Refactor GL surface format handling

ui/gl/gl_surface_format.cc

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/logging.h"
+#include "ui/gl/gl_surface_format.h"
+
+namespace gl {
+
+GLSurfaceFormat::GLSurfaceFormat() {
+}
+
+GLSurfaceFormat::GLSurfaceFormat(SurfacePixelLayout layout) {
+  is_default = false;
+  pixel_layout = layout;
+}
+
+GLSurfaceFormat::GLSurfaceFormat(const GLSurfaceFormat& other) = default;
+
+GLSurfaceFormat::~GLSurfaceFormat() {
+}
+
+bool GLSurfaceFormat::IsSurfaceless() {
+  return is_surfaceless;
+}
+
+GLSurfaceFormat::SurfacePixelLayout GLSurfaceFormat::GetPixelLayout() {
+  return pixel_layout;
+}
+
+void GLSurfaceFormat::SetDefaultPixelLayout(SurfacePixelLayout layout) {
+  if (pixel_layout == PIXEL_LAYOUT_DONT_CARE &&
+      layout != PIXEL_LAYOUT_DONT_CARE) {
+    pixel_layout = layout;
+    is_default = false;
+  }
+}
+
+void GLSurfaceFormat::SetRGB565() {
+  red_bits = blue_bits = 5;
+  green_bits = 6;
+  alpha_bits = 0;
+  is_default = false;
+}
+
+void GLSurfaceFormat::SetIsSurfaceless() {
+  is_surfaceless = true;
+  is_default = false;
+}
+
+static int GetValue(int num, int default_value) {
+  return num == -1 ? default_value : num;
+}
+
+static int GetBitSize(int num) {
+  return GetValue(num, 8);
+}
+
+
+bool GLSurfaceFormat::IsDefault() {
+  return is_default;
+}
+
+bool GLSurfaceFormat::IsCompatible(GLSurfaceFormat other) {
+  if (IsDefault() && other.IsDefault()) return true;
+
+  if (GetBitSize(red_bits) == GetBitSize(other.red_bits) &&
+      GetBitSize(green_bits) == GetBitSize(other.green_bits) &&
+      GetBitSize(blue_bits) == GetBitSize(other.blue_bits) &&
+      GetBitSize(alpha_bits) == GetBitSize(other.alpha_bits) &&
+      GetValue(stencil_bits, 8) == GetValue(other.stencil_bits, 8) &&
+      GetValue(depth_bits, 24) == GetValue(other.depth_bits, 24) &&
+      GetValue(samples, 0) == GetValue(other.samples, 0) &&
+      is_surfaceless == other.is_surfaceless &&
+      pixel_layout == other.pixel_layout) {
+    return true;
+  }
+  return false;
+}
+
+void GLSurfaceFormat::SetDepthBits(int bits) {
+  if (bits != -1) {
+    depth_bits = bits;
+    is_default = false;
+  }
+}
+
+int GLSurfaceFormat::GetDepthBits() {
+  return depth_bits;
+}
+
+void GLSurfaceFormat::SetStencilBits(int bits) {
+  if (bits != -1) {
+    stencil_bits = bits;
+    is_default = false;
+  }
+}
+
+int GLSurfaceFormat::GetStencilBits() {
+  return stencil_bits;
+}
+
+void GLSurfaceFormat::SetSamples(int num) {
+  if (num != -1) {
+    samples = num;
+    is_default = false;
+  }
+}
+
+int GLSurfaceFormat::GetSamples() {
+  return samples;
+}
+
+int GLSurfaceFormat::GetBufferSize() {
+  int bits = GetBitSize(red_bits) + GetBitSize(green_bits) +
+      GetBitSize(blue_bits) + GetBitSize(alpha_bits);
+  if (bits <= 16) {
+    return 16;
+  } else if (bits <= 32) {
+    return 32;
+  }
+  NOTREACHED();
+  return 64;
+}
+
+}  // namespace gl