From b366f3d0c573468ecd0b59da43dfcbc847334b19 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Fri, 14 Feb 2020 17:09:48 +0100
Subject: Add obj parser

---
 src/model_loader/ObjModelLoader.cpp | 143 ++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 src/model_loader/ObjModelLoader.cpp

(limited to 'src/model_loader')

diff --git a/src/model_loader/ObjModelLoader.cpp b/src/model_loader/ObjModelLoader.cpp
new file mode 100644
index 0000000..1bae458
--- /dev/null
+++ b/src/model_loader/ObjModelLoader.cpp
@@ -0,0 +1,143 @@
+#include "../../include/model_loader/ObjModelLoader.hpp"
+#include "../../include/File.hpp"
+#include "../../include/DataView.hpp"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <assert.h>
+
+namespace amalgine {
+    static StringView get_line(char *str, size_t size) {
+        #if 0
+        char *found_ptr = (char*)memchr(str, '\n', size);
+        if(!found_ptr)
+            found_ptr = str + size;
+        return { str, static_cast<size_t>(found_ptr - str) };
+        #endif
+        for(size_t i = 0; i < size; ++i) {
+            char c = str[i];
+            if(c == '\n')
+                return { str, i };
+        }
+        return { str, size };
+    }
+
+    static bool is_whitespace(char c) {
+        switch(c) {
+            case ' ':
+            case '\t':
+            case '\n':
+            case '\r':
+            case '\v':
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    static bool contains_non_whitespace(const char *str, size_t size) {
+        for(size_t i = 0; i < size; ++i)  {
+            if(!is_whitespace(str[i]))
+                return true;
+        }
+        return false;
+    }
+
+    // Return the number of columns, limited by @output_size
+    static int split_columns(const StringView &str, StringView *output, int output_size) {
+        char *data = str.data;
+        ssize_t size = str.size;
+
+        int column = 0;
+        while(size > 0) {
+            char *found_ptr = (char*)memchr(data, ' ', size);
+            if(!found_ptr)
+                found_ptr = data + size;
+
+            size_t column_size = static_cast<size_t>(found_ptr - data);
+            if(column_size > 0 && contains_non_whitespace(data, column_size)) {
+                output[column++] = { data, column_size };
+                if(column == output_size)
+                    break;
+            }
+
+            data = found_ptr + 1;
+            size -= (column_size + 1);
+        }
+
+        return column;
+    }
+
+    static size_t find_or_end(const StringView &str, char c) {
+        char *found_ptr = (char*)memchr(str.data, c, str.size);
+        if(!found_ptr)
+            found_ptr = str.data + str.size;
+        return static_cast<size_t>(found_ptr - str.data);
+    }
+
+    void ObjModelLoader::load_from_file(const char *filepath, std::vector<Triangle3D> &triangles) {
+        size_t file_size;
+        char *file_data = file_get_content(filepath, &file_size);
+        triangles.clear();
+        if(!file_data)
+            return;
+
+        const int max_columns = 12;
+        StringView columns[max_columns];
+
+        std::vector<Vertex3D> vertices;
+
+        char *data = file_data;
+        ssize_t size = file_size;
+        while(size > 0) {
+            StringView line_data = get_line(data, size);
+
+            if(line_data.size > 2 && memcmp(line_data.data, "v ", 2) == 0) {
+                //printf("line: |%.*s|\n", line_data.size, line_data.data);
+                StringView column_data = { line_data.data + 1, line_data.size - 1 };
+
+                int num_columns = split_columns(column_data, columns, max_columns);
+                if(num_columns >= 3) {
+                    columns[0].data[columns[0].size] = '\0';
+                    columns[1].data[columns[1].size] = '\0';
+                    columns[2].data[columns[2].size] = '\0';
+                    vertices.push_back({ atof(columns[0].data), atof(columns[1].data), atof(columns[2].data) });
+                }
+            } else if(line_data.size > 2 && memcmp(line_data.data, "f ", 2) == 0) {
+                //printf("line: |%.*s|\n", line_data.size, line_data.data);
+                StringView column_data = { line_data.data + 1, line_data.size - 1 };
+
+                int num_columns = split_columns(column_data, columns, max_columns);
+                if(num_columns == 3 || num_columns == 4) {
+                    bool valid = true;
+                    int indices[4];
+                    for(int i = 0; i < num_columns; ++i) {
+                        columns[i].size = find_or_end(columns[i], '/');
+                        columns[i].data[columns[i].size] = '\0';
+                        indices[i] = atoi(columns[i].data);
+                        //printf("column[%d] = %.*s = %d\n", i, columns[i].size, columns[i].data, vertices.size());
+                        if(indices[i] < 1 || indices[i] > vertices.size()) {
+                            valid = false;
+                            break;
+                        }
+                        --indices[i];
+                    }
+
+                    if(valid) {
+                        if(num_columns == 3) {
+                            triangles.push_back({ vertices[indices[0]], vertices[indices[1]], vertices[indices[2]] });
+                        } else if(num_columns == 4) {
+                            triangles.push_back({ vertices[indices[0]], vertices[indices[1]], vertices[indices[3]] });
+                            triangles.push_back({ vertices[indices[3]], vertices[indices[2]], vertices[indices[1]] });
+                        }
+                    }
+                }
+            }
+
+            data += (line_data.size + 1);
+            size -= (line_data.size + 1);
+        }
+
+        free(file_data);
+    }
+}
\ No newline at end of file
-- 
cgit v1.2.3