49 lines
2.0 KiB
C++
49 lines
2.0 KiB
C++
#include "Pixel_Frame.h"
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#include <cstring>
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#include <limits>
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namespace renderive::web {
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namespace {
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void write_u32_le(char* target, std::uint32_t value) {
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target[0] = static_cast<char>(value & 0xffU);
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target[1] = static_cast<char>((value >> 8U) & 0xffU);
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target[2] = static_cast<char>((value >> 16U) & 0xffU);
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target[3] = static_cast<char>((value >> 24U) & 0xffU);
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}
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void write_u64_le(char* target, std::uint64_t value) {
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write_u32_le(target, static_cast<std::uint32_t>(value));
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write_u32_le(target + 4, static_cast<std::uint32_t>(value >> 32U));
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}
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}
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std::string make_rgba8_pixel_frame(std::uint32_t width, std::uint32_t height, std::uint64_t sequence) {
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if (width == 0 || height == 0)
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return {};
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const std::size_t row_size = static_cast<std::size_t>(width) * 4U;
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if (static_cast<std::size_t>(height) > (std::numeric_limits<std::size_t>::max() - pixel_frame_header_size) / row_size)
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return {};
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std::string frame(pixel_frame_header_size + row_size * height, '\0');
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frame[0] = 'R';
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frame[1] = 'V';
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frame[2] = 'P';
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frame[3] = '2';
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write_u32_le(frame.data() + 4, width);
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write_u32_le(frame.data() + 8, height);
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write_u32_le(frame.data() + 12, static_cast<std::uint32_t>(row_size));
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write_u64_le(frame.data() + 16, sequence);
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return frame;
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}
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std::string encode_rgba8_pixel_frame(const std::byte* data, std::uint32_t width, std::uint32_t height, std::uint32_t stride, std::uint64_t sequence) {
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if (data == nullptr || stride < width * 4U)
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return {};
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std::string frame = make_rgba8_pixel_frame(width, height, sequence);
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if (frame.empty())
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return {};
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const std::size_t row_size = static_cast<std::size_t>(width) * 4U;
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char* output = frame.data() + pixel_frame_header_size;
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for (std::uint32_t y = 0; y < height; ++y) {
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const auto* row = data + static_cast<std::size_t>(y) * stride;
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std::memcpy(output + static_cast<std::size_t>(y) * row_size, row, row_size);
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}
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return frame;
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}
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}
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