Implemented fog for terrain and particles

Author: Cheng Xie

src/Material.cpp

@@ -0,0 +1,14 @@
+#include <GL/glew.h>
+#include "shader.h"
+#include "shadercache.h"
+#include "drawcontext.h"
+#include "scene.h"
+
+void Material::apply(DrawContext &context)
+{
+    shader_->bind();
+    context.shader = shader_;
+    
+    shader_->setUniformValue("fogColor", context.scene->fogColor());
+    shader_->setUniformValue("fogDensity", context.scene->fogDensity());
+}

src/camera.cpp

@@ -4,8 +4,8 @@
 
 Camera::Camera()
 {
-    near_ = 1;
-    far_ = 10000;
+    near_ = 0.1;
+    far_ = 1000;
     aspectRatio_ = 1;
     heightAngle_ = 60;
 
@@ -18,6 +18,8 @@ void Camera::apply(DrawContext &context)
     context.shader->setUniformValue("view", viewMatrix());
     context.shader->setUniformValue("projection", projectionMatrix());
     context.shader->setUniformValue("eyePositionW", position());
+    context.shader->setUniformValue("near", near());
+    context.shader->setUniformValue("far", far());
 }
 
 const mat4& Camera::projectionMatrix() const

src/final.pro

@@ -45,7 +45,8 @@ SOURCES += main.cpp \
     fpscameracontroller.cpp \
     Tornado.cpp \
     TornadoParticleSystem.cpp \
-    terrainmaterial.cpp
+    terrainmaterial.cpp \
+    material.cpp
 
 HEADERS += mainwindow.h \
     view.h \

src/material.h

@@ -8,7 +8,7 @@ class Material
 {
 public:
     virtual ~Material() {}
-    virtual void apply(DrawContext& context) = 0;
+    virtual void apply(DrawContext& context);
     virtual void endRender() {}
 
 protected:

src/particlematerial.cpp

@@ -11,11 +11,10 @@ ParticleMaterial::ParticleMaterial()
 
 void ParticleMaterial::apply(DrawContext &context)
 {
-    shader_->bind();
-    context.shader = shader_;
-    
     assert(texture_);
 
+    Material::apply(context);
+    
     texture_->apply(context, "map", 0);
 
     //glDisable(GL_DEPTH_TEST);

src/phongmaterial.cpp

@@ -17,8 +17,7 @@ PhongMaterial::~PhongMaterial()
 
 void PhongMaterial::apply(DrawContext &context)
 {
-    shader_->bind();
-    context.shader = shader_;
+    Material::apply(context);
 
     shader_->setUniformValue("ambient", ambient_);
     shader_->setUniformValue("diffuse", diffuse_);

src/scene.cpp

@@ -33,6 +33,9 @@ Scene::~Scene()
 
 void Scene::initialize()
 {   
+    setFogColor({0.45, 0.47, 0.5});
+    setFogDensity(0.008);
+    
     // Materials are owned (and deleted) by SceneObject
     PhongMaterial* material1 = new PhongMaterial;
     material1->setAmbient({0.2, 0.2, 0.2});
@@ -98,4 +101,25 @@ void Scene::render(DrawContext &context)
     }
 }
 
+const Color &Scene::fogColor() const
+{
+    return fogColor_;
+}
+
+void Scene::setFogColor(const Color &fogColor)
+{
+    fogColor_ = fogColor;
+}
+float Scene::fogDensity() const
+{
+    return fogDensity_;
+}
+
+void Scene::setFogDensity(float fogDensity)
+{
+    fogDensity_ = fogDensity;
+}
+
+
+
 

src/scene.h

@@ -20,12 +20,21 @@ class Scene
 
     void render(DrawContext& context);
 
+    const Color& fogColor() const;
+    void setFogColor(const Color &fogColor);
+    
+    float fogDensity() const;
+    void setFogDensity(float fogDensity);
+    
 private:
     SceneObjects sceneObjects_;
     Lights lights_;
 
     Skybox* skybox_;
     Tornado* tornado_;
+    
+    Color fogColor_;
+    float fogDensity_;
 };
 
 #endif // SCENE_H

src/shaders/particle.fs

@@ -2,9 +2,14 @@
 
 uniform sampler2D map;
 
