From 49721f0fd489b234a9089cb53bd51e6f1ab26f7d Mon Sep 17 00:00:00 2001
From: "Arthur Brainville (Ybalrid)" <ybalrid@ybalrid.info>
Date: Mon, 19 Feb 2018 14:30:28 +0100
Subject: [PATCH] Add the entry point for loading gltf files.

Also switch on the primitive mode of each mesh. Will only attempt to
load lists of triangles for now...

Signed-off by: Arthur Brainville (Ybalrid) <ybalrid@ybalrid.info>
---
 examples/raytrace/config.json    | 32 +++++++++++++++++-------
 examples/raytrace/gltf-loader.cc | 42 ++++++++++++++++++++++++++++++++
 examples/raytrace/main.cc        |  9 +++++++
 3 files changed, 74 insertions(+), 9 deletions(-)

diff --git a/examples/raytrace/config.json b/examples/raytrace/config.json
index 78d1024..6b4984d 100644
--- a/examples/raytrace/config.json
+++ b/examples/raytrace/config.json
@@ -1,9 +1,23 @@
-{ "obj_filename" : "cornellbox_suzanne.obj",
-  "scene_scale" : 1.0,
-  "width" : 512,
-  "height" : 512,
-  "eye" : [0, 2.5, 15],
-  "up" : [0, 1, 0],
-  "look_at" : [0, 0, 0],
-  "dummy" : 0
-}
+{
+  "obj_filename": "cornellbox_suzanne.obj",
+  "gltf_filename": "../../models/Cube/Cube.gltf",
+  "scene_scale": 1.0,
+  "width": 512,
+  "height": 512,
+  "eye": [
+    0,
+    2.5,
+    15
+  ],
+  "up": [
+    0,
+    1,
+    0
+  ],
+  "look_at": [
+    0,
+    0,
+    0
+  ],
+  "dummy": 0
+}
\ No newline at end of file
diff --git a/examples/raytrace/gltf-loader.cc b/examples/raytrace/gltf-loader.cc
index 26cdb48..5ab5ac7 100644
--- a/examples/raytrace/gltf-loader.cc
+++ b/examples/raytrace/gltf-loader.cc
@@ -47,6 +47,48 @@ bool LoadGLTF(const std::string &filename, float scale,
   }
 
   std::cerr << "LoadGLTF() function is not yet implemented!" << std::endl;
+
+  std::cout << "loaded glTF file has:\n"
+            << model.accessors.size() << " accessors\n"
+            << model.animations.size() << " animations\n"
+            << model.buffers.size() << " buffers\n"
+            << model.bufferViews.size() << " bufferViews\n"
+            << model.materials.size() << " materials\n"
+            << model.meshes.size() << " meshes\n"
+            << model.nodes.size() << " nodes\n"
+            << model.textures.size() << " textures\n"
+            << model.images.size() << " images\n"
+            << model.skins.size() << " skins\n"
+            << model.samplers.size() << " samplers\n"
+            << model.cameras.size() << " cameras\n"
+            << model.scenes.size() << " scenes\n"
+            << model.lights.size() << " lights\n";
+
+  for (const auto &gltfMesh : model.meshes) {
+    std::cout << "Current mesh has " << gltfMesh.primitives.size()
+              << " primitives:\n";
+    for (const auto &meshPrimitive : gltfMesh.primitives) {
+      switch (meshPrimitive.mode) {
+        case TINYGLTF_MODE_TRIANGLES:  // this is the simpliest case to handle
+          std::cout << "Will load a plain old list of trianges\n";
+          break;
+
+        // Other trigangle based modes
+        case TINYGLTF_MODE_TRIANGLE_FAN:
+        case TINYGLTF_MODE_TRIANGLE_STRIP:
+        default:
+          std::cerr << "primitive mode not implemented";
+          break;
+
+        // These aren't triangles:
+        case TINYGLTF_MODE_POINTS:
+        case TINYGLTF_MODE_LINE:
+        case TINYGLTF_MODE_LINE_LOOP:
+          std::cerr << "primitive is not triangle based, ignoring";
+      }
+    }
+  }
+
   return false;
 }
 
diff --git a/examples/raytrace/main.cc b/examples/raytrace/main.cc
index 37b8af6..5e17a8d 100644
--- a/examples/raytrace/main.cc
+++ b/examples/raytrace/main.cc
@@ -765,6 +765,15 @@ int main(int argc, char **argv) {
         gScene.AddNode(node);
       }
     }
+
+    if (!gRenderConfig.gltf_filename.empty()) {
+      std::cout << "Found gltf file : " << gRenderConfig.gltf_filename << "\n";
+
+      bool ret =
+          LoadGLTF(gRenderConfig.gltf_filename, gRenderConfig.scene_scale,
+                   &meshes, &materials, &textures);
+    }
+
     if (!gScene.Commit()) {
       std::cerr << "Failed to commit the scene." << std::endl;
       return -1;