3D Pixel art outline/highlight Shader (Old)

There’s now a general shader that can work as both an object or post-processing shader: https://godotshaders.com/shader/3d-pixel-art-outline-highlight-post-processing-shader/

Shader code
shader_type spatial;
render_mode unshaded;

// MIT License. Made by Leo Peltola
// Inspired by https://threejs.org/examples/webgl_postprocessing_pixel.html

uniform sampler2D DEPTH_TEXTURE : hint_depth_texture, filter_linear_mipmap;
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;
uniform sampler2D NORMAL_TEXTURE : hint_normal_roughness_texture, filter_nearest;

uniform bool shadows_enabled = true;
uniform bool highlights_enabled = true;
uniform float shadow_strength : hint_range(0.0, 1.0, 0.01) = 0.4;
uniform float highlight_strength : hint_range(0.0, 1.0, 0.01) = 0.1;
uniform vec3 highlight_color : source_color = vec3(1.);
uniform vec3 shadow_color : source_color = vec3(0.0);

varying mat4 model_view_matrix;


float getDepth(vec2 screen_uv, sampler2D depth_texture, mat4 inv_projection_matrix){
//	Credit: https://godotshaders.com/shader/depth-modulated-pixel-outline-in-screen-space/
	float raw_depth = texture(depth_texture, screen_uv)[0];
	vec3 normalized_device_coordinates = vec3(screen_uv * 2.0 - 1.0, raw_depth);
    vec4 view_space = inv_projection_matrix * vec4(normalized_device_coordinates, 1.0);	
	view_space.xyz /= view_space.w;	
	return -view_space.z;
}

vec3 getPos(float depth, mat4 mvm, mat4 ipm, vec2 suv, mat4 wm, mat4 icm){
  vec4 pos = inverse(mvm) * ipm * vec4((suv * 2.0 - 1.0), depth * 2.0 - 1.0, 1.0);
  pos.xyz /= (pos.w+0.0001*(1.-abs(sign(pos.w))));
  return (pos*icm).xyz+wm[3].xyz;
}

float normalIndicator(vec3 normalEdgeBias, vec3 baseNormal, vec3 newNormal, float depth_diff){
	// Credit: https://threejs.org/examples/webgl_postprocessing_pixel.html
	float normalDiff = dot(baseNormal - newNormal, normalEdgeBias);
	float normalIndicator = clamp(smoothstep(-.01, .01, normalDiff), 0.0, 1.0);
	float depthIndicator = clamp(sign(depth_diff * .25 + .0025), 0.0, 1.0);
	return (1.0 - dot(baseNormal, newNormal)) * depthIndicator * normalIndicator;
}

void vertex(){
    model_view_matrix = VIEW_MATRIX * mat4(INV_VIEW_MATRIX[0], INV_VIEW_MATRIX[1], INV_VIEW_MATRIX[2], MODEL_MATRIX[3]);
}

void fragment() {
	vec2 e = vec2(1./VIEWPORT_SIZE.xy);
	
//	Shadows
	float depth_diff = 0.0;
	float neg_depth_diff = .5;
	if (shadows_enabled) {
		float depth = getDepth(SCREEN_UV, DEPTH_TEXTURE, INV_PROJECTION_MATRIX);
		float du = getDepth(SCREEN_UV+vec2(0., -1.)*e, DEPTH_TEXTURE, INV_PROJECTION_MATRIX);
		float dr = getDepth(SCREEN_UV+vec2(1., 0.)*e, DEPTH_TEXTURE, INV_PROJECTION_MATRIX);
		float dd = getDepth(SCREEN_UV+vec2(0., 1.)*e, DEPTH_TEXTURE, INV_PROJECTION_MATRIX);
		float dl = getDepth(SCREEN_UV+vec2(-1., 0.)*e, DEPTH_TEXTURE, INV_PROJECTION_MATRIX);
		depth_diff += clamp(du - depth, 0., 1.);
		depth_diff += clamp(dd - depth, 0., 1.);
		depth_diff += clamp(dr - depth, 0., 1.);
		depth_diff += clamp(dl - depth, 0., 1.);
		neg_depth_diff += depth - du;
		neg_depth_diff += depth - dd;
		neg_depth_diff += depth - dr;
		neg_depth_diff += depth - dl;
		neg_depth_diff = clamp(neg_depth_diff, 0., 1.);
		neg_depth_diff = clamp(smoothstep(0.5, 0.5, neg_depth_diff)*10., 0., 1.);
		depth_diff = smoothstep(0.2, 0.3, depth_diff);
//		ALBEDO = vec3(neg_depth_diff);
	}
	
//	Highlights
	float normal_diff = 0.;
	if (highlights_enabled) {
		vec3 normal = texture(NORMAL_TEXTURE, SCREEN_UV).rgb * 2.0 - 1.0;
		vec3 nu = texture(NORMAL_TEXTURE, SCREEN_UV+vec2(0., -1.)*e).rgb * 2.0 - 1.0;
		vec3 nr = texture(NORMAL_TEXTURE, SCREEN_UV+vec2(1., 0.)*e).rgb * 2.0 - 1.0;
		vec3 nd = texture(NORMAL_TEXTURE, SCREEN_UV+vec2(0., 1.)*e).rgb * 2.0 - 1.0;
		vec3 nl = texture(NORMAL_TEXTURE, SCREEN_UV+vec2(-1., 0.)*e).rgb * 2.0 - 1.0;
		vec3 normal_edge_bias = (vec3(1., 1., 1.));
		normal_diff += normalIndicator(normal_edge_bias, normal, nu, depth_diff);
		normal_diff += normalIndicator(normal_edge_bias, normal, nr, depth_diff);
		normal_diff += normalIndicator(normal_edge_bias, normal, nd, depth_diff);
		normal_diff += normalIndicator(normal_edge_bias, normal, nl, depth_diff);
		normal_diff = smoothstep(0.2, 0.8, normal_diff);
		normal_diff = clamp(normal_diff-neg_depth_diff, 0., 1.);
//		ALBEDO = vec3(normal_diff);
	}
	

	vec3 original_color = texture(SCREEN_TEXTURE, SCREEN_UV).rgb;
	vec3 final_highlight_color = mix(original_color, highlight_color, highlight_strength);
	vec3 final_shadow_color = mix(original_color, shadow_color, shadow_strength);
	vec3 final = original_color;
	if (highlights_enabled) {
		final = mix(final, final_highlight_color, normal_diff);
	}
	if (shadows_enabled) {
		final = mix(final, final_shadow_color, depth_diff);
	}
	ALBEDO = final;

	float alpha_mask = depth_diff * float(shadows_enabled) + normal_diff * float(highlights_enabled);
	ALPHA = clamp((alpha_mask) * 5., 0., 1.);
}
Tags
3D pixelart, highlight, outline, pixelart
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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