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#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>
#include <math.h>
#include "til.h"
#include "til_fb.h"
#include "til_settings.h"
#include "draw.h"
/* Copyright (C) 2017-20 Philip J. Freeman <elektron@halo.nu> */
#define DEFAULT_ROT_ADJ .00003
static float stars_rot_adj = DEFAULT_ROT_ADJ;
struct points
{
float x, y, z;
struct points *next;
};
typedef struct stars_context_t {
struct points* points;
float rot_adj;
float rot_rate;
float rot_angle;
float offset_x;
float offset_y;
float offset_angle;
} stars_context_t;
float get_random_unit_coord() {
return (((float)rand()/(float)RAND_MAX)*2.0)-1.0;
}
static void * stars_create_context(unsigned ticks, unsigned num_cpus)
{
stars_context_t *ctxt;
float z;
struct points* p_ptr = NULL;
ctxt = malloc(sizeof(stars_context_t));
if (!ctxt)
return NULL;
ctxt->points = NULL;
ctxt->rot_adj = stars_rot_adj;
ctxt->rot_rate = 0.00;
ctxt->rot_angle = 0;
ctxt->offset_x = 0.5;
ctxt->offset_y = 0;
ctxt->offset_angle = 0.01;
//add a bunch of points
for(z=0.01; z<1; z=z+0.01) {
for(int i=0; i<rand()%16; i++){
p_ptr = malloc(sizeof(struct points));
if (!p_ptr)
return NULL;
p_ptr->x = get_random_unit_coord();
p_ptr->y = get_random_unit_coord();
p_ptr->z = z;
p_ptr->next = ctxt->points;
ctxt->points = p_ptr;
}
}
return ctxt;
}
static void stars_destroy_context(void *context)
{
stars_context_t *ctxt = context;
struct points* p_ptr;
struct points* last_ptr=NULL;
for ( p_ptr=ctxt->points; p_ptr != NULL; p_ptr = p_ptr->next)
{
if (last_ptr!=NULL)
free(last_ptr);
last_ptr=p_ptr;
}
free(last_ptr);
free(context);
}
static void stars_render_fragment(void *context, unsigned ticks, unsigned cpu, til_fb_fragment_t *fragment)
{
stars_context_t *ctxt = context;
struct points* iterator;
struct points* tmp_ptr;
struct points* last_ptr=NULL;
float x, y, pos_x, pos_y, rot_x, rot_y, opacity, x_mult, y_mult, max_radius;
int width = fragment->width, height = fragment->height;
if(width>height) {
x_mult=1.f;
y_mult=(float)width/(float)height;
} else {
x_mult=(float)height/(float)width;
y_mult=1.f;
}
max_radius=1.f+((width+height)*.001f);
til_fb_fragment_zero(fragment);
iterator=ctxt->points;
for(;;)
{
if(iterator == NULL)
break;
if(iterator->z >= 1) {
if(last_ptr == NULL)
ctxt->points = iterator->next;
else
last_ptr->next = iterator->next;
tmp_ptr = iterator;
iterator = iterator->next;
free(tmp_ptr);
continue;
}
x = (iterator->x / (1.f - iterator->z))*x_mult;
y = (iterator->y / (1.f - iterator->z))*y_mult;
rot_x = (x*cosf(ctxt->rot_angle))-(y*sinf(ctxt->rot_angle));
rot_y = (x*sinf(ctxt->rot_angle))+(y*cosf(ctxt->rot_angle));
pos_x = ((rot_x+ctxt->offset_x+1.f)*.5f)*(float)width;
pos_y = ((rot_y+ctxt->offset_y+1.f)*.5f)*(float)height;
if(iterator->z<0.1)
opacity = iterator->z*10;
else
opacity = 1;
if (pos_x>0 && pos_x<width && pos_y>0 && pos_y<height)
til_fb_fragment_put_pixel_unchecked(fragment, pos_x, pos_y,
makergb(0xFF, 0xFF, 0xFF, opacity));
for(int my_y=floorf(pos_y-max_radius); my_y<=(int)ceilf(pos_y+max_radius); my_y++)
for(int my_x=floorf(pos_x-max_radius); my_x<=(int)ceilf(pos_x+max_radius); my_x++) {
//Is the point within our viewing window?
if (!(my_x>0 && my_x<width && my_y>0 && my_y<height))
continue;
//Is the point within the circle?
if(powf(my_x-pos_x, 2)+powf(my_y-pos_y, 2) > powf((iterator->z*max_radius), 2))
continue;
til_fb_fragment_put_pixel_unchecked(fragment, my_x, my_y,
makergb(0xFF, 0xFF, 0xFF, opacity));
}
iterator->z += 0.01;
last_ptr=iterator;
iterator=iterator->next;
}
// add stars at horizon
for(int i=0; i<rand()%16; i++){
tmp_ptr = malloc(sizeof(struct points));
if (!tmp_ptr)
break;
tmp_ptr->x = get_random_unit_coord();
tmp_ptr->y = get_random_unit_coord();
tmp_ptr->z = 0.01;
tmp_ptr->next = ctxt->points;
ctxt->points = tmp_ptr;
}
// handle rotation parameters
if(ctxt->rot_angle>M_PI_4)
ctxt->rot_rate=ctxt->rot_rate-ctxt->rot_adj;
else
ctxt->rot_rate=ctxt->rot_rate+ctxt->rot_adj;
ctxt->rot_angle=ctxt->rot_angle+ctxt->rot_rate;
// handle offset parameters
float tmp_x = (ctxt->offset_x*cosf(ctxt->offset_angle))-
(ctxt->offset_y*sinf(ctxt->offset_angle));
float tmp_y = (ctxt->offset_x*sinf(ctxt->offset_angle))+
(ctxt->offset_y*cosf(ctxt->offset_angle));
ctxt->offset_x = tmp_x;
ctxt->offset_y = tmp_y;
}
int stars_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc)
{
const char *rot_adj;
const char *rot_adj_values[] = {
".0",
".00001",
".00003",
".0001",
".0003",
".001",
NULL
};
int r;
r = til_settings_get_and_describe_value(settings,
&(til_setting_desc_t){
.name = "Rotation rate",
.key = "rot_adj",
.regex = "\\.[0-9]+",
.preferred = TIL_SETTINGS_STR(DEFAULT_ROT_ADJ),
.values = rot_adj_values,
.annotations = NULL
},
&rot_adj,
res_setting,
res_desc);
if (r)
return r;
sscanf(rot_adj, "%f", &stars_rot_adj);
return 0;
}
til_module_t stars_module = {
.create_context = stars_create_context,
.destroy_context = stars_destroy_context,
.render_fragment = stars_render_fragment,
.setup = stars_setup,
.name = "stars",
.description = "Basic starfield",
.author = "Philip J Freeman <elektron@halo.nu>",
};
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