Add ability to move bricks

src/root.zig

@@ -38,26 +38,45 @@ const State = struct {
     frame_count: i32,
     mouse_pos: V2,
     camera: Camera,
+    brick: Brick,
 };
 
+fn pointInsideRect(p: V2, rect_start: V2, rect_size: V2) bool {
+    var result: bool = false;
+
+    const rect_end: V2 = rect_start.add(rect_size);
+
+    const inside_x = rect_start.x < p.x and p.x < rect_end.x;
+    const inside_y = rect_start.y < p.y and p.y < rect_end.y;
+
+    result = inside_x and inside_y;
+
+    return result;
+}
+
 fn fillRect(
     buffer: platform.OffscreenBuffer,
-    x: i32,
-    y: i32,
+    pos_x: i32,
+    pos_y: i32,
     width: i32,
     height: i32,
     color: u32,
 ) void {
     var pixels: []u32 = @ptrCast(@alignCast(buffer.data));
 
-    const start_x: usize = @intCast(x);
-    const end_x: usize = @intCast(x + width);
-    const start_y: usize = @intCast(y);
-    const end_y: usize = @intCast(y + height);
+    var start_x: i32 = pos_x;
+    var start_y: i32 = pos_y;
+    var end_x: i32 = pos_x + width;
+    var end_y: i32 = pos_y + height;
 
-    for (start_y..end_y) |i| {
-        for (start_x..end_x) |j| {
-            const idx: usize = i * @as(usize, @intCast(buffer.width)) + j;
+    if (start_x < 0) start_x = 0;
+    if (start_y < 0) start_y = 0;
+    if (buffer.width < end_x) end_x = buffer.width;
+    if (buffer.height < end_y) end_y = buffer.height;
+
+    for (@intCast(start_y) .. @intCast(end_y)) |y| {
+        for (@intCast(start_x) .. @intCast(end_x)) |x| {
+            const idx: usize = y * @as(usize, @intCast(buffer.width)) + x;
 
             pixels[idx] = color;
         }
@@ -77,11 +96,19 @@ fn fillSquare(
 pub fn updateAndRender(memory: *platform.AppMemory, buffer: platform.OffscreenBuffer, input: platform.AppInput) void {
     var state: *State = @ptrCast(@alignCast(memory.permanent_storage));
 
+    const mid = V2{ .x = @floatFromInt(@divTrunc(buffer.width, 2)), .y = @floatFromInt(@divTrunc(buffer.height, 2)), };
     if (!memory.initialized) {
-        state.camera.offset.x = @floatFromInt(@divTrunc(buffer.width, 2));
-        state.camera.offset.y = @floatFromInt(@divTrunc(buffer.height, 2));
+        state.camera.offset = mid;
 
-        state.camera.pos = state.camera.pos.add(state.camera.offset);
+        state.brick = Brick{
+            .pos = V2{ .x = 50, .y = 50},
+            .tiles = [4][4]u32{
+                .{1, 1, 1, 1},
+                .{1, 0, 0, 0},
+                .{0, 0, 0, 0},
+                .{0, 0, 0, 0},
+            },
+        };
 
         memory.initialized = true;
     }
@@ -89,27 +116,45 @@ pub fn updateAndRender(memory: *platform.AppMemory, buffer: platform.OffscreenBu
     // Update
     const mouse_pos = V2{ .x = @floatCast(input.mouse_x), .y = @floatCast(input.mouse_y) };
 
-    if (input.mouse_left_down) {
+    const tile_size = V2{
+        .x = TILE_SIZE,
+        .y = TILE_SIZE,
+    };
+
+    var mouse_on_brick = false;
+    for (state.brick.tiles, 0..) |row, i| {
+        for (row, 0..) |tile, j| {
+            if (tile == 1) {
+                const tile_pos = V2{
+                    .x = @floatFromInt(j * TILE_SIZE),
+                    .y = @floatFromInt(i * TILE_SIZE),
+                };
+                const pos = tile_pos.add(state.brick.pos);
+
+                const camera_pos = pos.add(state.camera.pos);
+                if (pointInsideRect(state.mouse_pos, camera_pos, tile_size)) {
+                    if (input.mouse_left_down) {
+                        const diff = mouse_pos.sub(state.mouse_pos);
+                        state.brick.pos = state.brick.pos.add(diff);
+                        mouse_on_brick = true;
+                    }
+                }
+            }
+        }
+    }
+
+    if (input.mouse_left_down and !mouse_on_brick) {
         const diff = mouse_pos.sub(state.mouse_pos);
         state.camera.pos = state.camera.pos.add(diff);
     }
 
-    state.mouse_pos = mouse_pos;
 
-    const brick = Brick{
-        .pos = V2{ .x = 50, .y = 50},
-        .tiles = [4][4]u32{
-            .{1, 1, 1, 1},
-            .{1, 0, 0, 0},
-            .{0, 0, 0, 0},
-            .{0, 0, 0, 0},
-        },
-    };
+    state.mouse_pos = mouse_pos;
 
     // Render
     fillRect(buffer, 0, 0, buffer.width, buffer.height, 0xFFFFFFFF);
 
-    const board_pos = V2{ .x = 64, .y = 64 };
+    const board_pos = mid;
     for (0..7) |i| {
         for (0..7) |j| {
             if (i == 0 and j == 6) continue;
@@ -128,17 +173,16 @@ pub fn updateAndRender(memory: *platform.AppMemory, buffer: platform.OffscreenBu
         }
     }
 
-    for (brick.tiles, 0..) |row, i| {
+    for (state.brick.tiles, 0..) |row, i| {
         for (row, 0..) |tile, j| {
             if (tile == 1) {
                 const pos = V2{
-                    .x = @floatFromInt(j * TILE_SIZE + 8),
-                    .y = @floatFromInt(i * TILE_SIZE + 8),
+                    .x = @floatFromInt(j * TILE_SIZE),
+                    .y = @floatFromInt(i * TILE_SIZE),
                 };
-                const camera_pos = brick.pos.add(pos).add(state.camera.pos);
+                const camera_pos = state.brick.pos.add(pos).add(state.camera.pos);
                 fillSquare(buffer, @intFromFloat(camera_pos.x), @intFromFloat(camera_pos.y), 30, 0xFFFF0000);
             }
-
         }
     }