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);
53 Geometry::Angle<float> spot_cutoff;
63 /** Sets the diffuse (direction-independent) color of the Light. Provided
64 to shaders with the name light_sources[i].diffuse. */
65 void set_diffuse(const Color &c);
67 /** Sets the specular (direction-dependent) color of the Light. Provided to
68 shaders with the name light_sources[i].specular. */
69 void set_specular(const Color &c);
71 const Color &get_diffuse() const { return diffuse; }
72 const Color &get_specular() const { return specular; }
74 /** Sets the postion and orientation of the Light from a matrix. Negative Z
75 axis is used as the spot direction, other axes are ignored. */
76 virtual void set_matrix(const Matrix &);
78 /** Sets the position of the Light. For a directional light, set the xyz
79 components to a vector pointing towards the light and the w component to 0. */
80 void set_position(const Vector4 &);
82 const Vector4 &get_position() const { return position; }
84 /** Sets the direction of a spotlight. Has no effect if spotlight cutoff is
86 void set_spot_direction(const Vector3 &);
88 /** Sets the angular falloff exponent of the spotlight. Must be >= 0. */
89 void set_spot_exponent(float);
91 /** Sets the cutoff angle of a spotlight. Beyond this angle from its axis
92 the spotlight provides no illumination. Must be between 0 and 90 degrees,
93 or exactly 180 degrees to indicate a non-spotlight. */
94 void set_spot_cutoff(const Geometry::Angle<float> &);
96 /** Disables spotlight, reverting to an omnidirectional point light.
97 Equivalent to setting the spot cutoff to 180 degrees. */
98 void disable_spot_cutoff();
100 const Vector3 &get_spot_direction() const { return spot_dir; }
101 float get_spot_exponent() const { return spot_exp; }
102 const Geometry::Angle<float> &get_spot_cutoff() const { return spot_cutoff; }
103 void set_attenuation(float, float, float);
104 const float *get_attenuation() const { return attenuation; }
106 /** Updates a ProgramData object with the uniforms for the Light. A view
107 matrix and light source index must be passed in. */
108 void update_shader_data(ProgramData &, const Matrix &, unsigned) const;