// Initialize texture storage. _REQUIRED_ before using it as a framebuffer target.
func (t *Texture) Init() {
With(t, func() {
// generate base level storage
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, t.W, t.H, 0, gl.RGBA, gl.UNSIGNED_BYTE, nil)
// generate required number of mipmaps given texture dimensions
gl.GenerateMipmap(gl.TEXTURE_2D)
})
}
func (self *OpenGLRenderer) LoadTexture(texture *render.Texture) gl.Texture {
glTexture := gl.GenTexture()
glTexture.Bind(gl.TEXTURE_2D)
defer glTexture.Unbind(gl.TEXTURE_2D)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
self.glTexImage2D(gl.TEXTURE_2D, texture)
gl.GenerateMipmap(gl.TEXTURE_2D)
return glTexture
}
func MakeTextureFromTGA(fname string) gl.Texture {
tex := gl.GenTexture()
tex.Bind(gl.TEXTURE_2D)
glfw.LoadTexture2D(fname, 0)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
gl.GenerateMipmap(gl.TEXTURE_2D)
// glh.OpenGLSentinel() // check for errors
return tex
}
// bind the given atlas to the current GL context
//
// the current implementation is very stupid, since it will
// upload the texture every single call.
//
// later, improve this to upload only if there is a real need for it
func (a *Atlas) bind() error {
// discard any possible error
if err := checkGlError(); err != nil {
return err
}
if gl.Object(a.gltex).IsTexture() {
a.gltex = gl.GenTexture()
}
a.gltex.Bind(gl.TEXTURE_2D)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, a.data.Bounds().Dx(), a.data.Bounds().Dy(), 0, gl.RGBA, gl.UNSIGNED_BYTE, a.data.Pix)
if err := checkGlError(gl.OUT_OF_MEMORY, gl.INVALID_OPERATION); err != nil {
return err
}
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
gl.GenerateMipmap(gl.TEXTURE_2D)
panicGlError()
return nil
}
func LoadSkybox() {
gl.ActiveTexture(gl.TEXTURE0)
if err := CheckGlError(); err != nil {
panic(err)
}
t := gl.GenTexture()
if err := CheckGlError(); err != nil {
panic(err)
}
t.Bind(gl.TEXTURE_CUBE_MAP)
if err := CheckGlError(); err != nil {
panic(err)
}
const filename = "Skybox_tut13_384x256.png"
img, err := LoadImage(filename)
if err != nil {
panic(err)
}
size := img.Bounds().Size()
w := size.X
h := size.Y
if w/3 != h/2 {
panic("incorrect aspect ratio")
}
s := h / 2 // Size of one face of the cube.
targets := [...]gl.GLenum{
gl.TEXTURE_CUBE_MAP_NEGATIVE_X,
gl.TEXTURE_CUBE_MAP_POSITIVE_X,
gl.TEXTURE_CUBE_MAP_NEGATIVE_Y,
gl.TEXTURE_CUBE_MAP_POSITIVE_Y,
gl.TEXTURE_CUBE_MAP_NEGATIVE_Z,
gl.TEXTURE_CUBE_MAP_POSITIVE_Z,
}
rs := []image.Rectangle{
image.Rect(0*s, 0*s, 1*s, 1*s), // 0 side.
image.Rect(1*s, 0*s, 2*s, 1*s), // 1 side.
image.Rect(2*s, 0*s, 3*s, 1*s), // 2 side.
image.Rect(0*s, 1*s, 1*s, 2*s), // 3 bottom.
image.Rect(1*s, 1*s, 2*s, 2*s), // 4 top.
image.Rect(2*s, 1*s, 3*s, 2*s), // 5 side.
}
// redirect must end with 3 and 4. This places the floor at -z and the
// sky at +z.
// All the sides look properly oriented (grass down) on the +y side.
// Considering that the sky is properly oriented the way it is, then
// rectangle 5 contains the picture that matches it on the +y side.
// Therefore, redirect must end with 5, 3, 4.
// Problem now: all the other sides, and maybe the floor too, need to be
// rotated in order to line up, that is having their sky on top.
redirect := [...]int{0, 2, 1, 5, 3, 4}
ID := matrix23{1, 0, 0, 1, 0, 0}
ms := [...]matrix23{
matrix23{0, -1, 1, 0, 0, s - 1},
matrix23{0, 1, -1, 0, s - 1, 0},
matrix23{-1, 0, 0, -1, s - 1, s - 1},
ID,
matrix23{-1, 0, 0, -1, s - 1, s - 1},
ID,
}
rgba := forceRGBA(img)
for i, target := range targets {
subimage := rgba.SubImage(rs[redirect[i]])
data := GlRgba(subimage, ms[i])
gl.TexImage2D(
target,
0, // Mipmap level.
gl.SRGB8_ALPHA8, // Format inside OpenGL.
s, // Width.
s, // Height.
0, // Border. Doc says it must be 0.
gl.RGBA, // Format of the data that...
gl.UNSIGNED_BYTE, // ... I give to OpenGL.
data, // And the data itself.
)
if err := CheckGlError(); err != nil {
panic(err)
}
}
const target = gl.TEXTURE_CUBE_MAP
gl.GenerateMipmap(target)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
if err := CheckGlError(); err != nil {
panic(err)
}
t.Unbind(target)
globaltexture = t
}
func LoadTexture() {
gl.ActiveTexture(gl.TEXTURE0)
if err := CheckGlError(); err != nil {
panic(err)
}
t := gl.GenTexture()
if err := CheckGlError(); err != nil {
panic(err)
}
const target = gl.TEXTURE_2D
t.Bind(target)
if err := CheckGlError(); err != nil {
panic(err)
}
img, err := LoadImage("test.jpg")
if err != nil {
panic(err)
}
data := GlRgba(img, matrix23{1, 0, 0, 1, 0, 0})
size := img.Bounds().Size()
gl.TexImage2D(
target,
0, // Mipmap level.
gl.SRGB8_ALPHA8, // Format inside OpenGL.
size.X, // Width.
size.Y, // Height.
0, // Border. Doc says it must be 0.
gl.RGBA, // Format of the data that...
gl.UNSIGNED_BYTE, // ... I give to OpenGL.
data, // And the data itself.
)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.GenerateMipmap(target)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
if err := CheckGlError(); err != nil {
panic(err)
}
gl.TexParameteri(target, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
if err := CheckGlError(); err != nil {
panic(err)
}
t.Unbind(target)
globaltexture = t
}
func (t *Texture) BuildMipmaps() {
t.Bind()
gl.GenerateMipmap(t.target)
}