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ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) NNNNAAAAMMMMEEEE ggggllllLLLLiiiigggghhhhttttffff,,,, ggggllllLLLLiiiigggghhhhttttiiii,,,, ggggllllLLLLiiiigggghhhhttttffffvvvv,,,, ggggllllLLLLiiiigggghhhhttttiiiivvvv - set light source parameters CCCC SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN void ggggllllLLLLiiiigggghhhhttttffff( GLenum _l_i_g_h_t, GLenum _p_n_a_m_e, GLfloat _p_a_r_a_m ) void ggggllllLLLLiiiigggghhhhttttiiii( GLenum _l_i_g_h_t, GLenum _p_n_a_m_e, GLint _p_a_r_a_m ) PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS _l_i_g_h_t Specifies a light. The number of lights depends on the implementation, but at least eight lights are supported. They are identified by symbolic names of the form GGGGLLLL____LLLLIIIIGGGGHHHHTTTTi where 0 _< i < GGGGLLLL____MMMMAAAAXXXX____LLLLIIIIGGGGHHHHTTTTSSSS. _p_n_a_m_e Specifies a single-valued light source parameter for _l_i_g_h_t. GGGGLLLL____SSSSPPPPOOOOTTTT____EEEEXXXXPPPPOOOONNNNEEEENNNNTTTT, GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF, GGGGLLLL____CCCCOOOONNNNSSSSTTTTAAAANNNNTTTT____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, GGGGLLLL____LLLLIIIINNNNEEEEAAAARRRR____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, and GGGGLLLL____QQQQUUUUAAAADDDDRRRRAAAATTTTIIIICCCC____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN are accepted. _p_a_r_a_m Specifies the value that parameter _p_n_a_m_e of light source _l_i_g_h_t will be set to. CCCC SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN void ggggllllLLLLiiiigggghhhhttttffffvvvv( GLenum _l_i_g_h_t, GLenum _p_n_a_m_e, const GLfloat *_p_a_r_a_m_s ) void ggggllllLLLLiiiigggghhhhttttiiiivvvv( GLenum _l_i_g_h_t, GLenum _p_n_a_m_e, const GLint *_p_a_r_a_m_s ) PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS _l_i_g_h_t Specifies a light. The number of lights depends on the implementation, but at least eight lights are supported. They are identified by symbolic names of the form GGGGLLLL____LLLLIIIIGGGGHHHHTTTTi where 0 _< i < GGGGLLLL____MMMMAAAAXXXX____LLLLIIIIGGGGHHHHTTTTSSSS. _p_n_a_m_e Specifies a light source parameter for _l_i_g_h_t. GGGGLLLL____AAAAMMMMBBBBIIIIEEEENNNNTTTT, GGGGLLLL____DDDDIIIIFFFFFFFFUUUUSSSSEEEE, GGGGLLLL____SSSSPPPPEEEECCCCUUUULLLLAAAARRRR, GGGGLLLL____PPPPOOOOSSSSIIIITTTTIIIIOOOONNNN, GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF, GGGGLLLL____SSSSPPPPOOOOTTTT____DDDDIIIIRRRREEEECCCCTTTTIIIIOOOONNNN, GGGGLLLL____SSSSPPPPOOOOTTTT____EEEEXXXXPPPPOOOONNNNEEEENNNNTTTT, GGGGLLLL____CCCCOOOONNNNSSSSTTTTAAAANNNNTTTT____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, GGGGLLLL____LLLLIIIINNNNEEEEAAAARRRR____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN, and GGGGLLLL____QQQQUUUUAAAADDDDRRRRAAAATTTTIIIICCCC____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN are accepted. _p_a_r_a_m_s Specifies a pointer to the value or values that parameter _p_n_a_m_e of light source _l_i_g_h_t will be set to. PPPPaaaaggggeeee 1111 ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN ggggllllLLLLiiiigggghhhhtttt sets the values of individual light source parameters. _l_i_g_h_t names the light and is a symbolic name of the form GGGGLLLL____LLLLIIIIGGGGHHHHTTTTi, where 0 _< i < GGGGLLLL____MMMMAAAAXXXX____LLLLIIIIGGGGHHHHTTTTSSSS. _p_n_a_m_e specifies one of ten light source parameters, again by symbolic name. _p_a_r_a_m_s is either a single value or a pointer to an array that contains the new values. To enable and disable lighting calculation, call ggggllllEEEEnnnnaaaabbbblllleeee and ggggllllDDDDiiiissssaaaabbbblllleeee with argument GGGGLLLL____LLLLIIIIGGGGHHHHTTTTIIIINNNNGGGG. Lighting is initially disabled. When it is enabled, light sources that are enabled contribute to the lighting calculation. Light source i is enabled and disabled using ggggllllEEEEnnnnaaaabbbblllleeee and ggggllllDDDDiiiissssaaaabbbblllleeee with argument GGGGLLLL____LLLLIIIIGGGGHHHHTTTTi. The ten light parameters are as follows: GGGGLLLL____AAAAMMMMBBBBIIIIEEEENNNNTTTT _p_a_r_a_m_s contains four integer or floating-point values that specify the ambient RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient light intensity is (0, 0, 0, 1). GGGGLLLL____DDDDIIIIFFFFFFFFUUUUSSSSEEEE _p_a_r_a_m_s contains four integer or floating-point values that specify the diffuse RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for GGGGLLLL____LLLLIIIIGGGGHHHHTTTT0000 is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 0). GGGGLLLL____SSSSPPPPEEEECCCCUUUULLLLAAAARRRR _p_a_r_a_m_s contains four integer or floating-point values that specify the specular RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for GGGGLLLL____LLLLIIIIGGGGHHHHTTTT0000 is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 0). GGGGLLLL____PPPPOOOOSSSSIIIITTTTIIIIOOOONNNN _p_a_r_a_m_s contains four integer or floating-point values that specify the position