From 04db6b0ccd81d988cfe3a1d09e4eb00eeea77273 Mon Sep 17 00:00:00 2001
From: quou <quou@disroot.org>
Date: Sat, 22 Feb 2025 17:01:35 +1100
Subject: basic shadows

---
 intermediate/surface.glsl | 68 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

(limited to 'intermediate/surface.glsl')

diff --git a/intermediate/surface.glsl b/intermediate/surface.glsl
index 9fc1c48..10944ae 100644
--- a/intermediate/surface.glsl
+++ b/intermediate/surface.glsl
@@ -74,6 +74,15 @@ type: float
 [variable]
 name: colour
 type: vec3
+[variable]
+name: caster_id
+type: int
+
+[struct]
+name: Caster
+[variable]
+name: projection
+type: mat4
 
 [cbuffer]
 name: c_vp
@@ -95,6 +104,11 @@ name: lights
 type: Light
 stage: fragment
 
+[sbuffer]
+name: casters
+type: Caster
+stage: fragment
+
 [texture]
 name: albedo
 stage: fragment
@@ -119,6 +133,10 @@ dimension: 2
 name: env_cube
 stage: fragment
 dimension: cube
+[texture]
+name: shadowmaps
+stage: fragment
+dimension: shadowArray
 
 [target]
 name: colour
@@ -174,6 +192,51 @@ float specular_brdf(vec2 uv, vec3 ref, vec3 l, vec3 v, vec3 n) {
 	return (D * F * G) / (4.0 * ndl * ndv + 0.001);
 }
 
+vec2 poissonDisk[16] = vec2[]( 
+	vec2(-0.94201624,  -0.39906216),
+	vec2(0.94558609,   -0.76890725),
+	vec2(-0.094184101, -0.92938870),
+	vec2(0.34495938,    0.29387760),
+	vec2(-0.91588581,   0.45771432),
+	vec2(-0.81544232,  -0.87912464),
+	vec2(-0.38277543,   0.27676845),
+	vec2(0.97484398,    0.75648379),
+	vec2(0.44323325,   -0.97511554),
+	vec2(0.53742981,   -0.47373420),
+	vec2(-0.26496911,  -0.41893023),
+	vec2(0.79197514,    0.19090188),
+	vec2(-0.24188840,   0.99706507),
+	vec2(-0.81409955,   0.91437590),
+	vec2(0.19984126,    0.78641367),
+	vec2(0.14383161,   -0.14100790)
+);
+
+float random(vec3 seed, int i){
+	vec4 seed4 = vec4(seed,i);
+	float dot_product = dot(seed4, vec4(12.9898,78.233,45.164,94.673));
+	return fract(sin(dot_product) * 43758.5453);
+}
+
+float get_shadow(Light l, vec3 wpos) {
+	const int taps = 4;
+	const float w = 1.0 / float(taps);
+	const float m = 1.0 / 1000.0;
+	int i;
+	float d = 0.0f;
+	Caster caster = casters[l.caster_id];
+	vec4 surf = caster.projection * vec4(wpos, 1.0);
+	surf /= surf.w;
+	surf.xy = surf.xy * 0.5 + 0.5;
+	surf.z -= 0.005;
+	for (i = 0; i < taps; i++) {
+		int index = int(16.0 * random(floor(wpos.xyz * 1000.0), i)) % 16;
+		vec2 coord = surf.xy + poissonDisk[index] * m;
+		vec4 vec = vec4(coord, float(l.caster_id), surf.z);
+		d += texture(shadowmaps, vec).r * w;
+	}
+	return d;
+}
+
 void main() {
 	int i;
 	vec2 uv = interpolator.uv;
@@ -210,7 +273,10 @@ void main() {
 			spec_col *
 			specular_brdf(uv, ref, light_dir, view_dir, nrm) *
 			cos_theta_i;
-		light += (diffuse + spec) * l.brightness * l.colour;
+		float shadow = 1.0f;
+		if (l.caster_id >= 0)
+			shadow = get_shadow(l, p);
+		light += (diffuse + spec) * l.brightness * l.colour * shadow;
 	}
 
 	colour = vec4(ambient + light, 1.0);
-- 
cgit v1.2.3-54-g00ecf