package texture

import "../image"
import "core:math"
import gl "vendor:OpenGL"

import "core:fmt"
@(require_results)
load :: proc(
    img: image.Image,
    image_error: image.Error = nil,
) -> (
    texture: Texture,
    image_error_fallthrough: image.Error,
) {
    image_error_fallthrough = image_error

    gl.CreateTextures(gl.TEXTURE_2D, 1, &texture.id)

    mipmap_levels := math.log2(f32(max(img.width, img.height))) + 1
    // fmt.printfln("{}, {}: using {} levels", img.width, img.height, mipmap_levels)

    gl.TextureStorage2D(texture.id, i32(mipmap_levels), gl.RGBA8, img.width, img.height)
    gl.TextureSubImage2D(
        texture.id,
        0,
        0,
        0,
        img.width,
        img.height,
        gl.RGBA,
        gl.UNSIGNED_BYTE,
        &img.pixels[0],
    )

    max_aniso: f32
    gl.GetFloatv(gl.MAX_TEXTURE_MAX_ANISOTROPY, &max_aniso)
    gl.TextureParameterf(texture.id, gl.TEXTURE_MAX_ANISOTROPY, max_aniso)
    gl.TextureParameteri(texture.id, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
    gl.TextureParameteri(texture.id, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
    //
    // gl.TextureParameteri(texture.id, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
    // gl.TextureParameteri(texture.id, gl.TEXTURE_MAG_FILTER, gl.NEAREST)

    gl.GenerateTextureMipmap(texture.id)

    return
}