diff options
Diffstat (limited to 'effect-pad.c')
| -rw-r--r-- | effect-pad.c | 129 |
1 files changed, 126 insertions, 3 deletions
diff --git a/effect-pad.c b/effect-pad.c index 61e0c79..702b372 100644 --- a/effect-pad.c +++ b/effect-pad.c @@ -3,6 +3,19 @@ #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()); \ @@ -13,8 +26,107 @@ 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 -handle_events(void) +process_events(void) { SDL_Event event; @@ -53,6 +165,8 @@ handle_events(void) int main(int argc, char **argv) { + SDL_Surface *fire_surface; + if (SDL_Init(SDL_INIT_VIDEO)) { SDL_ERROR("SDL_Init"); return EXIT_FAILURE; @@ -68,10 +182,19 @@ main(int argc, char **argv) return EXIT_FAILURE; } + fire_surface = effect_fire_init(); + for (;;) { - handle_events(); + 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_Delay(100); + SDL_Flip(screen); + SDL_Delay(50); } /* never reached */ |