tuxpaint-pencil-sharpener/magic/src/lightning.c
2021-11-08 23:33:49 +01:00

295 lines
8.5 KiB
C

/* lightning.c
Draws a lightning strike between the click
and drag+release positions.
Last modified: 2021.11.07
*/
#include <stdio.h>
#include <string.h>
#include <libintl.h>
#include <math.h>
#include "tp_magic_api.h"
#include "SDL_image.h"
#include "SDL_mixer.h"
Mix_Chunk *snd_effect;
float lightning_h, lightning_s, lightning_v;
int sx, sy;
Uint32 lightning_api_version(void);
int lightning_init(magic_api * api);
int lightning_get_tool_count(magic_api * api);
SDL_Surface *lightning_get_icon(magic_api * api, int which);
char *lightning_get_name(magic_api * api, int which);
int lightning_get_group(magic_api * api, int which);
char *lightning_get_description(magic_api * api, int which, int mode);
int lightning_requires_colors(magic_api * api, int which);
int lightning_modes(magic_api * api, int which);
void lightning_shutdown(magic_api * api);
void lightning_click(magic_api * api, int which, int mode,
SDL_Surface * canvas, SDL_Surface * snapshot, int x, int y, SDL_Rect * update_rect);
void lightning_set_color(magic_api * api, Uint8 r, Uint8 g, Uint8 b);
void lightning_drag(magic_api * api, int which, SDL_Surface * canvas,
SDL_Surface * snapshot, int ox, int oy, int x, int y, SDL_Rect * update_rect);
void lightning_line_callback_drag(void *ptr, int which, SDL_Surface * canvas, SDL_Surface * snapshot, int x, int y);
void lightning_draw_bolt(void * ptr, SDL_Surface * canvas, SDL_Surface * snapshot, float sx, float sy, float angle, float len, int thickness);
void lightning_release(magic_api * api, int which,
SDL_Surface * canvas, SDL_Surface * snapshot, int x, int y, SDL_Rect * update_rect);
void lightning_switchin(magic_api * api, int which, int mode, SDL_Surface * canvas);
void lightning_switchout(magic_api * api, int which, int mode, SDL_Surface * canvas);
Uint32 lightning_api_version(void)
{
return (TP_MAGIC_API_VERSION);
}
int lightning_init(magic_api * api)
{
char fname[1024];
snprintf(fname, sizeof(fname), "%ssounds/magic/lightning.ogg", api->data_directory);
snd_effect = Mix_LoadWAV(fname);
return (1);
}
int lightning_get_tool_count(magic_api * api ATTRIBUTE_UNUSED)
{
return (1);
}
SDL_Surface *lightning_get_icon(magic_api * api, int which ATTRIBUTE_UNUSED)
{
char fname[1024];
snprintf(fname, sizeof(fname), "%simages/magic/lightning.png", api->data_directory);
return (IMG_Load(fname));
}
char *lightning_get_name(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
return strdup(gettext("Lightning"));
}
int lightning_get_group(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
return MAGIC_TYPE_ARTISTIC;
}
char *lightning_get_description(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED)
{
return strdup(gettext("Click, drag, and release to draw a lightning bolt between two points."));
}
int lightning_requires_colors(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
return 1;
}
int lightning_modes(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
{
return MODE_PAINT;
}
void lightning_shutdown(magic_api * api ATTRIBUTE_UNUSED)
{
if (snd_effect != NULL)
Mix_FreeChunk(snd_effect);
}
void
lightning_click(magic_api * api, int which, int mode ATTRIBUTE_UNUSED,
SDL_Surface * canvas, SDL_Surface * snapshot, int x, int y, SDL_Rect * update_rect)
{
sx = x;
sy = y;
lightning_drag(api, which, canvas, snapshot, x, y, x, y, update_rect);
}
void
lightning_drag(magic_api * api, int which, SDL_Surface * canvas,
SDL_Surface * snapshot, int ox ATTRIBUTE_UNUSED, int oy ATTRIBUTE_UNUSED,
int x, int y, SDL_Rect * update_rect)
{
/* FIXME: This could be made more efficient
(only blit and update between (sx,sy) and (x,y), though
