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#include <inttypes.h>
#include <math.h>
#include <stdint.h>
#include <stdlib.h>
#include "fb.h"
#include "rototiller.h"
/* Copyright (C) 2017 Vito Caputo <vcaputo@pengaru.com> */
/* Normalize plasma size at 2*8K resolution, simply assume it's always being sampled
* smaller than this and ignore handling <1 fractional scaling factors.
*/
#define PLASMA_WIDTH 15360
#define PLASMA_HEIGHT 8640
#define FIXED_TRIG_LUT_SIZE 4096 /* size of the cos/sin look-up tables */
#define FIXED_BITS 9 /* fractional bits */
#define FIXED_EXP (1 << FIXED_BITS) /* 2^FIXED_BITS */
#define FIXED_MASK (FIXED_EXP - 1) /* fractional part mask */
#define FIXED_COS(_rad) costab[(_rad) & (FIXED_TRIG_LUT_SIZE-1)]
#define FIXED_SIN(_rad) sintab[(_rad) & (FIXED_TRIG_LUT_SIZE-1)]
#define FIXED_MULT(_a, _b) (((_a) * (_b)) >> FIXED_BITS)
#define FIXED_NEW(_i) ((_i) << FIXED_BITS)
#define FIXED_TO_INT(_f) ((_f) >> FIXED_BITS)
typedef struct color_t {
int r, g, b;
} color_t;
static int32_t costab[FIXED_TRIG_LUT_SIZE], sintab[FIXED_TRIG_LUT_SIZE];
typedef struct plasma_context_t {
unsigned rr;
unsigned n_cpus;
} plasma_context_t;
static inline uint32_t color2pixel(color_t *color)
{
return (FIXED_TO_INT(color->r) << 16) | (FIXED_TO_INT(color->g) << 8) | FIXED_TO_INT(color->b);
}
static void init_plasma(int32_t *costab, int32_t *sintab)
{
/* Generate fixed-point cos & sin LUTs. */
for (int i = 0; i < FIXED_TRIG_LUT_SIZE; i++) {
costab[i] = ((cos((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
sintab[i] = ((sin((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
}
}
static void * plasma_create_context(unsigned ticks, unsigned num_cpus)
{
static int initialized;
if (!initialized) {
initialized = 1;
init_plasma(costab, sintab);
}
return calloc(1, sizeof(plasma_context_t));
}
static void plasma_destroy_context(void *context)
{
free(context);
}
static int plasma_fragmenter(void *context, const fb_fragment_t *fragment, unsigned number, fb_fragment_t *res_fragment)
{
plasma_context_t *ctxt = context;
return fb_fragment_slice_single(fragment, ctxt->n_cpus, number, res_fragment);
}
/* Prepare a frame for concurrent drawing of fragment using multiple fragments */
static void plasma_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, fb_fragment_t *fragment, rototiller_fragmenter_t *res_fragmenter)
{
plasma_context_t *ctxt = context;
*res_fragmenter = plasma_fragmenter;
ctxt->n_cpus = n_cpus;
ctxt->rr += 3;
}
/* Draw a plasma effect */
static void plasma_render_fragment(void *context, unsigned ticks, unsigned cpu, fb_fragment_t *fragment)
{
plasma_context_t *ctxt = context;
int xstep = PLASMA_WIDTH / fragment->frame_width;
int ystep = PLASMA_HEIGHT / fragment->frame_height;
unsigned width = fragment->width * xstep, height = fragment->height * ystep;
int fw2 = FIXED_NEW(width / 2), fh2 = FIXED_NEW(height / 2);
int x, y, cx, cy, dx2, dy2;
uint32_t *buf = fragment->buf;
color_t c = { .r = 0, .g = 0, .b = 0 }, cscale;
unsigned rr2, rr6, rr8, rr16, rr20, rr12;
rr2 = ctxt->rr * 2;
rr6 = ctxt->rr * 6;
rr8 = ctxt->rr * 8;
rr16 = ctxt->rr * 16;
rr20 = ctxt->rr * 20;
rr12 = ctxt->rr * 12;
/* vary the color channel intensities */
cscale.r = FIXED_MULT(FIXED_COS(ctxt->rr / 2), FIXED_NEW(64)) + FIXED_NEW(64);
cscale.g = FIXED_MULT(FIXED_COS(ctxt->rr / 5), FIXED_NEW(64)) + FIXED_NEW(64);
cscale.b = FIXED_MULT(FIXED_COS(ctxt->rr / 7), FIXED_NEW(64)) + FIXED_NEW(64);
cx = FIXED_TO_INT(FIXED_MULT(FIXED_COS(ctxt->rr), fw2) + fw2);
cy = FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr2), fh2) + fh2);
for (y = fragment->y * ystep; y < fragment->y * ystep + height; y += ystep) {
int y2 = y << 1;
int y4 = y << 2;
dy2 = cy - y;
dy2 *= dy2;
for (x = fragment->x * xstep; x < fragment->x * xstep + width; x += xstep, buf++) {
int v;
int hyp;
dx2 = cx - x;
dx2 *= dx2;
hyp = (dx2 + dy2) >> 13; /* XXX: technically this should be a sqrt(), but >> 10 is a whole lot faster. */
#define S 4
v = FIXED_MULT( ((FIXED_COS(rr8 + ((hyp * 5) >> S))) +
(FIXED_SIN(-rr16 + ((x << 2) >> S))) +
(FIXED_COS(rr20 + (y4 >> S)))),
FIXED_EXP / 3); /* XXX: note these '/ 3' get optimized out. */
c.r = FIXED_MULT(v, cscale.r) + cscale.r;
v = FIXED_MULT( ((FIXED_COS(rr12 + ((hyp << 2) >> S))) +
(FIXED_COS(rr6 + ((x << 1) >> S))) +
(FIXED_SIN(rr16 + (y2 >> S)))),
FIXED_EXP / 3);
c.g = FIXED_MULT(v, cscale.g) + cscale.g;
v = FIXED_MULT( ((FIXED_SIN(rr6 + ((hyp * 6) >> S))) +
(FIXED_COS(-rr12 + ((x * 5) >> S))) +
(FIXED_SIN(-rr6 + (y2 >> S)))),
FIXED_EXP / 3);
c.b = FIXED_MULT(v, cscale.b) + cscale.b;
*buf = color2pixel(&c);
}
buf = ((void *)buf) + fragment->stride;
}
}
rototiller_module_t plasma_module = {
.create_context = plasma_create_context,
.destroy_context = plasma_destroy_context,
.prepare_frame = plasma_prepare_frame,
.render_fragment = plasma_render_fragment,
.name = "plasma",
.description = "Oldskool plasma effect (threaded)",
.author = "Vito Caputo <vcaputo@pengaru.com>",
.license = "GPLv2",
};
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