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#include <stdint.h>
#include <stdlib.h>
#include <time.h>
#include "til.h"
#include "til_fb.h"
#include "til_module_context.h"
/* Copyright (C) 2019 - Vito Caputo <vcaputo@pengaru.com> */
/* This implements white noise / snow just using rand() */
typedef union snow_seed_t {
char __padding[256]; /* prevent seeds sharing a cache-line */
unsigned seed;
} snow_seed_t;
typedef struct snow_context_t {
til_module_context_t til_module_context;
unsigned unused;
snow_seed_t seeds[];
} snow_context_t;
static til_module_context_t * snow_create_context(unsigned seed, unsigned ticks, unsigned n_cpus, til_setup_t *setup)
{
snow_context_t *ctxt;
ctxt = til_module_context_new(sizeof(snow_context_t) + n_cpus * sizeof(snow_seed_t), seed, ticks, n_cpus);
if (!ctxt)
return NULL;
for (unsigned i = 0; i < n_cpus; i++)
ctxt->seeds[i].seed = rand_r(&seed);
return &ctxt->til_module_context;
}
static void snow_prepare_frame(til_module_context_t *context, unsigned ticks, til_fb_fragment_t **fragment_ptr, til_frame_plan_t *res_frame_plan)
{
*res_frame_plan = (til_frame_plan_t){ .fragmenter = til_fragmenter_slice_per_cpu };
}
static void snow_render_fragment(til_module_context_t *context, unsigned ticks, unsigned cpu, til_fb_fragment_t **fragment_ptr)
{
snow_context_t *ctxt = (snow_context_t *)context;
til_fb_fragment_t *fragment = *fragment_ptr;
unsigned *seed = &ctxt->seeds[cpu].seed;
for (unsigned y = fragment->y; y < fragment->y + fragment->height; y++) {
for (unsigned x = fragment->x; x < fragment->x + fragment->width; x++) {
#ifdef __WIN32__
uint32_t pixel = rand();
#else
uint32_t pixel = rand_r(seed) % 256;
#endif
til_fb_fragment_put_pixel_unchecked(fragment, 0, x, y, pixel << 16 | pixel << 8 | pixel);
}
}
}
til_module_t snow_module = {
.create_context = snow_create_context,
.prepare_frame = snow_prepare_frame,
.render_fragment = snow_render_fragment,
.name = "snow",
.description = "TV snow / white noise (threaded)",
.author = "Vito Caputo <vcaputo@pengaru.com>",
};
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