func (s *Sprite) Draw() {
gg.UseProgram(s.program)
vattrib, err := gg.GetAttribLocation(s.program, "vertex_position")
if err != nil {
log.Fatal(err)
}
gg.EnableVertexAttribArray(vattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.pvbo)
gg.VertexAttribPointer(vattrib, 3, gg.FLOAT, false, 0, 0)
tattrib, err := gg.GetAttribLocation(s.program, "vertex_texture")
if err != nil {
log.Fatal(err)
}
gg.EnableVertexAttribArray(tattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.tvbo)
gg.VertexAttribPointer(tattrib, 2, gg.FLOAT, false, 0, 0)
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, s.tex)
texUniform, err := gg.GetUniformLocation(s.program, "tex_loc")
if err != nil {
log.Fatal(err)
}
gg.Uniform1i(texUniform, 0)
gg.DrawArrays(gg.TRIANGLE_FAN, 0, 4)
}
// TODO(dmac) Move into gg helpers package
func newImageTexture(path string) *gg.Texture {
img := js.Global.Get("Image").New()
img.Set("src", path)
img.Set("crossOrigin", "")
c := make(chan struct{})
img.Call("addEventListener", "load", func() { close(c) }, false)
<-c
tex := gg.CreateTexture()
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, tex)
gg.TexImage2D(
gg.TEXTURE_2D,
0,
gg.RGBA,
-1, -1, -1, // These args are ignored in the webgl backend.
gg.RGBA,
gg.UNSIGNED_BYTE,
img,
)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_S, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_T, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MAG_FILTER, gg.LINEAR)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MIN_FILTER, gg.LINEAR)
return tex
}
func newImageTexture(filename string) (*gg.Texture, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
img, err := png.Decode(f)
if err != nil {
return nil, err
}
var buf []byte
for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
r, g, b, a := img.At(x, y).RGBA()
buf = append(buf, byte(r/256))
buf = append(buf, byte(g/256))
buf = append(buf, byte(b/256))
buf = append(buf, byte(a/256))
}
}
tex := gg.CreateTexture()
gg.ActiveTexture(gg.TEXTURE0)
gg.Enable(gg.TEXTURE_2D)
gg.BindTexture(gg.TEXTURE_2D, tex)
gg.TexImage2D(
gg.TEXTURE_2D,
0,
gg.RGBA,
img.Bounds().Dx(),
img.Bounds().Dy(),
0,
gg.RGBA,
gg.UNSIGNED_BYTE,
buf,
)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_S, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_T, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MAG_FILTER, gg.LINEAR)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MIN_FILTER, gg.LINEAR)
return tex, nil
}
func NewTextureFromImage(img *js.Object) *gg.Texture {
tex := gg.CreateTexture()
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, tex)
gg.TexImage2D(
gg.TEXTURE_2D,
0,
gg.RGBA,
-1, -1, -1, // ignored by gg/webgl
gg.RGBA,
gg.UNSIGNED_BYTE,
img,
)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_S, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_WRAP_T, gg.CLAMP_TO_EDGE)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MAG_FILTER, gg.LINEAR)
gg.TexParameteri(gg.TEXTURE_2D, gg.TEXTURE_MIN_FILTER, gg.LINEAR)
return tex
}
func (s *Sprite) Draw() error {
gg.UseProgram(s.program)
model := s.transform()
modelUniform, err := gg.GetUniformLocation(s.program, "model")
if err != nil {
return err
}
gg.UniformMatrix4fv(modelUniform, model[:])
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, s.tex)
textureUniform, err := gg.GetUniformLocation(s.program, "tex_loc")
if err != nil {
return err
}
gg.Uniform1i(textureUniform, 0)
vattrib, err := gg.GetAttribLocation(s.program, "vertex_position")
if err != nil {
return err
}
gg.EnableVertexAttribArray(vattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.pbuf)
gg.VertexAttribPointer(vattrib, 3, gg.FLOAT, false, 0, 0)
tattrib, err := gg.GetAttribLocation(s.program, "vertex_texture")
if err != nil {
return err
}
gg.EnableVertexAttribArray(tattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.tbuf)
gg.VertexAttribPointer(tattrib, 2, gg.FLOAT, false, 0, 0)
gg.DrawArrays(gg.TRIANGLE_FAN, 0, 4)
return nil
}