Texture mapping with phong lighting - c++

Question

Im trying to add Phong lighting to my scene in which I have loaded mesh with textures. This is my mesh loadin class:
#define INVALID_OGL_VALUE 0xFFFFFFFF
#define INVALID_MATERIAL 0xFFFFFFFF
#define SAFE_DELETE(p) if (p) { delete p; p = NULL; }
Mesh::MeshEntry::MeshEntry()
{
VB = INVALID_OGL_VALUE;
IB = INVALID_OGL_VALUE;
NumIndices = 0;
MaterialIndex = INVALID_MATERIAL;
};
Mesh::MeshEntry::~MeshEntry()
{
if (VB != INVALID_OGL_VALUE)
{
glDeleteBuffers(1, &VB);
}
if (IB != INVALID_OGL_VALUE)
{
glDeleteBuffers(1, &IB);
}
}
void Mesh::MeshEntry::Init(const std::vector<Vertex>& Vertices,
const std::vector<unsigned int>& Indices)
{
NumIndices = Indices.size();
glGenBuffers(1, &VB);
glBindBuffer(GL_ARRAY_BUFFER, VB);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * Vertices.size(), &Vertices[0], GL_STATIC_DRAW);
glGenBuffers(1, &IB);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IB);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(unsigned int) * NumIndices, &Indices[0], GL_STATIC_DRAW);
}
Mesh::Mesh()
{
}
Mesh::~Mesh()
{
Clear();
}
void Mesh::Clear()
{
for (unsigned int i = 0 ; i < textures_cnt.size() ; i++) {
SAFE_DELETE(textures_cnt[i]);
}
}
/*Loads mesh
*#Filename - name of the .obj file
**********************************************************/
bool Mesh::LoadMesh(const std::string& Filename){
Assimp::Importer Importer;
bool rc = false;
//clear previous loaded mesh
Clear();
//read file content
const aiScene* oScene = Importer.ReadFile(Filename.c_str(), aiProcess_Triangulate | aiProcess_GenSmoothNormals | aiProcess_FlipUVs );
if(oScene){
printf (" %i animations\n", oScene->mNumAnimations);
printf (" %i cameras\n", oScene->mNumCameras);
printf (" %i lights\n", oScene->mNumLights);
printf (" %i materials\n", oScene->mNumMaterials);
printf (" %i meshes\n", oScene->mNumMeshes);
printf (" %i textures\n", oScene->mNumTextures);
submeshes_cnt.resize(oScene->mNumMeshes);
textures_cnt.resize(oScene->mNumMaterials);
/*.........Initialize the meshes in the scene one by one...........*/
for (unsigned int i = 0 ; i < submeshes_cnt.size() ; i++) {
const aiMesh* paiMesh = oScene->mMeshes[i];
InitMesh(i, paiMesh);
}
// Extract the directory part from the file name
std::string::size_type SlashIndex = Filename.find_last_of("/");
std::string Dir;
if (SlashIndex == std::string::npos) {
Dir = ".";
}
else if (SlashIndex == 0) {
Dir = "/";
}
else {
Dir = Filename.substr(0, SlashIndex);
}
/*.................Initialization of meshes end....................*/
/*.............Initialize the materials.............................*/
for(unsigned int i = 0 ; i < oScene->mNumMaterials ; i++) {
const aiMaterial* pMaterial = oScene->mMaterials[i];
textures_cnt[i] = NULL;
if (pMaterial->GetTextureCount(aiTextureType_DIFFUSE) > 0) {
aiString Path;
if (pMaterial->GetTexture(aiTextureType_DIFFUSE, 0, &Path, NULL, NULL, NULL, NULL, NULL) == AI_SUCCESS) {
std::string FullPath = Dir + "/" + Path.data;
textures_cnt[i] = new Texture(GL_TEXTURE_2D, FullPath.c_str());
if (!textures_cnt[i]->Load()) {
printf("Error loading texture '%s'\n", FullPath.c_str());
delete textures_cnt[i];
textures_cnt[i] = NULL;
rc = false;
}
else {
printf("Loaded texture '%s'\n", FullPath.c_str());
}
}
}
}
/*.................Initialization of materials end....................*/
}
else {
printf("Error parsing '%s': '%s'\n", Filename.c_str(), Importer.GetErrorString());
}
return rc;
}
void Mesh::InitMesh(unsigned int Index, const aiMesh* paiMesh)
{
submeshes_cnt[Index].MaterialIndex = paiMesh->mMaterialIndex;
std::vector<Vertex> Vertices;
std::vector<unsigned int> Indices;
const aiVector3D Zero3D(0.0f, 0.0f, 0.0f);
for (unsigned int i = 0 ; i < paiMesh->mNumVertices ; i++) {
const aiVector3D* pPos = &(paiMesh->mVertices[i]);
