Adds most of the toolsHEADmaster

4 files changed, 1040 insertions, 0 deletions

diff --git a/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/obj.v b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/obj.v
new file mode 100644
index 0000000..1d239a0
--- /dev/null
+++ b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/obj.v
@@ -0,0 +1,595 @@
+module obj
+
+/**********************************************************************
+*
+* .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:
+**********************************************************************/
+import gg.m4
+import strconv
+
+enum F_state {
+	start
+	first
+	ints
+	decimals
+	exp_start
+	exp_sign
+	exp_int
+}
+
+// read a int from a string
+fn get_int(s string, start_index int) (int, int) {
+	mut i := start_index
+	mut res := 0
+	mut sgn := 1
+
+	mut state := F_state.start
+	for true {
+		if i >= s.len {
+			break
+		}
+		c := s[i]
+		if state == .start {
+			match c {
+				`+` {
+					i++
+					state = .ints
+					continue
+				}
+				`-` {
+					sgn = -1
+					i++
+					state = .ints
+					continue
+				}
+				`0`...`9` {
+					state = .ints
+				}
+				` `, `\t` {
+					i++
+					continue
+				}
+				else { // no number found
+					break
+				}
+			}
+		}
+
+		if state == .ints {
+			match c {
+				`0`...`9` {
+					// println("$res => ${(int(c) - 48)}")
+					res = res * 10 + (int(c) - 48)
+					i++
+					continue
+				}
+				else {
+					break
+				}
+			}
+		}
+	}
+	// println("---")
+	return res * sgn, i
+}
+
+// reas a float number from a string
+fn get_float(s string, start_index int) (f64, int) {
+	mut i1 := start_index //+ 1
+	for i1 < s.len && s[i1] in [` `, `\t`] {
+		i1++
+	}
+	mut i := i1
+	for i < s.len {
+		if s[i] in [` `, `\t`] {
+			break
+		}
+		i++
+	}
+	// println(" get_float: ($start_index,$i) [${s[start_index..i]}]")
+	// f_res := strconv.atof_quick(s[start_index..i])
+	f_res := strconv.atof_quick(s[i1..i])
+	return f_res, i
+}
+
+// read 3 f32 in sequence from a string
+fn parse_3f(row string, start_index int) m4.Vec4 {
+	// println(row)
+	mut i := start_index //+ 1
+	mut f1 := f64(0)
+	mut f2 := f64(0)
+	f0, mut p := get_float(row, i)
+	// print("Here f0: $f0 $p ")
+	f1, p = get_float(row, p + 1)
+	// print("Here f1: $f1 $p ")
+	f2, p = get_float(row, p + 1)
+	// print("Here f2: $f2 $p ")
+	return m4.Vec4{
+		e: [f32(f0), f32(f1), f32(f2), 1]!
+	}
+}
+
+// reas a sequence of f32 from a string
+fn (mut m ObjPart) parse_floats(row string, start_index int) m4.Vec4 {
+	mut i := start_index //+ 1
+	mut res_f := f64(0)
+	mut res := m4.Vec4{
+		e: [f32(0), 0, 0, 1]!
+	}
+	mut c := 0
+	for true {
+		res_f, i = get_float(row, i)
+		unsafe {
+			res.e[c] = f32(res_f)
+		}
+		c++
+		i++
+		if i >= row.len {
+			break
+		}
+	}
+	return res
+}
+
+// read and manage all the faes from an .obj file data
+fn (mut p Part) parse_faces(row string, start_index int, obj ObjPart) {
+	mut i := start_index + 1
+	mut res := [][3]int{}
+	mut v := 0
+	mut t := 0
+	mut n := 0
+	// println("row: ${row[i..]}")
+	for true {
+		t = 0
+		n = 0
+		if i >= row.len {
+			break
+		}
+		mut c := row[i]
+		if (c > `9` || c < `0`) && c != `-` {
+			i++
+			continue
+		}
+		v, i = get_int(row, i)
+		if i < row.len && row[i] == `/` {
+			if row[i + 1] != `/` {
+				t, i = get_int(row, i + 1)
+				if i < row.len && row[i] == `/` {
+					n, i = get_int(row, i + 1)
+				}
+			} else {
+				i++
+				n, i = get_int(row, i + 1)
+			}
+		}
+		// manage negative indexes
+		// NOTE: not well suporeted now
+		if v < 0 {
+			// println("${obj.v.len} ${obj.v.len-c}")
+			v = obj.v.len - v + 1
+			// exit(0)
+		}
+		if n < 0 {
+			n = obj.vn.len - n + 1
+		}
+		if t < 0 {
+			t = obj.vt.len - t + 1
+		}
+		res << [v - 1, n - 1, t - 1]!
