tuxpaint-pencil-sharpener/magic/src/grass.c

#include <stdio.h>
#include <string.h>
#include <libintl.h>
#include "tp_magic_api.h"
#include "SDL_image.h"
#include "SDL_mixer.h"

/* Our globals: */

Mix_Chunk * grass_snd;
Uint8 grass_r, grass_g, grass_b;
SDL_Surface * img_grass;


/* Local prototypes: */

void do_grass(void * ptr, int which,
	      SDL_Surface * canvas, SDL_Surface * last,
	      int x, int y);

static int log2int(int x);


// No setup required:
int grass_init(magic_api * api)
{
  char fname[1024];

  snprintf(fname, sizeof(fname), "%s/sounds/magic/grass.wav",
	    api->data_directory);
  grass_snd = Mix_LoadWAV(fname);

  snprintf(fname, sizeof(fname), "%s/images/magic/grass_data.png",
	    api->data_directory);
  img_grass = IMG_Load(fname);

  return(1);
}

Uint32 grass_api_version(void) { return(TP_MAGIC_API_VERSION); }

// We have multiple tools:
int grass_get_tool_count(magic_api * api)
{
  return(1);
}

// Load our icons:
SDL_Surface * grass_get_icon(magic_api * api, int which)
{
  char fname[1024];

  snprintf(fname, sizeof(fname), "%s/images/magic/grass.png",
	   api->data_directory);

  return(IMG_Load(fname));
}

// Return our names, localized:
char * grass_get_name(magic_api * api, int which)
{
  return(strdup(gettext("Grass")));
}

// Return our descriptions, localized:
char * grass_get_description(magic_api * api, int which)
{
  return(strdup(gettext("Click and move to draw grass. Don’t forget the dirt!")));
}


// Affect the canvas on drag:
void grass_drag(magic_api * api, int which, SDL_Surface * canvas,
	          SDL_Surface * last, int ox, int oy, int x, int y)
{
  api->line(which, canvas, last, ox, oy, x, y, 4, do_grass);

  api->playsound(grass_snd,
                 (x * 255) / canvas->w, (y * 255) / canvas->h);
}

// Affect the canvas on click:
void grass_click(magic_api * api, int which,
	           SDL_Surface * canvas, SDL_Surface * last,
	           int x, int y)
{
  grass_drag(api, which, canvas, last, x, y, x, y);
}

// No setup happened:
void grass_shutdown(magic_api * api)
{
  if (grass_snd != NULL)
    Mix_FreeChunk(grass_snd);
}

// Record the color from Tux Paint:
void grass_set_color(magic_api * api, Uint8 r, Uint8 g, Uint8 b)
{
  grass_r = r;
  grass_g = g;
  grass_b = b;
}

// Use colors:
int grass_requires_colors(magic_api * api, int which)
{
  return 1;
}

void do_grass(void * ptr, int which,
	      SDL_Surface * canvas, SDL_Surface * last,
	      int x, int y)
{
  magic_api * api = (magic_api *) ptr;
  int xx, yy;
  // grass color: 82,180,17
  static int bucket;
  double tmp_red, tmp_green, tmp_blue;
  Uint8 r, g, b, a;
  SDL_Rect src, dest;

  if (!api->button_down())
    bucket = 0;
  bucket += (3.5 + (rand() / (double) RAND_MAX)) * 7.0;
  while (bucket >= 0)
  {
    int rank =
      log2int(((double) y / canvas->h) *
              (0.99 + (rand() / (double) RAND_MAX)) * 64);
    int ah = 1 << rank;
    bucket -= ah;
    src.x = (rand() % 4) * 64;
    src.y = ah;
    src.w = 64;
    src.h = ah;

    dest.x = x - 32;
    dest.y = y - 30 + (int) ((rand() / (double) RAND_MAX) * 30);

    tmp_red =
      api->sRGB_to_linear(grass_r) * 2.0 +
      (rand() / (double) RAND_MAX);
    tmp_green =
      api->sRGB_to_linear(grass_g) * 2.0 +
      (rand() / (double) RAND_MAX);
    tmp_blue =
      api->sRGB_to_linear(grass_b) * 2.0 +
      api->sRGB_to_linear(17);

    for (yy = 0; yy < ah; yy++)
    {
      for (xx = 0; xx < 64; xx++)
      {
        double rd, gd, bd;

        SDL_GetRGBA(api->getpixel(img_grass, xx + src.x, yy + src.y),
                    img_grass->format, &r, &g, &b, &a);

        rd = api->sRGB_to_linear(r) * 8.0 + tmp_red;
        rd = rd * (a / 255.0) / 11.0;
        gd = api->sRGB_to_linear(g) * 8.0 + tmp_green;
        gd = gd * (a / 255.0) / 11.0;
        bd = api->sRGB_to_linear(b) * 8.0 + tmp_blue;
        bd = bd * (a / 255.0) / 11.0;

        SDL_GetRGB(api->getpixel(canvas, xx + dest.x, yy + dest.y),
                   canvas->format, &r, &g, &b);

        r =
          api->linear_to_sRGB(api->sRGB_to_linear(r) * (1.0 - a / 255.0) +
                         rd);
        g =
          api->linear_to_sRGB(api->sRGB_to_linear(g) * (1.0 - a / 255.0) +
                         gd);
        b =
          api->linear_to_sRGB(api->sRGB_to_linear(b) * (1.0 - a / 255.0) +
                         bd);

        api->putpixel(canvas, xx + dest.x, yy + dest.y,
                 SDL_MapRGB(canvas->format, r, g, b));
      }
    }
  }
}

// this one rounds down
static int log2int(int x)
{
  int y = 0;
  if (x <= 1)
    return 0;
  x >>= 1;
  while (x)
  {
    x >>= 1;
    y++;
  }
  return y;
}