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#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);
}
}
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