wip: port obj loader

1 files changed, 358 insertions, 1 deletions

diff --git a/src/resources/obj.c b/src/resources/obj.c
index b646f58..9e12f79 100644
--- a/src/resources/obj.c
+++ b/src/resources/obj.c
@@ -1 +1,358 @@
-// TODO: Port code from old repo
\ No newline at end of file
+/**
+ * @file obj.c
+ * @brief Wavefront OBJ loader.
+ * @copyright Copyright (c) 2024
+ */
+#include <ctype.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "core.h"
+#include "darray.h"
+#include "log.h"
+#include "maths.h"
+#include "render.h"
+#include "render_types.h"
+
+struct face {
+  u32 vertex_indices[3];
+  u32 normal_indices[3];
+  u32 uv_indices[3];
+};
+typedef struct face face;
+
+KITC_DECL_TYPED_ARRAY(vec3)
+KITC_DECL_TYPED_ARRAY(vec2)
+KITC_DECL_TYPED_ARRAY(face)
+
+// Forward declarations
+void create_submesh(mesh_darray *meshes, vec3_darray *tmp_positions, vec3_darray *tmp_normals,
+                    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);
+
+model_handle model_load_obj(core *core, const char *path, bool invert_textures_y) {
+  const char *file_string = string_from_file(path);
+  model model;
+
+  bool success = model_load_obj_str(file_string, &model, invert_textures_y);
+
+  if (!success) {
+    exit(-1);  // FIXME: Return some sort of result type?
+  }
+
+  u32 index = model_darray_len(core->models);
+  model_darray_push(core->models, model);
+  return (model_handle){ .raw = index };
+}
+
+bool model_load_obj_str(const char *file_string, model *out_model, bool invert_textures_y) {
+  TRACE("Load OBJ from string");
+
+  // Setup temps
+  vec3_darray *tmp_positions = vec3_darray_new(1000);
+  vec3_darray *tmp_normals = vec3_darray_new(1000);
+  vec2_darray *tmp_uvs = vec2_darray_new(1000);
+  face_darray *tmp_faces = face_darray_new(1000);
+
+  mesh_darray *meshes = mesh_darray_new(1);
+  material_darray *materials = material_darray_new(1);
+
+  // Other state
+  bool object_set = false;
+  bool material_loaded = false;
+  char current_material_name[64];
+
+  char *pch;
+  char *rest = file_string;
+  pch = strtok_r((char *)file_string, "\n", &rest);
+
+  int line_num = 0;
+  char last_char_type = 'a';
+
+  while (pch != NULL) {
+    line_num++;
+    char line_header[128];
+    int offset = 0;
+
+    // skip whitespace
+    char *p = pch;
+
+    skip_space(pch);
+
+    if (*p == '\0') {
+      /* the string is empty */
+    } else {
+      // read the first word of the line
+      int res = sscanf(pch, "%s %n", line_header, &offset);
+      // printf("header: %s, offset : %d res: %d\n",line_header, offset, res);
+      if (res != 1) {
+        break;
+      }
+
+      if (strcmp(line_header, "o") == 0 || strcmp(line_header, "g") == 0) {
+        // if we're currently parsing one
+        if (!object_set) {
+          object_set = true;
+        } else {
+          create_submesh(meshes, tmp_positions, tmp_normals, tmp_uvs, tmp_faces, materials,
+                         material_loaded, current_material_name);
+          object_set = false;
+        }
+      } else if (strcmp(line_header, "v") == 0) {
+        // special logic: if we went from faces back to vertices trigger a mesh output.
