add perspective_matrix

liblava/core/math.hpp

@@ -83,4 +83,10 @@ namespace lava {
 
     constexpr v3 const default_color = v3{ 0.8118f, 0.0627f, 0.1255f }; // #CF1020 : 207, 16, 32
 
+    inline mat4 perspective_matrix(uv2 size, float fov = 90.f, float far_plane = 5.f) {
+        // Vulkan NDC is right-handed with Y pointing down
+        // we flip Y which makes it left-handed
+        return glm::scale(glm::identity<glm::mat4>(), { 1.f, -1.f, 1.f }) * glm::perspectiveLH_ZO(glm::radians(fov), float(size.x) / size.y, 0.1f, far_plane);
+    }
+
 } // namespace lava