zorldo

mipmap.go (8271B)

---

 // 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"
 	"math"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/affine"
 	"github.com/hajimehoshi/ebiten/v2/internal/buffered"
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
 )
 
 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) *Mipmap {
 	return &Mipmap{
 		width:  width,
 		height: height,
 		orig:   buffered.NewImage(width, height),
 	}
 }
 
 func NewScreenFramebufferMipmap(width, height int) *Mipmap {
 	return &Mipmap{
 		width:  width,
 		height: height,
 		orig:   buffered.NewScreenFramebufferImage(width, height),
 	}
 }
 
 func (m *Mipmap) SetVolatile(volatile bool) {
 	m.volatile = volatile
 	if m.volatile {
 		m.disposeMipmaps()
 	}
 	m.orig.SetVolatile(volatile)
 }
 
 func (m *Mipmap) DumpScreenshot(name string, blackbg bool) error {
 	return m.orig.DumpScreenshot(name, blackbg)
 }
 
 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
 	}
 	m.disposeMipmaps()
 	return nil
 }
 
 func (m *Mipmap) Pixels(x, y, width, height int) ([]byte, error) {
 	return m.orig.Pixels(x, y, width, height)
 }
 
 func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderImageNum]*Mipmap, vertices []float32, indices []uint16, colorm affine.ColorM, mode driver.CompositeMode, filter driver.Filter, address driver.Address, dstRegion, srcRegion driver.Region, subimageOffsets [graphics.ShaderImageNum - 1][2]float32, shader *Shader, uniforms []interface{}, evenOdd bool, 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")
 		}
 	}
 
 	var s *buffered.Shader
 	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, dstRegion, srcRegion, subimageOffsets, s, uniforms, evenOdd)
 	m.disposeMipmaps()
 }
 
 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("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
 	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)
 		filter = driver.FilterLinear
 	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)
 		vs = graphics.QuadVertices(0, 0, float32(w), float32(h), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
 		filter = driver.FilterLinear
 	default:
 		panic(fmt.Sprintf("ebiten: invalid level: %d", level))
 	}
 	is := graphics.QuadIndices()
 
 	w2 := sizeForLevel(m.width, level-1)
 	h2 := sizeForLevel(m.height, level-1)
 	if w2 == 0 || h2 == 0 {
 		m.setImg(level, nil)
 		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)
 	s.SetVolatile(m.volatile)
 
 	dstRegion := driver.Region{
 		X:      0,
 		Y:      0,
 		Width:  float32(w2),
 		Height: float32(h2),
 	}
 	s.DrawTriangles([graphics.ShaderImageNum]*buffered.Image{src}, vs, is, affine.ColorMIdentity{}, driver.CompositeModeCopy, filter, driver.AddressUnsafe, dstRegion, driver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, nil, nil, false)
 	m.setImg(level, s)
 
 	return m.imgs[level]
 }
 
 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) MarkDisposed() {
 	m.disposeMipmaps()
 	m.orig.MarkDisposed()
 	m.orig = nil
 }
 
 func (m *Mipmap) disposeMipmaps() {
 	for _, img := range m.imgs {
 		if img != nil {
 			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 {
 	const maxLevel = 6
 
 	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
 
 	// 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
 	}
 
 	if filter != driver.FilterLinear {
 		return 0
 	}
 
 	level := 0
 	for scale < 0.25 {
 		level++
 		scale *= 4
 	}
 
 	if level > 0 {
 		// If the image can be scaled into 0 size, adjust the level. (#839)
 		w, h := int(sx1-sx0), int(sy1-sy0)
 		for level >= 0 {
 			s := 1 << uint(level)
 			if (w > 0 && w/s == 0) || (h > 0 && h/s == 0) {
 				level--
 				continue
 			}
 			break
 		}
 
 		if level < 0 {
 			// As the render source is too small, nothing is rendered.
 			return 0
 		}
 	}
 
 	if level > maxLevel {
 		level = maxLevel
 	}
 
 	return level
 }
 
 func pow2(power int) float32 {
 	x := 1
 	return float32(x << uint(power))
 }
 
 type Shader struct {
 	shader *buffered.Shader
 }
 
 func NewShader(program *shaderir.Program) *Shader {
 	return &Shader{
 		shader: buffered.NewShader(program),
 	}
 }
 
 func (s *Shader) MarkDisposed() {
 	s.shader.MarkDisposed()
 	s.shader = nil
 }