Silently disable MSAA for FL0. (#9807)

Author: PatRibas

filament/include/filament/View.h

@@ -318,6 +318,8 @@ class UTILS_PUBLIC View : public FilamentAPI {
     /**
      * Sets how many samples are to be used for MSAA in the post-process stage.
      * Default is 1 and disables MSAA.
+     * Note that post-processing is disabled at FL0. If the feature level is 
+     * set to 0, values passed to this function are ignored.
      *
      * @param count number of samples to use for multi-sampled anti-aliasing.\n
      *              0: treated as 1
@@ -408,7 +410,9 @@ class UTILS_PUBLIC View : public FilamentAPI {
 
     /**
      * Enables or disable multi-sample anti-aliasing (MSAA). Disabled by default.
-     *
+     * Note that MSAA is a post-processing effect, and post-processing is disabled at FL0. 
+     * If the feature level is set to 0, values passed to this function are ignored.
+     * 
      * @param options multi-sample anti-aliasing options
      */
     void setMultiSampleAntiAliasingOptions(MultiSampleAntiAliasingOptions options) noexcept;

filament/src/details/View.cpp

@@ -106,6 +106,8 @@ FView::FView(FEngine& engine)
 {
     DriverApi& driver = engine.getDriverApi();
 
+    mFeatureLevel = engine.getSupportedFeatureLevel();
+
     auto const& layout = engine.getPerRenderableDescriptorSetLayout();
 
     // initialize the common descriptor set with dummy descriptors
@@ -1438,9 +1440,12 @@ void FView::setTemporalAntiAliasingOptions(TemporalAntiAliasingOptions options)
 }
 
 void FView::setMultiSampleAntiAliasingOptions(MultiSampleAntiAliasingOptions options) noexcept {
-    options.sampleCount = uint8_t(options.sampleCount < 1u ? 1u : options.sampleCount);
-    mMultiSampleAntiAliasingOptions = options;
-    assert_invariant(!options.enabled || !mRenderTarget || !mRenderTarget->hasSampleableDepth());
+    // MSAA is a post-process effect, and post-processing is disabled at FL0
+    if (mFeatureLevel >= backend::FeatureLevel::FEATURE_LEVEL_1) {
+        options.sampleCount = uint8_t(options.sampleCount < 1u ? 1u : options.sampleCount);
+        mMultiSampleAntiAliasingOptions = options;
+        assert_invariant(!options.enabled || !mRenderTarget || !mRenderTarget->hasSampleableDepth());
+    }
 }
 
 void FView::setScreenSpaceReflectionsOptions(ScreenSpaceReflectionsOptions options) noexcept {

filament/src/details/View.h

@@ -262,9 +262,12 @@ class FView : public View {
     }
 
     void setSampleCount(uint8_t count) noexcept {
-        count = uint8_t(count < 1u ? 1u : count);
-        mMultiSampleAntiAliasingOptions.sampleCount = count;
-        mMultiSampleAntiAliasingOptions.enabled = count > 1u;
+        // MSAA is a post-process effect, and post-processing is disabled at FL0
+        if (mFeatureLevel >= backend::FeatureLevel::FEATURE_LEVEL_1) {
+            count = uint8_t(count < 1u ? 1u : count);
+            mMultiSampleAntiAliasingOptions.sampleCount = count;
+            mMultiSampleAntiAliasingOptions.enabled = count > 1u;
+        }
     }
 
     uint8_t getSampleCount() const noexcept {
@@ -629,6 +632,8 @@ class FView : public View {
 
     utils::CString mName;
 
+    backend::FeatureLevel mFeatureLevel = backend::FeatureLevel::FEATURE_LEVEL_1;
+
     // the following values are set by prepare()
     Range mVisibleRenderables;
     Range mVisibleDirectionalShadowCasters;