From 446a3b3d26f29c3214092726c9caa7252df52a61 Mon Sep 17 00:00:00 2001
From: duck <duck@duckdesktop>
Date: Wed, 28 May 2025 22:44:08 +0500
Subject: [PATCH] Aspect ratio for camera

---
 src/graphics.zig        | 5 +++--
 src/graphics/camera.zig | 9 ++++++---
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/graphics.zig b/src/graphics.zig
index 0186229..8660b05 100644
--- a/src/graphics.zig
+++ b/src/graphics.zig
@@ -191,7 +191,8 @@ pub fn create() GameError!Self {
             .transform = .{},
             .near = 1.0,
             .far = 1024.0,
-            .lens = .{ 1.5 * 16.0 / 9.0, 1.5 },
+            .lens = 1.5,
+            .aspect = 16.0 / 9.0,
         },
     };
 }
@@ -321,7 +322,7 @@ pub fn beginDraw(self: *Self) GameError!bool {
     self.command_buffer = sdl.AcquireGPUCommandBuffer(self.device) orelse return GameError.SdlError;
     if (self.to_resize) |new_size| {
         try self.resetTextures(new_size[0], new_size[1]);
-        self.camera.lens[0] = self.camera.lens[1] * @as(f32, @floatFromInt(new_size[0])) / @as(f32, @floatFromInt(new_size[1]));
+        self.camera.aspect = @as(f32, @floatFromInt(new_size[0])) / @as(f32, @floatFromInt(new_size[1]));
         self.window_size = new_size;
         self.to_resize = null;
     }
diff --git a/src/graphics/camera.zig b/src/graphics/camera.zig
index 3cd7fdb..20502fc 100644
--- a/src/graphics/camera.zig
+++ b/src/graphics/camera.zig
@@ -4,13 +4,16 @@ const Transform = @import("transform.zig");
 const Camera = @This();
 
 transform: Transform,
-lens: @Vector(2, f32),
+/// tangent of the half of the view angle (90 degress = 1 "lens")
+lens: f32,
 near: f32,
 far: f32,
+/// width = height * aspect
+aspect: f32,
 
 pub fn matrix(camera: Camera) @Vector(16, f32) {
-    const xx = 1.0 / camera.lens[0];
-    const yy = 1.0 / camera.lens[1];
+    const xx = 1.0 / (camera.lens * camera.aspect);
+    const yy = 1.0 / camera.lens;
     const fnmod = 1.0 / (camera.far - camera.near);
     const zz = camera.far * fnmod;
     const wz = -camera.near * camera.far * fnmod;