.gitignore

@@ -3,3 +3,4 @@
 build/
 src/engine/CMakeFiles
 examples/CMakeFiles
+*.xopp

src/examples/2048.c

@@ -2,6 +2,31 @@
 #include <dangerzone/render/misc.h>
 #include <dangerzone/render/text.h>
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define SIZE 4
+
+typedef enum {
+    LEFT,
+    RIGHT,
+    UP,
+    DOWN
+} dir_e;
+
+typedef struct {
+    uint32_t x;
+    uint32_t y;
+} v2_t;
+
+typedef struct {
+    uint32_t area[SIZE][SIZE];
+    dir_e direction;
+} game_t;
+
+static game_t game;
+
 // polling events every frame
 void
 client_poll_event()
@@ -17,16 +42,234 @@ client_poll_event()
 		case SDLK_Q:
 			game_state->is_running = false;
 			break;
+        case SDLK_W:
+            game.direction = UP;
+            break;
+        case SDLK_S:
+            game.direction = DOWN;
+            break;
+        case SDLK_A:
+            game.direction = LEFT;
+            break;
+        case SDLK_D:
+            game.direction = RIGHT;
+            break;
 		default:
 			break;
 		}
 	}
 }
 
+void
+print_area()
+{
+    printf("AREA:\n");
+    for (int i = 0; i < SIZE; i++) {
+        printf("[");
+        for (int j = 0; j < SIZE - 1; j++) {
+            printf("%d, ", game.area[i][j]);
+        }
+        printf("%d]\n", game.area[i][SIZE - 1]);
+    }
+    printf("\n");
+}
+
+void
+move()
+{
+    switch (game.direction) {
+    case LEFT:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = 0; k < SIZE - 1; k++) {
+                    if (game.area[i][k] == 0) {
+                        game.area[i][k] = game.area[i][k + 1];
+                        game.area[i][k + 1] = 0;
+                    }
+                }
+            }
+        }
+        break;
+    case RIGHT:
+        for (int i = 0; i < SIZE; i++) {
+            uint32_t *row = game.area[i];
+            for (int j = SIZE - 1; j >= 0; j--) {
+                for (int k = SIZE - 1; k > 0; k--) {
+                    if (game.area[i][k] == 0) {
+                        game.area[i][k] = game.area[i][k - 1];
+                        game.area[i][k - 1] = 0;
+                    }
+                }
+            }
+        }
+        break;
+    case UP:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = 0; k < SIZE - 1; k++) {
+                    if (game.area[k][i] == 0) {
+                        game.area[k][i] = game.area[k + 1][i];
+                        game.area[k + 1][i] = 0;
+                    }
+                }
+            }
+        }
+        break;
+    case DOWN:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = SIZE - 1; j >= 0; j--) {
+                for (int k = SIZE - 1; k > 0; k--) {
+                    if (game.area[k][i] == 0) {
+                        game.area[k][i] = game.area[k - 1][i];
+                        game.area[k - 1][i] = 0;
+                    }
+                }
+            }
+        }
+        break;
+    default:
+        break;
+    }
+}
+
+/**
+ * Python alternative (only horizontal)
+ *
+# combines a shifted row as per the rules of 2048
+# returns whether there were modifications done
+def combine_row(row: list[int], to_left: bool) -> bool:
+    # make sure it is shifted
+    retval = shift_row(row, to_left)
+
+    if to_left:
+        direction = 1
+        start = 0
+        end = len(row) - 1
+    else:
+        direction = -1
+        start = len(row) - 1
+        end = 0
+
+    for i in range(start, end, direction):  
+        if row[i] == 0:
+            continue
+        if row[i] == row[i + direction]:
+            retval = True
+            row[i] *= 2
+            row[i + direction] = 0
+            for j in range(i + direction, end, direction):
+                row[j] = row[j + direction]
+            row[end] = 0
+
+    return retval
+*/
+
+void
+combine_horizontal()
+{
+    int8_t direction;
+    uint32_t start, end;
+    switch (game.direction) {
+    case LEFT:
+        // combine left
+        direction = -1;
+        start = 0;
+        end = SIZE - 1;
+        break;
+    case RIGHT:
+        // combine right
+        direction = 1;
+        start = SIZE - 1;
+        end = 0;
+        break;
+    default:
+        break;
+    }
+
+    for (int row_index = 0; row_index < SIZE; row_index++) {
+        uint32_t *row = game.area[row_index];
+
+        for (int i = start; (game.direction == LEFT) ? i < end : i > end; i -= direction) {
+            if (row[i] == 0) {
+                continue;
+            }
+            if (row[i] == row[i - direction]) {
+                row[i] *= 2;
+                row[i - direction] = 0;
+                for (int j = i - direction; (game.direction == LEFT) ? j < end : j > end; j -= direction) {
+                    row[j] = row[j - direction];
+                }
+                row[end] = 0;
+            }
+        }
+    }
+} 
+
+void
+combine_vertical()
+{
+    int8_t direction;
+    uint32_t start, end;
+    switch (game.direction) {
+    case UP:
+        // combine up
+        direction = -1;
+        start = 0;
+        end = SIZE - 1;
+        break;
+    case DOWN:
+        // combine down
+        direction = 1;
+        start = SIZE - 1;
+        end = 0;
+        break;
+    default:
+        break;
+    }
+
+    for (int col_index = 0; col_index < SIZE; col_index++) {
+        for (int i = start; (game.direction == UP) ? i < end : i > end; i -= direction) {
+            if (game.area[i][col_index] == 0) {
+                continue;
+            }
+            if (game.area[i][col_index] == game.area[i - direction][col_index]) {
+                game.area[i][col_index] *= 2;
+                game.area[i - direction][col_index] = 0;
+                for (int j = i - direction; (game.direction == UP) ? j < end : j > end; j -= direction) {
+                    game.area[j][col_index] = game.area[j - direction][col_index];
+                }
+                game.area[end][col_index] = 0;
+            }
+        }
+    }
+}
+
+void
+combine()
+{
+    if (game.direction == LEFT || game.direction == RIGHT) {
+        combine_horizontal();
+    } else {
+        combine_vertical();
+    }
+}
+
+void
+slide()
+{
+    // 1. move all squares in one direction
+    move();
+
+    // 2. then combine them and shift the potential rest by one in the given direction
+    combine();
+}
+
 // performed every frame
 void
 client_update_framebuffer()
 {
+    //slide();
+
 	// single green demo pixel
 	game_state->framebuffer[0] = 0x00FF00;
 