+	}
+	// println("ok res: ${res}")
+	// println(p.faces.len)
+	p.faces << res
+}
+
+// parse the obj file, if single_material is true it use only one default material
+pub fn (mut obj_part ObjPart) parse_obj_buffer(rows []string, single_material bool) {
+	mut mat_count := 0
+	mut row_count := 0
+	default_part := Part{
+		name: 'default part'
+	}
+	obj_part.part << default_part
+	// println("OBJ file has ${rows.len} rows")
+	for c, row in rows {
+		// println("$c $row")
+		mut i := 0
+		row_count++
+		for true {
+			if i >= row.len {
+				break
+			}
+			match row[i] {
+				`s` {
+					break
+				}
+				`m` {
+					if row[i..i + 6] == 'mtllib' {
+						obj_part.material_file = row[i + 7..].trim_space()
+						obj_part.load_materials()
+					}
+					break
+				}
+				`o`, `g` {
+					mut part := Part{}
+					part.name = row[i + 1..].trim_space()
+					obj_part.part << part
+					mat_count = 0
+					break
+				}
+				`u` {
+					if single_material == false && row[i..i + 6] == 'usemtl' {
+						material := row[i + 7..].trim_space()
+						// println("material: $material")
+						// manage multiple materials in an part
+						if obj_part.part[obj_part.part.len - 1].material.len > 0 {
+							mat_count++
+							mut part := Part{}
+							if mat_count > 1 {
+								li := obj_part.part[obj_part.part.len - 1].name.last_index('_m') or {
+									obj_part.part[obj_part.part.len - 1].name.len - 1
+								}
+								part.name = obj_part.part[obj_part.part.len - 1].name[..li] +
+									'_m${mat_count:02}'
+							} else {
+								part.name = obj_part.part[obj_part.part.len - 1].name + '_m01'
+							}
+							obj_part.part << part
+						}
+						obj_part.part[obj_part.part.len - 1].material = material
+					}
+					break
+				}
+				`v` {
+					i++
+					match row[i] {
+						// normals
+						`n` {
+							obj_part.vn << parse_3f(row, i + 2)
+							// println("Vertex line: $c")
+							break
+						}
+						// parameteres uvw
+						`p` {
+							obj_part.vp << parse_3f(row, i + 2)
+							// println("Vertex line: ${obj_part.vp.len}")
+							break
+						}
+						// texture uvw
+						`t` {
+							obj_part.vt << obj_part.parse_floats(row, i + 2)
+							// println("Vertex line: $c")
+							break
+						}
+						else {
+							obj_part.v << parse_3f(row, i + 1)
+							// println("$row => ${obj_part.v[obj_part.v.len-1]}")
+							break
+						}
+					}
+				}
+				`f` {
+					// println("$c $row")
+					obj_part.part[obj_part.part.len - 1].parse_faces(row, i, obj_part)
+					// println(obj_part.part[obj_part.part.len - 1].faces.len)
+					// println("Faces line: $c")
+					break
+				}
+				// end of the line, comments
+				`\n`, `#` {
+					break
+				}
+				else {}
+			}
+			i++
+		}
+		// if c == 2 { break }
+		if c % 100000 == 0 && c > 0 {
+			println('$c rows parsed')
+		}
+	}
+	println('$row_count .obj Rows parsed')
+	// remove default part if empty
+	if obj_part.part.len > 1 && obj_part.part[0].faces.len == 0 {
+		obj_part.part = obj_part.part[1..]
