/**
 ** sipp - SImple Polygon Processor
 **
 **  A general 3d graphic package
 **
 **  Copyright Equivalent Software HB  1992
 **
 ** This program is free software; you can redistribute it and/or modify
 ** it under the terms of the GNU General Public License as published by
 ** the Free Software Foundation; either version 1, or any later version.
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 ** You can receive a copy of the GNU General Public License from the
 ** Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 **/

/**
 ** shaders.h - This include file defines the different shaders availiable
 **             in sipp. Each shader is defined by a structure containing 
 **             the necessary parameters to describe how a surface should 
 **             be shaded with that particular shader, and the extern 
 **             declaration of the shader function itself.
 **/


#ifndef _SHADERS_H
#define _SHADERS_H


#include <sipp.h>



/*
 * Surface description used in phong_shader().
 */
typedef struct {
    double ambient;     /* Fraction of color visible in ambient light */
    double diffuse;     /* Diffuse reflexion factor */
    double specular;    /* Specular reflexion factor */
    int    spec_exp;    /* Exponent in the specular calculation */
    Color  color;       /* Color of the surface */
    Color  opacity;     /* Opacity of the surface */
} Phong_desc;



/*
 * Surface description used in strauss_shader().
 */
typedef struct {
    double ambient;       /* Fraction of color visible in ambient light */
    double smoothness;    /* Smoothness of the surface [0, 1] */
    double metalness;     /* Metalness of the surface [0, 1] */
    Color  color;         /* Base color of the surface */
    Color  opacity;       /* Opacity of the surface */
} Strauss_desc;



/* 
 * Surface description for the bozo shader.
 */
typedef struct {
    Color   *colors;
    int      no_of_cols;
    double   ambient;
    double   specular;
    double   c3;
    double   scale;        /* Scale the texture by this value */
    Color    opacity;      /* Opacity of the surface */
} Bozo_desc;
    


/*
 * Surface description used by the wood shader. This shader
 * creates a solid texture (using noise & turbulence) that
 * simulates wood.
 */
typedef struct {
    double   ambient;
    double   specular;
    double   c3;
    double   scale;        /* Scale the wood texture by this value */
    Color    base;         /* "Base" color of the surface */
    Color    ring;         /* Color of the darker rings */
    Color    opacity;      /* Opacity of the surface */
} Wood_desc;



/*
 * Surface description used by the marble shader. marble_shader
 * creates a solid texture (using noise & turbulence) that
 * simulates marble.
 */
typedef struct {
    double   ambient;
    double   specular;
    double   c3;
    double   scale;        /* Scale the marble texture by this value */
    Color    base;         /* "Base" color of the surface */
    Color    strip;        /* Color of the "stripes" in the marble */
    Color    opacity;      /* Opacity of the surface */
} Marble_desc;



/*
 * Surface description used by the granite shader. granite_shader
 * creates a solid texture (using noise) that mixes two colors
 * to simulate granite.
 */
typedef struct {
    double   ambient;
    double   specular;
    double   c3;
    double   scale;        /* Scale the texture by this value */
    Color    col1;         /* The two color components */
    Color    col2;
    Color    opacity;      /* Opacity of the surface */
} Granite_desc;



/*
 * Mask shader. It uses mask image (ususally a bitmap) to
 * choose between two other shaders. When a
 * surface is shaded it calls masker() to check the
 * u, v coordinate in the mask and calls one of two other 
 * shaders depending of the outcome of that test.
 */
typedef struct {
    Shader *t_shader;           /* Shader to call if mask(x, y) != 0 */
    void   *t_surface;          /* Surface description for fg_shader */
    Shader *f_shader;           /* Shader to call if mask(x, y) == 0 */
    void   *f_surface;          /* Surface description for bg_shader */
    void   *mask_data;          /* Pointer to data for masking function */
    bool  (*masker)();          /* Function that tests a pixel value */
} Mask_desc;


/*
 * Surface description for the bumpy_shader(). This shader 
 * fiddles with the surface normals of a surface so the surface 
 * looks bumpy.
 */

typedef struct {
    Shader *shader;
    void   *surface;
    double scale;
    bool   bumpflag;
    bool   holeflag;
} Bumpy_desc;


/*
 * Declarations of the actual shading functions.
 */
extern void strauss_shader();
extern void marble_shader();
extern void granite_shader();
extern void bozo_shader();
extern void mask_shader();
extern void bumpy_shader();
extern void planet_shader();
extern void wood_shader();

#endif /* _SHADERS_H */