added a path_parent function to get path of a file

Now we can load .mtl files without hardcoding the full path from top-level like before. that was a hack!

5 files changed, 55 insertions, 6 deletions

diff --git a/src/platform/path.c b/src/platform/path.c
new file mode 100644
index 0000000..e67102b
--- /dev/null
+++ b/src/platform/path.c
@@ -0,0 +1,15 @@
+#include "path.h"
+
+#include <libgen.h>
+#include <string.h>
+#include "str.h"
+
+#if defined(CEL_PLATFORM_LINUX) || defined(CEL_PLATFORM_MAC)
+path_opt path_parent(const char* path) {
+  char* path_dirname = dirname(path);
+  return (path_opt){ .path = str8_cstr_view(path_dirname), .has_value = true };
+}
+#endif
+#ifdef CEL_PLATFORM_WINDOWS
+// TODO: path_opt path_parent(const char* path)
+#endif
\ No newline at end of file
diff --git a/src/platform/path.h b/src/platform/path.h
new file mode 100644
index 0000000..0ec6993
--- /dev/null
+++ b/src/platform/path.h
@@ -0,0 +1,16 @@
+/**
+ * @file path.h
+ * @brief
+ * @date 2024-03-11
+ * @copyright Copyright (c) 2024
+ */
+#pragma once
+
+#include "str.h"
+
+typedef struct path_opt {
+  str8 path;
+  bool has_value;
+} path_opt;
+
+path_opt path_parent(const char* path);  // TODO: convert to using str8
\ No newline at end of file
diff --git a/src/resources/obj.c b/src/resources/obj.c
index 24d5d14..031377d 100644
--- a/src/resources/obj.c
+++ b/src/resources/obj.c
@@ -15,6 +15,7 @@
 #include "file.h"
 #include "log.h"
 #include "maths.h"
+#include "path.h"
 #include "render.h"
 #include "render_types.h"
 #include "str.h"
@@ -35,10 +36,16 @@ void create_submesh(mesh_darray *meshes, vec3_darray *tmp_positions, vec3_darray
                     vec2_darray *tmp_uvs, face_darray *tmp_faces, material_darray *materials,
                     bool material_loaded, char current_material_name[256]);
 bool load_material_lib(const char *path, material_darray *materials);
-bool model_load_obj_str(const char *file_string, model *out_model, bool invert_textures_y);
+bool model_load_obj_str(const char *file_string, str8 relative_path, model *out_model,
+                        bool invert_textures_y);
 
 model_handle model_load_obj(core *core, const char *path, bool invert_textures_y) {
   TRACE("Loading model at Path %s\n", path);
+  path_opt relative_path = path_parent(path);
+  if (!relative_path.has_value) {
+    WARN("Couldnt get a relative path for the path to use for loading materials & textures later");
+  }
+  printf("Relative path: %s\n", relative_path.path.buf);
   const char *file_string = string_from_file(path);
 
   // TODO: store the relative path without the name.obj at the end
@@ -48,7 +55,7 @@ model_handle model_load_obj(core *core, const char *path, bool invert_textures_y
   model.meshes = mesh_darray_new(1);
   model.materials = material_darray_new(1);
 
-  bool success = model_load_obj_str(file_string, &model, invert_textures_y);
+  bool success = model_load_obj_str(file_string, relative_path.path, &model, invert_textures_y);
 
   if (!success) {
     FATAL("Couldnt load OBJ file at path %s", path);
@@ -60,7 +67,8 @@ model_handle model_load_obj(core *core, const char *path, bool invert_textures_y
   return (model_handle){ .raw = index };
 }
 
-bool model_load_obj_str(const char *file_string, model *out_model, bool invert_textures_y) {
+bool model_load_obj_str(const char *file_string, str8 relative_path, model *out_model,
+                        bool invert_textures_y) {
   TRACE("Load OBJ from string");
 
   // Setup temps
@@ -170,9 +178,12 @@ bool model_load_obj_str(const char *file_string, model *out_model, bool invert_t
         //   f.vertex_indices[2], f.uv_indices[2], f.normal_indices[2]);
         face_darray_push(tmp_faces, f);
       } else if (strcmp(line_header, "mtllib") == 0) {
-        char path[1024] = "assets/";
-        sscanf(pch + offset, "%s", path + 7);
-        if (!load_material_lib(path, out_model->materials)) {
+        char filename[1024];
+        sscanf(pch + offset, "%s", filename);
+        char mtllib_path[1024];
+        snprintf(mtllib_path, sizeof(mtllib_path), "%s/%s", relative_path.buf, filename);
+        // sscanf(pch + offset, "%s", path + 7);
+        if (!load_material_lib(mtllib_path, out_model->materials)) {
           ERROR("couldnt load material lib");
           return false;
         }
diff --git a/src/std/str.c b/src/std/str.c
index 1c687fa..07a8e73 100644
--- a/src/std/str.c
+++ b/src/std/str.c
@@ -5,6 +5,8 @@
 
 str8 str8_create(u8* buf, size_t len) { return (str8){ .buf = buf, .len = len }; }
 
+str8 str8_cstr_view(char* string) { return str8_create((u8*)string, strlen(string)); }
+
 bool str8_equals(str8 a, str8 b) {
   if (a.len != b.len) {
     return false;
diff --git a/src/std/str.h b/src/std/str.h
index b87864e..1ebecac 100644
--- a/src/std/str.h
+++ b/src/std/str.h
@@ -38,6 +38,11 @@ char* str8_to_cstr(arena* a, str8 s);
 
 #define cstr(a, s) (str8_to_cstr(a, s))  // Shorthand
 
+/** @brief Return a str8 that references a statically allocated string.
+           `string` therefore must already be null-terminated.
+    @note  The backing `string` cannot be modified. */
+str8 str8_cstr_view(char* string);
+
 // --- Comparisons
 
 /** @brief Compare two strings for exact equality */