ebiten/internal/mipmap/mipmap.go

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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 mipmap
import (
"fmt"
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"image/color"
"math"
"github.com/hajimehoshi/ebiten/internal/affine"
"github.com/hajimehoshi/ebiten/internal/buffered"
"github.com/hajimehoshi/ebiten/internal/driver"
"github.com/hajimehoshi/ebiten/internal/graphics"
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"github.com/hajimehoshi/ebiten/internal/shaderir"
)
var graphicsDriver driver.Graphics
func SetGraphicsDriver(graphics driver.Graphics) {
graphicsDriver = graphics
}
func BeginFrame() error {
return buffered.BeginFrame()
}
func EndFrame() error {
return buffered.EndFrame()
}
// 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
volatile bool
orig *buffered.Image
imgs map[int]*buffered.Image
}
func New(width, height int, volatile bool) *Mipmap {
return &Mipmap{
width: width,
height: height,
volatile: volatile,
orig: buffered.NewImage(width, height, volatile),
imgs: map[int]*buffered.Image{},
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}
}
func NewScreenFramebufferMipmap(width, height int) *Mipmap {
return &Mipmap{
width: width,
height: height,
orig: buffered.NewScreenFramebufferImage(width, height),
imgs: map[int]*buffered.Image{},
}
}
func (m *Mipmap) Dump(name string, blackbg bool) error {
return m.orig.Dump(name, blackbg)
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}
func (m *Mipmap) Fill(clr color.RGBA) {
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m.orig.Fill(clr)
m.disposeMipmaps()
}
func (m *Mipmap) ReplacePixels(pix []byte, x, y, width, height int) error {
if err := m.orig.ReplacePixels(pix, x, y, width, height); err != nil {
return err
}
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m.disposeMipmaps()
return nil
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}
func (m *Mipmap) Pixels(x, y, width, height int) ([]byte, error) {
return m.orig.Pixels(x, y, width, height)
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}
func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderImageNum]*Mipmap, vertices []float32, indices []uint16, colorm *affine.ColorM, mode driver.CompositeMode, filter driver.Filter, address driver.Address, sourceRegion driver.Region, shader *Shader, uniforms []interface{}, 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 && !srcs[0].volatile && filter != driver.FilterScreen {
level = math.MaxInt32
for i := 0; i < len(indices)/3; i++ {
const n = graphics.VertexFloatNum
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, filter); level > l {
level = l
}
if l := mipmapLevelFromDistance(dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, filter); level > l {
level = l
}
if l := mipmapLevelFromDistance(dx2, dy2, dx0, dy0, sx2, sy2, sx0, sy0, filter); level > l {
level = l
}
}
if level == math.MaxInt32 {
panic("mipmap: level must be calculated at least once but not")
}
}
if colorm != nil && colorm.ScaleOnly() {
body, _ := colorm.UnsafeElements()
cr := body[0]
cg := body[5]
cb := body[10]
ca := body[15]
colorm = nil
const n = graphics.VertexFloatNum
for i := 0; i < len(vertices)/n; i++ {
vertices[i*n+4] *= cr
vertices[i*n+5] *= cg
vertices[i*n+6] *= cb
vertices[i*n+7] *= ca
}
}
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var s *buffered.Shader
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if shader != nil {
s = shader.shader
}
var imgs [graphics.ShaderImageNum]*buffered.Image
for i, src := range srcs {
if src == nil {
continue
}
if level != 0 {
if img := src.level(level); img != nil {
const n = graphics.VertexFloatNum
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, colorm, mode, filter, address, sourceRegion, s, uniforms)
m.disposeMipmaps()
}
func (m *Mipmap) level(level int) *buffered.Image {
if level == 0 {
panic("ebiten: level must be non-zero at level")
}
if m.volatile {
panic("ebiten: mipmap images for a volatile image is not implemented yet")
}
if img, ok := m.imgs[level]; ok {
return img
}
var src *buffered.Image
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var vs []float32
var filter driver.Filter
switch {
case level == 1:
src = m.orig
vs = graphics.QuadVertices(0, 0, float32(m.width), float32(m.height), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1, false)
