mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-14 15:07:26 +01:00
127 lines
3.5 KiB
Go
127 lines
3.5 KiB
Go
// Copyright 2014 Hajime Hoshi
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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 opengl
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import (
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"errors"
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"fmt"
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"github.com/go-gl/gl"
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"github.com/hajimehoshi/ebiten/internal"
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"image"
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"image/draw"
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)
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func adjustImageForTexture(img image.Image) *image.RGBA {
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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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internal.NextPowerOf2Int(width),
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internal.NextPowerOf2Int(height),
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},
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}
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if nrgba, ok := img.(*image.RGBA); ok && img.Bounds() == adjustedImageBounds {
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return nrgba
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}
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adjustedImage := image.NewRGBA(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) Size() (width, height int) {
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return t.width, t.height
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}
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func createNativeTexture(textureWidth, textureHeight int, pixels []uint8, filter Filter) (gl.Texture, error) {
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nativeTexture := gl.GenTexture()
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if nativeTexture < 0 {
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return 0, errors.New("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, int(filter))
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, int(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, nil
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}
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func NewTexture(width, height int, filter Filter) (*Texture, error) {
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w := internal.NextPowerOf2Int(width)
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h := internal.NextPowerOf2Int(height)
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if w < 4 {
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return nil, errors.New("width must be equal or more than 4.")
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}
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if h < 4 {
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return nil, errors.New("height must be equal or more than 4.")
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}
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native, err := createNativeTexture(w, h, nil, filter)
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if err != nil {
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return nil, err
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}
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return &Texture{native, width, height}, nil
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}
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func NewTextureFromImage(img image.Image, filter Filter) (*Texture, error) {
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origSize := img.Bounds().Size()
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if origSize.X < 4 {
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return nil, errors.New("width must be equal or more than 4.")
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}
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if origSize.Y < 4 {
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return nil, errors.New("height must be equal or more than 4.")
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}
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adjustedImage := adjustImageForTexture(img)
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size := adjustedImage.Bounds().Size()
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native, err := createNativeTexture(size.X, size.Y, adjustedImage.Pix, filter)
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if err != nil {
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return nil, err
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}
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return &Texture{native, origSize.X, origSize.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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func (t *Texture) Pixels() ([]uint8, error) {
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w, h := internal.NextPowerOf2Int(t.width), internal.NextPowerOf2Int(t.height)
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pixels := make([]uint8, 4*w*h)
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t.native.Bind(gl.TEXTURE_2D)
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gl.GetTexImage(gl.TEXTURE_2D, 0, gl.RGBA, gl.UNSIGNED_BYTE, pixels)
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if e := gl.GetError(); e != gl.NO_ERROR {
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// TODO: Use glu.ErrorString
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return nil, errors.New(fmt.Sprintf("gl error: %d", e))
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}
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return pixels, nil
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}
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