fix TAA when camera is far from the origin

The intermediate transforms needed to be kept in double precision.

filament/src/FrameHistory.h

@@ -31,14 +31,14 @@ struct FrameHistoryEntry {
     struct TemporalAA{
         FrameGraphTexture color;
         FrameGraphTexture::Descriptor desc;
-        math::mat4f projection;     // world space to clip space
+        math::mat4 projection;     // world space to clip space
         math::float2 jitter{};
         uint32_t frameId = 0;   // used for halton sequence
     } taa;
     struct {
         FrameGraphTexture color;
         FrameGraphTexture::Descriptor desc;
-        math::mat4f projection;
+        math::mat4 projection;
     } ssr;
 };
 

filament/src/PostProcessManager.cpp

@@ -482,23 +482,20 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::ssr(FrameGraph& fg,
         FrameGraphId<FrameGraphTexture> history;
     };
 
-    mat4f historyProjection;
-    FrameGraphId<FrameGraphTexture> history;
-
-    FrameHistoryEntry const& entry = frameHistory[0];
-    if (entry.ssr.color.handle) {
-        // the first time around we may not have a history buffer
-        history = fg.import("SSR history", entry.ssr.desc,
-                FrameGraphTexture::Usage::SAMPLEABLE, entry.ssr.color);
-        historyProjection = entry.ssr.projection;
+    auto const& previous = frameHistory.getPrevious().ssr;
+    if (!previous.color.handle) {
+        return {};
     }
 
+    FrameGraphId<FrameGraphTexture> history = fg.import("SSR history", previous.desc,
+            FrameGraphTexture::Usage::SAMPLEABLE, previous.color);
+    mat4 const& historyProjection = previous.projection;
     auto const& uvFromClipMatrix = mEngine.getUvFromClipMatrix();
 
     auto& ssrPass = fg.addPass<SSRPassData>("SSR Pass",
             [&](FrameGraph::Builder& builder, auto& data) {
 
-                // create our reflection buffer. We need an alpha channel, so we have to use RGBA16F
+                // Create our reflection buffer. We need an alpha channel, so we have to use RGBA16F
                 data.reflections = builder.createTexture("Reflections Texture", {
                         .width = desc.width, .height = desc.height,
                         .format = TextureFormat::RGBA16F });
@@ -537,8 +534,8 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::ssr(FrameGraph& fg,
 
                 // set screen-space reflections and screen-space refractions
                 mat4f const uvFromViewMatrix = uvFromClipMatrix * projection;
-                mat4f const reprojection = mat4f{ uvFromClipMatrix * historyProjection
-                        * inverse(userViewMatrix) };
+                mat4f const reprojection = uvFromClipMatrix *
+                        mat4f{ historyProjection * inverse(userViewMatrix) };
 
                 // the history sampler is a regular texture2D
                 TextureHandle const history = data.history ?
@@ -2493,7 +2490,7 @@ void PostProcessManager::prepareTaa(FrameGraph& fg, filament::Viewport const& sv
     auto& current = frameHistory.getCurrent().*pTaa;
 
     // compute projection
-    current.projection = mat4f{ inoutCameraInfo->projection * inoutCameraInfo->getUserViewMatrix() };
+    current.projection = inoutCameraInfo->projection * inoutCameraInfo->getUserViewMatrix();
     current.frameId = previous.frameId + 1;
 
     // sample position within a pixel [-0.5, 0.5]
@@ -2527,18 +2524,16 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::taa(FrameGraph& fg,
     auto const& previous = frameHistory.getPrevious().*pTaa;
     auto& current = frameHistory.getCurrent().*pTaa;
 
-    FrameGraphId<FrameGraphTexture> colorHistory;
-    mat4f historyProjection;
-    if (UTILS_UNLIKELY(!previous.color.handle)) {
-        // if we don't have a history yet, just use the current color buffer as history
-        colorHistory = input;
-        historyProjection = current.projection;
-    } else {
+    // if we don't have a history yet, just use the current color buffer as history
+    FrameGraphId<FrameGraphTexture> colorHistory = input;
+    if (UTILS_LIKELY(previous.color.handle)) {
         colorHistory = fg.import("TAA history", previous.desc,
                 FrameGraphTexture::Usage::SAMPLEABLE, previous.color);
-        historyProjection = previous.projection;
     }
 
+    mat4 const& historyProjection = previous.color.handle ?
+            previous.projection : current.projection;
+
     struct TAAData {
         FrameGraphId<FrameGraphTexture> color;
         FrameGraphId<FrameGraphTexture> depth;
@@ -2617,8 +2612,7 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::taa(FrameGraph& fg,
                 });
                 mi->setParameter("filterWeights",  weights, 9);
                 mi->setParameter("reprojection",
-                        historyProjection *
-                        inverse(current.projection) *
+                        mat4f{ historyProjection * inverse(current.projection) } *
                         normalizedToClip);
 
                 mi->commit(driver);

filament/src/details/Renderer.cpp

@@ -854,9 +854,11 @@ void FRenderer::renderJob(ArenaScope& arena, FView& view) {
                 ssReflectionsOptions,
                 { .width = svp.width, .height = svp.height });
 
-        // generate the mipchain
-        PostProcessManager::generateMipmapSSR(ppm, fg,
-                reflections, ssrConfig.reflection, false, ssrConfig);
+        if (UTILS_LIKELY(reflections)) {
+            // generate the mipchain
+            PostProcessManager::generateMipmapSSR(ppm, fg,
+                    reflections, ssrConfig.reflection, false, ssrConfig);
+        }
     }
 
     // --------------------------------------------------------------------------------------------
@@ -956,7 +958,7 @@ void FRenderer::renderJob(ArenaScope& arena, FView& view) {
             FrameGraphId<FrameGraphTexture> history;
         };
         // FIXME: should we use the TAA-modified cameraInfo here or not? (we are).
-        auto projection = mat4f{ cameraInfo.projection * cameraInfo.getUserViewMatrix() };
+        mat4 const projection = cameraInfo.projection * cameraInfo.getUserViewMatrix();
         fg.addPass<ExportSSRHistoryData>("Export SSR history",
                 [&](FrameGraph::Builder& builder, auto& data) {
                     // We need to use sideEffect here to ensure this pass won't be culled.

filament/src/details/View.cpp

@@ -394,7 +394,7 @@ CameraInfo FView::computeCameraInfo(FEngine& engine) const noexcept {
 
     /*
      * We apply a "world origin" to "everything" in order to implement the IBL rotation.
-     * The "world origin" is also be used to kee the origin close to the camera position to
+     * The "world origin" is also used to keep the origin close to the camera position to
      * improve fp precision in the shader for large scenes.
      */
     mat4 translation;