// loadVolatile will create the framebuffer and return true if successful
func (canvas *Canvas) loadVolatile() bool {
canvas.status = gl.FRAMEBUFFER_COMPLETE
// glTexImage2D is guaranteed to error in this case.
if canvas.width > maxTextureSize || canvas.height > maxTextureSize {
canvas.status = gl.FRAMEBUFFER_INCOMPLETE_ATTACHMENT
return false
}
canvas.Texture = newTexture(canvas.width, canvas.height, false)
//NULL means reserve texture memory, but texels are undefined
gl.TexImage2D(gl.TEXTURE_2D, 0, int(canvas.width), int(canvas.height), gl.RGBA, gl.UNSIGNED_BYTE, nil)
if gl.GetError() != gl.NO_ERROR {
canvas.Texture.Release()
canvas.status = gl.FRAMEBUFFER_INCOMPLETE_ATTACHMENT
return false
}
canvas.fbo, canvas.status = newFBO(canvas.getHandle())
if canvas.status != gl.FRAMEBUFFER_COMPLETE {
if canvas.fbo.Valid() {
gl.DeleteFramebuffer(canvas.fbo)
canvas.fbo = gl.Framebuffer{}
}
return false
}
return true
}
// Set the 'default' texture (id 0) as a repeating white pixel. Otherwise,
// texture2D calls inside a shader would return black when drawing graphics
// primitives, which would create the need to use different "passthrough"
// shaders for untextured primitives vs images.
func createDefaultTexture() {
gl_state.defaultTexture = gl.CreateTexture()
bindTexture(gl_state.defaultTexture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
pix := []byte{255, 255, 255, 255}
gl.TexImage2D(gl.TEXTURE_2D, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(pix))
}
// newImageTexture will generate a texture from an image. It will automatically
// upload the image data to the texture.
func newImageTexture(img image.Image, mipmaps bool) (*Texture, error) {
bounds := img.Bounds()
new_texture := newTexture(int32(bounds.Dx()), int32(bounds.Dy()), mipmaps)
//generate a uniform image and upload to vram
rgba := image.NewRGBA(img.Bounds())
draw.Draw(rgba, bounds, img, image.Point{0, 0}, draw.Src)
bindTexture(new_texture.getHandle())
gl.TexImage2D(gl.TEXTURE_2D, 0, bounds.Dx(), bounds.Dy(), gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(rgba.Pix))
if new_texture.mipmaps {
new_texture.generateMipmaps()
}
return new_texture, nil
}
