From f1c3197c3e035f4be0e10ff6a8d0cf0339824177 Mon Sep 17 00:00:00 2001
From: Eleni Maria Stea <estea@igalia.com>
Date: Mon, 21 Aug 2017 21:23:36 +0300
Subject: [PATCH] added fog (need to set the fog params)

---
 gl_shaders/default.f.glsl |   16 +++++++++++++---
 src/opengl/texture-gl.cc  |    7 ++++++-
 src/opengl/texture-gl.h   |    2 +-
 src/renderer.cc           |    2 +-
 src/texture.h             |    2 +-
 src/vulkan/texture-vk.cc  |    2 +-
 src/vulkan/texture-vk.h   |    2 +-
 7 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/gl_shaders/default.f.glsl b/gl_shaders/default.f.glsl
index 490efab..17d4353 100644
--- a/gl_shaders/default.f.glsl
+++ b/gl_shaders/default.f.glsl
@@ -11,11 +11,14 @@ varying vec3 normal;
 varying vec3 ldir;
 varying vec2 tex_coord;
 
+const float fog_density = 0.005;
+const vec4 sky_color = vec4(0.35, 0.5, 0.65, 1.0);
+
 out vec4 color;
 
 void main()
 {
-	vec3 p = normalize(pos);
+	vec3 p = normalize(pos); // view space dir
 	vec3 n = normalize(normal);
 	vec3 l = normalize(ldir);
 
@@ -25,7 +28,14 @@ void main()
 	float cdiff = max(dot(l, n), 0.0);
 	float cspec = pow(max(dot(r, vdir), 0.0), shininess);
 
+	float dist = -pos.z;
+	float fog = clamp(exp(-fog_density * dist), 0.0, 1.0);
+
 	vec4 texel = texture2D(tex, tex_coord);
-	color.xyz = diffuse.xyz * cdiff * texel.xyz + specular.xyz * cspec;
-	color.w = 1.0;
+
+	vec4 object_color;
+	object_color.xyz = diffuse.xyz * cdiff * texel.xyz + specular.xyz * cspec;
+	object_color.w = 1.0;
+
+	color = mix(sky_color, object_color, fog);
 }
diff --git a/src/opengl/texture-gl.cc b/src/opengl/texture-gl.cc
index 157d0bb..80db3ad 100644
--- a/src/opengl/texture-gl.cc
+++ b/src/opengl/texture-gl.cc
@@ -56,10 +56,15 @@ void TextureGL::update()
 	glGenerateMipmap(target);
 }
 
-void TextureGL::bind()
+void TextureGL::bind(int texture_unit)
 {
+	glActiveTexture(GL_TEXTURE0 + texture_unit);
+
 	unsigned int target = is_cubemap() ? GL_TEXTURE_CUBE_MAP : GL_TEXTURE_2D;
 	glBindTexture(target, tex);
+
+	//TODO: (not needed for now) if I ever use textures outside the Texture class
+	//glActiveTexture(GL_TEXTURE0);
 }
 
 void TextureGL::unbind()
diff --git a/src/opengl/texture-gl.h b/src/opengl/texture-gl.h
index aa2b3db..0b495ed 100644
--- a/src/opengl/texture-gl.h
+++ b/src/opengl/texture-gl.h
@@ -13,7 +13,7 @@ public:
 	TextureGL();
 	virtual ~TextureGL();
 
-	virtual void bind() override;
+	virtual void bind(int texture_unit = 0) override;
 	virtual void unbind() override;
 };
 
diff --git a/src/renderer.cc b/src/renderer.cc
index 380cf69..e383efa 100644
--- a/src/renderer.cc
+++ b/src/renderer.cc
@@ -98,7 +98,7 @@ void Renderer::draw_object(Object *object) const
 	/* texture */
 
 	if(m->dtex)
-		m->dtex->bind();
+		m->dtex->bind(0);
 
 	/* setting uniforms for matrices */
 
diff --git a/src/texture.h b/src/texture.h
index 3a850f1..a1b52d8 100644
--- a/src/texture.h
+++ b/src/texture.h
@@ -24,7 +24,7 @@ public:
 
 	virtual bool is_cubemap() const;
 
-	virtual void bind() = 0;
+	virtual void bind(int texture_unit = 0) = 0;
 	virtual void unbind() = 0;
 };
 
diff --git a/src/vulkan/texture-vk.cc b/src/vulkan/texture-vk.cc
index 3c56ebd..1c9ad46 100644
--- a/src/vulkan/texture-vk.cc
+++ b/src/vulkan/texture-vk.cc
@@ -12,7 +12,7 @@ void TextureVK::update()
 {
 }
 
-void TextureVK::bind()
+void TextureVK::bind(int texture_unit)
 {
 }
 
diff --git a/src/vulkan/texture-vk.h b/src/vulkan/texture-vk.h
index 56da38d..5b93917 100644
--- a/src/vulkan/texture-vk.h
+++ b/src/vulkan/texture-vk.h
@@ -11,7 +11,7 @@ public:
 	TextureVK();
 	virtual ~TextureVK();
 
-	virtual void bind() override;
+	virtual void bind(int texture_unit = 0) override;
 	virtual void unbind() override;
 };
 
-- 
1.7.10.4