From 1eadb384628c374cc88d2baad010dcd2b6abd297 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Thu, 8 Dec 2016 22:06:52 +0200
Subject: [PATCH] resize helper for perspective

* when window resized we only change aspect ratio, so projection still
keeps same
---
 include/cglm-cam.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/cglm-cam.h b/include/cglm-cam.h
index ef02a71..6d55637 100644
--- a/include/cglm-cam.h
+++ b/include/cglm-cam.h
@@ -153,6 +153,18 @@ glm_perspective_default(mat4 dest) {
                   dest);
 }
 
+CGLM_INLINE
+void
+glm_perspective_resize(mat4 proj) {
+  int32_t rect[4];
+
+  if (proj[0][0] == 0)
+    return;
+
+  glm_platfom_get_viewport_rect(rect);
+  proj[0][0] = (float)proj[1][1] * rect[3] / rect[2];
+}
+
 CGLM_INLINE
 void
 glm_lookat(vec3 eye,