quad.c

winNT技术操作系统,国外开放的原代码和LIUX一样

/*
** License Applicability. Except to the extent portions of this file are
** made subject to an alternative license as permitted in the SGI Free
** Software License B, Version 1.1 (the "License"), the contents of this
** file are subject only to the provisions of the License. You may not use
** this file except in compliance with the License. You may obtain a copy
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
**
** http://oss.sgi.com/projects/FreeB
**
** Note that, as provided in the License, the Software is distributed on an
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
**
** Original Code. The Original Code is: OpenGL Sample Implementation,
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
** Copyright in any portions created by third parties is as indicated
** elsewhere herein. All Rights Reserved.
**
** Additional Notice Provisions: The application programming interfaces
** established by SGI in conjunction with the Original Code are The
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
** Window System(R) (Version 1.3), released October 19, 1998. This software
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
** published by SGI, but has not been independently verified as being
** compliant with the OpenGL(R) version 1.2.1 Specification.
**
*/

#include "gluos.h"
#include "gluint.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/gl.h>
#include <GL/glu.h>

#ifndef GLU_ERROR
#define GLU_ERROR                          100103
#endif

/* Make it not a power of two to avoid cache thrashing on the chip */
#define CACHE_SIZE	240

#undef	PI
#define PI	      3.14159265358979323846

struct GLUquadric {
    GLint	normals;
    GLboolean	textureCoords;
    GLint	orientation;
    GLint	drawStyle;
    void	(GLAPIENTRY *errorCallback)( GLint );
};

GLUquadric * GLAPIENTRY
gluNewQuadric(void)
{
    GLUquadric *newstate;

    newstate = (GLUquadric *) malloc(sizeof(GLUquadric));
    if (newstate == NULL) {
	/* Can't report an error at this point... */
	return NULL;
    }
    newstate->normals = GLU_SMOOTH;
    newstate->textureCoords = GL_FALSE;
    newstate->orientation = GLU_OUTSIDE;
    newstate->drawStyle = GLU_FILL;
    newstate->errorCallback = NULL;
    return newstate;
}


void GLAPIENTRY
gluDeleteQuadric(GLUquadric *state)
{
    free(state);
}

static void gluQuadricError(GLUquadric *qobj, GLenum which)
{
    if (qobj->errorCallback) {
	qobj->errorCallback(which);
    }
}

void GLAPIENTRY
gluQuadricCallback(GLUquadric *qobj, GLenum which, _GLUfuncptr fn)
{
    switch (which) {
      case GLU_ERROR:
	qobj->errorCallback = (void (GLAPIENTRY *)(GLint)) fn;
	break;
      default:
	gluQuadricError(qobj, GLU_INVALID_ENUM);
	return;
    }
}

void GLAPIENTRY
gluQuadricNormals(GLUquadric *qobj, GLenum normals)
{
    switch (normals) {
      case GLU_SMOOTH:
      case GLU_FLAT:
      case GLU_NONE:
	break;
      default:
	gluQuadricError(qobj, GLU_INVALID_ENUM);
	return;
    }
    qobj->normals = normals;
}

void GLAPIENTRY
gluQuadricTexture(GLUquadric *qobj, GLboolean textureCoords)
{
    qobj->textureCoords = textureCoords;
}

void GLAPIENTRY
gluQuadricOrientation(GLUquadric *qobj, GLenum orientation)
{
    switch(orientation) {
      case GLU_OUTSIDE:
      case GLU_INSIDE:
	break;
      default:
	gluQuadricError(qobj, GLU_INVALID_ENUM);
	return;
    }
    qobj->orientation = orientation;
}

void GLAPIENTRY
gluQuadricDrawStyle(GLUquadric *qobj, GLenum drawStyle)
{
    switch(drawStyle) {
      case GLU_POINT:
      case GLU_LINE:
      case GLU_FILL:
      case GLU_SILHOUETTE:
	break;
      default:
	gluQuadricError(qobj, GLU_INVALID_ENUM);
	return;
    }
    qobj->drawStyle = drawStyle;
}

