add better colors for 2048

Reviewed-on: #29

src/engine/engine.c

@@ -2,6 +2,8 @@
 
 #include "internal/engine_internal.h"
 
+#include <stdlib.h>
+
 engine_internal_state_t *internal_state = NULL;
 game_state_t *game_state = NULL;
 

src/examples/2048.c

@@ -10,6 +10,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
+#include <math.h>
 
 #define SIZE 4
 #define MOVE_DURATION 0.12f
@@ -28,6 +29,14 @@ typedef struct {
     int col;
 } line_tile_t;
 
+typedef enum {
+    GAME_PLAYING,
+    GAME_WON,
+    GAME_LOST
+} game_status_t;
+
+static game_status_t game_status;
+
 typedef struct {
     uint32_t area[SIZE][SIZE];
     dir_e direction;
@@ -42,6 +51,17 @@ static size_t move_track_count;
 
 static double last_frame_time;
 
+static bool
+board_is_full(void)
+{
+    for (int r = 0; r < SIZE; ++r)
+        for (int c = 0; c < SIZE; ++c)
+            if (game.area[r][c] == 0)
+                return false;
+
+    return true;
+}
+
 /* Pixel size is calculated from the current window size while drawing. */
 static uint32_t
 colors(uint32_t number)
@@ -55,6 +75,42 @@ colors(uint32_t number)
     }
 }
 
+/* Maps positive values logarithmically: powers of two get evenly spaced hues.
+   Returns 0xRRGGBB. Values outside [min_value, max_value] are clamped. */
+uint32_t
+color_for_value(double value, double min_value, double max_value)
+{
+    if (min_value <= 0.0 || max_value <= min_value || value <= 0.0)
+        return 0xFFFFFF;
+
+    if (value < min_value) value = min_value;
+    if (value > max_value) value = max_value;
+
+    double t = (log2(value) - log2(min_value)) /
+               (log2(max_value) - log2(min_value));
+    
+    t = sqrt(t);  /* accelerates color changes near the low end */
+
+    /* Sweep hue from blue to red in HSV; full saturation and brightness. */
+    // double h = (1.0 - t) * 240.0;
+
+    double exponent = log2(value / min_value);  /* 0 at min_value, 1 per doubling */
+    double h = fmod(20.0 + exponent * 45.0, 360.0);
+
+    double c = 1.0;
+    double x = 1.0 - fabs(fmod(h / 60.0, 2.0) - 1.0);
+    double r, g, b;
+
+    if      (h < 60.0)  { r = c; g = x; b = 0.0; }
+    else if (h < 120.0) { r = x; g = c; b = 0.0; }
+    else if (h < 180.0) { r = 0.0; g = c; b = x; }
+    else                { r = 0.0; g = x; b = c; }
+
+    return ((uint32_t)(r * 255.0) << 16) |
+           ((uint32_t)(g * 255.0) << 8)  |
+            (uint32_t)(b * 255.0);
+}
+
 /*
  * Return the board coordinate for position p in a line, where p=0 is
  * the side toward which tiles move.
@@ -151,6 +207,8 @@ process_line(dir_e direction, int line, uint32_t output[SIZE])
         if (i + 1 < input_count &&
             input[i].value == input[i + 1].value) {
             uint32_t merged_value = input[i].value * 2;
+            if (merged_value >= 2048)
+                game_status = GAME_WON;
 
             output[output_count] = merged_value;
             game.score += merged_value;
@@ -194,6 +252,9 @@ process_line(dir_e direction, int line, uint32_t output[SIZE])
 static bool
 slide(dir_e direction)
 {
+    if (game_status != GAME_PLAYING || anim_is_active(&movement))
+        return false;
+
     if (anim_is_active(&movement))
         return false;
 
@@ -260,15 +321,23 @@ client_poll_event(void)
         game_state->is_running = false;
         break;
     case SDLK_W:
+    case SDLK_UP:
+        if (game_status == GAME_PLAYING)
            slide(UP);
         break;
     case SDLK_S:
+    case SDLK_DOWN:
+        if (game_status == GAME_PLAYING)
             slide(DOWN);
         break;
     case SDLK_A:
+    case SDLK_LEFT:
+        if (game_status == GAME_PLAYING)
             slide(LEFT);
         break;
     case SDLK_D:
+    case SDLK_RIGHT:
+        if (game_status == GAME_PLAYING)
             slide(RIGHT);
         break;
     default:
@@ -291,7 +360,7 @@ draw_tile_rect(uint32_t value, float x, float y, float w, float h)
     uint32_t iy = (uint32_t)y;
     uint32_t iw = (uint32_t)w;
     uint32_t ih = (uint32_t)h;
-    uint32_t color = colors(value);
+    uint32_t color = color_for_value((double)value, 2, 131072);
 
     put_rect(OVERDRAW, ix, iy, iw, ih, color);
 
@@ -324,7 +393,12 @@ client_update_framebuffer(void)
         dt = 0.05f;
 
     if (anim_is_active(&movement) && anim_update(&movement, dt)) {
+        if (game_status == GAME_PLAYING) {
             new_2();
+
+            if (board_is_full())
+                game_status = GAME_LOST;
+        }
     }
 
     uint32_t tile_size = game_state->width / SIZE;
@@ -332,7 +406,26 @@ client_update_framebuffer(void)
 
     clear_framebuffer(OVERDRAW, 0x000000);
 
-    /* Draw all cell backgrounds first. */
+    char score_text[32];
+    snprintf(score_text, sizeof score_text, "score: %u", game.score);
+    put_string(OVERDRAW, score_text,
+               border_width / 2, tile_size * SIZE + border_width / 2,
+               6, 1, 12, 0xFFFFFF, 0x000000);
+    
+    if (game_status != GAME_PLAYING) {
+        clear_framebuffer(BASE, 0x000000);
+        const char *message =
+            game_status == GAME_WON ? "YOU WIN!" : "YOU LOSE!";
+
+        put_string(OVERDRAW, message,
+                   0 + border_width * 2,
+                   game_state->height / 2,
+                   6, 1, 12, 0xFFFFFF, 0x000000);
+
+        return;
+    }
+
+    /* Draw all cell backgrounds. */
     for (int r = 0; r < SIZE; ++r) {
         for (int c = 0; c < SIZE; ++c) {
             uint32_t x = border_width / 2 + (uint32_t)c * tile_size;
@@ -360,17 +453,12 @@ client_update_framebuffer(void)
             }
         }
     }
-
-    char score_text[32];
-    snprintf(score_text, sizeof score_text, "score: %u", game.score);
-    put_string(OVERDRAW, score_text,
-               border_width / 2, tile_size * SIZE + border_width / 2,
-               6, 1, 12, 0xFFFFFF, 0x000000);
 }
 
 static void
 game_init(void)
 {
+    game_status = GAME_PLAYING;
     memset(&game, 0, sizeof game);
     anim_init(&movement);
     srand((unsigned)time(NULL));

src/examples/CMakeLists.txt

@@ -3,6 +3,7 @@
 
 add_executable(game_2048 2048.c)
 target_link_libraries(game_2048 PRIVATE dangerzone_engine)
+target_link_libraries(game_2048 PRIVATE m)
 
 #add_executable(game_window window.c)
 #target_link_libraries(game_window PRIVATE dangerzone_engine)