shapes.c

mesa-6.5-minigui源码

/*
 * freeglut_geometry.c
 *
 * Freeglut geometry rendering methods.
 *
 * Copyright (c) 1999-2000 Pawel W. Olszta. All Rights Reserved.
 * Written by Pawel W. Olszta, <[e-mail]>
 * Creation date: Fri Dec 3 1999
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * PAWEL W. OLSZTA BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <math.h>
#include "internal.h"

/*
 * TODO BEFORE THE STABLE RELEASE:
 *
 * Following functions have been contributed by Andreas Umbach.
 *
 *      glutWireCube()          -- looks OK
 *      glutSolidCube()         -- OK
 *
 * Those functions have been implemented by John Fay.
 *
 *      glutWireTorus()         -- looks OK
 *      glutSolidTorus()        -- looks OK
 *      glutWireDodecahedron()  -- looks OK
 *      glutSolidDodecahedron() -- looks OK
 *      glutWireOctahedron()    -- looks OK
 *      glutSolidOctahedron()   -- looks OK
 *      glutWireTetrahedron()   -- looks OK
 *      glutSolidTetrahedron()  -- looks OK
 *      glutWireIcosahedron()   -- looks OK
 *      glutSolidIcosahedron()  -- looks OK
 *
 *  The Following functions have been updated by Nigel Stewart, based
 *  on FreeGLUT 2.0.0 implementations:
 *
 *      glutWireSphere()        -- looks OK
 *      glutSolidSphere()       -- looks OK
 *      glutWireCone()          -- looks OK
 *      glutSolidCone()         -- looks OK
 */


/* -- INTERFACE FUNCTIONS -------------------------------------------------- */

/*
 * Draws a wireframed cube. Code contributed by Andreas Umbach <[e-mail]>
 */
void GLUTAPIENTRY glutWireCube( GLdouble dSize )
{
    double size = dSize * 0.5;

#   define V(a,b,c) glVertex3d( a size, b size, c size );
#   define N(a,b,c) glNormal3d( a, b, c );

    /*
     * PWO: I dared to convert the code to use macros...
     */
    glBegin( GL_LINE_LOOP ); N( 1.0, 0.0, 0.0); V(+,-,+); V(+,-,-); V(+,+,-); V(+,+,+); glEnd();
    glBegin( GL_LINE_LOOP ); N( 0.0, 1.0, 0.0); V(+,+,+); V(+,+,-); V(-,+,-); V(-,+,+); glEnd();
    glBegin( GL_LINE_LOOP ); N( 0.0, 0.0, 1.0); V(+,+,+); V(-,+,+); V(-,-,+); V(+,-,+); glEnd();
    glBegin( GL_LINE_LOOP ); N(-1.0, 0.0, 0.0); V(-,-,+); V(-,+,+); V(-,+,-); V(-,-,-); glEnd();
    glBegin( GL_LINE_LOOP ); N( 0.0,-1.0, 0.0); V(-,-,+); V(-,-,-); V(+,-,-); V(+,-,+); glEnd();
    glBegin( GL_LINE_LOOP ); N( 0.0, 0.0,-1.0); V(-,-,-); V(-,+,-); V(+,+,-); V(+,-,-); glEnd();

#   undef V
#   undef N
}

/*
 * Draws a solid cube. Code contributed by Andreas Umbach <[e-mail]>
 */
void GLUTAPIENTRY glutSolidCube( GLdouble dSize )
{
    double size = dSize * 0.5;

#   define V(a,b,c) glVertex3d( a size, b size, c size );
#   define N(a,b,c) glNormal3d( a, b, c );

    /*
     * PWO: Again, I dared to convert the code to use macros...
     */
    glBegin( GL_QUADS );
        N( 1.0, 0.0, 0.0); V(+,-,+); V(+,-,-); V(+,+,-); V(+,+,+);
        N( 0.0, 1.0, 0.0); V(+,+,+); V(+,+,-); V(-,+,-); V(-,+,+);
        N( 0.0, 0.0, 1.0); V(+,+,+); V(-,+,+); V(-,-,+); V(+,-,+);
        N(-1.0, 0.0, 0.0); V(-,-,+); V(-,+,+); V(-,+,-); V(-,-,-);
        N( 0.0,-1.0, 0.0); V(-,-,+); V(-,-,-); V(+,-,-); V(+,-,+);
        N( 0.0, 0.0,-1.0); V(-,-,-); V(-,+,-); V(+,+,-); V(+,-,-);
    glEnd();

#   undef V
#   undef N
}

/*
 * Compute lookup table of cos and sin values forming a cirle
 *
 * Notes:
 *    It is the responsibility of the caller to free these tables
 *    The size of the table is (n+1) to form a connected loop
 *    The last entry is exactly the same as the first
 *    The sign of n can be flipped to get the reverse loop
 */

static void circleTable(double **sint,double **cost,const int n)
{
    int i;

    /* Table size, the sign of n flips the circle direction */

    const int size = abs(n);

    /* Determine the angle between samples */

    const double angle = 2*M_PI/(double)n;

    /* Allocate memory for n samples, plus duplicate of first entry at the end */

    *sint = (double *) calloc(sizeof(double), size+1);
    *cost = (double *) calloc(sizeof(double), size+1);

    /* Bail out if memory allocation fails, fgError never returns */

    if (!(*sint) || !(*cost))
    {
        free(*sint);
        free(*cost);
        _glut_fatal("Failed to allocate memory in circleTable");
    }

    /* Compute cos and sin around the circle */

    for (i=0; i<size; i++)
    {
        (*sint)[i] = sin(angle*i);
        (*cost)[i] = cos(angle*i);
    }

