From 026768dff4053e8da15b940c96d2ca048dfb86fd Mon Sep 17 00:00:00 2001
From: Luke Hubmayer-Werner <mongoose41@gmail.com>
Date: Tue, 5 Jan 2021 01:38:38 +1030
Subject: [PATCH] Receptors shader refactor

---
 scripts/Receptors.gd     | 25 +++++++++------
 shaders/receptors.shader | 69 ++++++++++++++++++++--------------------
 2 files changed, 51 insertions(+), 43 deletions(-)

diff --git a/scripts/Receptors.gd b/scripts/Receptors.gd
index 443db9e..254f040 100644
--- a/scripts/Receptors.gd
+++ b/scripts/Receptors.gd
@@ -1,10 +1,12 @@
 tool
 extends MeshInstance2D
 
-var ring_px := 4  # Analogous to diameter
-var receptor_px := 24  # Diameter
-var shadow_px := 8  # Outer edge, analogous to radius
-var shadow_color := Color.black
+export var ring_px := 4  # Analogous to diameter
+export var receptor_px := 24  # Diameter
+export var shadow_px := 8  # Outer edge, analogous to radius
+export var line_color := Color.blue
+export var dot_color := Color.blue
+export var shadow_color := Color.black
 var center := Vector2(0.0, 0.0)
 
 var ring_vertex_count := 36
@@ -108,11 +110,11 @@ func update_ring_mesh():
 
 func _draw():
 #	draw_old(true, true)
-#	draw_tris()
-	var mesh_v = ring_vertex_count
-	var ring_thickness = receptor_px + shadow_px*2
-	var estimated_area = circumscribe_polygon_area(GameTheme.receptor_ring_radius+ring_thickness*0.5, mesh_v) - inscribe_polygon_area(GameTheme.receptor_ring_radius-ring_thickness*0.5, mesh_v)
-	var ideal_ring_area = PI * (pow(GameTheme.receptor_ring_radius+receptor_px/2+shadow_px, 2) - pow(GameTheme.receptor_ring_radius-receptor_px/2-shadow_px, 2))
+	draw_tris()
+#	var mesh_v = ring_vertex_count
+#	var ring_thickness = receptor_px + shadow_px*2
+#	var estimated_area = circumscribe_polygon_area(GameTheme.receptor_ring_radius+ring_thickness*0.5, mesh_v) - inscribe_polygon_area(GameTheme.receptor_ring_radius-ring_thickness*0.5, mesh_v)
+#	var ideal_ring_area = PI * (pow(GameTheme.receptor_ring_radius+receptor_px/2+shadow_px, 2) - pow(GameTheme.receptor_ring_radius-receptor_px/2-shadow_px, 2))
 
 	var quad_area = 4*pow(GameTheme.receptor_ring_radius+receptor_px/2+shadow_px, 2)
 
@@ -121,6 +123,10 @@ func _draw():
 	material.set_shader_param("shadow_thickness", shadow_px/GameTheme.receptor_ring_radius)
 	material.set_shader_param("shadow_thickness_taper", -0.75)
 	material.set_shader_param("px", 0.5/GameTheme.receptor_ring_radius)
+	material.set_shader_param("px2", 1.0/GameTheme.receptor_ring_radius)
+	material.set_shader_param("line_color", line_color)
+	material.set_shader_param("dot_color", dot_color)
+	material.set_shader_param("shadow_color", shadow_color)
 
 func set_ring_vertex_count(num: int):
 	assert(num > 3)
@@ -143,6 +149,7 @@ func _ready():
 	$"/root".connect("size_changed", self, "update")
 
 #func _process(delta):
+#	update()
 #	pass
 #	if not Engine.editor_hint:
 #		set_receptor_positions(sin(OS.get_ticks_msec()*0.001*0.0125*PI)*PI)
diff --git a/shaders/receptors.shader b/shaders/receptors.shader
index edc86d8..40a0e71 100644
--- a/shaders/receptors.shader
+++ b/shaders/receptors.shader
@@ -15,6 +15,7 @@ uniform float dot_radius = 0.033;
 uniform float shadow_thickness = 0.01;
 uniform float shadow_thickness_taper = 0.33;
 uniform float px = 0.002;  // Represents 1px in UV space, for AA purposes
+uniform float px2 = 0.004;  // Represents 2px in UV space, for AA purposes
 
 //void vertex() {
 //}
@@ -25,45 +26,45 @@ float angle_diff(float a, float b) {
 	return d;
 }
 
