Frag_m1.txt

//for filling linked list using fragments corrosponding to model

#version 430 core

layout(binding = 0 , offset=0) uniform atomic_uint count;

layout(binding = 0, r32ui) coherent uniform uimage2D head_ptr; //different uniforms can have same bindings if they are of different types



struct node
{
	vec4 color;
	float depth;
	int facing;
	uint next;
};

layout (binding=0, std430 ) buffer storage
{

	node storage_arr[];

};


void main()
{
	ivec2 loc = ivec2(gl_FragCoord.xy);//getting location on image

	uint i = atomicCounterIncrement(count); //index is 1 less than count so prev count == current index

	uint prev_head = imageAtomicExchange(head_ptr, loc , i); 
	


	storage_arr[i].color = vec4(1,1,1,1);
	storage_arr[i].depth = gl_FragCoord.z;//recording depth in list
	storage_arr[i].facing = gl_FrontFacing ? 1 : 0 ;//recording facing in list
	storage_arr[i].next = prev_head;

	//we are inserting new nodes at the begining of list so next of new node(which will now act as new head) should point to prev header's index


}