add collision

src/game/game.c

@@ -21,6 +21,8 @@ void game_init(GameData* const game_data) {
     for (uint8_t i = 0; i < ROWS; i++)
         game_data->row[i] = game_data->row_raw[i];
 
+    game_data->selected = (SelectedShape){TETROMINO_L, 0, 0};
+
     // set a random seed using the system clock
     srand(time(NULL));
 }
@@ -68,31 +70,13 @@ static void clear_rows(Row* row) {
     }
 }
 
-static void update_input(GameData* game_data, const uint8_t* keys) {
-    if (keys[SDL_SCANCODE_ESCAPE])
-        stop();
-
-    if (keys[SDL_SCANCODE_DOWN] || keys[SDL_SCANCODE_S] || keys[SDL_SCANCODE_SPACE])
-        game_data->selected.y++;
-
-    if (keys[SDL_SCANCODE_LEFT] || keys[SDL_SCANCODE_A])
-        game_data->selected.x--;
-
-    if (keys[SDL_SCANCODE_RIGHT] || keys[SDL_SCANCODE_D])
-        game_data->selected.x++;
-}
 
 
 // called every time the game's state is updated
 void game_update(GameData* game_data, const uint8_t* keys) {
-    static int x = 0;
-    if (!x) {
-        x = 1;
-        game_data->selected = (SelectedShape){TETROMINO_L, 0, 0};
-    }
+    if (keys[SDL_SCANCODE_ESCAPE])
+        stop();
 
-    update_input(game_data, keys);
-
-    // tmp_set_random(game_data);
-    dbg_set_all(game_data);
+    place_update(game_data, keys);
+    // dbg_set_all(game_data);
 }

src/game/tetromino/placing.c

@@ -5,6 +5,7 @@
 
 #include "../../window/colour.h"
 #include "../game.h"
+#include "SDL_scancode.h"
 #include "shapes.h"
 
 // sets a shape to the screen
@@ -27,6 +28,61 @@ static inline void set_shape(Row* row, const ShapeId id, const uint8_t pos_x, co
     set_shape_i(&row[pos_y], id, pos_x); // calls itself, but omitting the pos_y argument, instead opting for specifying the row
 }
 
+static bool shape_intersects(const Row* rows, const ShapeId id, const uint8_t x, const uint8_t y) {
+    const Shape shape = shape_from_id(id);
+
+    for (uint8_t y0 = 0; y0 < SHAPE_HEIGHT; y0++) {
+        const ShapeRow shape_row = shape_get_row(shape, y0); // get the shape row
+        if (shape_row == 0) continue;                        // if the row doesn't contain data; continue
+
+        for (uint8_t x0 = 0; x0 < SHAPE_WIDTH; x0++) {
+            if (is_set(shape_row, x0) == false) continue; // if the bit isn't set at this index; continue
+            const uint8_t x1 = x + x0;
+            const uint8_t y1 = y + y0;
+
+            if (x1 < 0 || x1 >= COLUMNS) return true;  // if X is out of bounds
+            if (y1 < 0 || y1 >= ROWS) return true;     // if Y is out of bounds
+            if (rows[y1][x1].packed != 0) return true; // if there is a block here
+        }
+    }
+    return false;
+}
+
+void place_update(GameData* const game_data, const uint8_t* const keys) {
+    int8_t move = 0;
+
+    if (keys[SDL_SCANCODE_LEFT] || keys[SDL_SCANCODE_A])
+        move |= 1;
+
+    if (keys[SDL_SCANCODE_RIGHT] || keys[SDL_SCANCODE_D])
+        move |= 2;
+
+    if (keys[SDL_SCANCODE_DOWN] || keys[SDL_SCANCODE_S] || keys[SDL_SCANCODE_SPACE])
+        move |= 4;
+
+    // set the shape if we moved vertically and collided
+    if (!!(move & 4)) {
+        const uint8_t y = game_data->selected.y + 1;
+        if (shape_intersects(game_data->row, game_data->selected.id, game_data->selected.x, y)) {
+            set_shape(game_data->row, game_data->selected.id, game_data->selected.x, y);
+            return;
+        }
+
+        game_data->selected.y = y;
+    }
+
+    // ignore if the movement cancles itself out
+    if ((move & 3) == 0 || (move & 3) == 3)
+        return;
+
+    const uint8_t x = game_data->selected.x + ((move & 3) == 1 ? -1 : 1);
+    if (shape_intersects(game_data->row, game_data->selected.id, x, game_data->selected.y))
+        return;
+
+    game_data->selected.x = x;
+    printf("%i\n", x);
+}
+
 #ifdef DEBUG
 void dbg_set_all(GameData* game_data) {
     for (uint8_t i = 0; i < TETROMINO_COUNT; i++)
@@ -34,17 +90,3 @@ void dbg_set_all(GameData* game_data) {
             set_shape(game_data->row, i | (r << 3), r * 4, i * 4);
 }
 #endif
-
-void tmp_set_random(GameData* game_data) {
-    static int finished = 0;
-    if (finished)
-        return;
-
-    finished = 1;
-    for (uint8_t y = 0; y <= ROWS - SHAPE_HEIGHT; y += SHAPE_HEIGHT) {
-        for (uint8_t x = 0; x <= COLUMNS - SHAPE_WIDTH; x += SHAPE_WIDTH) {
-            const ShapeId id = (rand() % TETROMINO_COUNT) | ((rand() % 4) << 3);
-            set_shape(game_data->row, id, x, y);
-        }
-    }
-}

src/game/tetromino/placing.h

@@ -1,7 +1,13 @@
 #pragma once
 
+#include <stdbool.h>
+#include <stdint.h>
+
 #include "../game.h"
+#include "shapes.h"
 
+void place_update(GameData* game_data, const uint8_t* keys);
 
-void tmp_set_random(GameData* game_data);
+#ifdef DEBUG
 void dbg_set_all(GameData* game_data);
+#endif