Eevee: Planar Reflection: Add contact hardening normal distortion.

Save radial distance to camera in alpha channel of the planar probe.
Use this distance to modulate distortion intensity when shading the surface.

source/blender/draw/engines/eevee/eevee_lightprobes.c

@@ -142,7 +142,7 @@ static void planar_pool_ensure_alloc(EEVEE_Data *vedata, int num_planar_ref)
 	if (!txl->planar_pool) {
 		if (num_planar_ref > 0) {
 			txl->planar_pool = DRW_texture_create_2D_array(width, height, max_ff(1, num_planar_ref),
-			                                                 DRW_TEX_RGB_11_11_10, DRW_TEX_FILTER | DRW_TEX_MIPMAP, NULL);
+			                                                 DRW_TEX_RGBA_16, DRW_TEX_FILTER | DRW_TEX_MIPMAP, NULL);
 		}
 		else if (num_planar_ref == 0) {
 			/* Makes Opengl Happy : Create a placeholder texture that will never be sampled but still bound to shader. */

source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl

@@ -143,6 +143,7 @@ vec4 saturate(vec4 a) { return clamp(a, 0.0, 1.0); }
 
 float distance_squared(vec2 a, vec2 b) { a -= b; return dot(a, a); }
 float distance_squared(vec3 a, vec3 b) { a -= b; return dot(a, a); }
+float len_squared(vec3 a) { return dot(a, a); }
 
 float inverse_distance(vec3 V) { return max( 1 / length(V), 1e-8); }
 
@@ -167,6 +168,13 @@ float line_plane_intersect_dist(vec3 lineorigin, vec3 linedirection, vec3 planeo
 	return dot(planenormal, planeorigin - lineorigin) / dot(planenormal, linedirection);
 }
 
+float line_plane_intersect_dist(vec3 lineorigin, vec3 linedirection, vec4 plane)
+{
+	vec3 plane_co = plane.xyz * (-plane.w / len_squared(plane.xyz));
+	vec3 h = lineorigin - plane_co;
+	return -dot(plane.xyz, h) / dot(plane.xyz, linedirection);
+}
+
 vec3 line_plane_intersect(vec3 lineorigin, vec3 linedirection, vec3 planeorigin, vec3 planenormal)
 {
 	float dist = line_plane_intersect_dist(lineorigin, linedirection, planeorigin, planenormal);

source/blender/draw/engines/eevee/shaders/default_frag.glsl

@@ -11,5 +11,5 @@ void main()
 	vec3 dielectric = vec3(0.034) * specular * 2.0;
 	vec3 diffuse = mix(basecol, vec3(0.0), metallic);
 	vec3 f0 = mix(dielectric, basecol, metallic);
-	FragColor = vec4(eevee_surface_lit((gl_FrontFacing) ? worldNormal : -worldNormal, diffuse, f0, roughness, 1.0), 1.0);
+	FragColor = vec4(eevee_surface_lit((gl_FrontFacing) ? worldNormal : -worldNormal, diffuse, f0, roughness, 1.0), length(viewPosition));
 }

source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl

@@ -388,8 +388,30 @@ vec3 eevee_surface_lit(vec3 world_normal, vec3 albedo, vec3 f0, float roughness,
 		if (influence > 0.0) {
 			float influ_spec = min(influence, (1.0 - spec_accum.a));
 
+			/* Sample reflection depth. */
 			vec4 refco = pd.reflectionmat * vec4(sd.W, 1.0);
 			refco.xy /= refco.w;
+			float ref_depth = textureLod(probePlanars, vec3(refco.xy, i), 0.0).a;
+
+			/* Find view vector / reflection plane intersection. (dist_to_plane is negative) */
+			float dist_to_plane = line_plane_intersect_dist(cameraPos, sd.V, pd.pl_plane_eq);
+			vec3 point_on_plane = cameraPos + sd.V * dist_to_plane;
+
+			/* How far the pixel is from the plane. */
+			ref_depth = ref_depth + dist_to_plane;
+
+			/* Compute distorded reflection vector based on the distance to the reflected object.
+			 * In other words find intersection between reflection vector and the sphere center
+			 * around point_on_plane. */
+			vec3 proj_ref = reflect(R * ref_depth, pd.pl_normal);
+
+			/* Final point in world space. */
+			vec3 ref_pos = point_on_plane + proj_ref;
+
+			/* Reproject to find texture coords. */
+			refco = pd.reflectionmat * vec4(ref_pos, 1.0);
+			refco.xy /= refco.w;
+
 			vec3 sample = textureLod(probePlanars, vec3(refco.xy, i), 0.0).rgb;
 
 			spec_accum.rgb += sample * influ_spec;

source/blender/gpu/shaders/gpu_shader_material.glsl

@@ -3894,9 +3894,9 @@ void node_eevee_specular(
 	result = vec4(eevee_surface_lit(normal, diffuse.rgb, specular.rgb, roughness, occlusion) + emissive.rgb, 1.0 - transp);
 }
 
-void node_output_eevee_material(vec4 Surface, out vec4 result)
+void node_output_eevee_material(vec4 surface, out vec4 result)
 {
-	result = Surface;
+	result = vec4(surface.rgb, length(viewPosition));
 }
 
 #endif