+        // PS: I hate OBJ
+        if (last_char_type == 'f') {
+          create_submesh(meshes, tmp_positions, tmp_normals, tmp_uvs, tmp_faces, materials,
+                         material_loaded, current_material_name);
+          object_set = false;
+        }
+
+        last_char_type = 'v';
+        vec3 vertex;
+        sscanf(pch + offset, "%f %f %f", &vertex.x, &vertex.y, &vertex.z);
+
+        vec3_darray_push(tmp_positions, vertex);
+      } else if (strcmp(line_header, "vt") == 0) {
+        last_char_type = 't';
+        vec2 uv;
+        char copy[1024];
+        memcpy(copy, pch + offset, strlen(pch + offset) + 1);
+        char *p = pch + offset;
+        while (isspace((unsigned char)*p)) ++p;
+
+        // I can't remember what is going on here
+        memset(copy, 0, 1024);
+        memcpy(copy, pch + offset, strlen(pch + offset) + 1);
+        int res = sscanf(copy, "%f %f", &uv.x, &uv.y);
+        memset(copy, 0, 1024);
+        memcpy(copy, pch + offset, strlen(pch + offset) + 1);
+        if (res != 1) {
+          // da frick? some .obj files have 3 uvs instead of 2
+          f32 dummy;
+          int res2 = sscanf(copy, "%f %f %f", &uv.x, &uv.y, &dummy);
+        }
+
+        if (invert_textures_y) {
+          uv.y = -uv.y;  // flip Y axis to be consistent with how other PNGs are being handled
+          // `texture_load` will flip it again
+        }
+        vec2_darray_push(tmp_uvs, uv);
+      } else if (strcmp(line_header, "vn") == 0) {
+        last_char_type = 'n';
+        vec3 normal;
+        sscanf(pch + offset, "%f %f %f", &normal.x, &normal.y, &normal.z);
+        vec3_darray_push(tmp_normals, normal);
+      } else if (strcmp(line_header, "f") == 0) {
+        last_char_type = 'f';
+        struct face f;
+        sscanf(pch + offset, "%d/%d/%d %d/%d/%d %d/%d/%d", &f.vertex_indices[0], &f.uv_indices[0],
+               &f.normal_indices[0], &f.vertex_indices[1], &f.uv_indices[1], &f.normal_indices[1],
+               &f.vertex_indices[2], &f.uv_indices[2], &f.normal_indices[2]);
+        // printf("f %d/%d/%d %d/%d/%d %d/%d/%d\n", f.vertex_indices[0], f.uv_indices[0],
+        // f.normal_indices[0],
+        //   f.vertex_indices[1], f.uv_indices[1], f.normal_indices[1],
+        //   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, materials)) {
+          ERROR("couldnt load material lib");
+        }
+      } else if (strcmp(line_header, "usemtl") == 0) {
+        material_loaded = true;
+        sscanf(pch + offset, "%s", current_material_name);
+      }
+    }
+
+    pch = strtok_r(NULL, "\n", &rest);
+  }
+
+  // last mesh or if one wasnt created with 'o' directive
+  if (face_darray_len(tmp_faces) > 0) {
+    TRACE("Last leftover mesh");
+    create_submesh(meshes, tmp_positions, tmp_normals, tmp_uvs, tmp_faces, materials,
+                   material_loaded, current_material_name);
+  }
+
+  // Free data
+  free((char *)file_string);
+  vec3_darray_free(tmp_positions);
+  vec3_darray_free(tmp_normals);
+  vec2_darray_free(tmp_uvs);
+  face_darray_free(tmp_faces);
+  TRACE("Freed temporary OBJ loading data");
+
+  memset(out_model, 0, sizeof(model));
+  if (mesh_darray_len(meshes) > 256) {
+    printf("num meshes: %ld\n", mesh_darray_len(meshes));
+  }
+  for (int i = 0; i < mesh_darray_len(meshes); i++) {
+    mesh_darray_push(&out_model->meshes, ((mesh *)meshes->data)[i]);
+    // TODO: bounding box calculation for each mesh
+  }
+  // TODO: bounding box calculation for model
+
+  for (int i = 0; i < material_darray_len(materials); i++) {
+    material_darray_push(&out_model->materials, ((material *)materials->data)[i]);
+  }
+
+  return true;
+}
+
+/**
+ * @brief Takes the current positions, normals, uvs arrays and constructs the vertex array
+ *        from those indices.
+ */
+void create_submesh(mesh_darray *meshes, vec3_darray *tmp_positions, vec3_darray *tmp_normals,
+                    vec2_darray *tmp_uvs, face_darray *tmp_faces, material_darray *materials,
+                    bool material_loaded, char current_material_name[256]) {
+  size_t num_verts = face_darray_len(tmp_faces) * 3;
+  vertex_darray *out_vertices = vertex_darray_new(num_verts);
+
+  face_darray_iter face_iter = face_darray_iter_new(tmp_faces);
+  struct face *f;
+
+  while ((f = face_darray_iter_next(&face_iter))) {
+    for (int j = 0; j < 3; j++) {
+      vertex vert = { 0 };
+      vert.position = tmp_positions->data[f->vertex_indices[j] - 1];
+      if (vec3_darray_len(tmp_normals) == 0) {
+        vert.normal = vec3_create(0.0, 0.0, 0.0);
+      } else {
+        vert.normal = tmp_normals->data[f->normal_indices[j] - 1];
+      }
+      vert.uv = tmp_uvs->data[f->uv_indices[j] - 1];
+      vertex_darray_push(out_vertices, vert);
