baines / halcyon

Retro C application framework

HALCYON is a C platform library in the vein of SDL, except with a focus on extreme API minimalism and artificial limitation.

NEW single header micro version hc0_linux.h for Linux (no kbd/audio)

• used by included demo program "spectre"

Features include:

• Single window locked to 480p (240p upscaled 2x)
• Fixed 60fps
• Software rendering primitives
  • Point
  • Line
  • Filled Triangle
  • Textured Triangle
• 4 channel sound (GameBoy inspired)
  • 2 pulse wave channels
  • 1 4-bit sample channel
  • 1 LSFR noise channel
• Keyboard and MIDI input available in extension header
• No mouse input

A demonstration "intro" is included.
A tracker is also under development, to be included soon™.

To build everything, type: make

halcyon's Issues

hc0_linux.h: hc_tri misses one pixel

The provided hc_tri function misses one pixel in some cases. I'm not too sure what the conditions are (the vertex order maybe?). Seems like an off-by-one error.

Full repro:

#define WHITE 0xFFFFFFFF

#include "hc0_linux.h"

static void
draw_quad(hc_v2 pos, int8_t side)
{
    hc_v2 a = { pos.x + side, pos.y + side };
    hc_v2 b = { pos.x + side, pos.y };
    hc_v2 c = { pos.x, pos.y + side };
    hc_v2 d = { pos.x, pos.y };
    hc_tri(a, b, c, WHITE, WHITE);
//    hc_tri(b, d, c, WHITE, WHITE);
}

int32_t
main(int32_t argc, char *argv[])
{
    hc_init("");

    for (;;) {
        hc_v2 pos = { WIN_W / 2, WIN_H / 2 };
        draw_quad(pos, 10);
        hc_finish(HC_CLEAR);
    }

    return(0);
}

The code above results in this image (the bottom-right pixel is missing):

hc0_linux.h: HC_FPS macro is not used

The single-file version of the library does not use the defined HC_FPS value. Instead, 60UL is hardcoded (see hc0_linux.h:234). Changing the define to 60UL from 60 and using it seems to have fixed the issue for me.