From a19049d7a6bed9b236c5e714dde844925750e39d Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sat, 19 Jul 2025 13:23:29 -0700
Subject: Implement camera pan

---
 demos/isomap/isomap.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

(limited to 'demos/isomap')

diff --git a/demos/isomap/isomap.c b/demos/isomap/isomap.c
index efae7fd..a940535 100644
--- a/demos/isomap/isomap.c
+++ b/demos/isomap/isomap.c
@@ -2,6 +2,7 @@
 #include <isogfx/isogfx.h>
 
 #include <gfx/app.h>
+#include <math/vec2.h>
 
 #include <assert.h>
 #include <stdbool.h>
@@ -15,6 +16,8 @@ static const int MAX_FPS       = 60;
 static const int SCREEN_WIDTH  = 704;
 static const int SCREEN_HEIGHT = 480;
 
+static const R CAMERA_SPEED = 400;
+
 #define MEMORY_SIZE (2 * 1024 * 1024)
 uint8_t MEMORY[MEMORY_SIZE];
 
@@ -23,6 +26,7 @@ typedef struct GfxAppState {
   IsoGfx*     iso;
   int         xpick;
   int         ypick;
+  vec2        camera;
   SpriteSheet stag_sheet;
   Sprite      stag;
 } GfxAppState;
@@ -67,11 +71,33 @@ static void shutdown(GfxAppState* state) {
   //
 }
 
+static vec2 get_camera_movement(R dt) {
+  vec2 offset = {0};
+  if (gfx_app_is_key_pressed(KeyA)) {
+    offset.x -= 1;
+  }
+  if (gfx_app_is_key_pressed(KeyD)) {
+    offset.x += 1;
+  }
+  if (gfx_app_is_key_pressed(KeyW)) {
+    offset.y -= 1;
+  }
+  if (gfx_app_is_key_pressed(KeyS)) {
+    offset.y += 1;
+  }
+  if ((offset.x != 0) || (offset.y != 0)) {
+    offset = vec2_scale(vec2_normalize(offset), dt * CAMERA_SPEED);
+  }
+  return offset;
+}
+
 static void update(GfxAppState* state, double t, double dt) {
   assert(state);
-  (void)dt;
+
+  state->camera = vec2_add(state->camera, get_camera_movement((R)dt));
 
   IsoGfx* iso = state->iso;
+  isogfx_set_camera(iso, (int)state->camera.x, (int)state->camera.y);
   isogfx_update(iso, t);
 }
 
-- 
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