mirror of
https://github.com/encounter/aurora.git
synced 2026-07-09 18:19:33 -07:00
Luke Street
111 lines
3.0 KiB
C++
111 lines
3.0 KiB
C++
#include "png_io.hpp"
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#include <cstring>
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#include "dds_io.hpp"
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#include "png.h"
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#include "../fs_helper.hpp"
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static aurora::Module Log("aurora::gfx::png");
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namespace aurora::gfx::png {
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struct PngStructs {
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png_structp pStruct = nullptr;
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png_infop pInfo = nullptr;
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~PngStructs() {
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png_destroy_read_struct(&pStruct, &pInfo, nullptr);
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}
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};
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struct MemoryCursor {
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ArrayRef<uint8_t> bytes;
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size_t pos = 0;
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};
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static void readPngData(png_structp png, png_bytep data, const size_t length) {
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auto* cursor = static_cast<MemoryCursor*>(png_get_io_ptr(png));
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if (length > cursor->bytes.size() - cursor->pos) {
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png_error(png, "unexpected end of data");
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}
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std::memcpy(data, cursor->bytes.data() + cursor->pos, length);
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cursor->pos += length;
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}
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std::optional<ConvertedTexture> parse_png_bytes(ArrayRef<uint8_t> bytes) noexcept {
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PngStructs structs{};
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MemoryCursor cursor{bytes};
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structs.pStruct = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
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if (!structs.pStruct) {
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Log.error("png_create_read_struct failed");
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return std::nullopt;
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}
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structs.pInfo = png_create_info_struct(structs.pStruct);
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if (!structs.pInfo) {
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Log.error("png_create_info_struct failed");
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return std::nullopt;
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}
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// I'm scared of putting any locals after that setjmp.
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std::vector<png_bytep> rowPointers;
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ByteBuffer imageData{};
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png_uint_32 width, height;
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int bit_depth, color_type, interlace_type, compression_type, filter_type;
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size_t rowBytes;
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int i;
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if (setjmp(png_jmpbuf(structs.pStruct))) {
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Log.error("libpng encountered an error");
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return std::nullopt;
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}
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png_set_read_fn(structs.pStruct, &cursor, readPngData);
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png_read_info(structs.pStruct, structs.pInfo);
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if (!png_get_IHDR(structs.pStruct, structs.pInfo, &width, &height, &bit_depth, &color_type, &interlace_type, &compression_type, &filter_type)) {
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Log.error("libpng unable to read IHDR");
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return std::nullopt;
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}
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// Always read as RGBA8.
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png_set_gray_to_rgb(structs.pStruct);
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png_set_filler(structs.pStruct, 0xFF, PNG_FILLER_AFTER);
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png_set_expand(structs.pStruct);
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png_set_strip_16(structs.pStruct);
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png_read_update_info(structs.pStruct, structs.pInfo);
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rowBytes = png_get_rowbytes(structs.pStruct, structs.pInfo);
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rowPointers.resize(height);
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imageData.append_zeroes(rowBytes * height);
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for (i = 0; i < height; i++) {
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rowPointers[i] = imageData.data() + i * rowBytes;
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}
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png_read_image(structs.pStruct, rowPointers.data());
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png_read_end(structs.pStruct, nullptr);
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return ConvertedTexture{
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.format = wgpu::TextureFormat::RGBA8Unorm,
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.width = width,
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.height = height,
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.mips = 1,
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.data = std::move(imageData)
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};
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}
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std::optional<ConvertedTexture>
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load_png_file(const std::filesystem::path& path) noexcept {
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const auto bytes = dds::read_binary_file(path);
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if (!bytes.has_value()) {
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Log.error("failed to open file: {}", fs_path_to_string(path));
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return std::nullopt;
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}
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return parse_png_bytes(*bytes);
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}
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}
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