mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 21:32:20 +02:00
114 lines
2.8 KiB
Go
114 lines
2.8 KiB
Go
/*
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Copyright 2014 Hajime Hoshi
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package opengl
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import (
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"github.com/go-gl/gl"
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"image"
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"image/draw"
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)
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func NextPowerOf2(x uint64) uint64 {
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x -= 1
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x |= (x >> 1)
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x |= (x >> 2)
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x |= (x >> 4)
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x |= (x >> 8)
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x |= (x >> 16)
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x |= (x >> 32)
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return x + 1
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}
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func AdjustSizeForTexture(size int) int {
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return int(NextPowerOf2(uint64(size)))
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}
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func adjustImageForTexture(img image.Image) *image.NRGBA {
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width, height := img.Bounds().Size().X, img.Bounds().Size().Y
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adjustedImageBounds := image.Rectangle{
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image.ZP,
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image.Point{
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AdjustSizeForTexture(width),
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AdjustSizeForTexture(height),
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},
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}
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if nrgba, ok := img.(*image.NRGBA); ok && img.Bounds() == adjustedImageBounds {
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return nrgba
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}
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adjustedImage := image.NewNRGBA(adjustedImageBounds)
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dstBounds := image.Rectangle{
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image.ZP,
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img.Bounds().Size(),
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}
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draw.Draw(adjustedImage, dstBounds, img, image.ZP, draw.Src)
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return adjustedImage
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}
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type Texture struct {
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native gl.Texture
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width int
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height int
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}
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func (t *Texture) Native() gl.Texture {
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return t.native
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}
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func (t *Texture) Width() int {
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return t.width
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}
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func (t *Texture) Height() int {
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return t.height
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}
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func createNativeTexture(textureWidth, textureHeight int, pixels []uint8, filter int) gl.Texture {
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nativeTexture := gl.GenTexture()
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if nativeTexture < 0 {
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panic("glGenTexture failed")
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}
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gl.PixelStorei(gl.UNPACK_ALIGNMENT, 4)
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nativeTexture.Bind(gl.TEXTURE_2D)
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defer gl.Texture(0).Bind(gl.TEXTURE_2D)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, filter)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, filter)
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gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, textureWidth, textureHeight, 0, gl.RGBA, gl.UNSIGNED_BYTE, pixels)
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return nativeTexture
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}
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func CreateTexture(width, height int, filter int) (*Texture, error) {
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w := AdjustSizeForTexture(width)
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h := AdjustSizeForTexture(height)
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native := createNativeTexture(w, h, nil, filter)
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return &Texture{native, width, height}, nil
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}
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func CreateTextureFromImage(img image.Image, filter int) (*Texture, error) {
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adjustedImage := adjustImageForTexture(img)
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size := adjustedImage.Bounds().Size()
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native := createNativeTexture(size.X, size.Y, adjustedImage.Pix, filter)
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return &Texture{native, size.X, size.Y}, nil
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}
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func (t *Texture) Dispose() {
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t.native.Delete()
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}
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