56 lines
1.6 KiB
GLSL
56 lines
1.6 KiB
GLSL
#version 330 core
|
|
|
|
uniform sampler2D depth_tex;
|
|
|
|
uniform vec2 fg_NearFar;
|
|
uniform mat4 fg_ViewMatrixInverse;
|
|
uniform mat4 fg_ProjectionMatrixInverse;
|
|
|
|
/*
|
|
* Reconstruct the view space position from the depth buffer. Mostly used by
|
|
* fullscreen post-processing shaders.
|
|
*
|
|
* Given a 2D screen UV in the range [0,1] and a depth value from the depth
|
|
* buffer, also in the [0,1] range, return the view space position.
|
|
*/
|
|
vec3 get_view_space_from_depth(vec2 uv, float depth, mat4 proj_matrix_inverse)
|
|
{
|
|
/*
|
|
* We are using a reversed depth buffer. 1.0 corresponds to the near plane
|
|
* and 0.0 to the far plane. We convert this back to NDC space by doing
|
|
* 1.0 - depth to undo the depth reversal
|
|
* 2.0 * depth - 1.0 to transform it to NDC space [-1,1]
|
|
*/
|
|
vec4 ndc_p = vec4(uv * 2.0 - 1.0, 1.0 - depth * 2.0, 1.0);
|
|
vec4 vs_p = proj_matrix_inverse * ndc_p;
|
|
return vs_p.xyz / vs_p.w;
|
|
}
|
|
|
|
vec3 get_view_space_from_depth(vec2 uv, float depth)
|
|
{
|
|
return get_view_space_from_depth(uv, depth, fg_ProjectionMatrixInverse);
|
|
}
|
|
|
|
vec3 get_view_space_from_depth(vec2 uv)
|
|
{
|
|
return get_view_space_from_depth(uv, texture(depth_tex, uv).r);
|
|
}
|
|
|
|
vec3 get_world_space_from_depth(vec2 uv, float depth)
|
|
{
|
|
vec4 vs_p = vec4(get_view_space_from_depth(uv, depth), 1.0);
|
|
return (fg_ViewMatrixInverse * vs_p).xyz;
|
|
}
|
|
|
|
vec3 get_world_space_from_depth(vec2 uv)
|
|
{
|
|
return get_world_space_from_depth(uv, texture(depth_tex, uv).r);
|
|
}
|
|
|
|
float linearize_depth(float depth)
|
|
{
|
|
// Undo the depth reversal
|
|
float z = 1.0 - depth;
|
|
return 2.0 * fg_NearFar.x
|
|
/ (fg_NearFar.y + fg_NearFar.x - z * (fg_NearFar.y - fg_NearFar.x));
|
|
}
|