of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped. PPPPaaaaggggeeee 2222 ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) The position is transformed by the modelview matrix when ggggllllLLLLiiiigggghhhhtttt is called (just as if it were a point), and it is stored in eye coordinates. If the w component of the position is 0, the light is treated as a directional source. Diffuse and specular lighting calculations take the light's direction, but not its actual position, into account, and attenuation is disabled. Otherwise, diffuse and specular lighting calculations are based on the actual location of the light in eye coordinates, and attenuation is enabled. The initial position is (0, 0, 1, 0); thus, the initial light source is directional, parallel to, and in the direction of the -z axis. GGGGLLLL____SSSSPPPPOOOOTTTT____DDDDIIIIRRRREEEECCCCTTTTIIIIOOOONNNN _p_a_r_a_m_s contains three integer or floating-point values that specify the direction of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The spot direction is transformed by the inverse of the modelview matrix when ggggllllLLLLiiiigggghhhhtttt is called (just as if it were a normal), and it is stored in eye coordinates. It is significant only when GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF is not 180, which it is initially. The initial direction is (0, 0, -1). GGGGLLLL____SSSSPPPPOOOOTTTT____EEEEXXXXPPPPOOOONNNNEEEENNNNTTTT _p_a_r_a_m_s is a single integer or floating-point value that specifies the intensity distribution of the light. Integer and floating-point values are mapped directly. Only values in the range [0,128] are accepted. Effective light intensity is attenuated by the cosine of the angle between the direction of the light and the direction from the light to the vertex being lighted, raised to the power of the spot exponent. Thus, higher spot exponents result in a more focused light source, regardless of the spot cutoff angle (see GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF, next paragraph). The initial spot exponent is 0, resulting in uniform light distribution. GGGGLLLL____SSSSPPPPOOOOTTTT____CCCCUUUUTTTTOOOOFFFFFFFF _p_a_r_a_m_s is a single integer or floating-point value that specifies the maximum spread angle of a light source. Integer and floating-point values are mapped directly. Only values in the range [0,90] and the special value 180 are accepted. If the angle between the direction of the light and the direction from the light to the vertex being lighted is greater than the spot cutoff angle, the light is completely masked. PPPPaaaaggggeeee 3333 ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee ggggllllLLLLiiiigggghhhhtttt((((3333GGGG)))) Otherwise, its intensity is controlled by the spot exponent and the attenuation factors. The initial spot cutoff is 180, resulting in uniform light distribution. GGGGLLLL____CCCCOOOONNNNSSSSTTTTAAAANNNNTTTT____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN GGGGLLLL____LLLLIIIINNNNEEEEAAAARRRR____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN GGGGLLLL____QQQQUUUUAAAADDDDRRRRAAAATTTTIIIICCCC____AAAATTTTTTTTEEEENNNNUUUUAAAATTTTIIIIOOOONNNN _p_a_r_a_m_s is a single integer or floating-point value that specifies one of the three light attenuation factors. Integer and floating-point values are mapped directly. Only nonnegative values are accepted. If the light is positional, rather than directional, its intensity is attenuated by the reciprocal of the sum of the constant factor, the linear factor times the distance between the light and the vertex being lighted, and the quadratic factor times the square of the same distance. The initial attenuation factors are (1, 0, 0), resulting in no attenuation. NNNNOOOOTTTTEEEESSSS It is always the case that GGGGLLLL____LLLLIIIIGGGGHHHHTTTTi = GGGGLLLL____LLLLIIIIGGGGHHHHTTTT0000 + i. EEEERRRRRRRROOOORRRRSSSS GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____EEEENNNNUUUUMMMM is generated if either _l_i_g_h_t or _p_n_a_m_e is not an accepted value. GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____VVVVAAAALLLLUUUUEEEE is generated if a spot exponent value is specified outside the range [0,128], or if spot cutoff is specified outside the range [0,90] (except for the special value 180), or if a negative attenuation factor is specified. GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____OOOOPPPPEEEERRRRAAAATTTTIIIIOOOONNNN is generated if ggggllllLLLLiiiigggghhhhtttt is executed between the execution of ggggllllBBBBeeeeggggiiiinnnn and the corresponding execution of ggggllllEEEEnnnndddd. AAAASSSSSSSSOOOOCCCCIIIIAAAATTTTEEEEDDDD GGGGEEEETTTTSSSS ggggllllGGGGeeeettttLLLLiiiigggghhhhtttt ggggllllIIIIssssEEEEnnnnaaaabbbblllleeeedddd with argument GGGGLLLL____LLLLIIIIGGGGHHHHTTTTIIIINNNNGGGG SSSSEEEEEEEE AAAALLLLSSSSOOOO ggggllllCCCCoooolllloooorrrrMMMMaaaatttteeeerrrriiiiaaaallll, ggggllllLLLLiiiigggghhhhttttMMMMooooddddeeeellll, ggggllllMMMMaaaatttteeeerrrriiiiaaaallll PPPPaaaaggggeeee 4444 
