Jazz2::Compatibility::JJ2Anims::ImageContentDecoder class

#include <Jazz2/Compatibility/JJ2Anims.h>

Incremental decoder for the image content written by WriteImageContent.

Keeps the decoder state between calls, so an image can be read a band of rows at a time into separate buffers instead of one allocation the size of the whole sheet - which for the larger tilesets is close to a megabyte, the single biggest block the game asks for, and the first one to fail on a console heap that a previous level has already fragmented. The bands have to be decoded in order and together cover exactly width * height pixels.

Constructors, destructors, conversion operators

ImageContentDecoder()

Public functions

void Decode(Stream& s, std::uint8_t* data, std::int32_t pixelCount, std::int32_t channelCount)

Decodes the next pixelCount pixels of the image into data.

void Decode(const std::uint8_t*& src, const std::uint8_t* end, std::uint8_t* data, std::int32_t pixelCount, std::int32_t channelCount)

Decodes the next pixelCount pixels from an in-memory copy of the content, advancing src.

Function documentation

void Jazz2::Compatibility::JJ2Anims::ImageContentDecoder::Decode(const std::uint8_t*& src, const std::uint8_t* end, std::uint8_t* data, std::int32_t pixelCount, std::int32_t channelCount)

Decodes the next pixelCount pixels from an in-memory copy of the content, advancing src.

Reading past end yields zero bytes. A byte read from memory is a load; through a stream it is a virtual call per byte, which on the consoles' in-order CPUs was most of the decode.