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Fix for #29 Normal Generation by Smoothing Group Id

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This commit is contained in:
gopalss
2018-01-29 18:37:39 -05:00
parent 12bf4165be
commit 15f47e2e35
3 changed files with 247 additions and 4 deletions
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2
examples/viewer/trackball.cc
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@@ -1,3 +1,5 @@
#include "stdafx.h" // Required to be included in a Visual Studio Win32 application
/*
* (c) Copyright 1993, 1994, Silicon Graphics, Inc.
* ALL RIGHTS RESERVED

209
examples/viewer/viewer.cc
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@@ -1,3 +1,4 @@
#include "stdafx.h" // Required to be included in a Visual Studio Win32 application
//
// Simple .obj viewer(vertex only)
//
@@ -151,7 +152,8 @@ static std::string GetBaseDir(const std::string& filepath) {
static bool FileExists(const std::string& abs_filename) {
bool ret;
FILE* fp = fopen(abs_filename.c_str(), "rb");
FILE* fp;
fopen_s(&fp, abs_filename.c_str(), "rb");
if (fp) {
ret = true;
fclose(fp);
@@ -191,9 +193,90 @@ static void CalcNormal(float N[3], float v0[3], float v1[3], float v2[3]) {
N[0] /= len;
N[1] /= len;
N[2] /= len;
}
}
namespace // Local utility functions
{
void addBtoA(float a[3], float b[3])
{
for (size_t i = 0; i < 3; ++i)
a[i] += b[i];
}
void assignBtoA(float a[3], float b[3])
{
for (size_t i = 0; i < 3; ++i)
a[i] = b[i];
}
void normalizeVector(float N[3])
{
float len2 = N[0] * N[0] + N[1] * N[1] + N[2] * N[2];
if (len2 > 0.0f) {
float len = sqrtf(len2);
N[0] /= len;
N[1] /= len;
N[2] /= len;
}
}
void computeSmoothingNormals(tinyobj::attrib_t &attrib, tinyobj::shape_t &shape,
std::map<int, float[3]>& smoothVertexNormals)
{
smoothVertexNormals.clear();
std::map<int, float[3]>::iterator iter;
for (size_t f = 0; f < shape.mesh.indices.size() / 3; f++) {
// Get the three indexes of the face (all faces are triangular)
tinyobj::index_t idx0 = shape.mesh.indices[3 * f + 0];
tinyobj::index_t idx1 = shape.mesh.indices[3 * f + 1];
tinyobj::index_t idx2 = shape.mesh.indices[3 * f + 2];
// Get the three vertex indexes and coordinates
int vi[3]; // indexes
float v[3][3]; // coordinates
for (int k = 0; k < 3; k++) {
vi[0] = idx0.vertex_index;
vi[1] = idx1.vertex_index;
vi[2] = idx2.vertex_index;
assert(vi[0] >= 0);
assert(vi[1] >= 0);
assert(vi[2] >= 0);
v[0][k] = attrib.vertices[3 * vi[0] + k];
v[1][k] = attrib.vertices[3 * vi[1] + k];
v[2][k] = attrib.vertices[3 * vi[2] + k];
}
// Compute the normal of the face
float normal[3];
CalcNormal(normal, v[0], v[1], v[2]);
// Add the normal to the three vertexes
for (size_t i = 0; i < 3; ++i)
{
iter = smoothVertexNormals.find(vi[i]);
if (iter != smoothVertexNormals.end())
addBtoA(iter->second, normal);
else
assignBtoA(smoothVertexNormals[vi[i]], normal);
}
} // f
// Normalize the normals, that is, make them unit vectors
for (iter = smoothVertexNormals.begin(); iter != smoothVertexNormals.end(); iter++)
{
normalizeVector(iter->second);
}
} // computeSmoothingNormals
} // namespace
static bool LoadObjAndConvert(float bmin[3], float bmax[3],
std::vector<DrawObject>* drawObjects,
std::vector<tinyobj::material_t>& materials,
@@ -307,6 +390,12 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
for (size_t s = 0; s < shapes.size(); s++) {
DrawObject o;
std::vector<float> buffer; // pos(3float), normal(3float), color(3float)
// Check for smoothing group and compute smoothing normals
std::map<int, float[3]> smoothVertexNormals;
if (shapes[s].smoothingGroupId > 0)
computeSmoothingNormals(attrib, shapes[s], smoothVertexNormals);
for (size_t f = 0; f < shapes[s].mesh.indices.size() / 3; f++) {
tinyobj::index_t idx0 = shapes[s].mesh.indices[3 * f + 0];
tinyobj::index_t idx1 = shapes[s].mesh.indices[3 * f + 1];
@@ -411,6 +500,20 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
invalid_normal_index = true;
}
if (invalid_normal_index && !smoothVertexNormals.empty()) {
// Use smoothing normals
int f0 = idx0.vertex_index;
int f1 = idx1.vertex_index;
int f2 = idx2.vertex_index;
if (f0 >= 0 && f1 >= 0 && f2 >= 0) {
assignBtoA(n[0], smoothVertexNormals[f0]);
assignBtoA(n[1], smoothVertexNormals[f1]);
assignBtoA(n[2], smoothVertexNormals[f2]);
invalid_normal_index = false;
}
}
if (invalid_normal_index) {
// compute geometric normal
CalcNormal(n[0], v[0], v[1], v[2]);
@@ -625,6 +728,10 @@ static void Draw(const std::vector<DrawObject>& drawObjects,
glBindTexture(GL_TEXTURE_2D, 0);
}
static bool bDrawWireFrame = false;
if (!bDrawWireFrame)
return;
// draw wireframe
glDisable(GL_POLYGON_OFFSET_FILL);
glPolygonMode(GL_FRONT, GL_LINE);
@@ -668,6 +775,13 @@ static void Init() {
up[2] = 0.0f;
}
// Gopal: I am commenting out the original main function.
// Then, I make a copy and split in to two fuctions -
// tinyObjectViewerMainCreateWindow and tinyObjectViewerMainLoop.
// I need to separate these two functions in my windows project.
// Ths first one is used to create the OpenGL window and link it to my
// main application window. After that the second function is called.
/*
int main(int argc, char** argv) {
if (argc < 2) {
std::cout << "Needs input.obj\n" << std::endl;
@@ -752,3 +866,96 @@ int main(int argc, char** argv) {
glfwTerminate();
}
*/
// The parameters bmin, bmax, materials and textures are shared between the two funations.
// They are also declared as static to retain the values.
static float bmin[3], bmax[3];
static std::vector<tinyobj::material_t> materials;
static std::map<std::string, GLuint> textures;
int tinyObjectViewerMainCreateWindow(int argc, char** argv) {
if (argc < 2) {
std::cout << "Needs input.obj\n" << std::endl;
return 0;
}
Init();
if (!glfwInit()) {
std::cerr << "Failed to initialize GLFW." << std::endl;
return -1;
}
window = glfwCreateWindow(width, height, "Obj viewer", NULL, NULL);
if (window == NULL) {
std::cerr << "Failed to open GLFW window. " << std::endl;
glfwTerminate();
return 1;
}
glfwMakeContextCurrent(window);
glfwSwapInterval(1);
// Callback
glfwSetWindowSizeCallback(window, reshapeFunc);
glfwSetKeyCallback(window, keyboardFunc);
glfwSetMouseButtonCallback(window, clickFunc);
glfwSetCursorPosCallback(window, motionFunc);
glewExperimental = true;
if (glewInit() != GLEW_OK) {
std::cerr << "Failed to initialize GLEW." << std::endl;
return -1;
}
reshapeFunc(window, width, height);
if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, materials, textures, argv[1])) {
return -1;
}
return 0;
}
void tinyObjectViewerMainLoop()
{
float maxExtent = 0.5f * (bmax[0] - bmin[0]);
if (maxExtent < 0.5f * (bmax[1] - bmin[1])) {
maxExtent = 0.5f * (bmax[1] - bmin[1]);
}
if (maxExtent < 0.5f * (bmax[2] - bmin[2])) {
maxExtent = 0.5f * (bmax[2] - bmin[2]);
}
while (glfwWindowShouldClose(window) == GL_FALSE) {
glfwPollEvents();
glClearColor(0.1f, 0.2f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glEnable(GL_TEXTURE_2D);
// camera & rotate
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
GLfloat mat[4][4];
gluLookAt(eye[0], eye[1], eye[2], lookat[0], lookat[1], lookat[2], up[0],
up[1], up[2]);
build_rotmatrix(mat, curr_quat);
glMultMatrixf(&mat[0][0]);
// Fit to -1, 1
glScalef(1.0f / maxExtent, 1.0f / maxExtent, 1.0f / maxExtent);
// Centerize object.
glTranslatef(-0.5 * (bmax[0] + bmin[0]), -0.5 * (bmax[1] + bmin[1]),
-0.5 * (bmax[2] + bmin[2]));
Draw(gDrawObjects, materials, textures);
glfwSwapBuffers(window);
}
glfwTerminate();
}

34
tiny_obj_loader.h
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@@ -229,6 +229,7 @@ typedef struct {
} mesh_t;
typedef struct {
int smoothingGroupId; // Smoothing group id.
std::string name;
mesh_t mesh;
} shape_t;
@@ -1684,7 +1685,11 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
std::map<std::string, int> material_map;
int material = -1;
// smoothing group id
int currentSmoothingId = 0; // Initial value. 0 means no smoothing.
shape_t shape;
shape.smoothingGroupId = currentSmoothingId;
std::string linebuf;
while (inStream->peek() != -1) {
@@ -1864,6 +1869,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
}
shape = shape_t();
shape.smoothingGroupId = currentSmoothingId;
// material = -1;
faceGroup.clear();
@@ -1901,6 +1907,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
// material = -1;
faceGroup.clear();
shape = shape_t();
shape.smoothingGroupId = currentSmoothingId;
// @todo { multiple object name? }
token += 2;
@@ -1939,6 +1946,33 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
tags.push_back(tag);
}
if (token[0] == 's' && IS_SPACE(token[1])) {
// smoothing group id
token += 2;
int smGroupId = parseInt(&token);
if (smGroupId == currentSmoothingId)
continue; // No change in smoothing group.
// Encountering new smoothing group Id.
// Export the current face group
if (!faceGroup.empty()) {
bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
triangulate, v);
if (ret) {
shapes->push_back(shape);
}
}
// Clear the face group and initialize the shape with new smoothing group id
// and keep the existing name and materials of the shape.
faceGroup.clear();
shape.mesh.indices.clear();
shape.mesh.num_face_vertices.clear();
shape.smoothingGroupId = smGroupId;
currentSmoothingId = smGroupId;
} // smoothing group id
// Ignore unknown command.
}