This library is currently unstable and may experience API changes
A simple graphics library wrapper for SDL2 providing a simple linear frame-buffer interface with palettized 256-color. Designed to allow quick prototyping with simple pixel graphics routines much like back in the DOS VGA days.
With one initialization call you now have an window and frame buffer where you can immediatly set a palette and start plotting pixels. Pixels are flushed to the screen using the rcgl_update method.
- SDL2 based for cross platform support.
- 8-bit indexed linear frame-buffer for ease of coding.
- Scaling of arbitrary sized buffer to arbitrary window sizes.
- Minimal set-up - start prototyping immediatly. See demo.c to see how fast you can be plotting pixels.
- Built-in preset palettes. Mode 13h VGA (EGA/CGA) and Greyscale
- Simple graphics primative functions. Lines, Rectangles, Circles, Arcs.
- Text rendering to buffer.
- Built in fonts for text rendering. 8x8 CGA, Apple ][, 9x16 VGA, and more.
- More built-in palettes
- Simple mouse and keyboard routines, polling based. Get clicked pixel as buffer coords.
- Togglable vsync. (Currently always on)
- Non-square pixel scaling. For emulating old compure aspect ratios. (eg. 320x200 as 4:3)
int rcgl_init(int w, int h, int ww, int wh, const char *title, int wflags);
Initializes library and create window, with the buffer scaled to fit the window size.
| Parameter | Purpose |
|---|---|
| w | buffer width |
| h | buffer height |
| ww | window width |
| wh | window height |
| title | window title |
| wflags | Window behaviour flags, see below. |
| Flag | Purpose |
|---|---|
| RCGL_RESIZE | Window can be freely resized |
| RCGL_FULLSCREEN | Window starts off fullscreen, using the resolution specified |
| RCGL_MAXIMIZED | Window starts off maximized, must be combined with RCGL_RESIZE |
| RCGL_FULLSCREEN_NATIVE | Window starts off fullscreen at the desktop resolution |
| RCGL_INTSCALE | Only scale to integer multiples, letter/pillarbox differences |
void rcgl_quit(void);
Frees up used resources and gracefully closes down the window.
int rcgl_update(void);
Renders the current buffer to the window, applying the current palette to the rendered pixels.
Returns -1 on error writing to the window.
void rcgl_setbuf(uint8_t *b);
Changes the buffer pointer to a new specified buffer. If b is NULL then set the buffer pointer back to the internal buffer.
uint8_t *rcgl_getbuf(void);
Returns a pointer to the current buffer. Call this after initialization to get a pointer to the internal buffer.
int rcgl_hasquit(void);
Returns true if a close event has occured and the video system has terminated
void rcgl_delay(uint32_t ms);
Waits for the given number of milliseconds before returning.
uint32_t rcgl_ticks(void);
Return number of milliseconds since start
void rcgl_plot(int x, int y, uint8_t c);
Plot a pixel to the coordinates x,y with color c
void rcgl_setpalette(const uint32_t palette[256]);
Copy the specified palette into the palette registers. Can be used to swap quickly between multiple palettes, or to return to one of the built-in palettes. eg:
rcgl_setpalette(RCGL_PALETTE_VGA);
| Palette name | Description |
|---|---|
| RCGL_PALETTE_VGA | The default palette for Mode 13h VGA |
| RCGL_PALETTE_GREY | A linear greyscale palette. 0 = #000000, 256 = #FFFFFF |
void rcgl_line(int x1, int y1, int x2, int y2, uint8_t c)
Draw an arbitrary line between two points with color c.
void rcgl_blit(uint8_t *b, int x, int y, int w, int h, int trans, uint8_t *plt)
Copy a bitmap of size w x h to the buffer at position x, y. If trans >= 0 then any pixels in the bitmap with that value will be ignored when blitting. If plt is not NULL then pixels from b will be passed through plt before being compared to trans and before being copied to the buffer.
The 256-color palette can be directly manipulated by the program to allow for palette swapping effects. It is present as a global variable:
extern uint32_t rcgl_palette[256];
The values are stored as ARGB (0xaarrggbb) where the alpha channel is ignored by the library, allowing for 24-bit color palettes. The palette defaults to the values from RCGL_PALETTE_VGA - the Mode 13h VGA palette.