Add Screen struct

1 files changed, 41 insertions, 37 deletions

diff --git a/src/isogfx.c b/src/isogfx.c
index b715ca8..e182dff 100644
--- a/src/isogfx.c
+++ b/src/isogfx.c
@@ -32,7 +32,11 @@ typedef struct vec2 {
 // Renderer state.
 // -----------------------------------------------------------------------------
 
-// TODO: Define a struct Screen with width, height and pixels.
+typedef struct Screen {
+  int    width;
+  int    height;
+  Pixel* pixels;
+} Screen;
 
 typedef struct SpriteInstance {
   struct SpriteInstance* next;
@@ -43,11 +47,9 @@ typedef struct SpriteInstance {
 } SpriteInstance;
 
 typedef struct IsoGfx {
-  int             screen_width;
-  int             screen_height;
+  Screen          screen;
   double          last_animation_time;
   Tile            next_tile; // For procedurally-generated tiles.
-  Pixel*          screen;
   Tm_Map*         map;
   Ts_TileSet*     tileset;
   SpriteInstance* head_sprite; // Head of sprites list.
@@ -90,21 +92,21 @@ static inline vec2 cart2iso(vec2 cart, int s, int t, int w) {
 }
 
 static inline const Pixel* screen_xy_const_ref(
-    const IsoGfx* iso, int x, int y) {
-  assert(iso);
+    const Screen* screen, int x, int y) {
+  assert(screen);
   assert(x >= 0);
   assert(y >= 0);
-  assert(x < iso->screen_width);
-  assert(y < iso->screen_height);
-  return &iso->screen[y * iso->screen_width + x];
+  assert(x < screen->width);
+  assert(y < screen->height);
+  return &screen->pixels[y * screen->width + x];
 }
 
-static inline Pixel screen_xy(IsoGfx* iso, int x, int y) {
-  return *screen_xy_const_ref(iso, x, y);
+static inline Pixel screen_xy(Screen* screen, int x, int y) {
+  return *screen_xy_const_ref(screen, x, y);
 }
 
-static inline Pixel* screen_xy_mut(IsoGfx* iso, int x, int y) {
-  return (Pixel*)screen_xy_const_ref(iso, x, y);
+static inline Pixel* screen_xy_mut(Screen* screen, int x, int y) {
+  return (Pixel*)screen_xy_const_ref(screen, x, y);
 }
 
 // -----------------------------------------------------------------------------
@@ -126,16 +128,17 @@ IsoGfx* isogfx_new(const IsoGfxDesc* desc) {
       memstack_alloc_aligned(&tmp.stack, sizeof(IsoGfx), alignof(IsoGfx));
   *iso = tmp;
 
-  iso->screen_width        = desc->screen_width;
-  iso->screen_height       = desc->screen_height;
-  iso->last_animation_time = 0.0;
-
   const size_t screen_size_bytes =
       desc->screen_width * desc->screen_height * sizeof(Pixel);
-  iso->screen =
+  Pixel* screen =
       memstack_alloc_aligned(&iso->stack, screen_size_bytes, alignof(Pixel));
 
-  iso->watermark = memstack_watermark(&iso->stack);
+  iso->screen = (Screen){.width  = desc->screen_width,
+                         .height = desc->screen_height,
+                         .pixels = screen};
+
+  iso->last_animation_time = 0.0;
+  iso->watermark           = memstack_watermark(&iso->stack);
 
   return iso;
 
@@ -469,7 +472,7 @@ typedef struct CoordSystem {
 /// expressed in the Cartesian system.
 static CoordSystem make_iso_coord_system(const IsoGfx* iso) {
   assert(iso);
-  const ivec2 o = {iso->screen_width / 2, 0};
+  const ivec2 o = {iso->screen.width / 2, 0};
   const ivec2 x = {
       .x = iso->map->base_tile_width / 2, .y = iso->map->base_tile_height / 2};
   const ivec2 y = {
@@ -517,9 +520,9 @@ static Pixel alpha_blend(Pixel src, Pixel dst) {
 /// 'pixels' is the palette and 'indices' the pixel indices. Otherwise, the
 /// image is assumed to be in plain RGBA format.
 static void draw_rect(
-    IsoGfx* iso, ivec2 top_left, int rect_width, int rect_height,
+    Screen* screen, ivec2 top_left, int rect_width, int rect_height,
     const Pixel* pixels, const uint8_t* indices) {
-  assert(iso);
+  assert(screen);
 
