go-opengl-pixel/pixelgl/texture.go

95 lines
2.1 KiB
Go

package pixelgl
import (
"runtime"
"github.com/faiface/mainthread"
"github.com/go-gl/gl/v3.3-core/gl"
"github.com/go-gl/mathgl/mgl32"
)
// Texture is an OpenGL texture.
type Texture struct {
tex binder
width, height int
}
// NewTexture creates a new texture with the specified width and height with some initial
// pixel values. The pixels must be a sequence of RGBA values.
func NewTexture(width, height int, smooth bool, pixels []uint8) *Texture {
if len(pixels) != width*height*4 {
panic("failed to create new texture: wrong number of pixels")
}
tex := &Texture{
tex: binder{
restoreLoc: gl.TEXTURE_BINDING_2D,
bindFunc: func(obj uint32) {
gl.BindTexture(gl.TEXTURE_2D, obj)
},
},
width: width,
height: height,
}
gl.GenTextures(1, &tex.tex.obj)
tex.Begin()
defer tex.End()
gl.TexImage2D(
gl.TEXTURE_2D,
0,
gl.RGBA,
int32(width),
int32(height),
0,
gl.RGBA,
gl.UNSIGNED_BYTE,
gl.Ptr(pixels),
)
borderColor := mgl32.Vec4{0, 0, 0, 0}
gl.TexParameterfv(gl.TEXTURE_2D, gl.TEXTURE_BORDER_COLOR, &borderColor[0])
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_BORDER)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_BORDER)
if smooth {
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
} else {
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
}
runtime.SetFinalizer(tex, (*Texture).delete)
return tex
}
func (t *Texture) delete() {
mainthread.CallNonBlock(func() {
gl.DeleteTextures(1, &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()
}