ebiten/opengl/texture.go
2014-12-09 22:19:30 +09:00

82 lines
2.1 KiB
Go

package opengl
import (
"github.com/go-gl/gl"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/opengl/internal/shader"
"image"
"image/draw"
)
func adjustImageForTexture(img image.Image) *image.NRGBA {
width, height := img.Bounds().Size().X, img.Bounds().Size().Y
adjustedImageBounds := image.Rectangle{
image.ZP,
image.Point{
shader.AdjustSizeForTexture(width),
shader.AdjustSizeForTexture(height),
},
}
if nrgba, ok := img.(*image.NRGBA); ok && img.Bounds() == adjustedImageBounds {
return nrgba
}
adjustedImage := image.NewNRGBA(adjustedImageBounds)
dstBounds := image.Rectangle{
image.ZP,
img.Bounds().Size(),
}
draw.Draw(adjustedImage, dstBounds, img, image.ZP, draw.Src)
return adjustedImage
}
type texture struct {
native gl.Texture
width int
height int
}
func createNativeTexture(textureWidth, textureHeight int, pixels []uint8, filter ebiten.Filter) gl.Texture {
nativeTexture := gl.GenTexture()
if nativeTexture < 0 {
panic("glGenTexture failed")
}
gl.PixelStorei(gl.UNPACK_ALIGNMENT, 4)
nativeTexture.Bind(gl.TEXTURE_2D)
defer gl.Texture(0).Bind(gl.TEXTURE_2D)
glFilter := 0
switch filter {
case ebiten.FilterLinear:
glFilter = gl.LINEAR
case ebiten.FilterNearest:
glFilter = gl.NEAREST
default:
panic("not reached")
}
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, glFilter)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, glFilter)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, textureWidth, textureHeight, 0, gl.RGBA, gl.UNSIGNED_BYTE, pixels)
return nativeTexture
}
func createTexture(width, height int, filter ebiten.Filter) (*texture, error) {
w := shader.AdjustSizeForTexture(width)
h := shader.AdjustSizeForTexture(height)
native := createNativeTexture(w, h, nil, filter)
return &texture{native, width, height}, nil
}
func createTextureFromImage(img image.Image, filter ebiten.Filter) (*texture, error) {
adjustedImage := adjustImageForTexture(img)
size := adjustedImage.Bounds().Size()
native := createNativeTexture(size.X, size.Y, adjustedImage.Pix, filter)
return &texture{native, size.X, size.Y}, nil
}
func (t *texture) dispose() {
t.native.Delete()
}