Build glyphs for distance field texts earlier in OpenGL RT

Build and cache glyphs for distance field texts at the first frame
regardless of text initial state. Glyph building is a heavy operation that
causes a visible freeze in the animation when a text element becomes active
after initial inactivity. Additionally, build associated shaders at
presentation load time.

Task-id: QT3DS-3503
Change-Id: If1e0c81f26d731f1bbd1cd7bcd745400c8ff6920
Reviewed-by: Jere Tuliniemi <jere.tuliniemi@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
 

4 files changed, 27 insertions, 7 deletions

diff --git a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
index 960e0a2f..290964b2 100644
--- a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
+++ b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
@@ -954,6 +954,7 @@ void Q3DSDistanceFieldRenderer::setContext(IQt3DSRenderContext &context)
 {
     m_context = &context;
     m_glyphCacheManager.setContext(context);
+    buildShaders();
 }
 
 ITextRendererCore &ITextRendererCore::createDistanceFieldRenderer(NVFoundationBase &fnd)
@@ -1046,4 +1047,14 @@ STextTextureAtlasEntryDetails Q3DSDistanceFieldRenderer::RenderAtlasEntry(QT3DSU
     return STextTextureAtlasEntryDetails();
 }
 
+bool Q3DSDistanceFieldRenderer::checkAndBuildGlyphs(SText &text)
+{
+    auto hashVal = getTextHashValue(text);
+    if (!m_glyphCache.contains(hashVal)) {
+        m_glyphCache[hashVal] = buildGlyphsPerTexture(text);
+        return true;
+    }
+
+    return false;
+}
 #endif
diff --git a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.h b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.h
index c82a0e80..3af19a98 100644
--- a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.h
+++ b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.h
@@ -105,6 +105,8 @@ public:
     void renderTextDepth(SText &text, const QT3DSMat44 &mvp);
     void setContext(IQt3DSRenderContext &context);
 
+    bool checkAndBuildGlyphs(SText &text);
+
     QT3DS_IMPLEMENT_REF_COUNT_ADDREF_RELEASE_OVERRIDE(m_foundation.getAllocator())
 
     void AddSystemFontDirectory(const char8_t *dir) override;
diff --git a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRenderableObjects.h b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRenderableObjects.h
index 39e73e8e..a369f7a1 100644
--- a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRenderableObjects.h
+++ b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRenderableObjects.h
@@ -413,6 +413,7 @@ namespace render {
             m_RenderableFlags.SetCustom(false);
             m_RenderableFlags.SetText(false);
             m_RenderableFlags.setDistanceField(true);
+            m_distanceFieldText.checkAndBuildGlyphs(text);
         }
 
         void Render(const QT3DSVec2 &inCameraVec);
diff --git a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
index d5aecc57..4f274574 100644
--- a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
+++ b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
@@ -415,8 +415,11 @@ namespace render {
                 theFlags, inText.GetGlobalPos(), m_Renderer, inText, inText.m_Bounds, theMVP,
                 inViewProjection, *inText.m_TextTexture, theTextOffset, theTextScale);
 #endif
-
-            m_TransparentObjects.push_back(theRenderable);
+            // After preparation, do not push object back to queue if it is not
+            // active, because we prepare text elements regardless of their
+            // visibility (=active status).
+            if (inText.m_Flags.IsGloballyActive())
+                m_TransparentObjects.push_back(theRenderable);
         }
         return retval;
     }
@@ -1041,11 +1044,14 @@ namespace render {
                 if (hasTextRenderer) {
                     SText *theText = static_cast<SText *>(theNode);
                     theText->CalculateGlobalVariables();
-                    if (theText->m_Flags.IsGloballyActive()) {
-                        bool wasTextDirty = PrepareTextForRender(*theText, inViewProjection,
-                                                                 theTextScaleFactor, ioFlags);
-                        wasDataDirty = wasDataDirty || wasTextDirty;
-                    }
+                    // Omit check for global active flag intentionally and force
+                    // render preparation for all Text items. This eliminates
+                    // large delay for distance field text items becoming active
+                    // mid-animation.
+                    bool wasTextDirty = PrepareTextForRender(*theText, inViewProjection,
+                                                             theTextScaleFactor, ioFlags);
+                    wasDataDirty = wasDataDirty || wasTextDirty;
+
                 }
             } break;
             case GraphObjectTypes::Path: {