void GLAPIENTRY
gluCylinder(GLUquadric *qobj, GLdouble baseRadius, GLdouble topRadius,
		GLdouble height, GLint slices, GLint stacks)
{
    GLint i,j;
    GLfloat sinCache[CACHE_SIZE];
    GLfloat cosCache[CACHE_SIZE];
    GLfloat sinCache2[CACHE_SIZE];
    GLfloat cosCache2[CACHE_SIZE];
    GLfloat sinCache3[CACHE_SIZE];
    GLfloat cosCache3[CACHE_SIZE];
    GLfloat angle;
    GLfloat zLow, zHigh;
    GLfloat sintemp, costemp;
    GLfloat length;
    GLfloat deltaRadius;
    GLfloat zNormal;
    GLfloat xyNormalRatio;
    GLfloat radiusLow, radiusHigh;
    int needCache2, needCache3;

    if (slices >= CACHE_SIZE) slices = CACHE_SIZE-1;

    if (slices < 2 || stacks < 1 || baseRadius < 0.0 || topRadius < 0.0 ||
	    height < 0.0) {
	gluQuadricError(qobj, GLU_INVALID_VALUE);
	return;
    }

    /* Compute length (needed for normal calculations) */
    deltaRadius = baseRadius - topRadius;
    length = SQRT(deltaRadius*deltaRadius + height*height);
    if (length == 0.0) {
	gluQuadricError(qobj, GLU_INVALID_VALUE);
	return;
    }

    /* Cache is the vertex locations cache */
    /* Cache2 is the various normals at the vertices themselves */
    /* Cache3 is the various normals for the faces */
    needCache2 = needCache3 = 0;
    if (qobj->normals == GLU_SMOOTH) {
	needCache2 = 1;
    }

    if (qobj->normals == GLU_FLAT) {
	if (qobj->drawStyle != GLU_POINT) {
	    needCache3 = 1;
	}
	if (qobj->drawStyle == GLU_LINE) {
	    needCache2 = 1;
	}
    }

    zNormal = deltaRadius / length;
    xyNormalRatio = height / length;

    for (i = 0; i < slices; i++) {
	angle = 2 * PI * i / slices;
	if (needCache2) {
	    if (qobj->orientation == GLU_OUTSIDE) {
		sinCache2[i] = xyNormalRatio * SIN(angle);
		cosCache2[i] = xyNormalRatio * COS(angle);
	    } else {
		sinCache2[i] = -xyNormalRatio * SIN(angle);
		cosCache2[i] = -xyNormalRatio * COS(angle);
	    }
	}
	sinCache[i] = SIN(angle);
	cosCache[i] = COS(angle);
    }

    if (needCache3) {
	for (i = 0; i < slices; i++) {
	    angle = 2 * PI * (i-0.5) / slices;
	    if (qobj->orientation == GLU_OUTSIDE) {
		sinCache3[i] = xyNormalRatio * SIN(angle);
		cosCache3[i] = xyNormalRatio * COS(angle);
	    } else {
		sinCache3[i] = -xyNormalRatio * SIN(angle);
		cosCache3[i] = -xyNormalRatio * COS(angle);
	    }
	}
    }

    sinCache[slices] = sinCache[0];
    cosCache[slices] = cosCache[0];
    if (needCache2) {
	sinCache2[slices] = sinCache2[0];
	cosCache2[slices] = cosCache2[0];
    }
    if (needCache3) {
	sinCache3[slices] = sinCache3[0];
	cosCache3[slices] = cosCache3[0];
    }

    switch (qobj->drawStyle) {
      case GLU_FILL:
	/* Note:
	** An argument could be made for using a TRIANGLE_FAN for the end
	** of the cylinder of either radii is 0.0 (a cone).  However, a
	** TRIANGLE_FAN would not work in smooth shading mode (the common
	** case) because the normal for the apex is different for every
	** triangle (and TRIANGLE_FAN doesn't let me respecify that normal).
	** Now, my choice is GL_TRIANGLES, or leave the GL_QUAD_STRIP and
	** just let the GL trivially reject one of the two triangles of the
	** QUAD.  GL_QUAD_STRIP is probably faster, so I will leave this code
	** alone.
	*/
	for (j = 0; j < stacks; j++) {
	    zLow = j * height / stacks;
	    zHigh = (j + 1) * height / stacks;
	    radiusLow = baseRadius - deltaRadius * ((float) j / stacks);
	    radiusHigh = baseRadius - deltaRadius * ((float) (j + 1) / stacks);

