go-opengl-pixel/pixelgl/texture.go

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package pixelgl
import (
"runtime"
"github.com/go-gl/gl/v3.3-core/gl"
)
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// Texture is an OpenGL texture.
type Texture struct {
tex binder
width, height int
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}
// NewTexture creates a new texture with the specified width and height.
// The pixels must be a sequence of RGBA values.
func NewTexture(width, height int, smooth bool, pixels []uint8) (*Texture, error) {
texture := &Texture{
tex: binder{
restoreLoc: gl.TEXTURE_BINDING_2D,
bindFunc: func(obj uint32) {
gl.BindTexture(gl.TEXTURE_2D, obj)
},
},
width: width,
height: height,
}
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gl.GenTextures(1, &texture.tex.obj)
texture.Begin()
defer texture.End()
gl.TexImage2D(
gl.TEXTURE_2D,
0,
gl.RGBA,
int32(width),
int32(height),
0,
gl.RGBA,
gl.UNSIGNED_BYTE,
gl.Ptr(pixels),
)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.MIRRORED_REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.MIRRORED_REPEAT)
if smooth {
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
} else {
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
}
gl.GenerateMipmap(gl.TEXTURE_2D)
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runtime.SetFinalizer(texture, (*Texture).delete)
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return texture, nil
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}
func (t *Texture) delete() {
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DoNoBlock(func() {
gl.DeleteTextures(1, &t.tex.obj)
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})
}
// ID returns an OpenGL identifier of a texture.
func (t *Texture) ID() uint32 {
return t.tex.obj
}
// Width returns the width of a texture in pixels.
func (t *Texture) Width() int {
return t.width
}
// Height returns the height of a texture in pixels.
func (t *Texture) Height() int {
return t.height
}
// Begin binds a texture. This is necessary before using the texture.
func (t *Texture) Begin() {
t.tex.bind()
}
// End unbinds a texture and restores the previous one.
func (t *Texture) End() {
t.tex.restore()
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}