From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 9 Oct 2022 13:22:18 +0000 (+0300)
Subject: Add reflection and refaction to the water in forest pond
X-Git-Url: https://git.tdb.fi/?a=commitdiff_plain;h=4068ffedbd32bd9f1de211a88d00d71547bbcf27;p=libs%2Fgl.git

Add reflection and refaction to the water in forest pond
---

diff --git a/demos/forestpond/data/water.glsl b/demos/forestpond/data/water.glsl
index d200b6d7..4e680f68 100644
--- a/demos/forestpond/data/water.glsl
+++ b/demos/forestpond/data/water.glsl
@@ -1,5 +1,6 @@
 import msp_interface;
 import lighting;
+import environment;
 
 uniform Tessellation
 {
@@ -46,11 +47,11 @@ void main()
 	float w1 = gl_TessCoord.x*(1.0-gl_TessCoord.y);
 	float w2 = gl_TessCoord.x*gl_TessCoord.y;
 	float w3 = (1.0-gl_TessCoord.x)*gl_TessCoord.y;
-	vec4 pos = w0*gl_in[0].gl_Position+w1*gl_in[1].gl_Position+w2*gl_in[2].gl_Position+w3*gl_in[3].gl_Position;
-	out vec2 texcoord = pos.xy*region.scale+region.offset;
-	pos.z = textureLod(surface, texcoord, 0).x*region.amplitude-0.01;
-	out vec3 world_look = pos.xyz-world_eye_matrix[3].xyz;
-	gl_Position = clip_eye_matrix*eye_world_matrix*pos;
+	out vec4 world_pos = w0*gl_in[0].gl_Position+w1*gl_in[1].gl_Position+w2*gl_in[2].gl_Position+w3*gl_in[3].gl_Position;
+	out vec2 texcoord = world_pos.xy*region.scale+region.offset;
+	world_pos.z = textureLod(surface, texcoord, 0).x*region.amplitude-0.01;
+	out vec3 world_look = world_pos.xyz-world_eye_matrix[3].xyz;
+	gl_Position = clip_eye_matrix*eye_world_matrix*world_pos;
 }
 
 #pragma MSP stage(fragment)
@@ -91,9 +92,15 @@ void main()
 	float std_dev = sqrt(slope_var);
 	float fresnel_e = 0.02+0.98*pow(1.0+dot(look, normal), 5.0*exp(-2.69*std_dev))/(1+22.7*pow(std_dev, 1.5));
 	vec3 reflect_dir = reflect(look, normal);
-	vec3 env_color = (reflect_dir.z>0 ? vec3(0.34, 0.54, 0.9) : vec3(0.0));
-
-	color += env_color*fresnel_e;
+	vec3 refract_dir = refract(look, normal, 0.75);
+	float roughness = 1.0-pow(2.0, -slope_var);
+	vec3 reflect_color = get_environment_sample(world_pos.xyz, reflect_dir, roughness);
+	vec3 refract_color = get_environment_sample(world_pos.xyz, refract_dir, roughness);
+	/* It would be more correct to use the distance along the refracted ray, but
+	there's no easy way to get it.  Water depth is a good enough approximation. */
+	float transmittance = pow(0.1, depth/100.0);
+
+	color += reflect_color*fresnel_e + refract_color*(1-fresnel_e)*transmittance;
 
 	frag_color = vec4(color, 1.0);
 }
diff --git a/demos/forestpond/source/forestpond.cpp b/demos/forestpond/source/forestpond.cpp
index b327489d..d1a0d032 100644
--- a/demos/forestpond/source/forestpond.cpp
+++ b/demos/forestpond/source/forestpond.cpp
@@ -23,8 +23,17 @@ ForestPond::ForestPond(int, char **):
 	seq_bld.set_renderable("content", content);
 	sequence.reset(seq_bld.build(view));
 
+	GL::SequenceBuilder env_bld(resources.get<GL::SequenceTemplate>("Forest_environment.seq"));
+	env_bld.set_debug_name("Environment sequence");
+	env_bld.set_renderable("content", *sequence->get_steps().front().get_renderable());
+	env_seq.reset(env_bld.build());
+
+	env_map = std::make_unique<GL::EnvironmentMap>(512, GL::RGBA16F, 5, water, *env_seq);
+	env_map->set_debug_name("Water environment");
+	env_map->set_fixed_position(GL::Vector3(-3, 2, 1));
+
 	content.add(resources.get<GL::Scene>("Forest.scene"));
-	content.add(water);
+	content.add(*env_map);
 	water.set_matrix(GL::Matrix::translation(GL::Vector3(-3, 2, 0)));
 
 	view.set_content(sequence.get());
diff --git a/demos/forestpond/source/forestpond.h b/demos/forestpond/source/forestpond.h
index c035dcd8..b22db689 100644
--- a/demos/forestpond/source/forestpond.h
+++ b/demos/forestpond/source/forestpond.h
@@ -5,6 +5,7 @@
 #include <msp/core/application.h>
 #include <msp/datafile/directorysource.h>
 #include <msp/gl/device.h>
+#include <msp/gl/environmentmap.h>
 #include <msp/gl/orderedscene.h>
 #include <msp/gl/resourcemanager.h>
 #include <msp/gl/resources.h>
@@ -38,6 +39,8 @@ private:
 
 	Msp::GL::OrderedScene content;
 	Water water;
+	std::unique_ptr<Msp::GL::Sequence> env_seq;
+	std::unique_ptr<Msp::GL::EnvironmentMap> env_map;
 
 public:
 	ForestPond(int, char **);