rj-action-library/External/Imposter/materials/depth_baker.gdshader

shader_type spatial;
render_mode unshaded, depth_test_disabled;
uniform float depth_scaler = 1.0f;

uniform sampler2D DEPTH_TEXTURE:hint_depth_texture,filter_linear_mipmap;
varying mat4 CAMERA;

void vertex()
{
	POSITION = vec4(VERTEX, 1.0);
	CAMERA = INV_VIEW_MATRIX;
}

void fragment()
{

  float depth = texture( DEPTH_TEXTURE, SCREEN_UV ).x;

//Vulkan.z size range 0-1 ，penGL.z size range -1，1
  vec3 ndc = vec3(SCREEN_UV * 2.0 - 1.0, depth);
//  vec3 ndc = vec3(SCREEN_UV, depth) * 2.0 - 1.0;

  vec4 world = CAMERA * INV_PROJECTION_MATRIX * vec4(ndc, 1.0);
  vec3 world_position = world.xyz / world.w;

  float aabb_full = depth_scaler;

  world_position *= 2.0; // going back to aabb but around 0
  world_position.z = aabb_full/2.0 - world_position.z;

  ALBEDO = vec3(clamp(world_position.z/aabb_full,0,1));
}