 #define rect_pixel(X, Y) \
   (indices ? pixels[indices[Y * rect_width + X]] : pixels[Y * rect_width + X])
@@ -532,16 +535,16 @@ static void draw_rect(
 
   // Rect can exceed screen bounds, so clip along Y and X as we draw.
   for (int py = py_offset;
-       (py < rect_height) && (top_left.y + py < iso->screen_height); ++py) {
+       (py < rect_height) && (top_left.y + py < screen->height); ++py) {
     const int sy = top_left.y + py;
     for (int px = px_offset;
-         (px < rect_width) && (top_left.x + px < iso->screen_width); ++px) {
+         (px < rect_width) && (top_left.x + px < screen->width); ++px) {
       const Pixel colour = rect_pixel(px, py);
       if (colour.a > 0) {
-        const int   sx              = top_left.x + px;
-        const Pixel dst             = screen_xy(iso, sx, sy);
-        const Pixel final           = alpha_blend(colour, dst);
-        *screen_xy_mut(iso, sx, sy) = final;
+        const int   sx                 = top_left.x + px;
+        const Pixel dst                = screen_xy(screen, sx, sy);
+        const Pixel final              = alpha_blend(colour, dst);
+        *screen_xy_mut(screen, sx, sy) = final;
       }
     }
   }
@@ -567,16 +570,17 @@ static void draw_tile(IsoGfx* iso, ivec2 screen_origin, Tile tile) {
       pTile->height - iso->map->base_tile_height};
   const ivec2 top_left = ivec2_add(screen_origin, offset);
 
-  draw_rect(iso, top_left, pTile->width, pTile->height, pixels, 0);
+  draw_rect(
+      &iso->screen, top_left, pTile->width, pTile->height, pixels, nullptr);
 }
 
 static void draw_world(IsoGfx* iso) {
   assert(iso);
 
-  const int W = iso->screen_width;
-  const int H = iso->screen_height;
+  const int W = iso->screen.width;
+  const int H = iso->screen.height;
 
-  memset(iso->screen, 0, W * H * sizeof(Pixel));
+  memset(iso->screen.pixels, 0, W * H * sizeof(Pixel));
 
   const CoordSystem iso_space = make_iso_coord_system(iso);
 
@@ -609,7 +613,7 @@ static void draw_sprite(
   const Ss_Row*  row   = ss_get_sprite_sheet_row(sheet, sprite->animation);
   const uint8_t* frame = ss_get_sprite_sheet_sprite(sheet, row, sprite->frame);
   draw_rect(
-      iso, origin, sheet->sprite_width, sheet->sprite_height,
+      &iso->screen, origin, sheet->sprite_width, sheet->sprite_height,
       sheet->palette.colours, frame);
 }
 
@@ -651,13 +655,13 @@ void isogfx_get_screen_size(const IsoGfx* iso, int* width, int* height) {
   assert(iso);
   assert(width);
   assert(height);
-  *width  = iso->screen_width;
-  *height = iso->screen_height;
+  *width  = iso->screen.width;
+  *height = iso->screen.height;
 }
 
 const Pixel* isogfx_get_screen_buffer(const IsoGfx* iso) {
   assert(iso);
-  return iso->screen;
+  return iso->screen.pixels;
 }
 
 void isogfx_pick_tile(
@@ -668,7 +672,7 @@ void isogfx_pick_tile(
 
   const vec2 xy_iso = cart2iso(
       (vec2){.x = xcart, .y = ycart}, iso->map->base_tile_width,
-      iso->map->base_tile_height, iso->screen_width);
+      iso->map->base_tile_height, iso->screen.width);
 
   if ((0 <= xy_iso.x) && (xy_iso.x < iso->map->world_width) &&
       (0 <= xy_iso.y) && (xy_iso.y < iso->map->world_height)) {