@@ -36,9 +279,123 @@ client_update_framebuffer()
 	);
 }
 
+bool
+v2_eq(v2_t a, v2_t b)
+{
+    return a.x == b.x && a.y == b.y;
+}
+
+bool
+v2_contains(v2_t v[], size_t size, v2_t elem)
+{
+    for (int i = 0; i < size; i++) {
+        if (v2_eq(v[i], elem)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void
+game_init()
+{
+    srand(time(NULL));
+
+    // generate MAX_NUMBER_OF_4 + MAX_NUMBER_OF_2 random indices in range 0..15 (row in 0..3, col in 0..3)
+    // this means that there will be at least MAX_NUMBER_OF_2 of 2s and MAX_NUMBER_OF_4 <= MAX_NUMBER_OF_2 4s
+    // => usually less 4s than 2s because the indices can get replaced
+#define MAX_NUMBER_OF_4 1
+#define MAX_NUMBER_OF_2 2
+
+    uint8_t row, col;
+    v2_t elem;
+    v2_t fours[MAX_NUMBER_OF_4], twos[MAX_NUMBER_OF_2];
+
+    int i = 0;
+    while (i < MAX_NUMBER_OF_4) {
+        row = rand() % SIZE;
+        col = rand() % SIZE;
+        elem = (v2_t){ .x = col, .y = row };
+        if (!v2_contains(twos, MAX_NUMBER_OF_4, elem)) {
+            fours[i++] = elem;
+        }
+    }
+    
+    i = 0;
+    while (i < MAX_NUMBER_OF_2) {
+        row = rand() % SIZE;
+        col = rand() % SIZE;
+        elem = (v2_t){ .x = col, .y = row };
+        if (!v2_contains(twos, MAX_NUMBER_OF_2, elem)) {
+            twos[i++] = elem;
+        }
+    }
+
+    for (i = 0; i < MAX_NUMBER_OF_4; i++) {
+        game.area[fours[i].y][fours[i].x] = 4;
+    }
+
+    for (i = 0; i < MAX_NUMBER_OF_2; i++) {
+        game.area[twos[i].y][twos[i].x] = 2;
+    }
+    
+    game.direction = RIGHT;
+}
+
+void
+tests()
+{
+    puts("---------- TEST SHIFT LEFT <- -------------\n");
+    for (int i = 0; i < SIZE; i++) {
+        memset(game.area[i], 0, sizeof game.area[i]);
+    }
+    game.area[0][2] = 2;
+    game.area[0][3] = 2;
+    game.area[2][2] = 4;
+    game.direction = LEFT;
+
+    slide();
+
+    puts("---------- TEST SHIFT RIGHT -> ------------\n");
+    for (int i = 0; i < SIZE; i++) {
+        memset(game.area[i], 0, sizeof game.area[i]);
+    }
+    game.area[0][0] = 2;
+    game.area[0][1] = 2;
+    game.area[2][0] = 4;
+    game.direction = RIGHT;
+
+    slide();
+
+    puts("---------- TEST SHIFT UP ^^ ---------------\n");
+    for (int i = 0; i < SIZE; i++) {
+        memset(game.area[i], 0, sizeof game.area[i]);
+    }
+    game.area[2][0] = 2;
+    game.area[3][0] = 2;
+    game.area[2][2] = 4;
+    game.direction = UP;
+
+    slide();
+
+    puts("---------- TEST SHIFT DOWN vv -------------\n");
+    for (int i = 0; i < SIZE; i++) {
+        memset(game.area[i], 0, sizeof game.area[i]);
+    }
+    game.area[0][0] = 2;
+    game.area[1][0] = 2;
+    game.area[0][2] = 4;
+    game.direction = DOWN;
+
+    slide();
+}
+
 int 
 main()
 {
+    game_init();
+
 	// initialize the engine
 	if (engine_init(
 		500, 500,

src/internal/engine_internal.h

@@ -46,3 +46,4 @@ void
 engine_sdl_destroy(
 	engine_sdl_state_t *state
 );
+