+	}
+}
+
+// load the materials if found the .mtl file
+fn (mut obj_part ObjPart) load_materials() {
+	rows := read_lines_from_file(obj_part.material_file)
+	println('Material file [$obj_part.material_file] $rows.len Rows.')
+	for row in rows {
+		// println("$row")
+		mut i := 0
+		for true {
+			if i >= row.len {
+				break
+			}
+			match row[i] {
+				`n` {
+					if row[i..i + 6] == 'newmtl' {
+						name := row[i + 6..].trim_space()
+						mut mat := Material{
+							name: name
+						}
+						obj_part.mat << mat
+						break
+					}
+				}
+				`K` {
+					if row[i + 1] !in [`a`, `d`, `e`, `s`] {
+						break
+					}
+					k_name := row[i..i + 2]
+					i += 3
+					value := parse_3f(row, i)
+					obj_part.mat[obj_part.mat.len - 1].ks[k_name] = value
+					break
+				}
+				`N` {
+					n_name := row[i..i + 2]
+					i += 3
+					value, _ := get_float(row, i)
+					obj_part.mat[obj_part.mat.len - 1].ns[n_name] = f32(value)
+					break
+				}
+				`m` {
+					if row[i..i + 4] == 'map_' {
+						name := row[i..i + 6]
+						if (i + 7) < row.len {
+							file_name := row[i + 7..].trim_space()
+							obj_part.mat[obj_part.mat.len - 1].maps[name] = file_name
+						}
+						break
+					}
+				}
+				// trasparency
+				`d` {
+					if row[i + 1] == ` ` {
+						value, _ := get_float(row, i + 2)
+						obj_part.mat[obj_part.mat.len - 1].ns['Tr'] = f32(value)
+					}
+				}
+				`T` {
+					if row[i + 1] == `r` {
+						value, _ := get_float(row, i + 3)
+						obj_part.mat[obj_part.mat.len - 1].ns['Tr'] = f32(1.0 - value)
+					}
+				}
+				// end of the line, comments
+				`\n`, `#` {
+					break
+				}
+				` `, `\t` {
+					i++
+					continue
+				}
+				else {
+					break
+				}
+			}
+			i++
+		}
+	}
+
+	// create map material name => material index
+	for i, m in obj_part.mat {
+		if m.name !in obj_part.mat_map {
+			obj_part.mat_map[m.name] = i
+		}
+	}
+
+	println('Material Loading Done!')
+}
+
+//==============================================================================
+// Sokol data
+//==============================================================================
+
+// vertex data struct
+pub struct Vertex_pnct {
+pub mut:
+	x     f32 // poistion
+	y     f32
+	z     f32
+	nx    f32 // normal
+	ny    f32
+	nz    f32
+	color u32 = 0xFFFFFFFF // color
+	u     f32 // uv
+	v     f32
+	// u u16   // for compatibility with D3D11
+	// v u16   // for compatibility with D3D11
+}
+
+// struct used to pass the data to the sokol calls
+pub struct Skl_buffer {
+pub mut:
+	vbuf     []Vertex_pnct
+	ibuf     []u32
+	n_vertex u32
+}
+
+// transforms data from .obj format to buffer ready to be used in the render
+pub fn (mut obj_part ObjPart) get_buffer(in_part_list []int) Skl_buffer {
+	// in_part           := 0
+	mut v_count_index := 0
+	mut out_buf := Skl_buffer{}
+
+	mut cache := map[string]int{}
+	mut cache_hit := 0
+
+	// has_normals := obj_part.vn.len > 0
+	// has_uvs     := obj_part.vt.len > 0
+
+	for in_part in in_part_list {
+		part := obj_part.part[in_part]
+		for fc, face in part.faces {
+			// println("$fc $face")
+			// default 3 faces
+			mut v_seq := [0, 1, 2]
+			if face.len == 4 {
+				v_seq = [0, 1, 2, 0, 2, 3]
+			}
+