+    }
+  }
+
+  DEBUG("Loaded submesh\n  vertices: %zu\n  uvs: %zu\n  normals: %zu\n  faces: %zu",
+        vec3_darray_len(tmp_positions), vec2_darray_len(tmp_uvs), vec3_darray_len(tmp_normals),
+        face_darray_len(tmp_faces));
+
+  // Clear current object faces
+  face_darray_clear(tmp_faces);
+
+  mesh m = { .vertices = out_vertices };
+  if (material_loaded) {
+    // linear scan to find material
+    bool found = false;
+    DEBUG("Num of materials : %ld", material_darray_len(materials));
+    material_darray_iter mat_iter = material_darray_iter_new(materials);
+    blinn_phong_material *cur_material;
+    while ((cur_material = material_darray_iter_next(&mat_iter))) {
+      printf("Material name %s vs %s \n", cur_material->name, current_material_name);
+      if (strcmp(cur_material->name, current_material_name) == 0) {
+        DEBUG("Found match");
+        m.material_index = mat_iter.current_idx - 1;
+        found = true;
+        break;
+      }
+    }
+
+    if (!found) {
+      // TODO: default material
+      m.material_index = 0;
+      DEBUG("Set default material");
+    }
+  }
+  mesh_darray_push(meshes, m);
+}
+
+bool load_material_lib(const char *path, material_darray *materials) {
+  TRACE("BEGIN load material lib at %s", path);
+
+  const char *file_string = string_from_file(path);
+  if (file_string == NULL) {
+    ERROR("couldnt load %s", path);
+    return false;
+  }
+
+  char *pch;
+  char *saveptr;
+  pch = strtok_r((char *)file_string, "\n", &saveptr);
+
+  material current_material = DEFAULT_MATERIAL;
+
+  bool material_set = false;
+
+  while (pch != NULL) {
+    char line_header[128];
+    int offset = 0;
+    // read the first word of the line
+    int res = sscanf(pch, "%s %n", line_header, &offset);
+    if (res != 1) {
+      break;
+    }
+
+    // When we see "newmtl", start a new material, or flush the previous one
+    if (strcmp(line_header, "newmtl") == 0) {
+      if (material_set) {
+        // a material was being parsed, so flush that one and start a new one
+        material_darray_push(materials, current_material);
+        DEBUG("pushed material with name %s", current_material.name);
+        WARN("Reset current material");
+        current_material = DEFAULT_MATERIAL;
+      } else {
+        material_set = true;
+      }
+      // scan the new material name
+      char material_name[64];
+      sscanf(pch + offset, "%s", current_material.name);
+      DEBUG("material name %s\n", current_material.name);
+      // current_material.name = material_name;
+    } else if (strcmp(line_header, "Ka") == 0) {
+      // ambient
+      sscanf(pch + offset, "%f %f %f", &current_material.ambient_colour.x,
+             &current_material.ambient_colour.y, &current_material.ambient_colour.z);
+    } else if (strcmp(line_header, "Kd") == 0) {
+      // diffuse
+      sscanf(pch + offset, "%f %f %f", &current_material.diffuse.x, &current_material.diffuse.y,
+             &current_material.diffuse.z);
+    } else if (strcmp(line_header, "Ks") == 0) {
+      // specular
+      sscanf(pch + offset, "%f %f %f", &current_material.specular.x, &current_material.specular.y,
+             &current_material.specular.z);
+    } else if (strcmp(line_header, "Ns") == 0) {
+      // specular exponent
+      sscanf(pch + offset, "%f", &current_material.spec_exponent);
+    } else if (strcmp(line_header, "map_Kd") == 0) {
+      char diffuse_map_path[1024] = "assets/";
+      sscanf(pch + offset, "%s", diffuse_map_path + 7);
+      printf("load from %s\n", diffuse_map_path);
+      // --------------
+      texture diffuse_texture = texture_data_load(diffuse_map_path, true);
+      current_material.diffuse_texture = diffuse_texture;
+      strcpy(current_material.diffuse_tex_path, diffuse_map_path);
+      texture_data_upload(&current_material.diffuse_texture);
+      // --------------
+    } else if (strcmp(line_header, "map_Ks") == 0) {
+      char specular_map_path[1024] = "assets/";
+      sscanf(pch + offset, "%s", specular_map_path + 7);
+      // --------------
+      texture specular_texture = texture_data_load(specular_map_path, true);
+      current_material.specular_texture = specular_texture;
+      strcpy(current_material.specular_tex_path, specular_map_path);
+      texture_data_upload(&current_material.specular_texture);
+      // --------------
+    } else if (strcmp(line_header, "map_Bump") == 0) {
+      // TODO
+    }
+
+    pch = strtok_r(NULL, "\n", &saveptr);
+  }
+
+  // last mesh or if one wasnt created with 'o' directive
+  // TRACE("Last leftover material");
+  material_darray_push(materials, current_material);
+
+  INFO("Loaded %ld materials", material_darray_len(materials));
+  TRACE("END load material lib");
+  return true;
+}