ebiten/internal/mipmap/mipmap.go

278 lines
7.3 KiB
Go
Raw Normal View History

// 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 mipmap
import (
"fmt"
2023-04-27 17:55:10 +02:00
"image"
"math"
"github.com/hajimehoshi/ebiten/v2/internal/atlas"
2020-10-03 19:35:13 +02:00
"github.com/hajimehoshi/ebiten/v2/internal/buffered"
"github.com/hajimehoshi/ebiten/v2/internal/graphics"
"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
)
func canUseMipmap(imageType atlas.ImageType) bool {
switch imageType {
case atlas.ImageTypeRegular, atlas.ImageTypeUnmanaged:
return true
}
return false
}
// Mipmap is a set of buffered.Image sorted by the order of mipmap level.
// The level 0 image is a regular image and higher-level images are used for mipmap.
type Mipmap struct {
width int
height int
imageType atlas.ImageType
orig *buffered.Image
imgs map[int]*buffered.Image
}
func New(width, height int, imageType atlas.ImageType) *Mipmap {
return &Mipmap{
width: width,
height: height,
orig: buffered.NewImage(width, height, imageType),
imageType: imageType,
2019-09-18 19:13:11 +02:00
}
}
func (m *Mipmap) DumpScreenshot(graphicsDriver graphicsdriver.Graphics, name string, blackbg bool) (string, error) {
return m.orig.DumpScreenshot(graphicsDriver, name, blackbg)
2019-09-18 19:13:11 +02:00
}
2023-04-27 17:55:10 +02:00
func (m *Mipmap) WritePixels(pix []byte, region image.Rectangle) {
m.orig.WritePixels(pix, region)
m.deallocateMipmaps()
2019-09-18 19:27:20 +02:00
}
func (m *Mipmap) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) (ok bool, err error) {
2023-04-27 17:55:10 +02:00
return m.orig.ReadPixels(graphicsDriver, pixels, region)
2019-09-18 19:27:20 +02:00
}
func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Mipmap, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *atlas.Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, canSkipMipmap bool) {
if len(indices) == 0 {
return
}
level := 0
// TODO: Do we need to check all the sources' states of being volatile?
if !canSkipMipmap && srcs[0] != nil && canUseMipmap(srcs[0].imageType) {
level = math.MaxInt32
for i := 0; i < len(indices)/3; i++ {
const n = graphics.VertexFloatCount
dx0 := vertices[n*indices[3*i]+0]
dy0 := vertices[n*indices[3*i]+1]
sx0 := vertices[n*indices[3*i]+2]
sy0 := vertices[n*indices[3*i]+3]
dx1 := vertices[n*indices[3*i+1]+0]
dy1 := vertices[n*indices[3*i+1]+1]
sx1 := vertices[n*indices[3*i+1]+2]
sy1 := vertices[n*indices[3*i+1]+3]
dx2 := vertices[n*indices[3*i+2]+0]
dy2 := vertices[n*indices[3*i+2]+1]
sx2 := vertices[n*indices[3*i+2]+2]
sy2 := vertices[n*indices[3*i+2]+3]
if l := mipmapLevelFromDistance(dx0, dy0, dx1, dy1, sx0, sy0, sx1, sy1); level > l {
level = l
}
if l := mipmapLevelFromDistance(dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2); level > l {
level = l
}
if l := mipmapLevelFromDistance(dx2, dy2, dx0, dy0, sx2, sy2, sx0, sy0); level > l {
level = l
}
}
if level == math.MaxInt32 {
panic("mipmap: level must be calculated at least once but not")
}
}
var imgs [graphics.ShaderSrcImageCount]*buffered.Image
for i, src := range srcs {
if src == nil {
continue
}
if level != 0 {
if img := src.level(level); img != nil {
const n = graphics.VertexFloatCount
s := float32(pow2(level))
for i := 0; i < len(vertices)/n; i++ {
vertices[i*n+2] /= s
vertices[i*n+3] /= s
}
imgs[i] = img
continue
}
}
imgs[i] = src.orig
}
m.orig.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