+			// if big faces => use the fan of triangles as solution
+			// Note: this trick doesn't work with concave faces
+			if face.len > 4 {
+				v_seq = []
+				mut i := 1
+				for i < (face.len - 1) {
+					v_seq << 0
+					v_seq << i
+					v_seq << (i + 1)
+					i++
+				}
+				// println("BIG FACES! ${fc} ${face.len} v_seq:${v_seq.len}")
+			}
+
+			// no vertex index, generate normals
+			if face[0][1] == -1 && face.len >= 3 {
+				mut v_count := 0
+				v0 := face[v_count + 0][0]
+				v1 := face[v_count + 1][0]
+				v2 := face[v_count + 2][0]
+
+				vec0 := obj_part.v[v2] - obj_part.v[v1]
+				vec1 := obj_part.v[v0] - obj_part.v[v1]
+				tmp_normal := vec0 % vec1
+
+				for v_count < face.len {
+					obj_part.vn << tmp_normal
+					obj_part.part[in_part].faces[fc][v_count][1] = obj_part.vn.len - 1
+					v_count++
+				}
+			}
+
+			for vertex_index in v_seq {
+				// position
+				if vertex_index >= face.len {
+					continue
+				}
+				v_index := face[vertex_index][0] // vertex index
+				n_index := face[vertex_index][1] // normal index
+				t_index := face[vertex_index][2] // uv texture index
+				key := '${v_index}_${n_index}_$t_index'
+				if key !in cache {
+					cache[key] = v_count_index
+					mut pnct := Vertex_pnct{
+						x: obj_part.v[v_index].e[0]
+						y: obj_part.v[v_index].e[1]
+						z: obj_part.v[v_index].e[2]
+					}
+					// normal
+					if n_index >= 0 {
+						pnct.nx = obj_part.vn[n_index].e[0]
+						pnct.ny = obj_part.vn[n_index].e[1]
+						pnct.nz = obj_part.vn[n_index].e[2]
+					}
+					// texture uv
+					if t_index >= 0 {
+						pnct.u = obj_part.vt[t_index].e[0]
+						pnct.v = obj_part.vt[t_index].e[1]
+					}
+
+					out_buf.vbuf << pnct
+					out_buf.ibuf << u32(v_count_index)
+					v_count_index++
+				} else {
+					// println("Cache used! $key")
+					out_buf.ibuf << u32(cache[key])
+					cache_hit++
+				}
+			}
+		}
+	}
+
+	/*
+	println("------------")
+	for c1, x1 in out_buf.vbuf[..10] {
+		println("$c1 $x1")
+	}
+	println(out_buf.ibuf[..10])
+	*/
+	// println("vbuf size: ${out_buf.vbuf.len} ibuf size: ${out_buf.ibuf.len} Cache hit: $cache_hit")
+	out_buf.n_vertex = u32(out_buf.ibuf.len)
+	return out_buf
+}
+
+//==============================================================================
+// Utility
+//==============================================================================
+// print on the console the summary of the .obj model loaded
+pub fn (obj_part ObjPart) summary() {
+	println('---- Stats     ----')
+	println('vertices: $obj_part.v.len')
+	println('normals : $obj_part.vn.len')
+	println('uv      : $obj_part.vt.len')
+	println('parts   : $obj_part.part.len')
+	// Parts
+	println('---- Parts     ----')
+	for c, x in obj_part.part {
+		println('${c:3} [${x.name:-16}] mat:[${x.material:-10}] ${x.faces.len:7} faces')
+	}
+	// Materials
+	println('---- Materials ----')
+	println('Material dict: $obj_part.mat_map.keys()')
+	for c, mat in obj_part.mat {
+		println('${c:3} [${mat.name:-16}]')
+		for k, v in mat.ks {
+			print('$k = $v')
+		}
+		for k, v in mat.ns {
+			println('$k = $v')
+		}
+		for k, v in mat.maps {
+			println('$k = $v')
+		}
+	}
+}
+
+// debug test function, do not remove.
