Fix glTF camera aspect ratio (google#2807)

daichen · Jul 13, 2020 · 7c4661c · 7c4661c
1 parent c7b6d45
commit 7c4661c
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Showing 4 changed files with 14 additions and 4 deletions.
diff --git a/filament/include/filament/Camera.h b/filament/include/filament/Camera.h
@@ -212,7 +212,13 @@ class UTILS_PUBLIC Camera : public FilamentAPI {
      * First, pass an aspect of 1.0 to setProjection. Then set the scaling with the desired aspect
      * ratio:
      *
-     *     camera->setScaling(double4 {1.0, width / height, 1.0, 1.0});
+     *     const double aspect = width / height;
+     *
+     *     // with Fov::HORIZONTAL passed to setProjection:
+     *     camera->setScaling(double4 {1.0, aspect, 1.0, 1.0});
+     *
+     *     // with Fov::VERTICAL passed to setProjection:
+     *     camera->setScaling(double4 {1.0 / aspect, 1.0, 1.0, 1.0});
      *
      *
      * By default, this is an identity matrix.

diff --git a/libs/gltfio/include/gltfio/FilamentAsset.h b/libs/gltfio/include/gltfio/FilamentAsset.h
@@ -88,6 +88,10 @@ class FilamentAsset {
      * The camera's scaling matrix allows clients to adjust the aspect ratio independently from the
      * camera's projection.
      *
+     * To change the aspect ratio of the glTF camera:
+     *
+     *     camera->setScaling(double4 {1.0 / newAspectRatio, 1.0, 1.0, 1.0});
+     *
      * @see filament::Camera::setScaling
      */
     const utils::Entity* getCameraEntities() const noexcept;

diff --git a/libs/gltfio/src/AssetLoader.cpp b/libs/gltfio/src/AssetLoader.cpp
@@ -827,7 +827,7 @@ void FAssetLoader::createCamera(const cgltf_camera* camera, Entity entity) {
         const double aspect = projection.aspect_ratio > 0.0 ? projection.aspect_ratio : 1.0;
 
         // Use the scaling matrix to set the aspect ratio, so clients can easily change it.
-        filamentCamera->setScaling(double4 {1.0, aspect, 1.0, 1.0});
+        filamentCamera->setScaling(double4 {1.0 / aspect, 1.0, 1.0, 1.0});
     } else if (camera->type == cgltf_camera_type_orthographic) {
         auto& projection = camera->data.orthographic;
 

diff --git a/samples/gltf_viewer.cpp b/samples/gltf_viewer.cpp
@@ -770,7 +770,7 @@ int main(int argc, char** argv) {
         }
         const Viewport& vp = view->getViewport();
         double aspectRatio = (double) vp.width / vp.height;
-        camera.setScaling(double4 {1.0, aspectRatio, 1.0, 1.0});
+        camera.setScaling(double4 {1.0 / aspectRatio, 1.0, 1.0, 1.0});
     };
 
     auto gui = [&app](Engine* engine, View* view) {
@@ -799,7 +799,7 @@ int main(int argc, char** argv) {
                 // camera to the viewport.
                 const Viewport& vp = view->getViewport();
                 double aspectRatio = (double) vp.width / vp.height;
-                c->setScaling(double4 {1.0, aspectRatio, 1.0, 1.0});
+                c->setScaling(double4 {1.0 / aspectRatio, 1.0, 1.0, 1.0});
             } else {
                 // gltfCamera is out of bounds. Reset camera selection to main camera.
                 app.currentCamera = 0;