From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Wed, 18 Mar 2015 10:26:38 +0000 (+0100)
Subject: added distance fog
X-Git-Url: http://git.localhorst.tv/?a=commitdiff_plain;h=b368ecb2c0f34e27b1d3b97cceb218b554dee324;p=blank.git

added distance fog
---

diff --git a/src/chunk.cpp b/src/chunk.cpp
index d298fb2..81c8698 100644
--- a/src/chunk.cpp
+++ b/src/chunk.cpp
@@ -462,8 +462,8 @@ ChunkLoader::ChunkLoader(const BlockTypeRegistry &reg, const Generator &gen)
 , loaded()
 , to_generate()
 , to_free()
-, load_dist(4)
-, unload_dist(5) {
+, load_dist(6)
+, unload_dist(8) {
 
 }
 
diff --git a/src/hud.cpp b/src/hud.cpp
index 266b80a..0747cff 100644
--- a/src/hud.cpp
+++ b/src/hud.cpp
@@ -62,6 +62,8 @@ void HUD::Display(const Block &b) {
 void HUD::Render(DirectionalLighting &program) {
 	if (block_visible) {
 		program.SetLightDirection({ 1.0f, 3.0f, 5.0f });
+		// disable distance fog
+		program.SetFogDensity(0.0f);
 		GLContext::ClearDepthBuffer();
 		program.SetMVP(block_transform, view, projection);
 		block.Draw();
diff --git a/src/shader.cpp b/src/shader.cpp
index 43b3910..eb09b10 100644
--- a/src/shader.cpp
+++ b/src/shader.cpp
@@ -143,9 +143,11 @@ DirectionalLighting::DirectionalLighting()
 , light_color(0.9f, 0.9f, 0.9f)
 , vp(1.0f)
 , m_handle(0)
+, mv_handle(0)
 , mvp_handle(0)
 , light_direction_handle(0)
-, light_color_handle(0) {
+, light_color_handle(0)
+, fog_density_handle(0) {
 	program.LoadShader(
 		GL_VERTEX_SHADER,
 		"#version 330 core\n"
@@ -153,11 +155,14 @@ DirectionalLighting::DirectionalLighting()
 		"layout(location = 1) in vec3 vtx_color;\n"
 		"layout(location = 2) in vec3 vtx_normal;\n"
 		"uniform mat4 M;\n"
+		"uniform mat4 MV;\n"
 		"uniform mat4 MVP;\n"
 		"out vec3 frag_color;\n"
+		"out vec3 vtx_viewspace;\n"
 		"out vec3 normal;\n"
 		"void main() {\n"
 			"gl_Position = MVP * vec4(vtx_position, 1);\n"
+			"vtx_viewspace = (MV * vec4(vtx_position, 1)).xyz;\n"
 			"normal = (M * vec4(vtx_normal, 0)).xyz;\n"
 			"frag_color = vtx_color;\n"
 		"}\n"
@@ -166,16 +171,23 @@ DirectionalLighting::DirectionalLighting()
 		GL_FRAGMENT_SHADER,
 		"#version 330 core\n"
 		"in vec3 frag_color;\n"
+		"in vec3 vtx_viewspace;\n"
 		"in vec3 normal;\n"
 		"uniform vec3 light_direction;\n"
 		"uniform vec3 light_color;\n"
+		"uniform float fog_density;\n"
 		"out vec3 color;\n"
 		"void main() {\n"
 			"vec3 ambient = vec3(0.1, 0.1, 0.1) * frag_color;\n"
+			// this should be the same as the clear color, otherwise looks really weird
+			"vec3 fog_color = vec3(0, 0, 0);\n"
+			"float e = 2.718281828;\n"
 			"vec3 n = normalize(normal);\n"
 			"vec3 l = normalize(light_direction);\n"
 			"float cos_theta = clamp(dot(n, l), 0, 1);\n"
-			"color = ambient + frag_color * light_color * cos_theta;\n"
+			"vec3 reflect_color = ambient + frag_color * light_color * cos_theta;\n"
+			"float value = pow(e, -pow(fog_density * length(vtx_viewspace), 5));"
+			"color = mix(fog_color, reflect_color, value);\n"
 		"}\n"
 	);
 	program.Link();
@@ -185,9 +197,11 @@ DirectionalLighting::DirectionalLighting()
 	}
 
 	m_handle = program.UniformLocation("M");
+	mv_handle = program.UniformLocation("MV");
 	mvp_handle = program.UniformLocation("MVP");
 	light_direction_handle = program.UniformLocation("light_direction");
 	light_color_handle = program.UniformLocation("light_color");
+	fog_density_handle = program.UniformLocation("fog_density");
 }
 
 
@@ -201,8 +215,10 @@ void DirectionalLighting::Activate() {
 }
 
 void DirectionalLighting::SetM(const glm::mat4 &m) {
+	glm::mat4 mv(view * m);
 	glm::mat4 mvp(vp * m);
 	glUniformMatrix4fv(m_handle, 1, GL_FALSE, &m[0][0]);
+	glUniformMatrix4fv(mv_handle, 1, GL_FALSE, &mv[0][0]);
 	glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 }
 
@@ -211,6 +227,11 @@ void DirectionalLighting::SetLightDirection(const glm::vec3 &dir) {
 	glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
 }
 
+void DirectionalLighting::SetFogDensity(float f) {
+	fog_density = f;
+	glUniform1f(fog_density_handle, fog_density);
+}
+
 void DirectionalLighting::SetProjection(const glm::mat4 &p) {
 	projection = p;
 	vp = p * view;
diff --git a/src/shader.hpp b/src/shader.hpp
index ea5b844..f42d19b 100644
--- a/src/shader.hpp
+++ b/src/shader.hpp
@@ -69,6 +69,8 @@ public:
 
 	void SetLightDirection(const glm::vec3 &);
 
+	void SetFogDensity(float);
+
 	void SetM(const glm::mat4 &m);
 	void SetProjection(const glm::mat4 &p);
 	void SetView(const glm::mat4 &v);
@@ -85,14 +87,18 @@ private:
 	glm::vec3 light_direction;
 	glm::vec3 light_color;
 
+	float fog_density;
+
 	glm::mat4 projection;
 	glm::mat4 view;
 	glm::mat4 vp;
 
 	GLuint m_handle;
+	GLuint mv_handle;
 	GLuint mvp_handle;
 	GLuint light_direction_handle;
 	GLuint light_color_handle;
+	GLuint fog_density_handle;
 
 };
 
diff --git a/src/world.cpp b/src/world.cpp
index 7ab7fe4..f0d96f8 100644
--- a/src/world.cpp
+++ b/src/world.cpp
@@ -198,6 +198,11 @@ void World::Update(int dt) {
 
 void World::Render(DirectionalLighting &program) {
 	program.SetLightDirection({ -1.0f, -3.0f, -2.0f });
+	// fade out reaches 1/e (0.3679) at 1/fog_density,
+	// gets less than 0.01 at e/(2 * fog_density)
+	// I chose 0.011 because it yields 91 and 124 for those, so
+	// slightly less than 6 and 8 chunks
+	program.SetFogDensity(0.011f);
 	program.SetView(glm::inverse(player->Transform(player->ChunkCoords())));
 
 	for (Chunk &chunk : chunks.Loaded()) {