From c82f69094327162406056776fe04cfd20bfa289e Mon Sep 17 00:00:00 2001
From: Austin Morlan <mail@austinmorlan.com>
Date: Tue, 4 Sep 2018 19:50:27 -0700
Subject: [PATCH] Add OBJ file loading

---
 Makefile           |  6 +--
 include/geometry.h | 21 +++++++++++
 include/loader.h   | 11 ++++++
 include/point.h    | 24 ++++++++++++
 src/engine.cpp     | 13 +++++++
 src/loader.cpp     | 93 ++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 165 insertions(+), 3 deletions(-)
 create mode 100644 include/geometry.h
 create mode 100644 include/loader.h
 create mode 100644 include/point.h
 create mode 100644 src/loader.cpp

diff --git a/Makefile b/Makefile
index 1df73ef..6a0199b 100644
--- a/Makefile
+++ b/Makefile
@@ -31,15 +31,15 @@ CC=clang++
 WARNINGS_ON=-Weverything
 WARNINGS_OFF=-Wno-missing-braces -Wno-gnu-anonymous-struct -Wno-old-style-cast\
 			 -Wno-zero-as-null-pointer-constant -Wno-nested-anon-types\
-			 -Wno-padded
+			 -Wno-padded -Wno-exit-time-destructors -Wno-global-constructors
 
 CFLAGS=$(D) $(O) -std=c++11 $(WARNINGS_ON) $(WARNINGS_OFF) -I$(INCLUDE_DIR)
 LIBS=-lSDL2
 
-_HEADERS = engine.h platform.h util.h
+_HEADERS = engine.h loader.h geometry.h platform.h point.h util.h
 HEADERS = $(patsubst %,$(INCLUDE_DIR)/%,$(_HEADERS))
 
-_OBJS = engine.o main.o platform.o
+_OBJS = engine.o loader.o main.o platform.o
 OBJS = $(patsubst %,$(BUILD_DIR)/%,$(_OBJS))
 
 $(BUILD_DIR)/%.o: $(SRC_DIR)/%.cpp $(HEADERS)
diff --git a/include/geometry.h b/include/geometry.h
new file mode 100644
index 0000000..8352526
--- /dev/null
+++ b/include/geometry.h
@@ -0,0 +1,21 @@
+#ifndef GEOMETRY_H
+
+#include "point.h"
+#include <vector>
+
+
+struct Face
+{
+    unsigned int vertIndex[3];
+};
+
+struct Mesh
+{
+    std::vector<Point> verts;
+    std::vector<Face> faces;
+};
+
+
+#define GEOMETRY_H
+#endif
+
diff --git a/include/loader.h b/include/loader.h
new file mode 100644
index 0000000..6e0642a
--- /dev/null
+++ b/include/loader.h
@@ -0,0 +1,11 @@
+#ifndef LOADER_H
+
+#include "geometry.h"
+
+
+int LoadMesh(char *filename, Mesh &mesh);
+
+
+#define LOADER_H
+#endif
+
diff --git a/include/point.h b/include/point.h
new file mode 100644
index 0000000..9406bb4
--- /dev/null
+++ b/include/point.h
@@ -0,0 +1,24 @@
+#ifndef POINT_H
+
+
+// STRUCTURE
+struct Point
+{
+    inline Point(void) : x(0), y(0), z(0), w(1) {}
+    inline Point(float x, float y, float z) : x(x), y(y), z(z), w(1) {}
+
+    union
+    {
+        float e[4];
+
+        struct
+        {
+            float x, y, z, w;
+        };
+    };
+};
+
+
+#define POINT_H
+#endif
+
diff --git a/src/engine.cpp b/src/engine.cpp
index abc9ff4..4444180 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -1,7 +1,20 @@
 #include "engine.h"
+#include "loader.h"
+
+
+// GLOBALS
+static Mesh mesh;
+
 
 int Engine_Init(char *filename)
 {
+    int result = LoadMesh(filename, mesh);
+
+    if (result < 0)
+    {
+        return -1;
+    }
+
     return 0;
 }
 
diff --git a/src/loader.cpp b/src/loader.cpp
new file mode 100644
index 0000000..4f8197e
--- /dev/null
+++ b/src/loader.cpp
@@ -0,0 +1,93 @@
+#include "loader.h"
+#include <cctype>
+#include <cstdio>
+#include <cstring>
+
+
+// STATIC PROTOTYPES
+static char *GetLine(char *buffer, int maxLength, FILE *fp);
+
+
+// PUBLIC FUNCTIONS
+int LoadMesh(char *filename, Mesh &mesh)
+{
+    FILE *fp;
+    char buffer[256];
+    char *token;
+
+    char garbage[5];
+
+    fp = fopen(filename, "r");
+
+    if (fp == NULL)
+    {
+        fprintf(stderr, "Error loading file: %s\n", filename);
+        return -1;
+    }
+
+    token = GetLine(buffer, sizeof(buffer), fp);
+
+    while (token != NULL)
+    {
+        if (token[0] == 'v')
+        {
+            Point v;
+
+            sscanf(
+                    token, "%s %f %f %f",
+                    garbage,
+                    &v.x,
+                    &v.y,
+                    &v.z);
+
+            mesh.verts.push_back(v);
+        }
+        else if (token[0] == 'f')
+        {
+            Face f;
+
+            sscanf(token, "%s %d %d %d",
+                    garbage,
+                    &f.vertIndex[0],
+                    &f.vertIndex[1],
+                    &f.vertIndex[2]);
+
+            // Convert to 0-indexed
+            f.vertIndex[0] -= 1;
+            f.vertIndex[1] -= 1;
+            f.vertIndex[2] -= 1;
+
+            mesh.faces.push_back(f);
+        }
+
+        token = GetLine(buffer, sizeof(buffer), fp);
+    }
+
+    printf("OBJ: %s\n", filename);
+    printf("Verts: %lu\n", mesh.verts.size());
+    printf("Faces: %lu\n", mesh.faces.size());
+
+    fclose(fp);
+
+    return 0;
+}
+
+static char *GetLine(char *buffer, int maxLength, FILE *fp)
+{
+    while(true)
+    {
+        if (!fgets(buffer, maxLength, fp))
+        {
+            return NULL;
+        }
+
+        // for (length = strlen(buffer), index = 0; isspace(buffer[index]); ++index);
+
+        if (buffer[0] != 'v' && buffer[0] != 'f')
+        {
+            continue;
+        }
+
+        return buffer;
+    }
+}