From 303f5dc58dd8e8266df3c62fc84d9799db8047b9 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Tue, 27 Jun 2023 16:12:45 -0700
Subject: Initial renderer.
---
gfx-iso/src/isogfx.c | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
diff --git a/gfx-iso/src/isogfx.c b/gfx-iso/src/isogfx.c
index 27981f9..b38efe7 100644
--- a/gfx-iso/src/isogfx.c
+++ b/gfx-iso/src/isogfx.c
@@ -52,14 +52,22 @@ static inline ivec2 iso2cart(ivec2 iso, int s, int t, int w) {
.x = (iso.x - iso.y) * (s / 2) + (w / 2), .y = (iso.x + iso.y) * (t / 2)};
}
+// Method 1.
+// static inline vec2 cart2iso(vec2 cart, int s, int t, int w) {
+// const double x = cart.x - (double)(w / 2);
+// const double xiso = (x * t + cart.y * s) / (double)(s * t);
+// return (vec2){
+// .x = (int)(xiso), .y = (int)((2.0 / (double)t) * cart.y - xiso)};
+//}
+
+// Method 2.
static inline vec2 cart2iso(vec2 cart, int s, int t, int w) {
const double one_over_s = 1. / (double)s;
const double one_over_t = 1. / (double)t;
const double x = cart.x - (double)(w / 2);
-
return (vec2){
- .x = (int)(one_over_s * x + one_over_t * cart.y),
- .y = (int)(-one_over_s * x + one_over_t * cart.y)};
+ .x = (one_over_s * x + one_over_t * cart.y),
+ .y = (-one_over_s * x + one_over_t * cart.y)};
}
Pixel* tile_xy_mut(const IsoGfx* iso, TileData* tile, int x, int y) {
@@ -120,7 +128,7 @@ static inline Pixel* screen_xy_mut(IsoGfx* iso, int x, int y) {
return &iso->screen[y * iso->screen_width + x];
}
-static void draw_tile(IsoGfx* iso, ivec2 so, Tile tile) {
+static void draw_tile(IsoGfx* iso, ivec2 origin, Tile tile) {
assert(iso);
const TileData* data = mempool_get_block(&iso->tiles, tile);
@@ -129,8 +137,8 @@ static void draw_tile(IsoGfx* iso, ivec2 so, Tile tile) {
for (int py = 0; py < iso->tile_height; ++py) {
for (int px = 0; px < iso->tile_width; ++px) {
const Pixel colour = tile_xy(iso, data, px, py);
- const int sx = so.x + px;
- const int sy = so.y + py;
+ const int sx = origin.x + px;
+ const int sy = origin.y + py;
if ((sx >= 0) && (sy >= 0) && (sx < iso->screen_width) &&
(sy < iso->screen_height)) {
const uint8_t mask = iso->tile_mask[py * iso->tile_width + px];
@@ -154,8 +162,9 @@ static void draw(IsoGfx* iso) {
const ivec2 x = {.x = iso->tile_width / 2, .y = iso->tile_height / 2};
const ivec2 y = {.x = -iso->tile_width / 2, .y = iso->tile_height / 2};
- // TODO: Since the world will generally be larger than the screen, it
- // would be best to walk in screen space and fetch the tile.
+ // TODO: Culling.
+ // Ex: map the screen corners to tile space to cull.
+ // Ex: walk in screen space and fetch the tile.
// The tile-centric approach might be more cache-friendly, however, since the
// screen-centric approach would juggle multiple tiles throughout the scan.
for (int ty = 0; ty < iso->world_height; ++ty) {
@@ -312,15 +321,13 @@ void isogfx_pick_tile(
(vec2){.x = xcart, .y = ycart}, iso->tile_width, iso->tile_height,
iso->screen_width);
- const int x = (int)xy_iso.x;
- const int y = (int)xy_iso.y;
-
- if ((0 <= x) && (x < iso->world_width) && (0 <= y) &&
- (y < iso->world_height)) {
- *xiso = x;
- *yiso = y;
+ if ((0 <= xy_iso.x) && (xy_iso.x < iso->world_width) && (0 <= xy_iso.y) &&
+ (xy_iso.y < iso->world_height)) {
+ *xiso = (int)xy_iso.x;
+ *yiso = (int)xy_iso.y;
} else {
*xiso = -1;
+ *yiso = -1;
}
}
--
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