Fixed lag and false game overs!

The game logic loop/collision-detection was at fault

source/main.cpp

@@ -276,18 +276,19 @@ bool can_shape_move(
             if (shape_image.getPixelValue(x, y) != 0) {
                 // calculate the translated position, including origin
                 Point destination = origin + Point(x, y);
-                // if Y is negative, skip this pixel as a special case
-                if (destination.y < 0) {
-                    continue; // we allow Blocks to be out of the top frame
-                }
                 // if out-of-bounds, of course it can't move
                 if (
                     destination.x < 0 or
                     destination.x > 4 or
                     destination.y > 4
+                    // NOTE: there is no check for negative Y since we allow it
                 ) {
                     return false;
                 }
+                // if Y is negative, we don't need to check this row
+                if (destination.y < 0) {
+                    break; // no point checking this row, out of screen
+                }
                 // check if the translated position of this pixel is not free
                 if (stacked.getPixelValue(destination.x, destination.y) != 0) {
                     return false;
@@ -388,8 +389,13 @@ void start_new_game() {
         Point origin(1, -3);
         // this is the down unit-vector
         Vector down(0, 1);
+        // draw the scene
+        UBIT.display.print(stacked_shapes);
+        // draw Block with transparency enabled on clear image pixels
+        UBIT.display.print(block.image(), origin.x, origin.y, 1);
         // while Block can go down
-        while (can_shape_move(block, origin, stacked_shapes, down)) {
+        if (can_shape_move(block, origin, stacked_shapes, down)) {
+            while (true) {
                 // allow player to shift the Block left or right
                 /*
                  * read accelerometer manually for more controlled movement
@@ -416,8 +422,12 @@ void start_new_game() {
                     // check if enough time has elapsed to move the block
                     unsigned long stopwatch_now = UBIT.systemTime();
                     if ((stopwatch_now - stopwatch) >= move_speed) {
-                    // shift the shape down
+                        // shift the shape down if it can
+                        if (can_shape_move(block, origin, stacked_shapes, down)) {
                             origin = origin + down;
+                        } else {
+                            break;
+                        }
                         // update the "stopwatch"
                         stopwatch = stopwatch_now;
                     }
@@ -429,6 +439,7 @@ void start_new_game() {
                 // delay
                 UBIT.sleep(10); // 10ms sleep = 100ticks/second
             }
+        }
         // if Block Y origin is less than 0 upon not being able to go down
         if (origin.y < 0) {
             // it's Game Over, because the Block could never fully enter screen