1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
#include <stdio.h>
#include <stdlib.h>
#include <SDL.h>
#define NARRAY(ARRAY) \
(sizeof(ARRAY) / sizeof(ARRAY[0]))
#define SDL_MAYBE_LOCK(SURFACE) do { \
if (SDL_MUSTLOCK(SURFACE)) \
SDL_LockSurface(SURFACE); \
} while (0)
#define SDL_MAYBE_UNLOCK(SURFACE) do { \
if (SDL_MUSTLOCK(SURFACE)) \
SDL_UnlockSurface(SURFACE); \
} while (0)
#define SDL_ERROR(FMT, ...) do { \
fprintf(stderr, "%s(%d): " FMT ": %s\n", \
__FILE__, __LINE__, ##__VA_ARGS__, SDL_GetError()); \
} while (0)
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
static SDL_Surface *screen;
static inline SDL_Surface *
effect_fire_init(void)
{
SDL_Surface *surface;
static SDL_Color colors[256];
surface = SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_SRCCOLORKEY,
screen->w, screen->h, 8, 0, 0, 0, 0);
if (surface == NULL) {
SDL_ERROR("SDL_CreateRGBSurface");
exit(EXIT_FAILURE);
}
if (SDL_SetColorKey(surface, SDL_SRCCOLORKEY, 0)) {
SDL_ERROR("SDL_SetColorKey");
SDL_FreeSurface(surface);
exit(EXIT_FAILURE);
}
for (int i = 0; i < 32; i++) {
/* black to blue, 32 values */
colors[i].b = i << 1;
/* blue to red, 32 values */
colors[i + 32].r = i << 3;
colors[i + 32].b = 64 - (i << 1);
/*red to yellow, 32 values */
colors[i + 64].r = 255;
colors[i + 64].g = i << 3;
/* yellow to white, 162 */
colors[i + 96].r = 255;
colors[i + 96].g = 255;
colors[i + 96].b = i << 2;
colors[i + 128].r = 255;
colors[i + 128].g = 255;
colors[i + 128].b = 64 + (i << 2);
colors[i + 160].r = 255;
colors[i + 160].g = 255;
colors[i + 160].b = 128 + (i << 2);
colors[i + 192].r = 255;
colors[i + 192].g = 255;
colors[i + 192].b = 192 + i;
colors[i + 224].r = 255;
colors[i + 224].g = 255;
colors[i + 224].b = 224 + i;
}
SDL_SetPalette(surface, SDL_LOGPAL | SDL_PHYSPAL, colors,
0, NARRAY(colors));
return surface;
}
static inline void
effect_fire_update(SDL_Surface *surface)
{
int mouse_x, mouse_y;
SDL_MAYBE_LOCK(surface);
if (SDL_GetMouseState(&mouse_x, &mouse_y) & SDL_BUTTON(1)) {
Uint8 *p = (Uint8 *)surface->pixels;
float r = (float)rand()/RAND_MAX;
p[mouse_y*surface->pitch + mouse_x] = r > .3 ? 255 : 0;
}
for (Uint8 *p = (Uint8 *)surface->pixels + surface->pitch*surface->h - 1;
p >= (Uint8 *)surface->pixels + surface->pitch;
p--) {
Uint16 acc;
if (!((p - (Uint8 *)surface->pixels) % surface->pitch)) {
/* left edge */
acc = (Uint16)p[0] + p[1];
if (acc/2 > p[-surface->pitch])
p[-surface->pitch] = (acc + p[-surface->pitch])/3;
} else if (!((p - (Uint8 *)surface->pixels + 1) % surface->pitch)) {
/* right edge */
acc = (Uint16)p[-1] + p[0];
if (acc/2 > p[-surface->pitch])
p[-surface->pitch] = (acc + p[-surface->pitch])/3;
} else {
/* somewhere inbetween */
acc = (Uint16)p[-1] + p[0] + p[1];
if (acc/3 > p[-surface->pitch])
p[-surface->pitch] = (acc + p[-surface->pitch])/4;
}
/* decay */
if (p[-surface->pitch] > 0)
p[-surface->pitch]--;
}
SDL_MAYBE_UNLOCK(surface);
}
static inline void
process_events(void)
{
SDL_Event event;
while (SDL_PollEvent(&event)) {
switch (event.type) {
case SDL_KEYDOWN:
switch (event.key.keysym.sym) {
case SDLK_f:
if (!SDL_WM_ToggleFullScreen(screen)) {
SDL_ERROR("SDL_WM_ToggleFullScreen");
exit(EXIT_FAILURE);
}
break;
case SDLK_m:
SDL_ShowCursor(!SDL_ShowCursor(SDL_QUERY));
break;
case SDLK_ESCAPE:
exit(EXIT_SUCCESS);
default:
break;
}
break;
case SDL_QUIT:
exit(EXIT_SUCCESS);
default:
break;
}
}
}
int
main(int argc, char **argv)
{
SDL_Surface *fire_surface;
if (SDL_Init(SDL_INIT_VIDEO)) {
SDL_ERROR("SDL_Init");
return EXIT_FAILURE;
}
atexit(SDL_Quit);
SDL_WM_SetCaption("Effect Pad", NULL);
screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 32,
SDL_HWSURFACE | SDL_DOUBLEBUF);
if (screen == NULL) {
SDL_ERROR("SDL_SetVideoMode");
return EXIT_FAILURE;
}
fire_surface = effect_fire_init();
for (;;) {
process_events();
SDL_FillRect(screen, NULL,
SDL_MapRGB(screen->format, 0, 0, 0));
effect_fire_update(fire_surface);
SDL_BlitSurface(fire_surface, NULL, screen, NULL);
SDL_Flip(screen);
SDL_Delay(50);
}
/* never reached */
return EXIT_FAILURE;
}
|