-void fragment() {
-	if (COLOR.rgba != vec4(1.0, 0.0, 0.0, 1.0)) {
-	COLOR.rgba = vec4(0.0);
-	lowp float dist = distance(UV, vec2(0.0));
-	lowp float angle = atan(-UV.y, UV.x);
-	float line_alpha = 0.0;
-	float dot_alpha = 0.0;
-	float shadow_alpha = 0.0;
-	float px2 = px/2.0;
-	
-	float diff = abs(dist - 1.0);
-	float d2 = diff - line_thickness;
-	if (d2 < -px2){
-		line_alpha = 1.0;
-	} else if (d2 < shadow_thickness){
-		if (d2 < px2)
-			line_alpha = 1.0 - (d2 + px2)/px;
-		shadow_alpha = 1.0 - min((d2 - shadow_thickness*shadow_thickness_taper)/(shadow_thickness*(1.0-shadow_thickness_taper)), 1.0);
-	}
-	
+vec2 line_alpha(float dist) {
+	// Returns [line, shadow]
+	vec2 output = vec2(0.0);
+	float d = abs(dist - 1.0) - line_thickness;
+	output.x = clamp(-d/px - 1.0, 0.0, 1.0);
+	output.y = clamp(1.0 - (d - shadow_thickness*shadow_thickness_taper)/(shadow_thickness*(1.0-shadow_thickness_taper)), 0, 1.0);
+	return output;
+}
+
+vec2 dot_alpha(vec2 uv) {
+	// Returns [dot, shadow]
+	vec2 output = vec2(0.0);
 	// Iterate over all the receptors and check distance to them
 	float receptor_spacing = TAU/float(num_receptors);
 	for (float rads=receptor_offset; rads<TAU; rads+=receptor_spacing){
 		// Check for dot distance
-		vec2 uv = vec2(cos(rads), -sin(rads));
-		float dist2 = distance(UV, uv);
-		float diff2 = dist2 - dot_radius;
-		if (diff2 < -px2){
-			dot_alpha = 1.0;
-		} else if (diff2 < shadow_thickness){
-			if (diff2 < px2)
-				dot_alpha = 1.0 - (diff2 + px2)/px;
-			shadow_alpha = max(shadow_alpha, 1.0-min((diff2 - shadow_thickness*shadow_thickness_taper)/(shadow_thickness*(1.0-shadow_thickness_taper)), 1.0));
-		}
+		vec2 dot_uv = vec2(cos(rads), -sin(rads));
+		float d = distance(uv, dot_uv) - dot_radius;
+		output.x = clamp(-d/px - 1.0, output.x, 1.0);
+		output.y = clamp(1.0 - (d - shadow_thickness*shadow_thickness_taper)/(shadow_thickness*(1.0-shadow_thickness_taper)), output.y, 1.0);
 	}
-	line_alpha = max(line_alpha - dot_alpha, 0.0);
+	return output;
+}
 
-	COLOR.rgb = (dot_color.rgb*dot_alpha) + (line_color.rgb*line_alpha) + (shadow_color.rgb*shadow_alpha);
-	COLOR.a = dot_alpha + line_alpha*(1.0-dot_alpha);
-	COLOR.a = COLOR.a + shadow_alpha*(1.0-COLOR.a);
+const vec4 dbg_color = vec4(1.0, 0.0, 0.0, 1.0);
+void fragment() {
+	if (COLOR.rgba != dbg_color) {  // Can't use return in fragment() function
+	COLOR.rgba = vec4(0.0);
+	lowp float dist = distance(UV, vec2(0.0));
+	lowp float angle = atan(-UV.y, UV.x);
+	vec3 lds_alpha = vec3(0.0);
+	
+	lds_alpha.yz = dot_alpha(UV);
+	lds_alpha.xz = clamp(line_alpha(dist), vec2(0.0, lds_alpha.z), vec2(1.0-lds_alpha.y));
+//	lds_alpha.x = clamp(line_alpha(dist).x, 0.0, 1.0-lds_alpha.y);
+	lds_alpha = clamp(lds_alpha, 0.0, 1.0);
+
+	COLOR.rgb = (dot_color.rgb*lds_alpha.y) + (line_color.rgb*lds_alpha.x) + (shadow_color.rgb*lds_alpha.z);
+	COLOR.a = lds_alpha.y + lds_alpha.x*(1.0-lds_alpha.y);
+	COLOR.a = COLOR.a + lds_alpha.z*(1.0-COLOR.a);
 	COLOR.a = clamp(COLOR.a, 0.0, 1.0); }
 }
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