[Tizen] Implement partial update

[platform/core/uifw/dali-core.git] / dali / internal / render / common / render-manager.cpp

diff --git a/dali/internal/render/common/render-manager.cpp b/dali/internal/render/common/render-manager.cpp
index 630f870..986e430 100755 (executable)
--- a/dali/internal/render/common/render-manager.cpp
+++ b/dali/internal/render/common/render-manager.cpp
@@ -62,10 +62,38 @@ Debug::Filter* gLogFilter = Debug::Filter::New(Debug::NoLogging, false, "LOG_REN
 } // unnamed namespace
 #endif
 
-const int partialUpdateMargin = 4u;
+namespace
+{
 const float partialUpdateRatio = 0.8f; // If the partial update area exceeds 80%, change to full update.
 
 /**
+ * @brief Find the intersection of two AABB rectangles.
+ * This is a logical AND operation. IE. The intersection is the area overlapped by both rectangles.
+ * @param[in]     aabbA                  Rectangle A
+ * @param[in]     aabbB                  Rectangle B
+ * @return                               The intersection of rectangle A & B (result is a rectangle)
+ */
+inline ClippingBox IntersectAABB( const ClippingBox& aabbA, const ClippingBox& aabbB )
+{
+  ClippingBox intersectionBox;
+
+  // First calculate the largest starting positions in X and Y.
+  intersectionBox.x = std::max( aabbA.x, aabbB.x );
+  intersectionBox.y = std::max( aabbA.y, aabbB.y );
+
+  // Now calculate the smallest ending positions, and take the largest starting
+  // positions from the result, to get the width and height respectively.
+  // If the two boxes do not intersect at all, then we need a 0 width and height clipping area.
+  // We use max here to clamp both width and height to >= 0 for this use-case.
+  intersectionBox.width =  std::max( std::min( aabbA.x + aabbA.width,  aabbB.x + aabbB.width  ) - intersectionBox.x, 0 );
+  intersectionBox.height = std::max( std::min( aabbA.y + aabbA.height, aabbB.y + aabbB.height ) - intersectionBox.y, 0 );
+
+  return intersectionBox;
+}
+
+}
+
+/**
  * Structure to contain internal data
  */
 struct RenderManager::Impl
@@ -646,10 +674,27 @@ bool GetDamagedRect( Rect<int32_t> &viewportRect, RenderInstruction& instruction
 
   if( isPartialUpdate )
   {
-    damagedRect.x = dx1 - partialUpdateMargin;
-    damagedRect.y = dy1 - partialUpdateMargin;
-    damagedRect.width = dx2 - dx1 + ( 2 * partialUpdateMargin );
-    damagedRect.height = dy2 - dy1 + ( 2 * partialUpdateMargin );
+    if( dx1 < 0.0f )
+    {
+      dx1 = 0.0f;
+    }
+    if( dy1 < 0.0f )
+    {
+      dy1 = 0.0f;
+    }
+    if( dx2 > viewportRect.width )
+    {
+      dx2 = viewportRect.width;
+    }
+    if( dy2 > viewportRect.height )
+    {
+      dy2 = viewportRect.height;
+    }
+
+    damagedRect.x = dx1;
+    damagedRect.y = dy1;
+    damagedRect.width = dx2 - dx1;
+    damagedRect.height = dy2 - dy1;
   }
 
   return isPartialUpdate;
@@ -663,6 +708,7 @@ void RenderManager::DoRender( RenderInstruction& instruction )
   Rect<int32_t> damagedRect;
   Rect<int32_t> mergedRect;
   Dali::ClippingBox scissorBox;
+  Dali::ClippingBox intersectRect;
 
   if ( instruction.mIsClearColorSet )
   {
@@ -793,13 +839,15 @@ void RenderManager::DoRender( RenderInstruction& instruction )
   // It is important to clear all 3 buffers when they are being used, for performance on deferred renderers
   // e.g. previously when the depth & stencil buffers were NOT cleared, it caused the DDK to exceed a "vertex count limit",
   // and then stall. That problem is only noticeable when rendering a large number of vertices per frame.
-  mImpl->currentContext->SetScissorTest( false );
-
   if( isPartialUpdate )
   {
     mImpl->currentContext->SetScissorTest( true );
     mImpl->currentContext->Scissor( scissorBox.x, scissorBox.y, scissorBox.width, scissorBox.height );
   }
+  else
+  {
+    mImpl->currentContext->SetScissorTest( false );
+  }
 
   GLbitfield clearMask = GL_COLOR_BUFFER_BIT;
 
@@ -899,7 +947,8 @@ void RenderManager::DoRender( RenderInstruction& instruction )
     mImpl->currentContext->SetScissorTest( true );
     if( isPartialUpdate )
     {
-      mImpl->currentContext->Scissor( scissorBox.x, scissorBox.y, scissorBox.width, scissorBox.height );
+      intersectRect = IntersectAABB( scissorBox, viewportRect );
+      mImpl->currentContext->Scissor( intersectRect.x, intersectRect.y, intersectRect.width, intersectRect.height );
     }
     else
     {