+pub fn tst() {
+	/*
+	//fname := "capsule.obj"
+	//fname := "Forklift.obj"
+	fname := "cube.obj"
+	//fname := "Orange Robot 3D ObjPart.obj"
+	
+	mut obj := ObjPart{}
+	buf := os.read_lines(fname) or { panic(err.msg) }
+	obj.parse_obj_buffer(buf)
+	obj.summary()
+	*/
+	/*
+	a :="f 7048 7070 7071 7072 7073 7074 7075 7076 7077 7078 7079 7080 7003"
+	mut f1 := 0
+	mut f2 := 0
+	f0,mut p := get_int(a,1)
+	f1, p = get_int(a,p)
+	f2, p = get_int(a,p)
+	println("res: ${f0} ${f1} ${f2}")
+	*/
+	/*
+	a :="v -0 0.107769 -0.755914"
+	println("${parse_3f(a,1)}")
+	*/
+	/*
+	ort := m4.ortho(0,300,0,200,0,0)
+	println(ort)
+	a := m4.vec3(0,0,0)
+	println("a: $a")
+	res := m4.mul_vec(ort, a)
+	println("res:\n${res}")
+	*/
+	s := 'K 1 1 1'
+	r := strconv.atof_quick(s[1..s.len - 1])
+	println(r)
+}
diff --git a/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/rend.v b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/rend.v
new file mode 100644
index 0000000..d4ea3bc
--- /dev/null
+++ b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/rend.v
@@ -0,0 +1,297 @@
+/**********************************************************************
+*
+* .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 sokol.gfx
+import gg.m4
+import math
+import stbi
+
+/******************************************************************************
+* Texture functions
+******************************************************************************/
+pub fn create_texture(w int, h int, buf &byte) C.sg_image {
+	sz := w * h * 4
+	mut img_desc := C.sg_image_desc{
+		width: w
+		height: h
+		num_mipmaps: 0
+		min_filter: .linear
+		mag_filter: .linear
+		// usage: .dynamic
+		wrap_u: .clamp_to_edge
+		wrap_v: .clamp_to_edge
+		label: &byte(0)
+		d3d11_texture: 0
+	}
+	// comment if .dynamic is enabled
+	img_desc.data.subimage[0][0] = C.sg_range{
+		ptr: buf
+		size: size_t(sz)
+	}
+
+	sg_img := C.sg_make_image(&img_desc)
+	return sg_img
+}
+
+pub fn destroy_texture(sg_img C.sg_image) {
+	C.sg_destroy_image(sg_img)
+}
+
+pub fn load_texture(file_name string) C.sg_image {
+	buffer := read_bytes_from_file(file_name)
+	stbi.set_flip_vertically_on_load(true)
+	img := stbi.load_from_memory(buffer.data, buffer.len) or {
+		eprintln('Texure file: [$file_name] ERROR!')
