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71 lines
1.9 KiB
71 lines
1.9 KiB
// Copyright 2019 The Amber Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "samples/ppm.h"
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#include <cassert>
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#include "amber/result.h"
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#include "amber/value.h"
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namespace ppm {
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namespace {
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const uint32_t kMaximumColorValue = 255;
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uint8_t byte0(uint32_t word) {
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return static_cast<uint8_t>(word & 0xff);
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}
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uint8_t byte1(uint32_t word) {
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return static_cast<uint8_t>((word >> 8) & 0xff);
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}
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uint8_t byte2(uint32_t word) {
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return static_cast<uint8_t>((word >> 16) & 0xff);
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}
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} // namespace
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amber::Result ConvertToPPM(uint32_t width,
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uint32_t height,
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const std::vector<amber::Value>& values,
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std::vector<uint8_t>* buffer) {
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assert(values.size() == (width * height) &&
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"Buffer values != width * height");
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assert(!values.empty() && "Buffer empty");
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// Write PPM header
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std::string image = "P6\n";
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image += std::to_string(width) + " " + std::to_string(height) + "\n";
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image += std::to_string(kMaximumColorValue) + "\n";
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for (char ch : image)
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buffer->push_back(static_cast<uint8_t>(ch));
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// Write PPM data
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for (amber::Value value : values) {
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const uint32_t pixel = value.AsUint32();
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// We assume B8G8R8A8_UNORM here:
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buffer->push_back(byte2(pixel)); // R
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buffer->push_back(byte1(pixel)); // G
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buffer->push_back(byte0(pixel)); // B
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// PPM does not support alpha channel
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}
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return {};
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}
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} // namespace ppm
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