Support fog in lighting and shaders

[libs/gl.git] / source / lighting.cpp

diff --git a/source/lighting.cpp b/source/lighting.cpp
index a927d622fade9b0c81a916f51ef31bce079bf825..5cda4f4c6a4e005a5ad71c22427ddc0c5d0d69c7 100644 (file)
--- a/source/lighting.cpp
+++ b/source/lighting.cpp
@@ -1,4 +1,5 @@
 #include <stdexcept>
+#include <cmath>
 #include <msp/gl/extensions/msp_legacy_features.h>
 #include "error.h"
 #include "light.h"
@@ -15,7 +16,9 @@ namespace GL {
 Lighting::Lighting():
        ambient(0.2),
        sky_direction(0, 0, 1),
-       horizon_angle(Geometry::Angle<float>::zero())
+       horizon_angle(Geometry::Angle<float>::zero()),
+       fog_color(0.0f, 0.0f, 0.0f, 0.0f),
+       fog_density(0.0f)
 { }
 
 void Lighting::set_ambient(const Color &a)
@@ -38,6 +41,24 @@ void Lighting::set_horizon_angle(const Geometry::Angle<float> &a)
        horizon_angle = a;
 }
 
+void Lighting::set_fog_color(const Color &c)
+{
+       fog_color = c;
+}
+
+void Lighting::set_fog_density(float d)
+{
+       if(d<0)
+               throw invalid_argument("Lighting::set_fog_density");
+
+       fog_density = d;
+}
+
+void Lighting::set_fog_half_distance(float d)
+{
+       set_fog_density(-log(pow(0.5, 1.0/d)));
+}
+
 void Lighting::attach(unsigned i, const Light &l)
 {
        if(i>=lights.size())
@@ -69,6 +90,8 @@ void Lighting::update_shader_data(ProgramData &shdata, const Matrix &view_matrix
        shdata.uniform("sky_color", sky_color);
        shdata.uniform("eye_sky_dir", view_matrix.block<3, 3>(0, 0)*sky_direction);
        shdata.uniform("horizon_limit", horizon_angle.radians());
+       shdata.uniform("fog_color", fog_color);
+       shdata.uniform("fog_density", fog_density);
 
        for(unsigned i=0; i<lights.size(); ++i)
                if(lights[i])
@@ -89,6 +112,14 @@ void Lighting::bind() const
        for(unsigned i=0; i<lights.size(); ++i)
                if(lights[i])
                        lights[i]->bind_to(i);
+
+       if(fog_density)
+       {
+               enable(GL_FOG);
+               glFogi(GL_FOG_MODE, GL_EXP);
+               glFogf(GL_FOG_DENSITY, fog_density);
+               glFogfv(GL_FOG_COLOR, &fog_color.r);
+       }
 }
 
 void Lighting::unbind()
@@ -102,6 +133,8 @@ void Lighting::unbind()
                        Light::unbind_from(i);
 
        disable(GL_LIGHTING);
+       if(old->fog_density)
+               disable(GL_FOG);
 }
 
 } // namespace GL