m.deallocateMipmaps()
}
func (m *Mipmap) setImg(level int, img *buffered.Image) {
if m.imgs == nil {
m.imgs = map[int]*buffered.Image{}
}
m.imgs[level] = img
}
func (m *Mipmap) level(level int) *buffered.Image {
if level == 0 {
panic("mipmap: level must be non-zero at level")
}
if !canUseMipmap(m.imageType) {
panic("mipmap: mipmap images for a volatile or a screen image is not implemented yet")
}
if img, ok := m.imgs[level]; ok {
return img
}
var src *buffered.Image
vs := make([]float32, 4*graphics.VertexFloatCount)
shader := atlas.NearestFilterShader
switch {
case level == 1:
src = m.orig
graphics.QuadVertices(vs, 0, 0, float32(m.width), float32(m.height), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
shader = atlas.LinearFilterShader
case level > 1:
src = m.level(level - 1)
if src == nil {
m.setImg(level, nil)
return nil
}
w := sizeForLevel(m.width, level-1)
h := sizeForLevel(m.height, level-1)
graphics.QuadVertices(vs, 0, 0, float32(w), float32(h), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
shader = atlas.LinearFilterShader
default:
panic(fmt.Sprintf("mipmap: invalid level: %d", level))
}
is := graphics.QuadIndices()
w2 := sizeForLevel(m.width, level)
h2 := sizeForLevel(m.height, level)
2019-09-20 22:56:34 +02:00
if w2 == 0 || h2 == 0 {
m.setImg(level, nil)
2019-09-20 22:56:34 +02:00
return nil
}
// buffered.NewImage panics with a too big size when actual allocation happens.
// 4096 should be a safe size in most environments (#1399).
// Unfortunately a precise max image size cannot be obtained here since this requires GPU access.
if w2 > 4096 || h2 > 4096 {
m.setImg(level, nil)
return nil
}
s := buffered.NewImage(w2, h2, m.imageType)
dstRegion := image.Rect(0, 0, w2, h2)
s.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, shader, nil, graphicsdriver.FillRuleFillAll)
m.setImg(level, s)
2019-09-20 22:56:34 +02:00
return m.imgs[level]
2019-09-20 22:56:34 +02:00
}
func sizeForLevel(x int, level int) int {
for i := 0; i < level; i++ {
x /= 2
if x == 0 {
return 0
}
}
return x
}
func (m *Mipmap) Deallocate() {
m.deallocateMipmaps()
m.orig.Deallocate()
}
func (m *Mipmap) deallocateMipmaps() {
for _, img := range m.imgs {
if img != nil {
img.Deallocate()
}
}
for k := range m.imgs {
delete(m.imgs, k)
}
}
// mipmapLevel returns an appropriate mipmap level for the given distance.
func mipmapLevelFromDistance(dx0, dy0, dx1, dy1, sx0, sy0, sx1, sy1 float32) int {
const maxLevel = 6
d := (dx1-dx0)*(dx1-dx0) + (dy1-dy0)*(dy1-dy0)
s := (sx1-sx0)*(sx1-sx0) + (sy1-sy0)*(sy1-sy0)
if s == 0 {
return 0
}
scale := d / s
// Scale can be infinite when the specified scale is extremely big (#1398).
if math.IsInf(float64(scale), 0) {
return 0
}
// Scale can be zero when the specified scale is extremely small (#1398).
if scale == 0 {
return 0
}
level := 0
for scale < 0.25 {
level++
scale *= 4
}
2020-07-15 17:52:41 +02:00
if level > 0 {
// If the image can be scaled into 0 size, adjust the level. (#839)
w, h := int(sx1-sx0), int(sy1-sy0)
2020-07-15 17:52:41 +02:00
for level >= 0 {
s := 1 << uint(level)
if (w > 0 && w/s == 0) || (h > 0 && h/s == 0) {
2020-07-15 17:52:41 +02:00
level--
continue
}
break
}
if level < 0 {
// As the render source is too small, nothing is rendered.
return 0
}
}
if level > maxLevel {
level = maxLevel
2020-07-15 17:52:41 +02:00
}
return level
}
func pow2(power int) float32 {
x := 1
return float32(x << uint(power))
}