From a97fa446b4ec6fa292196040b00f14b892543164 Mon Sep 17 00:00:00 2001
From: Muaz Ahmad <m.ahmed_2000@hotmail.com>
Date: Wed, 3 May 2023 13:19:03 +0500
Subject: [PATCH] Added mtl file loading

---
 .gitignore         |  2 ++
 3dobj-renderer.pro |  2 +-
 obj.cpp            | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 obj.h              | 38 ++++++++++++++++++++++++++++++++++++
 opglwidget.cpp     |  4 ++++
 opglwidget.h       |  1 +
 6 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 obj.cpp
 create mode 100644 obj.h

diff --git a/.gitignore b/.gitignore
index 716ab95..574c181 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 *.o
 Makefile
 ui_mainwindow.h
+untitled.mtl
+untitled.obj
diff --git a/3dobj-renderer.pro b/3dobj-renderer.pro
index 10ca2df..d86befc 100644
--- a/3dobj-renderer.pro
+++ b/3dobj-renderer.pro
@@ -17,6 +17,6 @@ DEPENDPATH += . \
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
 
 # Input
-SOURCES += main.cpp opglwidget.cpp
+SOURCES += main.cpp opglwidget.cpp obj.cpp
 FORMS += mainwindow.ui
 QT += core gui widgets
diff --git a/obj.cpp b/obj.cpp
new file mode 100644
index 0000000..14cd47e
--- /dev/null
+++ b/obj.cpp
@@ -0,0 +1,48 @@
+#include "obj.h"
+#include <fstream>
+#include <vector>
+#include <string>
+#include <cstring>
+
+void ObjectLoader::load_mtl(string filename) {
+	string tmp;
+	ifstream f(filename);
+	int mtl_idx = -1;
+	while (getline(f, tmp)) {
+		if (tmp.rfind("newmtl", 0) == 0) {
+			mtl_idx += 1;
+			mtls.push_back(*(new Material));
+			mtls.back().name = tmp.substr(tmp.rfind(' ') + 1);
+		} else if (tmp[0] == 'K') {
+			float* target_list;
+			switch (tmp[1]) {
+				case 'a':
+					target_list = mtls.back().ambient;
+					break;
+				case 'd':
+					target_list = mtls.back().diffuse;
+					break;
+				case 's':
+					target_list = mtls.back().specular;
+					break;
+				default:
+					continue;
+			};
+			char delim = ' ';
+			char *token = strtok(const_cast<char*>(tmp.c_str()), &delim);
+			for (int i = 0; i < 3; i++) {
+				token = strtok(NULL, &delim);
+				target_list[i] = atof(token);
+			};
+			target_list[3] = 1.0f;
+		};
+	};
+};
+
+void ObjectLoader::load_obj(string filename) {
+	string tmp;
+	ifstream f(filename);
+	while (getline(f, tmp)) {
+
+	}
+}
diff --git a/obj.h b/obj.h
new file mode 100644
index 0000000..f2a3ac9
--- /dev/null
+++ b/obj.h
@@ -0,0 +1,38 @@
+#include <vector>
+#include <string>
+using namespace std;
+struct Vertex {
+	float pos[3];
+};
+
+struct Normal {
+	float pos[3];
+};
+
+struct Material {
+	int idx;
+	string name;
+	float ambient[4];
+	float specular[4];
+	float diffuse[4];
+};
+
+struct Face {
+	vector<Vertex> vertices;
+	Normal normal;
+	Material mtl;
+};
+
+class ObjectLoader 
+{
+public:
+	void load_obj(string filename);
+	void load_mtl(string filename);
+	
+	vector<Face> faces;
+
+protected:
+	vector<Vertex> vertices;
+	vector<Normal> normals;
+	vector<Material> mtls;
+};
diff --git a/opglwidget.cpp b/opglwidget.cpp
index 280a79a..9e137bd 100644
--- a/opglwidget.cpp
+++ b/opglwidget.cpp
@@ -2,6 +2,7 @@
 #include <GL/gl.h>
 #include <GL/glu.h>
 #include <math.h>
+#include "obj.h"
 
 void OPGLWidget::initializeGL() {
 	glClearDepth(1.0f);
@@ -20,6 +21,9 @@ void OPGLWidget::initializeGL() {
 	glLightfv(GL_LIGHT0, GL_SPECULAR, light_array);
 	glLightfv(GL_LIGHT0, GL_POSITION, light_position);
 	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+
+	ObjectLoader obj;
+	obj.load_mtl("untitled.mtl");
 }
 
 void OPGLWidget::paintGL() {
diff --git a/opglwidget.h b/opglwidget.h
index 180f9d3..2c56299 100644
--- a/opglwidget.h
+++ b/opglwidget.h
@@ -10,5 +10,6 @@ protected:
 	void resizeGL(int w, int h);
 	void reorient();
 
+	int mtl_idx = -1;
 	float loc[3] = {-10, 0, -10};
 };