mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 05:12:18 +02:00
275 lines
7.4 KiB
Go
275 lines
7.4 KiB
Go
// Copyright 2018 The Ebiten Authors
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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 mipmap
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import (
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"fmt"
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"image"
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"math"
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"github.com/hajimehoshi/ebiten/v2/internal/atlas"
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"github.com/hajimehoshi/ebiten/v2/internal/buffered"
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"github.com/hajimehoshi/ebiten/v2/internal/graphics"
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"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
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)
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func canUseMipmap(imageType atlas.ImageType) bool {
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switch imageType {
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case atlas.ImageTypeRegular, atlas.ImageTypeUnmanaged:
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return true
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}
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return false
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}
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// Mipmap is a set of buffered.Image sorted by the order of mipmap level.
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// The level 0 image is a regular image and higher-level images are used for mipmap.
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type Mipmap struct {
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width int
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height int
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imageType atlas.ImageType
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orig *buffered.Image
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imgs map[int]*buffered.Image
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}
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func New(width, height int, imageType atlas.ImageType) *Mipmap {
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return &Mipmap{
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width: width,
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height: height,
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orig: buffered.NewImage(width, height, imageType),
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imageType: imageType,
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}
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}
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func (m *Mipmap) DumpScreenshot(graphicsDriver graphicsdriver.Graphics, name string, blackbg bool) (string, error) {
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return m.orig.DumpScreenshot(graphicsDriver, name, blackbg)
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}
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func (m *Mipmap) WritePixels(pix []byte, region image.Rectangle) {
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m.orig.WritePixels(pix, region)
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m.deallocateMipmaps()
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}
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func (m *Mipmap) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) (ok bool, err error) {
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return m.orig.ReadPixels(graphicsDriver, pixels, region)
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}
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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) {
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if len(indices) == 0 {
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return
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}
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level := 0
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if !canSkipMipmap && srcs[0] != nil && canUseMipmap(srcs[0].imageType) {
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level = math.MaxInt32
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for i := 0; i < len(indices); i += 3 {
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idx0 := indices[i]
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idx1 := indices[i+1]
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idx2 := indices[i+2]
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dx0 := vertices[graphics.VertexFloatCount*idx0]
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dy0 := vertices[graphics.VertexFloatCount*idx0+1]
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sx0 := vertices[graphics.VertexFloatCount*idx0+2]
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sy0 := vertices[graphics.VertexFloatCount*idx0+3]
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dx1 := vertices[graphics.VertexFloatCount*idx1]
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dy1 := vertices[graphics.VertexFloatCount*idx1+1]
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sx1 := vertices[graphics.VertexFloatCount*idx1+2]
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sy1 := vertices[graphics.VertexFloatCount*idx1+3]
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dx2 := vertices[graphics.VertexFloatCount*idx2]
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dy2 := vertices[graphics.VertexFloatCount*idx2+1]
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sx2 := vertices[graphics.VertexFloatCount*idx2+2]
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sy2 := vertices[graphics.VertexFloatCount*idx2+3]
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if l := mipmapLevelFromDistance(dx0, dy0, dx1, dy1, sx0, sy0, sx1, sy1); level > l {
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level = l
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}
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if l := mipmapLevelFromDistance(dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2); level > l {
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level = l
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}
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if l := mipmapLevelFromDistance(dx2, dy2, dx0, dy0, sx2, sy2, sx0, sy0); level > l {
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level = l
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}
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}
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if level == math.MaxInt32 {
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panic("mipmap: level must be calculated at least once but not")
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}
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}
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var imgs [graphics.ShaderSrcImageCount]*buffered.Image
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for i, src := range srcs {
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if src == nil {
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continue
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}
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if level != 0 {
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if img := src.level(level); img != nil {
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s := float32(pow2(level))
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for i := 0; i < len(vertices); i += graphics.VertexFloatCount {
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vertices[i+2] /= s
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vertices[i+3] /= s
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}
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imgs[i] = img
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continue
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}
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}
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imgs[i] = src.orig
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}
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m.orig.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
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m.deallocateMipmaps()
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}
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func (m *Mipmap) setImg(level int, img *buffered.Image) {
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if m.imgs == nil {
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m.imgs = map[int]*buffered.Image{}
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}
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m.imgs[level] = img
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}
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func (m *Mipmap) level(level int) *buffered.Image {
