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// Copyright 2018 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ebiten
import (
"image"
"math"
"github.com/hajimehoshi/ebiten/internal/driver"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/shareable"
)
type mipmap struct {
orig *shareable.Image
imgs map[image.Rectangle][]*shareable.Image
}
func newMipmap(s *shareable.Image) *mipmap {
return &mipmap{
orig: s,
imgs: map[image.Rectangle][]*shareable.Image{},
}
}
func (m *mipmap) original() *shareable.Image {
return m.orig
}
func (m *mipmap) level(r image.Rectangle, level int) *shareable.Image {
if level <= 0 {
panic("ebiten: level must be positive at level")
}
imgs, ok := m.imgs[r]
if !ok {
imgs = []*shareable.Image{}
m.imgs[r] = imgs
}
idx := level - 1
size := r.Size()
w, h := size.X, size.Y
if len(imgs) > 0 {
w, h = imgs[len(imgs)-1].Size()
}
for len(imgs) < idx+1 {
if m.orig.IsVolatile() {
panic("ebiten: mipmap images for a volatile image is not implemented yet")
}
w2 := w / 2
h2 := h / 2
if w2 == 0 || h2 == 0 {
return nil
}
s := shareable.NewImage(w2, h2)
var src *shareable.Image
vs := vertexSlice(4)
if l := len(imgs); l == 0 {
src = m.orig
graphics.PutQuadVertices(vs, src, r.Min.X, r.Min.Y, r.Max.X, r.Max.Y, 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
} else {
src = m.level(r, l)
graphics.PutQuadVertices(vs, src, 0, 0, w, h, 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
}
is := graphics.QuadIndices()
s.DrawTriangles(src, vs, is, nil, driver.CompositeModeCopy, driver.FilterLinear, driver.AddressClampToZero)
imgs = append(imgs, s)
w = w2
h = h2
}
m.imgs[r] = imgs
if len(imgs) <= idx {
return nil
}
return imgs[idx]
}
func (m *mipmap) isDisposed() bool {
return m.orig == nil
}
func (m *mipmap) dispose() {
m.disposeMipmaps()
m.orig.Dispose()
m.orig = nil
}
func (m *mipmap) disposeMipmaps() {
for _, a := range m.imgs {
for _, img := range a {
img.Dispose()
}
}
for k := range m.imgs {
delete(m.imgs, k)
}
}
func (m *mipmap) clearFramebuffer() {
m.orig.ClearFramebuffer()
}
func (m *mipmap) resetRestoringState() {
m.orig.ResetRestoringState()
}
// mipmapLevel returns an appropriate mipmap level for the given determinant of a geometry matrix.
//
// mipmapLevel returns -1 if det is 0.
//
// mipmapLevel panics if det is NaN.
func mipmapLevel(det float32) int {
if math.IsNaN(float64(det)) {
panic("graphicsutil: det must be finite")
}
if det == 0 {
return -1
}
d := math.Abs(float64(det))
level := 0
for d < 0.25 {
level++
d *= 4
}
return level
}
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