+		exit(0)
+	}
+	res := create_texture(int(img.width), int(img.height), img.data)
+	img.free()
+	return res
+}
+
+/******************************************************************************
+* Pipeline
+******************************************************************************/
+pub fn (mut obj_part ObjPart) create_pipeline(in_part []int, shader C.sg_shader, texture C.sg_image) Render_data {
+	mut res := Render_data{}
+	obj_buf := obj_part.get_buffer(in_part)
+	res.n_vert = obj_buf.n_vertex
+	res.material = obj_part.part[in_part[0]].material
+
+	// vertex buffer
+	mut vert_buffer_desc := C.sg_buffer_desc{
+		label: 0
+	}
+	unsafe { C.memset(&vert_buffer_desc, 0, sizeof(vert_buffer_desc)) }
+
+	vert_buffer_desc.size = size_t(obj_buf.vbuf.len * int(sizeof(Vertex_pnct)))
+	vert_buffer_desc.data = C.sg_range{
+		ptr: obj_buf.vbuf.data
+		size: size_t(obj_buf.vbuf.len * int(sizeof(Vertex_pnct)))
+	}
+
+	vert_buffer_desc.@type = .vertexbuffer
+	vert_buffer_desc.label = 'vertbuf_part_${in_part:03}'.str
+	vbuf := gfx.make_buffer(&vert_buffer_desc)
+
+	// index buffer
+	mut index_buffer_desc := C.sg_buffer_desc{
+		label: 0
+	}
+	unsafe { C.memset(&index_buffer_desc, 0, sizeof(index_buffer_desc)) }
+
+	index_buffer_desc.size = size_t(obj_buf.ibuf.len * int(sizeof(u32)))
+	index_buffer_desc.data = C.sg_range{
+		ptr: obj_buf.ibuf.data
+		size: size_t(obj_buf.ibuf.len * int(sizeof(u32)))
+	}
+
+	index_buffer_desc.@type = .indexbuffer
+	index_buffer_desc.label = 'indbuf_part_${in_part:03}'.str
+	ibuf := gfx.make_buffer(&index_buffer_desc)
+
+	mut pipdesc := C.sg_pipeline_desc{}
+	unsafe { C.memset(&pipdesc, 0, sizeof(pipdesc)) }
+	pipdesc.layout.buffers[0].stride = int(sizeof(Vertex_pnct))
+
+	// the constants [C.ATTR_vs_a_Position, C.ATTR_vs_a_Color, C.ATTR_vs_a_Texcoord0] are generated by sokol-shdc
+	pipdesc.layout.attrs[C.ATTR_vs_a_Position].format = .float3 // x,y,z as f32
+	pipdesc.layout.attrs[C.ATTR_vs_a_Normal].format = .float3 // x,y,z as f32
+	pipdesc.layout.attrs[C.ATTR_vs_a_Color].format = .ubyte4n // color as u32
+	pipdesc.layout.attrs[C.ATTR_vs_a_Texcoord0].format = .float2 // u,v as f32
+	// pipdesc.layout.attrs[C.ATTR_vs_a_Texcoord0].format  = .short2n  // u,v as u16
+	pipdesc.index_type = .uint32
+
+	color_state := C.sg_color_state{
+		blend: C.sg_blend_state{
+			enabled: true
+			src_factor_rgb: gfx.BlendFactor(C.SG_BLENDFACTOR_SRC_ALPHA)
+			dst_factor_rgb: gfx.BlendFactor(C.SG_BLENDFACTOR_ONE_MINUS_SRC_ALPHA)
+		}
+	}
+	pipdesc.colors[0] = color_state
+
+	pipdesc.depth = C.sg_depth_state{
+		write_enabled: true
+		compare: gfx.CompareFunc(C.SG_COMPAREFUNC_LESS_EQUAL)
+	}
+	pipdesc.cull_mode = .front
+
+	pipdesc.label = 'pip_part_${in_part:03}'.str
+
+	// shader
+	pipdesc.shader = shader
+
+	res.bind.vertex_buffers[0] = vbuf
+	res.bind.index_buffer = ibuf
+	res.bind.fs_images[C.SLOT_tex] = texture
+	res.pipeline = gfx.make_pipeline(&pipdesc)
+	// println('Buffers part [$in_part] init done!')