	    glBegin(GL_QUAD_STRIP);
	    for (i = 0; i <= slices; i++) {
		switch(qobj->normals) {
		  case GLU_FLAT:
		    glNormal3f(sinCache3[i], cosCache3[i], zNormal);
		    break;
		  case GLU_SMOOTH:
		    glNormal3f(sinCache2[i], cosCache2[i], zNormal);
		    break;
		  case GLU_NONE:
		  default:
		    break;
		}
		if (qobj->orientation == GLU_OUTSIDE) {
		    if (qobj->textureCoords) {
			glTexCoord2f(1 - (float) i / slices,
				(float) j / stacks);
		    }
		    glVertex3f(radiusLow * sinCache[i],
			    radiusLow * cosCache[i], zLow);
		    if (qobj->textureCoords) {
			glTexCoord2f(1 - (float) i / slices,
				(float) (j+1) / stacks);
		    }
		    glVertex3f(radiusHigh * sinCache[i],
			    radiusHigh * cosCache[i], zHigh);
		} else {
		    if (qobj->textureCoords) {
			glTexCoord2f(1 - (float) i / slices,
				(float) (j+1) / stacks);
		    }
		    glVertex3f(radiusHigh * sinCache[i],
			    radiusHigh * cosCache[i], zHigh);
		    if (qobj->textureCoords) {
			glTexCoord2f(1 - (float) i / slices,
				(float) j / stacks);
		    }
		    glVertex3f(radiusLow * sinCache[i],
			    radiusLow * cosCache[i], zLow);
		}
	    }
	    glEnd();
	}
	break;
      case GLU_POINT:
	glBegin(GL_POINTS);
	for (i = 0; i < slices; i++) {
	    switch(qobj->normals) {
	      case GLU_FLAT:
	      case GLU_SMOOTH:
		glNormal3f(sinCache2[i], cosCache2[i], zNormal);
		break;
	      case GLU_NONE:
	      default:
		break;
	    }
	    sintemp = sinCache[i];
	    costemp = cosCache[i];
	    for (j = 0; j <= stacks; j++) {
		zLow = j * height / stacks;
		radiusLow = baseRadius - deltaRadius * ((float) j / stacks);

		if (qobj->textureCoords) {
		    glTexCoord2f(1 - (float) i / slices,
			    (float) j / stacks);
		}
		glVertex3f(radiusLow * sintemp,
			radiusLow * costemp, zLow);
	    }
	}
	glEnd();
	break;
      case GLU_LINE:
	for (j = 1; j < stacks; j++) {
	    zLow = j * height / stacks;
	    radiusLow = baseRadius - deltaRadius * ((float) j / stacks);

	    glBegin(GL_LINE_STRIP);
	    for (i = 0; i <= slices; i++) {
		switch(qobj->normals) {
		  case GLU_FLAT:
		    glNormal3f(sinCache3[i], cosCache3[i], zNormal);
		    break;
		  case GLU_SMOOTH:
		    glNormal3f(sinCache2[i], cosCache2[i], zNormal);
		    break;
		  case GLU_NONE:
		  default:
		    break;
		}
		if (qobj->textureCoords) {
		    glTexCoord2f(1 - (float) i / slices,
			    (float) j / stacks);
		}
		glVertex3f(radiusLow * sinCache[i],
			radiusLow * cosCache[i], zLow);
	    }
	    glEnd();
	}
	/* Intentionally fall through here... */
      case GLU_SILHOUETTE:
	for (j = 0; j <= stacks; j += stacks) {
	    zLow = j * height / stacks;
	    radiusLow = baseRadius - deltaRadius * ((float) j / stacks);

	    glBegin(GL_LINE_STRIP);
	    for (i = 0; i <= slices; i++) {
		switch(qobj->normals) {
		  case GLU_FLAT:
		    glNormal3f(sinCache3[i], cosCache3[i], zNormal);
		    break;
		  case GLU_SMOOTH:
		    glNormal3f(sinCache2[i], cosCache2[i], zNormal);
		    break;
		  case GLU_NONE:
		  default:
		    break;