src/game/level/background.c

   1 #include <assert.h>
   2
   3 #include "game/level/background.h"
   4 #include "math/rand.h"
   5 #include "math/rect.h"
   6 #include "system/error.h"
   7 #include "system/lt.h"
   8
   9 #define BACKGROUND_CHUNK_COUNT 5
  10 #define BACKGROUND_CHUNK_WIDTH 250.0f
  11 #define BACKGROUND_CHUNK_HEIGHT 250.0f
  12
  13 static void chunk_of_point(Point p, int *x, int *y);
  14 int render_chunk(const Background *background,
  15                  Camera *camera,
  16                  int x, int y,
  17                  Color color,
  18                  Vec position,
  19                  float parallax);
  20
  21 struct Background
  22 {
  23     Lt *lt;
  24     Color base_color;
  25     Vec position;
  26     int debug_mode;
  27 };
  28
  29 Background *create_background(Color base_color)
  30 {
  31     Lt *lt = create_lt();
  32     if (lt == NULL) {
  33         return NULL;
  34     }
  35
  36     Background *background = PUSH_LT(lt, malloc(sizeof(Background)), free);
  37     if (background == NULL) {
  38         RETURN_LT(lt, NULL);
  39     }
  40
  41     background->base_color = base_color;
  42     background->position = vec(0.0f, 0.0f);
  43     background->debug_mode = 0;
  44     background->lt = lt;
  45
  46     return background;
  47 }
  48
  49 Background *create_background_from_stream(FILE *stream)
  50 {
  51     char color[7];
  52     if (fscanf(stream, "%6s", color) == EOF) {
  53         throw_error(ERROR_TYPE_LIBC);
  54         return NULL;
  55     }
  56
  57     return create_background(
  58         color_from_hexstr(color));
  59 }
  60
  61 void destroy_background(Background *background)
  62 {
  63     assert(background);
  64     RETURN_LT0(background->lt);
  65 }
  66
  67 /* TODO(#182): background chunks are randomly disappearing when the size of the window is less than size of the chunk  */
  68 int background_render(const Background *background,
  69                       Camera *camera)
  70 {
  71     assert(background);
  72     assert(camera);
  73
  74     if (camera_clear_background(
  75             camera,
  76             background->base_color) < 0) {
  77         return -1;
  78     }
  79
  80     const Rect view_port = camera_view_port(camera);
  81     const Vec position = vec(view_port.x, view_port.y);
  82
  83     for (int l = 0; l < 3; ++l) {
  84         const float parallax = 1.0f - 0.2f * (float)l;
  85
  86         int min_x = 0, min_y = 0;
  87         chunk_of_point(vec(view_port.x - position.x * parallax,
  88                            view_port.y - position.y * parallax),
  89                        &min_x, &min_y);
  90
  91         int max_x = 0, max_y = 0;
  92         chunk_of_point(vec(view_port.x - position.x * parallax + view_port.w,
  93                            view_port.y - position.y * parallax + view_port.h),
  94                        &max_x, &max_y);
  95
  96         for (int x = min_x; x <= max_x; ++x) {
  97             for (int y = min_y; y <= max_y; ++y) {
  98                 if (render_chunk(
  99                         background,
 100                         camera,
 101                         x, y,
 102                         color_darker(background->base_color, 0.05f * (float)(l + 1)),
 103                         position,
 104                         parallax) < 0) {
 105                     return -1;
 106                 }
 107             }
 108         }
 109     }
 110
 111     return 0;
 112 }
 113
 114 /* Private Function */
 115
 116 static void chunk_of_point(Point p, int *x, int *y)
 117 {
 118     assert(x);
 119     assert(y);
 120     *x = (int) (p.x / BACKGROUND_CHUNK_WIDTH);
 121     *y = (int) (p.y / BACKGROUND_CHUNK_HEIGHT);
 122 }
 123
 124 int render_chunk(const Background *background,
 125                  Camera *camera,
 126                  int chunk_x, int chunk_y,
 127                  Color color,
 128                  Vec position,
 129                  float parallax)
 130 {
 131     (void) background;
 132
 133     if (background->debug_mode) {
 134         return 0;
 135     }
 136
 137     srand((unsigned int)(roundf((float)chunk_x + (float)chunk_y + parallax)));
 138
 139     for (size_t i = 0; i < BACKGROUND_CHUNK_COUNT; ++i) {
 140         const float rect_x = rand_float_range((float) chunk_x * BACKGROUND_CHUNK_WIDTH,
 141                                               (float) (chunk_x + 1) * BACKGROUND_CHUNK_WIDTH);
 142         const float rect_y = rand_float_range((float) chunk_y * BACKGROUND_CHUNK_HEIGHT,
 143                                               (float) (chunk_y + 1) * BACKGROUND_CHUNK_HEIGHT);
 144         const float rect_w = rand_float_range(0.0f, BACKGROUND_CHUNK_WIDTH * 0.5f);
 145         const float rect_h = rand_float_range(rect_w * 0.5f, rect_w * 1.5f);
 146
 147         if (camera_fill_rect(
 148                 camera,
 149                 rect(rect_x + position.x * parallax,
 150                      rect_y + position.y * parallax,
 151                      rect_w,
 152                      rect_h),
 153                 color) < 0) {
 154             return -1;
 155         }
 156     }
 157
 158     return 0;
 159 }
 160
 161 void background_toggle_debug_mode(Background *background)
 162 {
 163     background->debug_mode = !background->debug_mode;
 164 }