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Lightning Magic tool looking good

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Could be better, but it's a start.
This commit is contained in:
Bill Kendrick 2021-09-27 00:53:01 -07:00
parent 4965cc95f1
commit e7c7a51a00
2 changed files with 112 additions and 10 deletions
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2
docs/CHANGES.txt
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@ -8,7 +8,7 @@ http://www.tuxpaint.org/
$Id$
2021.September.26 (0.9.27)
2021.September.27 (0.9.27)
* New Magic Tools:
----------------
* WIP "Lightning" - Draws a bolt of lightning striking between

120
magic/src/lightning.c
View file

@ -3,7 +3,7 @@
Draws a lightning strike between the click
and drag+release positions.
Last modified: 2021.09.26
Last modified: 2021.09.27
*/
#include <stdio.h>
@ -16,13 +16,14 @@
#include "SDL_mixer.h"
Mix_Chunk *snd_effect;
Uint8 lightning_r, lightning_g, lightning_b;
float lightning_h, lightning_s, lightning_v;
int sx, sy;
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);
Uint32 lightning_api_version(void)
@ -121,6 +122,7 @@ lightning_release(magic_api * api, int which,
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
@ -138,25 +140,125 @@ lightning_release(magic_api * api, int which,
a = (x - sx);
b = (y - sy);
len = sqrt((a * a) + (b * b));
angle = acos((x - sx) / len);
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 * 180.0) / M_PI);
sx, sy, x, y, a, b, len, angle);
fflush(stdout);
#endif
// FIXME: Do something
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, pct;
int xx, yy, t;
Uint8 r, g, b, or, og, ob;
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_v;
light_h = lightning_h;
light_s = lightning_s;
light_v = lightning_v;
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)
{
lightning_r = r;
lightning_g = g;
lightning_b = b;
api->rgbtohsv(r, g, b, &lightning_h, &lightning_s, &lightning_v);
}