From 00e7d75fda05a4460668ac5cd398bfa96b534664 Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Fri, 31 Jan 2025 15:49:48 -0600
Subject: [PATCH] add material and object structs

---
 generate_cpp.py | 33 +++++++++++++++++++++++++++------
 obj.py          | 24 +++++++++++++++++++++---
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/generate_cpp.py b/generate_cpp.py
index cd76c0b..62da5d4 100644
--- a/generate_cpp.py
+++ b/generate_cpp.py
@@ -4,14 +4,14 @@ import sys
 
 def generate_vec3(vs):
     for v in vs:
-        yield f"{{{v.x}f, {v.y}f, {v.z}f}},"
+        yield f"{{{v.x:.6f}f, {v.y:.6f}f, {v.z:.6f}f}},"
 
 def generate_vec2(vs):
     for v in vs:
-        yield f"{{{v.x}f, {v.y}f}},"
+        yield f"{{{v.x:.6f}f, {v.y:.6f}f}},"
 
 def generate_vec(name, type, func, vs):
-    yield f"vertex_{type} {name}_{type}[] = {{"
+    yield f"const vertex_{type} {name}_{type}[] = {{"
     yield from func(vs)
     yield "};"
 
@@ -25,7 +25,7 @@ def generate_ptn(ptn):
         yield f"{{{p.position}, {p.texture}, {p.normal}}},"
 
 def generate_faces(group_name, model_name, faces, type, n):
-    yield f"union {type} {group_name}_{model_name}_triangles = {{"
+    yield f"const union {type} {group_name}_{model_name}_{type}[] = {{"
     for face in filter_n(faces, n):
         yield "{ .v = {"
         yield from generate_ptn(face.ptn)
@@ -33,14 +33,32 @@ def generate_faces(group_name, model_name, faces, type, n):
     yield "};"
 
 def generate_object(group_name, object):
-    yield f"struct object {group_name}_{object.name} = {{"
+    yield f"const struct object {group_name}_{object.name} = {{"
     yield f".triangle = &{group_name}_{object.name}_triangle[0],"
     yield f".quadrilateral = &{group_name}_{object.name}_quadrilateral[0],"
     triangle_count = sum(1 for _ in filter_n(object.faces, 3))
     quadrilateral_count = sum(1 for _ in filter_n(object.faces, 4))
     yield f".triangle_count = {triangle_count},"
     yield f".quadrilateral_count = {quadrilateral_count},"
-    yield ".material = 0,"
+    if object.material is None:
+        yield ".material = 0,"
+    else:
+        yield f".material = {group_name}_{object.material.name},"
+    yield "};"
+
+def generate_object_array(group_name, obj_file):
+    yield f"const struct object * {group_name}_object[] = {{"
+    for object in obj_file.objects:
+        yield f"&{group_name}_{object.name},"
+    yield "};"
+
+def generate_model(group_name):
+    yield f"const struct model {group_name}_model = {{"
+    yield f".position = {group_name}_position,"
+    yield f".texture = {group_name}_texture,"
+    yield f".normal = {group_name}_normal,"
+    yield f".object = {group_name}_object,"
+    yield f".object_count = {len(obj_file.objects)}"
     yield "};"
 
 def generate_obj_file(group_name, obj_file):
@@ -54,6 +72,9 @@ def generate_obj_file(group_name, obj_file):
         yield from generate_faces(group_name, object.name, object.faces, "quadrilateral", 4)
         yield from generate_object(group_name, object)
 
+    yield from generate_object_array(group_name, obj_file)
+    yield from generate_model(group_name)
+
 if __name__ == "__main__":
     obj_file = parse_obj_file(sys.argv[1])
     render, out = renderer(indent_length=4)
diff --git a/obj.py b/obj.py
index 7c0db1a..c36c5fb 100644
--- a/obj.py
+++ b/obj.py
@@ -33,14 +33,20 @@ class FacePTN:
 class Face:
     ptn: list[FacePTN]
 
+@dataclass
+class Material:
+    name: str
+
 @dataclass
 class Object:
     name: str
     faces: list[Face]
+    material: Material
 
     def __init__(self, name):
         self.name = name
         self.faces = []
+        self.material = None
 
 @dataclass
 class ObjFile:
@@ -56,13 +62,15 @@ class ObjFile:
         self.objects = []
 
 def parse_float(s):
+    sign = -1 if s.startswith("-") else 1
+    s = s.removeprefix("-")
     if '.' not in s:
-        return int(s, 10)
+        return sign * int(s, 10)
     i, f = s.split('.')
     f_digits = len(f)
     i = int(i, 10)
     f = int(f, 10)
-    return i + (f / 10 ** f_digits)
+    return sign * (i + (f / 10 ** f_digits))
 
 def parse_vertex(line, n, type):
     assert len(line) == n
@@ -98,12 +106,17 @@ def parse_object_event(line):
     name, = line
     return ObjectEvent(name)
 
+def parse_usemtl(line):
+    assert len(line) == 1
+    name, = line
+    return Material(name)
+
 def parse_line(line):
     t, *line = line.split(' ')
     if t == '#':
         return None
     if t == 'usemtl':
-        return None
+        return parse_usemtl(line)
     if t == 'mtllib':
         return None
     if t == 'o':
@@ -141,6 +154,11 @@ def parse_obj_lines(lines):
             object = Object(x.name)
         elif type(x) is Face:
             object.faces.append(x)
+        elif type(x) is Material:
+            if object.material != None:
+                file.objects.append(object)
+                object = Object(object.name + "_mtl_" + x.name)
+            object.material = x
         else:
             assert False, x
     if object.faces: