/*
glm.c
Nate Robins, 1997, 2000
nate@pobox.com, http://www.pobox.com/~nate
Wavefront OBJ model file format reader/writer/manipulator.
Includes routines for generating smooth normals with
preservation of edges, welding redundant vertices & texture
coordinate generation (spheremap and planar projections) + more.
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "glm.h"
#define T(x) (model->triangles[(x)])
/* _GLMnode: general purpose node */
typedef struct _GLMnode {
GLuint index;
GLboolean averaged;
struct _GLMnode* next;
} GLMnode;
/* glmMax: returns the maximum of two floats */
static GLfloat
glmMax(GLfloat a, GLfloat b)
{
if (b > a)
return b;
return a;
}
/* glmAbs: returns the absolute value of a float */
static GLfloat
glmAbs(GLfloat f)
{
if (f < 0)
return -f;
return f;
}
/* glmDot: compute the dot product of two vectors
*
* u - array of 3 GLfloats (GLfloat u[3])
* v - array of 3 GLfloats (GLfloat v[3])
*/
static GLfloat
glmDot(GLfloat* u, GLfloat* v)
{
assert(u); assert(v);
return u[0]*v[0] + u[1]*v[1] + u[2]*v[2];
}
/* glmCross: compute the cross product of two vectors
*
* u - array of 3 GLfloats (GLfloat u[3])
* v - array of 3 GLfloats (GLfloat v[3])
* n - array of 3 GLfloats (GLfloat n[3]) to return the cross product in
*/
static GLvoid
glmCross(GLfloat* u, GLfloat* v, GLfloat* n)
{
assert(u); assert(v); assert(n);
n[0] = u[1]*v[2] - u[2]*v[1];
n[1] = u[2]*v[0] - u[0]*v[2];
n[2] = u[0]*v[1] - u[1]*v[0];
}
/* glmNormalize: normalize a vector
*
* v - array of 3 GLfloats (GLfloat v[3]) to be normalized
*/
static GLvoid
glmNormalize(GLfloat* v)
{
GLfloat l;
assert(v);
l = (GLfloat)sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
v[0] /= l;
v[1] /= l;
v[2] /= l;
}
/* glmEqual: compares two vectors and returns GL_TRUE if they are
* equal (within a certain threshold) or GL_FALSE if not. An epsilon
* that works fairly well is 0.000001.
*
* u - array of 3 GLfloats (GLfloat u[3])
* v - array of 3 GLfloats (GLfloat v[3])
*/
static GLboolean
glmEqual(GLfloat* u, GLfloat* v, GLfloat epsilon)
{
if (glmAbs(u[0] - v[0]) < epsilon &&
glmAbs(u[1] - v[1]) < epsilon &&
glmAbs(u[2] - v[2]) < epsilon)
{
return GL_TRUE;
}
return GL_FALSE;
}
/* glmWeldVectors: eliminate (weld) vectors that are within an
* epsilon of each other.
*
* vectors - array of GLfloat[3]'s to be welded
* numvectors - number of GLfloat[3]'s in vectors
* epsilon - maximum difference between vectors
*
*/
GLfloat*
glmWeldVectors(GLfloat* vectors, GLuint* numvectors, GLfloat epsilon)
{
GLfloat* copies;
GLuint copied;
GLuint i, j;
copies = (GLfloat*)malloc(sizeof(GLfloat) * 3 * (*numvectors + 1));
memcpy(copies, vectors, (sizeof(GLfloat) * 3 * (*numvectors + 1)));
copied = 1;
for (i = 1; i <= *numvectors; i++) {
for (j = 1; j <= copied; j++) {
if (glmEqual(&vectors[3 * i], &copies[3 * j], epsilon)) {
goto duplicate;
}
}
/* must not be any duplicates -- add to the copies array */
copies[3 * copied + 0] = vectors[3 * i + 0];
copies[3 * copied + 1] = vectors[3 * i + 1];
copies[3 * copied + 2] = vectors[3 * i + 2];
j = copied; /* pass this along for below */
copied++;
duplicate:
/* set the first component of this vector to point at the correct
index into the new copies array */
vectors[3 * i + 0] = (GLfloat)j;
}
*numvectors = copied-1;
return copies;
}
/* glmFindGroup: Find a group in the model */
GLMgroup*
glmFindGroup(GLMmodel* model, char* name)
{
GLMgroup* group;
assert(model);
group = model->groups;
while(group) {
if (!strcmp(name, group->name))
break;
group = group->next;
}
return group;
}
/* glmAddGroup: Add a group to the model */
GLMgroup*
glmAddGroup(GLMmodel* model, char* name)
{
GLMgroup* group;
group = glmFindGroup(model, name);
if (!group) {
group = (GLMgroup*)malloc(sizeof(GLMgroup));
group->name = strdup(name);
group->material = 0;
group->numtriangles = 0;
group->triangles = NULL;
group->next = model->groups;
model->groups = group;
model->numgroups++;
}
return group;
}
/* glmFindGroup: Find a material in the model */
GLuint
glmFindMaterial(GLMmodel* model, char* name)
{
GLuint i;
/* XXX doing a linear search on a string key'd list is pretty lame,
but it works and is fast enough for now. */
for (i = 0; i < model->nummaterials; i++) {
if (!strcmp(model->materials[i].name, name))
goto found;
}
/* didn't find the name, so print a warning and return the default
material (0). */
printf("glmFindMaterial(): can't find material \"%s\".\n", name);
i = 0;
found:
return i;
}
/* glmDirName: return the directory given a path
*
* path - filesystem path
*
* NOTE: the return value should be free'd.
*/
static char*
glmDirName(char* path)
{
char* dir;
char* s;
dir = strdup(path);
s = strrchr(dir, '/');
if (s)
s[1] = '\0';
else
dir[0] = '\0';
return dir;
}
/* glmReadMTL: read a wavefront material library file
*
* model - properly initialized GLMmodel structure
* name - name of the material library
*/
static GLvoid
glmReadMTL(GLMmodel* model, char* name)
{
FILE* file;
char* dir;
char* filename;
char buf[128];
GLuint nummaterials, i;
dir = glmDirName(model->pathname);
filename = (char*)malloc(sizeof(char) * (strlen(dir) + strlen(name) + 1));
strcpy(filename, dir);
strcat(filename, name);
free(dir);
file = fopen(filename, "r");
if (!file) {
fprintf(stderr, "glmReadMTL() failed: can't open material file \"%s\".\n",
filename);
exit(1);
}
free(filename);
/* count the number of materials in the file */
nummaterials = 1;
while(fscanf(file, "%s", buf) != EOF) {
switch(buf[0]) {
case '#': /* comment */
/* eat up rest of line */
fgets(buf, sizeof(buf), file);
break;
case 'n': /* newmtl */
fgets(buf, sizeof(buf), file);
nummaterials++;
sscanf(buf, "%s %s", buf, buf);
break;
default:
/* eat up rest of line */
fgets(buf, sizeof(buf), file);
break;
}
}
rewind(file);
model->materials = (GLMmaterial*)malloc(sizeof(GLMmaterial) * nummaterials);
model->nummaterials = nummaterials;
/* set the default material */
for (i = 0; i < nummaterials; i++) {
model->materials[i].name = NULL;
model->materials[i].shininess = 65.0;
model->materials[i].diffuse[0] = 0.8;
model->materials[i].diffuse[1] = 0.8;
model->materials[i].diffuse[2] = 0.8;
model->materials[i].diffuse[3] = 1.0;
model->materials[i].ambient[0] = 0.2;
model->materials[i].ambient[1] = 0.2;
model->materials[i].ambient[2] = 0.2;
model->materials[i].ambient[3] = 1.0;
model->materials[i].specular[0] = 0.0;
model->materials[i].specular[1] = 0.0;
model->materials[i].specular[2] = 0.0;
model->materials[i].specular[3] = 1.0;
}
model->materials[0].name = strdup("default");
/* now, read in the data */
nummaterials = 0;
while(fscanf(file, "%s", buf) != EOF) {
switch(buf[0]) {
case '#': /* comment */
/* eat up rest of line */
fge
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SigGraph.rar_openGL物体移动_opengl 汽车_opengl汽车_siggraph_汽车opengl
共51个文件
dsp:9个
c:8个
exe:7个
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基于opengl图像编程关于改变坐标模拟汽车等物体移动
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SigGraph.rar (51个子文件)
SigGraph
SigGraph TUTORS
shapes.c 56KB
texture.exe 68KB
glm.h 10KB
texture.opt 48KB
shapes.exe 52KB
texture.plg 2KB
all.dsp 2KB
projection.c 24KB
glut32.dll 204KB
data
porsche.mtl 536B
dolphins.mtl 342B
porsche.obj 488KB
fishermen.ppm 48KB
soccerball.obj 195KB
soccerball.mtl 136B
f-16.mtl 536B
flowers.obj 673KB
opengl.ppm 192KB
checker.ppm 48KB
f-16.obj 278KB
dolphins.obj 49KB
flowers.mtl 401B
al.obj 182KB
rose+vase.obj 245KB
marble.ppm 48KB
rose+vase.mtl 971B
al.mtl 2KB
train.ppm 192KB
transformation.exe 68KB
lightposition.dsp 4KB
glm.c 64KB
Tutors.dsw 3KB
shapes.dsp 4KB
lightmaterial.dsp 4KB
projection.exe 68KB
lightposition.exe 68KB
lightmaterial.c 41KB
lightposition.c 20KB
fog.dsp 4KB
texture.c 35KB
projection.dsp 4KB
fog.c 13KB
texture.dsp 4KB
lightmaterial.exe 76KB
texture.dsw 537B
transformation.c 19KB
glm.dsp 3KB
materials.h 3KB
fog.exe 64KB
transformation.dsp 4KB
texture.ncb 41KB
共 51 条
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