    /* Last sample is duplicate of the first */

    (*sint)[size] = (*sint)[0];
    (*cost)[size] = (*cost)[0];
}

/*
 * Draws a solid sphere
 */
void GLUTAPIENTRY glutSolidSphere(GLdouble radius, GLint slices, GLint stacks)
{
    int i,j;

    /* Adjust z and radius as stacks are drawn. */

    double z0,z1;
    double r0,r1;

    /* Pre-computed circle */

    double *sint1,*cost1;
    double *sint2,*cost2;
    circleTable(&sint1,&cost1,-slices);
    circleTable(&sint2,&cost2,stacks*2);

    /* The top stack is covered with a triangle fan */

    z0 = 1.0;
    z1 = cost2[1];
    r0 = 0.0;
    r1 = sint2[1];

    glBegin(GL_TRIANGLE_FAN);

        glNormal3d(0,0,1);
        glVertex3d(0,0,radius);

        for (j=slices; j>=0; j--)
        {       
            glNormal3d(cost1[j]*r1,        sint1[j]*r1,        z1       );
            glVertex3d(cost1[j]*r1*radius, sint1[j]*r1*radius, z1*radius);
        }

    glEnd();

    /* Cover each stack with a quad strip, except the top and bottom stacks */

    for( i=1; i<stacks-1; i++ )
    {
        z0 = z1; z1 = cost2[i+1];
        r0 = r1; r1 = sint2[i+1];

        glBegin(GL_QUAD_STRIP);

            for(j=0; j<=slices; j++)
            {
                glNormal3d(cost1[j]*r1,        sint1[j]*r1,        z1       );
                glVertex3d(cost1[j]*r1*radius, sint1[j]*r1*radius, z1*radius);
                glNormal3d(cost1[j]*r0,        sint1[j]*r0,        z0       );
                glVertex3d(cost1[j]*r0*radius, sint1[j]*r0*radius, z0*radius);
            }

        glEnd();
    }

    /* The bottom stack is covered with a triangle fan */

    z0 = z1;
    r0 = r1;

    glBegin(GL_TRIANGLE_FAN);

        glNormal3d(0,0,-1);
        glVertex3d(0,0,-radius);

        for (j=0; j<=slices; j++)
        {
            glNormal3d(cost1[j]*r0,        sint1[j]*r0,        z0       );
            glVertex3d(cost1[j]*r0*radius, sint1[j]*r0*radius, z0*radius);
        }

    glEnd();

    /* Release sin and cos tables */

    free(sint1);
    free(cost1);
    free(sint2);
    free(cost2);
}

/*
 * Draws a solid sphere
 */
void GLUTAPIENTRY glutWireSphere(GLdouble radius, GLint slices, GLint stacks)
{
    int i,j;

    /* Adjust z and radius as stacks and slices are drawn. */

    double r;
    double x,y,z;

    /* Pre-computed circle */
        
    double *sint1,*cost1;
    double *sint2,*cost2;
    circleTable(&sint1,&cost1,-slices  );
    circleTable(&sint2,&cost2, stacks*2);

    /* Draw a line loop for each stack */

    for (i=1; i<stacks; i++)
    {
        z = cost2[i];
        r = sint2[i];

        glBegin(GL_LINE_LOOP);

            for(j=0; j<=slices; j++)
            {
                x = cost1[j];
                y = sint1[j];

                glNormal3d(x,y,z);
                glVertex3d(x*r*radius,y*r*radius,z*radius);
            }

        glEnd();
    }

    /* Draw a line loop for each slice */

    for (i=0; i<slices; i++)
    {
        glBegin(GL_LINE_STRIP);

            for(j=0; j<=stacks; j++)
            {
                x = cost1[i]*sint2[j];
                y = sint1[i]*sint2[j];
                z = cost2[j];

                glNormal3d(x,y,z);
                glVertex3d(x*radius,y*radius,z*radius);
            }

        glEnd();
    }

    /* Release sin and cos tables */

    free(sint1);
    free(cost1);
    free(sint2);
    free(cost2);
}

/*
 * Draws a solid cone
 */
void GLUTAPIENTRY glutSolidCone( GLdouble base, GLdouble height, GLint slices, GLint stacks )
{
    int i,j;

    /* Step in z and radius as stacks are drawn. */

    double z0,z1;
    double r0,r1;

    const double zStep = height/stacks;
    const double rStep = base/stacks;

    /* Scaling factors for vertex normals */

    const double cosn = ( height / sqrt ( height * height + base * base ));
    const double sinn = ( base   / sqrt ( height * height + base * base ));

    /* Pre-computed circle */

    double *sint,*cost;
    circleTable(&sint,&cost,-slices);

    /* Cover the circular base with a triangle fan... */

    z0 = 0.0;
    z1 = zStep;

    r0 = base;
    r1 = r0 - rStep;

    glBegin(GL_TRIANGLE_FAN);

        glNormal3d(0.0,0.0,-1.0);
        glVertex3d(0.0,0.0, z0 );

        for (j=0; j<=slices; j++)
            glVertex3d(cost[j]*r0, sint[j]*r0, z0);

    glEnd();

    /* Cover each stack with a quad strip, except the top stack */

    for( i=0; i<stacks-1; i++ )
    {
        glBegin(GL_QUAD_STRIP);

            for(j=0; j<=slices; j++)
            {
                glNormal3d(cost[j]*sinn, sint[j]*sinn, cosn);
                glVertex3d(cost[j]*r0,   sint[j]*r0,   z0  );
                glVertex3d(cost[j]*r1,   sint[j]*r1,   z1  );
            }

            z0 = z1; z1 += zStep;
            r0 = r1; r1 -= rStep;

        glEnd();
    }

    /* The top stack is covered with individual triangles */

    glBegin(GL_TRIANGLES);

        glNormal3d(cost[0]*sinn, sint[0]*sinn, cosn);