1 #ifndef MSP_GL_LIGHT_H_
2 #define MSP_GL_LIGHT_H_
5 #include <msp/datafile/objectloader.h>
16 Stores properties of a single light source. Lights can be directional, point
17 lights or spotlights. No explicit type parameter is provided; rather the
18 other parameters determine what kind of light it is. If the fourth component
19 of position is zero, it's a directional light. Otherwise, if the spot cutoff
20 is not 180 degrees, it's a spotlight. Otherwise it's an omnidirectional point
23 Lights are usually grouped with a Lighting object, which can be used in a
26 Lights do not cast shadows by themselves. See ShadowMap for that.
28 class Light: public Placeable
31 class Loader: public DataFile::ObjectLoader<Light>
37 void attenuation(float, float, float);
38 void diffuse(float, float, float);
39 void position(float, float, float, float);
40 void specular(float, float, float);
41 void spot_direction(float, float, float);
42 void spot_exponent(float);
43 void spot_cutoff(float);
64 Geometry::Angle<float> spot_cutoff;
72 void update_parameter(int, int = -1) const;
76 /** Sets the diffuse (direction-independent) color of the Light. Provided
77 to shaders with the name light_sources[i].diffuse. */
78 void set_diffuse(const Color &c);
80 /** Sets the specular (direction-dependent) color of the Light. Provided to
81 shaders with the name light_sources[i].specular. */
82 void set_specular(const Color &c);
84 const Color &get_diffuse() const { return diffuse; }
85 const Color &get_specular() const { return specular; }
87 /** Sets the postion and orientation of the Light from a matrix. Negative Z
88 axis is used as the spot direction, other axes are ignored. */
89 virtual void set_matrix(const Matrix &);
91 /** Sets the position of the Light. For a directional light, set the xyz
92 components to a vector pointing towards the light and the w component to 0. */
93 void set_position(const Vector4 &);
95 const Vector4 &get_position() const { return position; }
97 /** Sets the direction of a spotlight. Has no effect if spotlight cutoff is
99 void set_spot_direction(const Vector3 &);
101 /** Sets the angular falloff exponent of the spotlight. Must be >= 0. */
102 void set_spot_exponent(float);
105 void set_spot_cutoff(float);
107 /** Sets the cutoff angle of a spotlight. Beyond this angle from its axis
108 the spotlight provides no illumination. Must be between 0 and 90 degrees,
109 or exactly 180 degrees to indicate a non-spotlight. */
110 void set_spot_cutoff(const Geometry::Angle<float> &);
112 /** Disables spotlight, reverting to an omnidirectional point light.
113 Equivalent to setting the spot cutoff to 180 degrees. */
114 void disable_spot_cutoff();
116 const Vector3 &get_spot_direction() const { return spot_dir; }
117 float get_spot_exponent() const { return spot_exp; }
118 const Geometry::Angle<float> &get_spot_cutoff() const { return spot_cutoff; }
119 void set_attenuation(float, float, float);
120 const float *get_attenuation() const { return attenuation; }
122 /** Updates a ProgramData object with the uniforms for the Light. A view
123 matrix and light source index must be passed in. */
124 void update_shader_data(ProgramData &, const Matrix &, unsigned) const;
126 void bind() const { return bind_to(0); }
127 void bind_to(unsigned) const;
129 static const Light *current(unsigned = 0);
130 static void unbind() { return unbind_from(0); }
131 static void unbind_from(unsigned);