[WebGL 2] primitive restart should be always enabled

gpu/command_buffer/service/buffer_manager.cc

Index: gpu/command_buffer/service/buffer_manager.cc
diff --git a/gpu/command_buffer/service/buffer_manager.cc b/gpu/command_buffer/service/buffer_manager.cc
index 914d9b09da06e8fb3a71c2162e9a8e6291dea962..04b03ca2e6aac3d67d4caadc8b18fb9769ee3a8c 100644
--- a/gpu/command_buffer/service/buffer_manager.cc
+++ b/gpu/command_buffer/service/buffer_manager.cc
@@ -34,6 +34,7 @@ BufferManager::BufferManager(MemoryTracker* memory_tracker,
       allow_buffers_on_multiple_targets_(false),
       allow_fixed_attribs_(false),
       buffer_count_(0),
+      primitive_restart_enabled_(false),
       have_context_(true),
       use_client_side_arrays_for_stream_buffers_(
           feature_info
@@ -199,13 +200,17 @@ void Buffer::ClearCache() {
 }
 
 template <typename T>
-GLuint GetMaxValue(const void* data, GLuint offset, GLsizei count) {
+GLuint GetMaxValue(const void* data, GLuint offset, GLsizei count,
+    GLuint primitive_restart_index) {
   GLuint max_value = 0;
   const T* element =
       reinterpret_cast<const T*>(static_cast<const int8_t*>(data) + offset);
   const T* end = element + count;
   for (; element < end; ++element) {
     if (*element > max_value) {
+      if (*element == primitive_restart_index) {
+        continue;
+      }
       max_value = *element;
     }
   }
@@ -241,23 +246,36 @@ bool Buffer::GetMaxValueForRange(
 
   // Scan the range for the max value and store
   GLuint max_v = 0;
+  GLuint primitive_restart_index = 0;
   switch (type) {
     case GL_UNSIGNED_BYTE:
-      max_v = GetMaxValue<uint8_t>(shadow_.get(), offset, count);
+      if (manager_->primitive_restart_enabled_) {
+        primitive_restart_index = 0xFF;
+      }
+      max_v = GetMaxValue<uint8_t>(shadow_.get(), offset, count,
+          primitive_restart_index);
       break;
     case GL_UNSIGNED_SHORT:
       // Check we are not accessing an odd byte for a 2 byte value.
       if ((offset & 1) != 0) {
         return false;
       }
-      max_v = GetMaxValue<uint16_t>(shadow_.get(), offset, count);
+      if (manager_->primitive_restart_enabled_) {
+        primitive_restart_index = 0xFFFF;
+      }
+      max_v = GetMaxValue<uint16_t>(shadow_.get(), offset, count,
+          primitive_restart_index);
       break;
     case GL_UNSIGNED_INT:
       // Check we are not accessing a non aligned address for a 4 byte value.
       if ((offset & 3) != 0) {
         return false;
       }
-      max_v = GetMaxValue<uint32_t>(shadow_.get(), offset, count);
+      if (manager_->primitive_restart_enabled_) {
+        primitive_restart_index = 0xFFFFFFFF;
+      }
+      max_v = GetMaxValue<uint32_t>(shadow_.get(), offset, count,
+          primitive_restart_index);
       break;
     default:
       NOTREACHED();  // should never get here by validation.
@@ -536,6 +554,19 @@ Buffer* BufferManager::GetBufferInfoForTarget(
   }
 }
 
+void BufferManager::SetPrimitiveRestartState(bool enabled) {
+  if (primitive_restart_enabled_ != enabled) {
+    primitive_restart_enabled_ = enabled;
+
+    for (BufferMap::const_iterator it = buffers_.begin();
+       it != buffers_.end(); ++it) {

[Zhenyao Mo, 2016/03/15 18:24:37]

nit: wrong indent

[yunchao, 2016/03/16 16:05:39]

Done.

+      if (it->second->initial_target() == GL_ELEMENT_ARRAY_BUFFER) {
+        it->second->range_set_.clear();
+      }
+    }
+  }
+}
+
 bool BufferManager::OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                                  base::trace_event::ProcessMemoryDump* pmd) {
   const int client_id = memory_tracker_->ClientId();