+uniform vec3 fogColor;
+
 in vec2 uv;
+in float fogFactor;
+
 out vec4 fragColor;
 
 void main() {
-    fragColor = texture(map, uv);
+    vec4 color = texture(map, uv);
+    fragColor = vec4(mix(color.xyz, fogColor, fogFactor), color.a);
 }

src/shaders/particle.gs

@@ -7,8 +7,10 @@ uniform mat4 projection;
 
 in float dim[];
 in float rot[];
+in float fog_factor[];
 
 out vec2 uv;
+out float fogFactor;
 
 void main() {
     float size = dim[0];
@@ -23,21 +25,25 @@ void main() {
     vec4 offset = rotMat * vec4(-size, -size, 0.0, 0.0);
     gl_Position = projection * (offset + gl_in[0].gl_Position);
     uv = vec2(0.0, 0.0);
+    fogFactor = fog_factor[0];
     EmitVertex();
 
     offset = rotMat * vec4(size, -size, 0.0, 0.0);
     gl_Position = projection * (offset + gl_in[0].gl_Position);
     uv = vec2(1.0, 0.0);
+    fogFactor = fog_factor[0];
     EmitVertex();
 
     offset = rotMat * vec4(-size, size, 0.0, 0.0);
     gl_Position = projection * (offset + gl_in[0].gl_Position);
     uv = vec2(0.0, 1.0);
+    fogFactor = fog_factor[0];
     EmitVertex();
 
     offset = rotMat * vec4(size, size, 0.0, 0.0);
     gl_Position = projection * (offset + gl_in[0].gl_Position);
     uv = vec2(1.0, 1.0);
+    fogFactor = fog_factor[0];
     EmitVertex();
 
     EndPrimitive();

src/shaders/particle.vs

@@ -9,10 +9,17 @@ uniform mat4 worldView;
 out float dim;
 out float rot;
 
+uniform float fogDensity;
+
+out float fog_factor;
+
 void main() {
     dim = size;
     rot = rotation / 180 * 3.1415926;
     gl_Position = worldView * vec4(position, 1);
+
+    vec4 positionV = worldView * vec4(position, 1);
+    fog_factor = 1 - 1 / pow(exp(-positionV.z * fogDensity), 2);
 }
 
 

src/shaders/terrain.fs

@@ -1,14 +1,19 @@
 #version 330
 
 in vec3 normalW;
-in vec3 positionW;
 in vec2 uv;
+in float fogFactor;
+
+uniform float near;
+uniform float far;
 
 uniform vec3 lightDir;
 uniform vec3 lightColor;
 
 uniform vec3 ambient;
 
+uniform vec3 fogColor;
+
 uniform sampler2D diffuseMap;
 
 out vec4 fragColor;
@@ -25,6 +30,8 @@ void main()
 
     vec3 color = Li * brdf_diffuse;
     color += ambient * brdf_diffuse;
+    
+    color = mix(color, fogColor, fogFactor);
 
     fragColor = vec4(color, 1);
 }

src/shaders/terrain.vs

@@ -4,15 +4,18 @@ layout (location = 0) in vec3 positionL;
 layout (location = 2) in vec2 uvL;
 
 uniform mat4 world;
+uniform mat4 worldView;
 uniform mat4 worldViewProjection;
 
 uniform float heightScale;
 
 uniform sampler2D heightMap;
 
+uniform float fogDensity;
+
 out vec3 normalW;
-out vec3 positionW;
 out vec2 uv;
+out float fogFactor;
 
 void main()
 {
@@ -33,9 +36,11 @@ void main()
     vec3 dv = normalize(vec3(0, h_pos_v - h_neg_v, -turbulence));
     normal = cross(du, dv);
 
-    positionW = (world * vec4(position, 1)).xyz;
     normalW = (world * vec4(normal, 0)).xyz;
     uv = uvL;
 
     gl_Position = worldViewProjection * vec4(position, 1);
+
+    vec4 positionV = worldView * vec4(position, 1);
+    fogFactor = 1 - 1 / pow(exp(-positionV.z * fogDensity), 2);
 }

src/skybox.cpp

@@ -15,8 +15,5 @@ Skybox::Skybox(string name)
     material->setTexture(texture);
     setMaterial(material);
 
-    transform().translate(0, -50, 0);
-    transform().scale(1000);
-    
-    
+    transform().translate(0, 0, 0);
 }

src/skyboxmaterial.cpp

@@ -17,8 +17,7 @@ void SkyboxMaterial::setTexture(Texture *texture)
 
 void SkyboxMaterial::apply(DrawContext &context)
 {
-    shader_->bind();
-    context.shader = shader_;
+    Material::apply(context);
 
     assert(texture_);
 

src/terrainmaterial.cpp

@@ -13,8 +13,7 @@ void TerrainMaterial::apply(DrawContext &context)
     assert(heightMap_);
     assert(diffuseMap_);
 
-    shader_->bind();
-    context.shader = shader_;
+    Material::apply(context);
 
     shader_->setUniformValue("ambient", ambient_);
     shader_->setUniformValue("heightScale", heightScale_);