EP-NICCC

简介

在明日方舟电子通行证平台上的 Atari ST demo „STNICCC 2000“ by Oxygene 的移植版。 主要是演示DRM_warpper、fbdraw等驱动库的使用。

编译

mkdir build
cd build
cmake ..
make

数据说明

来自：https://arsantica-online.com/st-niccc-competition/

File description:

The stream contains flags, palette-data and vertex-/polygon-data for 1800 frames.
The stream is segmented in 64KB blocks.
A frame never crosses such a 64KB boundary.
Polygons can have 3-15 vertices.
Polygons can cover each other, so a non-convex polygon filler is needed.
Polygons are rendered to a 256×200 pixel screen in 4 bit color depth.
The palette (16 out of 512 colors) can change from frame to frame.
Words are 2 bytes in big endian order.
Colors are stored as words in Atari-ST format 00000RRR0GGG0BBB (512 possible colors).

Every frame stores the following data:

1 byte Flags Bit 0: Frame needs to clear the screen.
Bit 1: Frame contains palette data.
Bit 2: Frame is stored in indexed mode.

If frame contains palette data
{
1 word Bitmask

For every set bit in the Bitmask (0-15)
{
1 word Color The color has to be copied into the palette at the reverse index of the actual bit,
because the bitmask is stored in reverse order.
In other words: If bit 15 of mask is set -> update color 0 of palette,
…
if bit 0 of mask is set -> update color 15 of palette.
}
}

If frame is stored in indexed mode
{
1 byte Number of vertices (0-255)

For every Vertex
{
1 byte X-position
1 byte Y-position
}

While (…)
{
1 byte Poly-descriptor Contains: hi-nibble – 4 bits color-index
lo-nibble – 4 bits number of polygon vertices

Some special cases are encoded in the descriptor byte:
$ff = End of frame
$fe = End of frame and the stream skips to the next 64KB block
$fd = End of stream (we are done \o/)

For every vertex of the polygon
{
1 byte Vertex-id (0-255)
}
}
}
Else if frame is stored in non-indexed mode
{
while (…)
{
1 byte Poly-descriptor (See indexed mode)

For every vertex of the polygon
{
1 byte X-position
1 byte Y-position
}
}
}