src/game/level/background.c

   1 #include "system/stacktrace.h"
   2
   3 #include "game/level/background.h"
   4 #include "math/rand.h"
   5 #include "math/rect.h"
   6 #include "system/line_stream.h"
   7 #include "system/lt.h"
   8 #include "system/nth_alloc.h"
   9 #include "system/log.h"
  10
  11 #define BACKGROUND_CHUNK_COUNT 5
  12 #define BACKGROUND_CHUNK_WIDTH 250.0f
  13 #define BACKGROUND_CHUNK_HEIGHT 250.0f
  14
  15 static void chunk_of_point(Point p, int *x, int *y);
  16 int render_chunk(const Background *background,
  17                  Camera *camera,
  18                  int x, int y,
  19                  Color color,
  20                  Vec position,
  21                  float parallax);
  22
  23 struct Background
  24 {
  25     Lt *lt;
  26     Color base_color;
  27     Vec position;
  28     int debug_mode;
  29 };
  30
  31 Background *create_background(Color base_color)
  32 {
  33     Lt *lt = create_lt();
  34
  35     Background *background = PUSH_LT(lt, nth_calloc(1, sizeof(Background)), free);
  36     if (background == NULL) {
  37         RETURN_LT(lt, NULL);
  38     }
  39
  40     background->base_color = base_color;
  41     background->position = vec(0.0f, 0.0f);
  42     background->debug_mode = 0;
  43     background->lt = lt;
  44
  45     return background;
  46 }
  47
  48 Background *create_background_from_line_stream(LineStream *line_stream)
  49 {
  50     char color[7];
  51     if (sscanf(line_stream_next(line_stream), "%6s", color) == EOF) {
  52         log_fail("Could not read background's color\n");
  53         return NULL;
  54     }
  55
  56     return create_background(hexstr(color));
  57 }
  58
  59 void destroy_background(Background *background)
  60 {
  61     trace_assert(background);
  62     RETURN_LT0(background->lt);
  63 }
  64
  65 /* TODO(#182): background chunks are randomly disappearing when the size of the window is less than size of the chunk  */
  66 int background_render(const Background *background,
  67                       Camera *camera)
  68 {
  69     trace_assert(background);
  70     trace_assert(camera);
  71
  72     if (camera_clear_background(
  73             camera,
  74             background->base_color) < 0) {
  75         return -1;
  76     }
  77
  78     const Rect view_port = camera_view_port(camera);
  79     const Vec position = vec(view_port.x, view_port.y);
  80
  81     for (int l = 0; l < 3; ++l) {
  82         const float parallax = 1.0f - 0.2f * (float)l;
  83
  84         int min_x = 0, min_y = 0;
  85         chunk_of_point(vec(view_port.x - position.x * parallax,
  86                            view_port.y - position.y * parallax),
  87                        &min_x, &min_y);
  88
  89         int max_x = 0, max_y = 0;
  90         chunk_of_point(vec(view_port.x - position.x * parallax + view_port.w,
  91                            view_port.y - position.y * parallax + view_port.h),
  92                        &max_x, &max_y);
  93
  94         for (int x = min_x; x <= max_x; ++x) {
  95             for (int y = min_y; y <= max_y; ++y) {
  96                 if (render_chunk(
  97                         background,
  98                         camera,
  99                         x, y,
 100                         color_darker(background->base_color, 0.05f * (float)(l + 1)),
 101                         position,
 102                         parallax) < 0) {
 103                     return -1;
 104                 }
 105             }
 106         }
 107     }
 108
 109     return 0;
 110 }
 111
 112 /* Private Function */
 113
 114 static void chunk_of_point(Point p, int *x, int *y)
 115 {
 116     trace_assert(x);
 117     trace_assert(y);
 118     *x = (int) (p.x / BACKGROUND_CHUNK_WIDTH);
 119     *y = (int) (p.y / BACKGROUND_CHUNK_HEIGHT);
 120 }
 121
 122 int render_chunk(const Background *background,
 123                  Camera *camera,
 124                  int chunk_x, int chunk_y,
 125                  Color color,
 126                  Vec position,
 127                  float parallax)
 128 {
 129     (void) background;
 130
 131     if (background->debug_mode) {
 132         return 0;
 133     }
 134
 135     srand((unsigned int)(roundf((float)chunk_x + (float)chunk_y + parallax)));
 136
 137     for (size_t i = 0; i < BACKGROUND_CHUNK_COUNT; ++i) {
 138         const float rect_x = rand_float_range((float) chunk_x * BACKGROUND_CHUNK_WIDTH,
 139                                               (float) (chunk_x + 1) * BACKGROUND_CHUNK_WIDTH);
 140         const float rect_y = rand_float_range((float) chunk_y * BACKGROUND_CHUNK_HEIGHT,
 141                                               (float) (chunk_y + 1) * BACKGROUND_CHUNK_HEIGHT);
 142         const float rect_w = rand_float_range(0.0f, BACKGROUND_CHUNK_WIDTH * 0.5f);
 143         const float rect_h = rand_float_range(rect_w * 0.5f, rect_w * 1.5f);
 144
 145         if (camera_fill_rect(
 146                 camera,
 147                 rect(rect_x + position.x * parallax,
 148                      rect_y + position.y * parallax,
 149                      rect_w,
 150                      rect_h),
 151                 color) < 0) {
 152             return -1;
 153         }
 154     }
 155
 156     return 0;
 157 }
 158
 159 void background_toggle_debug_mode(Background *background)
 160 {
 161     background->debug_mode = !background->debug_mode;
 162 }