GeoM) Invert() {
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g.impl = g.impl.Invert()
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}
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// Rotate rotates the matrix by theta.
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// The unit is radian.
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func (g *GeoM) Rotate(theta float64) {
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g.impl = g.impl.Rotate(theta)
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}
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// SetElement sets an element at (i, j).
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func (g *GeoM) SetElement(i, j int, element float64) {
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g.impl = g.impl.SetElement(i, j, element)
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}
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// ScaleGeo is deprecated as of 1.2.0-alpha. Use Scale instead.
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func ScaleGeo(x, y float64) GeoM {
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g := GeoM{}
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g.Scale(x, y)
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return g
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}
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// TranslateGeo is deprecated as of 1.2.0-alpha. Use Translate instead.
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func TranslateGeo(tx, ty float64) GeoM {
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g := GeoM{}
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g.Translate(tx, ty)
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return g
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}
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// RotateGeo is deprecated as of 1.2.0-alpha. Use Rotate instead.
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func RotateGeo(theta float64) GeoM {
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g := GeoM{}
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g.Rotate(theta)
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return g
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}
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