filter = driver.FilterLinear
case level > 1:
src = m.level(level - 1)
if src == nil {
m.imgs[level] = nil
return nil
}
w := sizeForLevel(m.width, level-1)
h := sizeForLevel(m.height, level-1)
vs = graphics.QuadVertices(0, 0, float32(w), float32(h), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1, false)
filter = driver.FilterLinear
case level == -1:
src = m.orig
vs = graphics.QuadVertices(0, 0, float32(m.width), float32(m.height), 2, 0, 0, 2, 0, 0, 1, 1, 1, 1, false)
filter = driver.FilterNearest
case level < -1:
src = m.level(level + 1)
if src == nil {
m.imgs[level] = nil
return nil
}
w := sizeForLevel(m.width, level-1)
h := sizeForLevel(m.height, level-1)
vs = graphics.QuadVertices(0, 0, float32(w), float32(h), 2, 0, 0, 2, 0, 0, 1, 1, 1, 1, false)
filter = driver.FilterNearest
default:
panic(fmt.Sprintf("ebiten: invalid level: %d", level))
}
is := graphics.QuadIndices()
w2 := sizeForLevel(m.width, level-1)
h2 := sizeForLevel(m.height, level-1)
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if w2 == 0 || h2 == 0 {
m.imgs[level] = nil
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return nil
}
s := buffered.NewImage(w2, h2, m.volatile)
s.DrawTriangles([graphics.ShaderImageNum]*buffered.Image{src}, vs, is, nil, driver.CompositeModeCopy, filter, driver.AddressUnsafe, driver.Region{}, nil, nil)
m.imgs[level] = s
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return m.imgs[level]
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}
func sizeForLevel(x int, level int) int {
if level > 0 {
for i := 0; i < level; i++ {
x /= 2
if x == 0 {
return 0
}
}
} else {
for i := 0; i < -level; i++ {
x *= 2
}
}
return x
}
func (m *Mipmap) MarkDisposed() {
m.disposeMipmaps()
m.orig.MarkDisposed()
m.orig = nil
}
func (m *Mipmap) disposeMipmaps() {
for _, img := range m.imgs {
img.MarkDisposed()
}
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, filter driver.Filter) int {
if filter == driver.FilterScreen {
return 0
}
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
// Use 'negative' mipmap to render edges correctly (#611, #907).
// It looks like 128 is the enlargement factor that causes edge missings to pass the test TestImageStretch,
// but we use 64 here for environments where the float precision is low (#1044, #1270).
var tooBigScale float32 = 64
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if scale >= tooBigScale*tooBigScale {
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// If the filter is not nearest, the target needs to be rendered with graduation. Don't use mipmaps.
if filter != driver.FilterNearest {
return 0
}
const mipmapMaxSize = 1024
w, h := sx1-sx0, sy1-sy0
if w >= mipmapMaxSize || h >= mipmapMaxSize {
return 0
}
level := 0
for scale >= tooBigScale*tooBigScale {
level--
scale /= 4
w *= 2
h *= 2
if w >= mipmapMaxSize || h >= mipmapMaxSize {
break
}
}
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// If tooBigScale is 64, level -6 means that the maximum scale is 64 * 2^6 = 4096. This should be
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// enough.
if level < -6 {
level = -6
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}
return level
}
if filter != driver.FilterLinear {
return 0
}
level := 0
for scale < 0.25 {
level++
scale *= 4
}
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if level > 0 {
// If the image can be scaled into 0 size, adjust the level. (#839)
w, h := int(sx1-sx0), int(sy1-sy0)
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for level >= 0 {
s := 1 << uint(level)
if (w > 0 && w/s == 0) || (h > 0 && h/s == 0) {
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level--
continue
}
break
}
if level < 0 {
// As the render source is too small, nothing is rendered.
return 0
}
}
if level > 6 {
level = 6
}
return level
}
func pow2(power int) float32 {
if power >= 0 {
x := 1
return float32(x << uint(power))
}
x := float32(1)
for i := 0; i < -power; i++ {
x /= 2
}
return x
}
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type Shader struct {
shader *buffered.Shader
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}
func NewShader(program *shaderir.Program) *Shader {
return &Shader{
shader: buffered.NewShader(program),
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}
}
func (s *Shader) MarkDisposed() {
s.shader.MarkDisposed()
s.shader = nil
}