+
+	return res
+}
+
+/******************************************************************************
+* Render functions
+******************************************************************************/
+// agregate all the part by materials
+pub fn (mut obj_part ObjPart) init_render_data(texture C.sg_image) {
+	// create shader
+	// One shader for all the model
+	shader := gfx.make_shader(C.gouraud_shader_desc(gfx.query_backend()))
+
+	mut part_dict := map[string][]int{}
+	for i, p in obj_part.part {
+		if p.faces.len > 0 {
+			part_dict[p.material] << i
+		}
+	}
+	obj_part.rend_data.clear()
+	// println("Material dict: ${obj_part.mat_map.keys()}")
+
+	for k, v in part_dict {
+		// println("$k => Parts $v")
+
+		mut txt := texture
+
+		if k in obj_part.mat_map {
+			mat_map := obj_part.mat[obj_part.mat_map[k]]
+			if 'map_Kd' in mat_map.maps {
+				file_name := mat_map.maps['map_Kd']
+				if file_name in obj_part.texture {
+					txt = obj_part.texture[file_name]
+					// println("Texture [${file_name}] => from CACHE")
+				} else {
+					txt = load_texture(file_name)
+					obj_part.texture[file_name] = txt
+					// println("Texture [${file_name}] => LOADED")
+				}
+			}
+		}
+		// key := obj_part.texture.keys()[0]
+		// obj_part.rend_data << obj_part.create_pipeline(v, shader, obj_part.texture[key])
+		obj_part.rend_data << obj_part.create_pipeline(v, shader, txt)
+	}
+	// println("Texture array len: ${obj_part.texture.len}")
+	// println("Calc bounding box.")
+	obj_part.calc_bbox()
+	println('init_render_data DONE!')
+}
+
+pub fn (obj_part ObjPart) bind_and_draw(rend_data_index int, in_data Shader_data) u32 {
+	// apply the pipline and bindings
+	mut part_render_data := obj_part.rend_data[rend_data_index]
+
+	// pass light position
+	mut tmp_fs_params := Tmp_fs_param{}
+	tmp_fs_params.ligth = in_data.fs_data.ligth
+
+	if part_render_data.material in obj_part.mat_map {
+		mat_index := obj_part.mat_map[part_render_data.material]
+		mat := obj_part.mat[mat_index]
+
+		// ambient
+		tmp_fs_params.ka = in_data.fs_data.ka
+		if 'Ka' in mat.ks {
+			tmp_fs_params.ka = mat.ks['Ka']
+		}
+
+		// specular
+		tmp_fs_params.ks = in_data.fs_data.ks
+		if 'Ks' in mat.ks {
+			tmp_fs_params.ks = mat.ks['Ks']
+		}
+
+		//  specular exponent Ns
+		if 'Ns' in mat.ns {
+			tmp_fs_params.ks.e[3] = mat.ns['Ns'] / 1000.0
+		} else {
+			// defautl value is 10
+			tmp_fs_params.ks.e[3] = f32(10) / 1000.0
+		}
+
+		// diffuse
+		tmp_fs_params.kd = in_data.fs_data.kd
+		if 'Kd' in mat.ks {
+			tmp_fs_params.kd = mat.ks['Kd']
+		}
+
+		// alpha/transparency
+		if 'Tr' in mat.ns {
+			tmp_fs_params.kd.e[3] = mat.ns['Tr']
+		}
+	}
+
+	gfx.apply_pipeline(part_render_data.pipeline)
+	gfx.apply_bindings(part_render_data.bind)
+
+	vs_uniforms_range := C.sg_range{
+		ptr: in_data.vs_data
+		size: size_t(in_data.vs_len)
+	}
+	fs_uniforms_range := C.sg_range{
+		ptr: unsafe { &tmp_fs_params }
+		size: size_t(in_data.fs_len)
+	}
+
+	gfx.apply_uniforms(C.SG_SHADERSTAGE_VS, C.SLOT_vs_params, &vs_uniforms_range)
+	gfx.apply_uniforms(C.SG_SHADERSTAGE_FS, C.SLOT_fs_params, &fs_uniforms_range)
+	gfx.draw(0, int(part_render_data.n_vert), 1)
+	return part_render_data.n_vert
+}
+
+pub fn (obj_part ObjPart) bind_and_draw_all(in_data Shader_data) u32 {
+	mut n_vert := u32(0)
+	// println("Parts: ${obj_part.rend_data.len}")
+	for i, _ in obj_part.rend_data {
+		n_vert += obj_part.bind_and_draw(i, in_data)
+	}
+	return n_vert
+}
+
+pub fn (mut obj_part ObjPart) calc_bbox() {
+	obj_part.max = m4.Vec4{
+		e: [f32(-math.max_f32), -math.max_f32, -math.max_f32, 0]!
