Modifying SaschaWillems demo's uniforms?

Vulkan
1

I’m trying to modify uniform blocks:
c++

struct {
		glm::mat4 projection;
		glm::mat4 model;
		glm::mat4 view;
		glm::vec4 instancePos[3];
		int layer;
	} uboVS, uboOffscreenVS;

	// This UBO stores the shadow matrices for all of the light sources
	// The matrices are indexed using geometry shader instancing
	// The instancePos is used to place the models using instanced draws
	struct {
		glm::mat4 mvp[LIGHT_COUNT];
		glm::vec4 instancePos[3];
	} uboShadowGS;

to: (just adding uint32_t totalInstances = 1)

struct {
		glm::mat4 projection;
		glm::mat4 model;
		glm::mat4 view;
		uint32_t totalInstances = 1;
		glm::vec4 instancePos[3];
		int layer;
	} uboVS, uboOffscreenVS;

	// This UBO stores the shadow matrices for all of the light sources
	// The matrices are indexed using geometry shader instancing
	// The instancePos is used to place the models using instanced draws
	struct {
		glm::mat4 mvp[LIGHT_COUNT];
		uint32_t totalInstances = 1;
		glm::vec4 instancePos[3];
	} uboShadowGS;

And in the 2 shaders from:

layout (binding = 0) uniform UBO 
{
	mat4 mvp[LIGHT_COUNT];
	vec4 instancePos[3];
} ubo;

layout (binding = 0) uniform UBO 
{
	mat4 projection;
	mat4 model;
	mat4 view;
	vec4 instancePos[3];
} ubo;

to:

layout (binding = 0) uniform UBO 
{
	mat4 mvp[LIGHT_COUNT];
	int totalInstances;
	vec4 instancePos[3];
} ubo;

layout (binding = 0) uniform UBO 
{
	mat4 projection;
	mat4 model;
	mat4 view;
	int totalInstances;
	vec4 instancePos[3];
} ubo;

Not working, anything else to do?
Thanks.

2

I don’t really see the C++ code match the shaders. The structs are probably further processed down the road.
Can you link the exact example?