add selected shape drawing

src/game/game.c

@@ -51,7 +51,7 @@ static void update_input(GameData* game_data, const uint8_t* keys) {
         game_data->selected.x--;
 
     if (keys[SDL_SCANCODE_RIGHT] || keys[SDL_SCANCODE_D])
-        game_data->selected.y++;
+        game_data->selected.x++;
 }
 
 

src/window/colour.h

@@ -34,3 +34,28 @@ typedef union {
 #define COLOUR_BLUE    ((Colour){BLUE})
 #define COLOUR_MAGENTA ((Colour){MAGENTA})
 #define COLOUR_WHITE   ((Colour){WHITE})
+
+// gets the red channel in 32 bit colour space
+static inline uint8_t colour_red32(Colour colour) {
+    return colour.r * 0x55;
+}
+
+// gets the green channel in 32 bit colour space
+static inline uint8_t colour_green32(Colour colour) {
+    return colour.g * 0x55;
+}
+
+// gets the blue channel in 32 bit colour space
+static inline uint8_t colour_blue32(Colour colour) {
+    return colour.b * 0x55;
+}
+
+// gets the alpha channel in 32 bit colour space
+static inline uint8_t colour_alpha32(Colour colour) {
+    return colour.a * 0x55;
+}
+
+// gets the packed colour in 32 bit colour space
+static inline uint32_t colour_packed32(Colour colour) {
+    return colour.packed * 0x55;
+}

src/window/renderer.c

@@ -10,6 +10,7 @@
 
 #include "../errors.h"
 #include "../game/game.h"
+#include "../game/tetromino/shapes.h"
 #include "colour.h"
 #include "renderer.h"
 
@@ -32,6 +33,14 @@ int renderer_init(SDL_Window** window, SDL_Renderer** renderer) {
     return 0;
 }
 
+static inline int draw_block(SDL_Renderer* renderer, uint8_t x, uint8_t y) {
+    return SDL_RenderFillRect(renderer, &(SDL_Rect){x * BLOCK_WIDTH + 1, y * BLOCK_HEIGHT + 1, BLOCK_WIDTH - 1, BLOCK_HEIGHT - 1});
+}
+
+static inline void set_colour(SDL_Renderer* renderer, Colour c) {
+    (void)SDL_SetRenderDrawColor(renderer, colour_red32(c), colour_green32(c), colour_blue32(c), colour_alpha32(c));
+}
+
 void renderer_update(const RenderData* render_data) {
     SDL_Renderer* renderer = render_data->renderer;
     GameData* data = render_data->game_data;
@@ -42,17 +51,32 @@ void renderer_update(const RenderData* render_data) {
     success |= SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 0xFF);
     success |= SDL_RenderClear(renderer);
 
+    SelectedShape selected = render_data->game_data->selected;
+    Shape selected_shape = shape_from_id(selected.id);
+    Colour selected_colour = colour_from_id(selected.id);
+
+    set_colour(renderer, selected_colour);
+
+    // draw the selected block
+    for (uint8_t y = 0; y < SHAPE_HEIGHT; y++) {
+        ShapeRow shape_row = shape_get_row(selected_shape, y);
+
+        if (shape_row == 0)
+            continue;
+
+        for (uint8_t x = 0; x < SHAPE_WIDTH; x++)
+            if (is_set(shape_row, x))
+                draw_block(renderer, selected.x + x, selected.y + y);
+    }
+
+    // draw the block data in the level
     for (uint8_t y = 0; y < ROWS; y++) {
         Row row = data->row[y];
 
         for (uint8_t x = 0; x < COLUMNS; x++) {
             if (row.columns[x].packed != 0) {
-                success |= SDL_SetRenderDrawColor(renderer,
-                                                  0x55 * row.columns[x].r, // repeat the 2 bits by multiplying by 0x55
-                                                  0x55 * row.columns[x].g,
-                                                  0x55 * row.columns[x].b,
-                                                  0x55 * row.columns[x].a);
-                success |= SDL_RenderFillRect(renderer, &(SDL_Rect){x * BLOCK_WIDTH + 1, y * BLOCK_HEIGHT + 1, BLOCK_WIDTH - 1, BLOCK_HEIGHT - 1});
+                set_colour(renderer, row.columns[x]);
+                success |= draw_block(renderer, x, y);
             }
         }
     }