commit bc3b5e63e5ef8c28d85e9ec59f1ca6f1d411aaae
author Corentin Wallez <cwallez@chromium.org> Tue Jul 07 10:08:05 2015 -0700
committer Corentin Wallez <cwallez@chromium.org> Thu Jul 09 15:45:21 2015 +0000
tree bce9d6abdcdeb6f8e145e2bef33e4a8a1756a87b
parent 58832204fc00e40226bf1e23768676a337a7e400

D3D11: map index buffers only when needed.

Before this patch, index buffers where always mapped in case we needed the
index data for the indexed point sprites workaround.
This patch makes it so the index buffer is only mapped in this case, when
we need to stream index data or when we need to fill the static copies of
the index buffers.

This make the memory usage of
http://alteredqualia.com/xg/examples/mammoth.html go down from 41MB to
28MB.

BUG=angleproject:516

Change-Id: I937506d06fd6f074ef2120469dbd235e20245fca
Reviewed-on: https://chromium-review.googlesource.com/283626
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>

src/libANGLE/renderer/d3d/IndexDataManager.cpp

diff --git a/src/libANGLE/renderer/d3d/IndexDataManager.cpp b/src/libANGLE/renderer/d3d/IndexDataManager.cpp
index 0d1db5a..5328a03 100644
--- a/src/libANGLE/renderer/d3d/IndexDataManager.cpp
+++ b/src/libANGLE/renderer/d3d/IndexDataManager.cpp
@@ -133,9 +133,13 @@
     const gl::Type &srcTypeInfo = gl::GetTypeInfo(srcType);
     const gl::Type &dstTypeInfo = gl::GetTypeInfo(dstType);
 
+    BufferD3D *buffer = glBuffer ? GetImplAs<BufferD3D>(glBuffer) : nullptr;
+
     translated->indexType = dstType;
     if (sourceData)
     {
+        sourceData->srcBuffer = buffer;
+        sourceData->srcIndices = indices;
         sourceData->srcIndexType = srcType;
         sourceData->srcCount = count;
     }
@@ -144,16 +148,10 @@
     if (glBuffer == nullptr)
     {
         translated->storage = nullptr;
-        if (sourceData)
-        {
-            sourceData->srcIndices = indices;
-        }
         return streamIndexData(indices, count, srcType, dstType, translated);
     }
 
     // Case 2: the indices are already in a buffer
-    BufferD3D *buffer = GetImplAs<BufferD3D>(glBuffer);
-
     unsigned int offset = static_cast<unsigned int>(reinterpret_cast<uintptr_t>(indices));
     ASSERT(srcTypeInfo.bytes * static_cast<unsigned int>(count) + offset <= buffer->getSize());
 
@@ -166,21 +164,6 @@
       default: UNREACHABLE(); offsetAligned = false;
     }
 
-    // TODO(cwallez) avoid doing this in all cases as it prevents optimizations
-    // of the sysmem buffer copy
-    const uint8_t *bufferData = nullptr;
-    gl::Error error = buffer->getData(&bufferData);
-    if (error.isError())
-    {
-        return error;
-    }
-    ASSERT(bufferData != nullptr);
-
-    if (sourceData)
-    {
-        sourceData->srcIndices = bufferData + offset;
-    }
-
     // Case 2a: the buffer can be used directly
     if (offsetAligned && buffer->supportsDirectBinding() &&
         dstType == srcType && !primitiveRestartWorkaround)
@@ -213,7 +196,15 @@
 
     if (staticBuffer == nullptr || !offsetAligned)
     {
-        gl::Error error = streamIndexData(bufferData, count, srcType, dstType, translated);
+        const uint8_t *bufferData = nullptr;
+        gl::Error error = buffer->getData(&bufferData);
+        if (error.isError())
+        {
+            return error;
+        }
+        ASSERT(bufferData != nullptr);
+
+        error = streamIndexData(bufferData, count, srcType, dstType, translated);
         if (error.isError())
         {
             return error;
@@ -223,9 +214,17 @@
     {
         if (!staticBufferInitialized)
         {
+            const uint8_t *bufferData = nullptr;
+            gl::Error error = buffer->getData(&bufferData);
+            if (error.isError())
+            {
+                return error;
+            }
+            ASSERT(bufferData != nullptr);
+
             unsigned int convertCount = buffer->getSize() >> srcTypeInfo.bytesShift;
-            gl::Error error = StreamInIndexBuffer(staticBuffer, bufferData, convertCount,
-                                                  srcType, dstType, nullptr);
+            error = StreamInIndexBuffer(staticBuffer, bufferData, convertCount,
+                                        srcType, dstType, nullptr);
             if (error.isError())
             {
                 return error;