+	}
+	obj_part.min = m4.Vec4{
+		e: [f32(math.max_f32), math.max_f32, math.max_f32, 0]!
+	}
+	for v in obj_part.v {
+		if v.e[0] > obj_part.max.e[0] {
+			obj_part.max.e[0] = v.e[0]
+		}
+		if v.e[1] > obj_part.max.e[1] {
+			obj_part.max.e[1] = v.e[1]
+		}
+		if v.e[2] > obj_part.max.e[2] {
+			obj_part.max.e[2] = v.e[2]
+		}
+
+		if v.e[0] < obj_part.min.e[0] {
+			obj_part.min.e[0] = v.e[0]
+		}
+		if v.e[1] < obj_part.min.e[1] {
+			obj_part.min.e[1] = v.e[1]
+		}
+		if v.e[2] < obj_part.min.e[2] {
+			obj_part.min.e[2] = v.e[2]
+		}
+	}
+	val1 := obj_part.max.mod3()
+	val2 := obj_part.min.mod3()
+	if val1 > val2 {
+		obj_part.radius = f32(val1)
+	} else {
+		obj_part.radius = f32(val2)
+	}
+	// println("BBox: ${obj_part.min} <=> ${obj_part.max}\nRadius: ${obj_part.radius}")
+}
diff --git a/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/struct.v b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/struct.v
new file mode 100644
index 0000000..55a528b
--- /dev/null
+++ b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/struct.v
@@ -0,0 +1,104 @@
+/**********************************************************************
+*
+* .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
+
+// part struct mantain the fae indexes list
+pub struct Part {
+pub mut:
+	faces    [][][3]int // v n t index order, if -1 not available
+	name     string
+	material string
+}
+
+// materias 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 C.sg_pipeline
+	bind     C.sg_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        // maping material name to its material index
+	texture       map[string]C.sg_image // GPU loaded texture map
+	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           // childs
+	// 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:
+	ligth 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
+	vs_len  int
+	fs_data &Tmp_fs_param
+	fs_len  int
+}
diff --git a/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/util.v b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/util.v
new file mode 100644
index 0000000..a1e596a
--- /dev/null
+++ b/v_windows/v/examples/sokol/06_obj_viewer/modules/obj/util.v
@@ -0,0 +1,44 @@
+module obj
+
+import os
+
+// read a file as single lines
+pub fn read_lines_from_file(file_path string) []string {
+	mut path := ''
+	mut rows := []string{}
+	$if android {
+		path = 'models/' + file_path
+		bts := os.read_apk_asset(path) or {
+			eprintln('File [$path] NOT FOUND!')
+			return rows
+		}
+		rows = bts.bytestr().split_into_lines()
+	} $else {
+		path = os.resource_abs_path('assets/models/' + file_path)
+		rows = os.read_lines(path) or {
+			eprintln('File [$path] NOT FOUND! file_path: $file_path')
+			return rows
+		}
+	}
+	return rows
+}
+
+// read a file as []byte
+pub fn read_bytes_from_file(file_path string) []byte {
+	mut path := ''
+	mut buffer := []byte{}
+	$if android {
+		path = 'models/' + file_path
+		buffer = os.read_apk_asset(path) or {
+			eprintln('Texure file: [$path] NOT FOUND!')
+			exit(0)
+		}
+	} $else {
+		path = os.resource_abs_path('assets/models/' + file_path)
+		buffer = os.read_bytes(path) or {
+			eprintln('Texure file: [$path] NOT FOUND!')
+			exit(0)
+		}
+	}
+	return buffer
+}