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if level == 0 {
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panic("mipmap: level must be non-zero at level")
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}
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if !canUseMipmap(m.imageType) {
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panic("mipmap: mipmap images for a screen image is not implemented yet")
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}
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if img, ok := m.imgs[level]; ok {
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return img
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}
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var src *buffered.Image
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vs := make([]float32, 4*graphics.VertexFloatCount)
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switch {
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case level == 1:
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src = m.orig
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graphics.QuadVerticesFromSrcAndMatrix(vs, 0, 0, float32(m.width), float32(m.height), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
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case level > 1:
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src = m.level(level - 1)
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if src == nil {
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m.setImg(level, nil)
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return nil
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}
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w := sizeForLevel(m.width, level-1)
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h := sizeForLevel(m.height, level-1)
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graphics.QuadVerticesFromSrcAndMatrix(vs, 0, 0, float32(w), float32(h), 0.5, 0, 0, 0.5, 0, 0, 1, 1, 1, 1)
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default:
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panic(fmt.Sprintf("mipmap: invalid level: %d", level))
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}
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is := graphics.QuadIndices()
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w2 := sizeForLevel(m.width, level)
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h2 := sizeForLevel(m.height, level)
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if w2 == 0 || h2 == 0 {
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m.setImg(level, nil)
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return nil
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}
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// buffered.NewImage panics with a too big size when actual allocation happens.
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// 4096 should be a safe size in most environments (#1399).
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// Unfortunately a precise max image size cannot be obtained here since this requires GPU access.
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if w2 > 4096 || h2 > 4096 {
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m.setImg(level, nil)
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return nil
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}
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s := buffered.NewImage(w2, h2, m.imageType)
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dstRegion := image.Rect(0, 0, w2, h2)
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s.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.LinearFilterShader, nil, graphicsdriver.FillRuleFillAll)
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m.setImg(level, s)
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return m.imgs[level]
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}
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func sizeForLevel(x int, level int) int {
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for i := 0; i < level; i++ {
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x /= 2
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if x == 0 {
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return 0
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}
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}
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return x
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}
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func (m *Mipmap) Deallocate() {
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m.deallocateMipmaps()
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m.orig.Deallocate()
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}
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func (m *Mipmap) deallocateMipmaps() {
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for _, img := range m.imgs {
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if img != nil {
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img.Deallocate()
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}
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}
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for k := range m.imgs {
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delete(m.imgs, k)
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}
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}
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// mipmapLevel returns an appropriate mipmap level for the given distance.
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func mipmapLevelFromDistance(dx0, dy0, dx1, dy1, sx0, sy0, sx1, sy1 float32) int {
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const maxLevel = 6
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d := (dx1-dx0)*(dx1-dx0) + (dy1-dy0)*(dy1-dy0)
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s := (sx1-sx0)*(sx1-sx0) + (sy1-sy0)*(sy1-sy0)
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if s == 0 {
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return 0
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}
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scale := d / s
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// Scale can be infinite when the specified scale is extremely big (#1398).
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if math.IsInf(float64(scale), 0) {
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return 0
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}
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// Scale can be zero when the specified scale is extremely small (#1398).
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if scale == 0 {
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return 0
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}
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level := 0
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for scale < 0.25 {
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level++
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scale *= 4
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}
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if level > 0 {
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// If the image can be scaled into 0 size, adjust the level. (#839)
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w, h := int(sx1-sx0), int(sy1-sy0)
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for level >= 0 {
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s := 1 << uint(level)
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if (w > 0 && w/s == 0) || (h > 0 && h/s == 0) {
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level--
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continue
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}
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break
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}
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if level < 0 {
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// As the render source is too small, nothing is rendered.
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return 0
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}
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}
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if level > maxLevel {
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level = maxLevel
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}
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return level
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}
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func pow2(power int) float32 {
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x := 1
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return float32(x << uint(power))
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}
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