cobalt/renderer/backend/graphics_context.cc

// Copyright 2017 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "cobalt/renderer/backend/graphics_context.h"

#include <string.h>

#include "base/logging.h"
#include "starboard/gles.h"
#include "starboard/string.h"

namespace cobalt {
namespace renderer {
namespace backend {

GraphicsContext::GraphicsContext(GraphicsSystem* system) : system_(system) {
  graphics_extension_ = static_cast<const CobaltExtensionGraphicsApi*>(
      SbSystemGetExtension(kCobaltExtensionGraphicsName));
  if (graphics_extension_) {
    // Verify it's the extension needed.
    if (strcmp(graphics_extension_->name, kCobaltExtensionGraphicsName) != 0 ||
        graphics_extension_->version < 1) {
      LOG(WARNING) << "Not using supplied cobalt graphics extension: " << "'"
                   << graphics_extension_->name << "' ("
                   << graphics_extension_->version << ")";
      graphics_extension_ = nullptr;
    }
  }
}

float GraphicsContext::GetMaximumFrameIntervalInMilliseconds() {
  if (graphics_extension_) {
    return graphics_extension_->GetMaximumFrameIntervalInMilliseconds();
  }

  // Allow the rasterizer to delay rendering indefinitely if nothing has
  // changed.
  return -1.0f;
}

float GraphicsContext::GetMinimumFrameIntervalInMilliseconds() {
  if (graphics_extension_ && graphics_extension_->version >= 2) {
    return graphics_extension_->GetMinimumFrameIntervalInMilliseconds();
  }

  // Return negative value, if the GraphicsExtension is not implemented
  // or the GraphicsExtension version is below 2.
  return -1.0f;
}

bool GraphicsContext::IsMapToMeshEnabled(
    const GraphicsContext* graphics_context) {
  const CobaltExtensionGraphicsApi* graphics_ext =
      graphics_context ? graphics_context->graphics_extension_ : nullptr;
#if defined(ENABLE_MAP_TO_MESH)
#error "ENABLE_MAP_TO_MESH is deprecated after Starboard version 12, use "
  "the Cobalt graphics extension function IsMapToMeshEnabled() instead."
#endif  // defined(ENABLE_MAP_TO_MESH)
      if (graphics_ext && graphics_ext->version >= 3) {
    return graphics_ext->IsMapToMeshEnabled();
  }

  // If there is a callable gles interface, assume map to mesh is enabled, as
  // it is for most platforms.
  return SbGetGlesInterface() != nullptr;
}

}  // namespace backend
}  // namespace renderer
}  // namespace cobalt