/**********************************************************************
*
* .obj loader
*
* Copyright (c) 2021 Dario Deledda. All rights reserved.
* Use of this source code is governed by an MIT license
* that can be found in the LICENSE file.
*
* TODO:
**********************************************************************/
module obj

import gg.m4
import sokol.gfx

// part struct maintaining the face indices
pub struct Part {
pub mut:
    faces    [][][3]int // v n t index order, if -1 not available
    name     string
    material string
}

// material struct, all Ks and Ns are stored as maps of string
pub struct Material {
pub mut:
    name string
    ks   map[string]m4.Vec4
    ns   map[string]f32
    maps map[string]string
}

// render data used for the rendering
pub struct Render_data {
pub mut:
    pipeline gfx.Pipeline
    bind     gfx.Bindings
    n_vert   u32
    material string
}

// base object parts struct
pub struct ObjPart {
pub mut:
    v  []m4.Vec4 // position
    vn []m4.Vec4 // normals
    vp []m4.Vec4 // vertex params
    vt []m4.Vec4 // textures

    name          string
    part          []Part                 // parts of the ObjPart
    mat           []Material             // list of the materials of the ObjPart
    mat_map       map[string]int         // mapping material name to its material index
    texture       map[string]gfx.Image   // GPU loaded texture map
    sampler       map[string]gfx.Sampler // GPU loaded sampler
    material_file string                 // .mtl file name for the .obj

    rend_data []Render_data // render data used for the rendering

    t_m m4.Mat4 = m4.unit_m4() // transform matrix for this ObjPart
    // child []ObjPart
    // stats
    min    m4.Vec4 // min 3d position in the ObjPart
    max    m4.Vec4 // max 3d position in the ObjPart
    radius f32     // bounding circle radius of the ObjPart
}

// used in to pass the matrices to the shader
pub struct Mats {
pub mut:
    mv  m4.Mat4
    mvp m4.Mat4
    nm  m4.Mat4
}

// data passed to the vertex shader
pub struct Tmp_vs_param {
pub mut:
    mv  m4.Mat4
    mvp m4.Mat4
    nm  m4.Mat4
}

// data passed to the pixel shader
pub struct Tmp_fs_param {
pub mut:
    light m4.Vec4
    ka    m4.Vec4 = m4.Vec4{
        e: [f32(0.1), 0.0, 0.0, 1.0]!
    }
    kd    m4.Vec4 = m4.Vec4{
        e: [f32(0.5), 0.5, 0.5, 1.0]!
    }
    ks    m4.Vec4 = m4.Vec4{
        e: [f32(1.0), 1.0, 1.0, 1.0]!
    }
}

// shader data for the rendering
pub struct Shader_data {
pub mut:
    vs_data &Tmp_vs_param = unsafe { nil }
    vs_len  int
    fs_data &Tmp_fs_param = unsafe { nil }
    fs_len  int
}