it should also cover the area extending to (ox,oy),
to avoid leaving trails */
update_rect->x = 0;
update_rect->y = 0;
update_rect->w = canvas->w;
update_rect->h = canvas->h;
SDL_BlitSurface(snapshot, update_rect, canvas, update_rect);
api->line((void *)api, which, canvas, snapshot, sx, sy, x, y, 1, lightning_line_callback_drag);
}
void
lightning_release(magic_api * api, int which ATTRIBUTE_UNUSED,
SDL_Surface * canvas, SDL_Surface * snapshot, int x, int y, SDL_Rect * update_rect)
{
float a, b, len, angle;
int thickness;
/* FIXME: This could be made more efficient
(only blit and update between (sx,sy) and (x,y), though
it should also cover the area extending to (ox,oy),
to avoid leaving trails */
update_rect->x = 0;
update_rect->y = 0;
update_rect->w = canvas->w;
update_rect->h = canvas->h;
SDL_BlitSurface(snapshot, update_rect, canvas, update_rect);
api->stopsound();
api->playsound(snd_effect, (x * 255) / canvas->w, 255);
a = (x - sx);
b = (y - sy);
len = sqrt((a * a) + (b * b));
if (len < 100)
len = 100;
angle = acos((x - sx) / len) * 180.0 / M_PI;
if (y < sy)
angle = -angle;
#ifdef DEBUG
printf("(%d,%d)->(%d,%d) => a = %.2f, b = %.2f, c (len) = %.2f; angle = %.2f degrees\n",
sx, sy, x, y, a, b, len, angle);
fflush(stdout);
#endif
thickness = len / 50;
if (thickness < 4)
thickness = 4;
lightning_draw_bolt((void *) api, canvas, snapshot, (float) sx, (float) sy, angle, len, thickness);
}
void lightning_draw_bolt(void * ptr, SDL_Surface * canvas, SDL_Surface * snapshot, float sx, float sy, float angle, float len, int thickness)
{
magic_api *api = (magic_api *) ptr;
float i;
float x, y, orig_angle;
int xx, yy, t;
Uint8 r, g, b;
float h, s, v, new_h, new_s, new_v;
float adj;
x = sx;
y = sy;
orig_angle = angle;
t = thickness / 3;
if (t < 1)
t = 1;
for (i = 0; i < len; i++)
{
x = x + cos(angle * M_PI / 180.0);
y = y + sin(angle * M_PI / 180.0);
angle = angle + ((float) (rand() % 15) - 7.5);
if (angle < orig_angle - 10.0)
angle = orig_angle - 10.0;
else if (angle > orig_angle + 10.0)
angle = orig_angle + 10.0;
for (yy = -t; yy <= t; yy++)
{
for (xx = -t; xx <= t; xx++)
{
if (api->in_circle(xx, yy, t))
{
float light_h, light_s;
light_h = lightning_h;
light_s = lightning_s;
SDL_GetRGB(api->getpixel(canvas, x + xx, y + yy), canvas->format, &r, &g, &b);
api->rgbtohsv(r, g, b, &h, &s, &v);
adj = 1.0 - (sqrt((xx * xx) + (yy * yy)) / t);
new_v = v + adj;
if (new_v > 1.0)
{
light_s = light_s / (new_v * 2);
new_v = 1.0;
}
if (light_h == -1)
{
new_h = h;
new_s = (s * 25) / 100;
}
else
{
new_h = ((light_h * 75) + (h * 25)) / 100;
new_s = ((light_s * 75) + (s * 25)) / 100;
}
api->hsvtorgb(new_h, new_s, new_v, &r, &g, &b);
api->putpixel(canvas, x + xx, y + yy, SDL_MapRGB(canvas->format, r, g, b));
}
}
}
if (((rand() % 50) == 0 || (int) i == (int) (len / 2)) && thickness > 1 && len >= 4)
{
float new_angle;
if ((rand() % 10) == 0)
{
new_angle = angle + ((float) (rand() % 180) - 90.0);
}
else
{
new_angle = angle + ((float) (rand() % 90) - 45.0);
}
lightning_draw_bolt((void *) api, canvas, snapshot, x, y,
new_angle,
((len / 8) + (rand() % (int) (len / 4))),
thickness - 1
);
}
}
}
void lightning_set_color(magic_api * api, Uint8 r, Uint8 g, Uint8 b)
{
api->rgbtohsv(r, g, b, &lightning_h, &lightning_s, &lightning_v);
}
void lightning_line_callback_drag(void *ptr, int which ATTRIBUTE_UNUSED, SDL_Surface * canvas, SDL_Surface * snapshot ATTRIBUTE_UNUSED, int x, int y)
{
magic_api *api = (magic_api *) ptr;
api->xorpixel(canvas, x, y);
}
void lightning_switchin(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED, SDL_Surface * canvas ATTRIBUTE_UNUSED)
{
}
void lightning_switchout(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED, SDL_Surface * canvas ATTRIBUTE_UNUSED)
{
}