[idd] transport: intersect frame capabilities

idd/LGIdd/transport/lgmp/CLGMPFrameCaps.cpp

@@ -0,0 +1,112 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "transport/lgmp/CLGMPFrameCaps.h"
+
+#include <d3d12.h>
+#include <limits>
+
+namespace
+{
+  static const uint64_t FRAME_BYTES_PER_PIXEL = 4;
+
+  bool AlignUp(uint64_t value, uint64_t alignment, uint64_t& result)
+  {
+    if (!alignment || (alignment & (alignment - 1)))
+      return false;
+
+    const uint64_t mask = alignment - 1;
+    if (value > (std::numeric_limits<uint64_t>::max)() - mask)
+      return false;
+    result = (value + mask) & ~mask;
+    return true;
+  }
+
+  bool CalculateFrameSize(
+    const FrameMode& mode, uint64_t& frameSize)
+  {
+    frameSize = 0;
+    if (!mode.width || !mode.height || !mode.refreshMilliHz)
+      return false;
+
+    uint64_t pitch;
+    if (!AlignUp((uint64_t)mode.width * FRAME_BYTES_PER_PIXEL,
+        D3D12_TEXTURE_DATA_PITCH_ALIGNMENT, pitch) ||
+        pitch > (std::numeric_limits<uint64_t>::max)() / mode.height)
+      return false;
+
+    frameSize = pitch * mode.height;
+    return true;
+  }
+
+  uint32_t RecommendedSizeMiB(uint64_t requiredSize)
+  {
+    uint64_t sizeMiB = requiredSize / 1048576;
+    if (requiredSize % 1048576)
+      ++sizeMiB;
+
+    uint64_t result = 1;
+    while (result < sizeMiB && result <= UINT32_MAX / 2)
+      result <<= 1;
+    return result < sizeMiB ? UINT32_MAX : (uint32_t)result;
+  }
+}
+
+CLGMPFrameCaps::CLGMPFrameCaps(uint64_t capacity,
+    uint64_t frameMemoryOffset, uint32_t bufferCount) :
+  m_capacity(capacity),
+  m_frameMemoryOffset(frameMemoryOffset),
+  m_bufferCount(bufferCount)
+{
+}
+
+bool CLGMPFrameCaps::CanUseMode(const FrameMode& mode,
+  uint32_t * requiredSizeMiB) const
+{
+  if (requiredSizeMiB)
+    *requiredSizeMiB = 0;
+
+  const uint64_t alignment =
+    D3D12_DEFAULT_RESOURCE_PLACEMENT_ALIGNMENT;
+  uint64_t frameSize;
+  if (!m_frameMemoryOffset || !m_bufferCount ||
+      !CalculateFrameSize(mode, frameSize) ||
+      frameSize > (std::numeric_limits<uint64_t>::max)() - alignment)
+    return false;
+
+  uint64_t frameAllocationSize;
+  uint64_t frameMemoryStart;
+  if (!AlignUp(frameSize + alignment, alignment,
+        frameAllocationSize) ||
+      !AlignUp(m_frameMemoryOffset, alignment, frameMemoryStart) ||
+      frameAllocationSize >
+        ((std::numeric_limits<uint64_t>::max)() - frameMemoryStart) /
+          m_bufferCount)
+    return false;
+
+  const uint64_t requiredSize = frameMemoryStart +
+    frameAllocationSize * m_bufferCount;
+  if (requiredSize <= m_capacity)
+    return true;
+
+  if (requiredSizeMiB)
+    *requiredSizeMiB = RecommendedSizeMiB(requiredSize);
+  return false;
+}