Accumulation in Viewer Screenshots

• Add option to increase accumulation in viewer screenshot tool
• Fix adaptive sample count interactions during screenshots

viewer/glow-extras/viewer/ViewerApp.cc

@@ -111,13 +111,16 @@ void ViewerApp::updateLayoutNodes(float dt, tg::ivec2 size)
     layout::build_linear_nodes(rootNode, {0, 0}, size, mLayoutNodes, mSubviewMargin);
 }
 
-void ViewerApp::renderFrame(int width, int height)
+void ViewerApp::renderFrame(int width, int height, bool maximizeSamples)
 {
 #ifdef GLOW_EXTRAS_OPENGL_DEBUG_GROUPS
     GLOW_SCOPED(debugGroup, "Render Viewer");
 #endif
     mRenderer.beginFrame(mSubviewMarginColor);
 
+    if (maximizeSamples)
+        mRenderer.maximizeSamples();
+
     for (auto& node : mLayoutNodes)
     {
 #ifdef GLOW_EXTRAS_OPENGL_DEBUG_GROUPS
@@ -139,7 +142,7 @@ void ViewerApp::renderFrame(int width, int height)
         }
     }
 
-    mRenderer.endFrame(getLastGpuTimeMs());
+    mRenderer.endFrame(maximizeSamples ? 0.f : getLastGpuTimeMs());
 }
 
 void ViewerApp::resetCameraToScene()
@@ -446,6 +449,8 @@ void ViewerApp::onGui()
 
             ImGui::Checkbox("Show non-transparent pixels", &mShowNonTransparentPixels);
 
+            ImGui::SliderInt("Accumulation Count", &mScreenshotAccumulationCount, 1, 64);
+
             ImGui::Checkbox("Custom Resolution", &mScreenshotCustomRes);
             if (ImGui::SliderInt("Screenshot Width", &mScreenshotWidth, 1, 16000))
                 mScreenshotCustomRes = true;
@@ -477,7 +482,8 @@ void ViewerApp::renderScreenshot(const std::string& filename, int w, int h)
 
     {
         auto fbo = temporaryFbo->bind();
-        renderFrame(screenW, screenH);
+        for (auto _ = 0; _ < mScreenshotAccumulationCount; ++_)
+            renderFrame(screenW, screenH, true);
     }
 
     target->bind().writeToFile(filename);