const aiVector3D* pNormal = &(paiMesh->mNormals[i]);
const aiVector3D* pTexCoord = paiMesh->HasTextureCoords(0) ? &(paiMesh->mTextureCoords[0][i]) : &Zero3D;
Vertex v(Vector3f(pPos->x, pPos->y, pPos->z),
Vector2f(pTexCoord->x, pTexCoord->y),
Vector3f(pNormal->x, pNormal->y, pNormal->z));
Vertices.push_back(v);
}
for (unsigned int i = 0 ; i < paiMesh->mNumFaces ; i++) {
const aiFace& Face = paiMesh->mFaces[i];
assert(Face.mNumIndices == 3);
Indices.push_back(Face.mIndices[0]);
Indices.push_back(Face.mIndices[1]);
Indices.push_back(Face.mIndices[2]);
}
submeshes_cnt[Index].Init(Vertices, Indices);
}
void Mesh::Render(){
//enable VAOs for vertices, normals, textures
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
for(unsigned int i = 0 ; i < submeshes_cnt.size() ; i++){
glBindBuffer(GL_ARRAY_BUFFER, submeshes_cnt[i].VB);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*)12);
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*)20);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, submeshes_cnt[i].IB);
const unsigned int MaterialIndex = submeshes_cnt[i].MaterialIndex;
if (MaterialIndex < textures_cnt.size() && textures_cnt[MaterialIndex]) {
textures_cnt[MaterialIndex]->Bind(GL_TEXTURE0);
}
glDrawElements(GL_TRIANGLES, submeshes_cnt[i].NumIndices, GL_UNSIGNED_INT, 0);
}
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glDisableVertexAttribArray(2);
}
vertex shader:
#version 420
uniform mat4 camera;
uniform mat4 model;
in vec3 vert;
in vec2 vertTexCoord;
out vec2 fragTexCoord;
void main() {
// Pass the tex coord straight through to the fragment shader
fragTexCoord = vertTexCoord;
// Apply all matrix transformations to vert
gl_Position = camera * model * vec4(vert, 1);
}
fragment shader:
#version 420
uniform sampler2D tex;
in vec2 fragTexCoord;
out vec4 finalColor;
void main() {
//note: the texture function was called texture2D in older versions of GLSL
finalColor = texture(tex, fragTexCoord);
}
this is what i get:
before
but when i try to add phong lighting, when I add in attribute for normals to my vertex shader this is what I get:
after
Where is the problem?
Thank you for help.
//edit
shader loading and link
shprogram::shprogram(const std::vector<shader>& shaders) :
_object(0)
{
if(shaders.size() <= 0)
throw std::runtime_error("No shaders were provided to create the program");
//create the program object
_object = glCreateProgram();
if(_object == 0)
throw std::runtime_error("glCreateProgram failed");
//attach all the shaders
for(unsigned i = 0; i < shaders.size(); ++i)
glAttachShader(_object, shaders[i].getObject());
//link the shaders together
glLinkProgram(_object);
//detach all the shaders
for(unsigned i = 0; i < shaders.size(); ++i)
glDetachShader(_object, shaders[i].getObject());
//throw exception if linking failed
GLint status;
glGetProgramiv(_object, GL_LINK_STATUS, &status);
if (status == GL_FALSE) {
std::string msg("Program linking failure: ");
GLint infoLogLength;
glGetProgramiv(_object, GL_INFO_LOG_LENGTH, &infoLogLength);
char* strInfoLog = new char[infoLogLength + 1];
glGetProgramInfoLog(_object, infoLogLength, NULL, strInfoLog);
msg += strInfoLog;
delete[] strInfoLog;
glDeleteProgram(_object); _object = 0;
throw std::runtime_error(msg);
}
}
shprogram::~shprogram() {
//might be 0 if ctor fails by throwing exception
if(_object != 0) glDeleteProgram(_object);
}
GLuint shprogram::object() const {
return _object;
}
void shprogram::use() const {
glUseProgram(_object);
}
bool shprogram::isInUse() const {
GLint currentProgram = 0;
glGetIntegerv(GL_CURRENT_PROGRAM, &currentProgram);
return (currentProgram == (GLint)_object);
}
void shprogram::stopUsing() const {
assert(isInUse());
glUseProgram(0);
}
GLint shprogram::attrib(const GLchar* attribName) const {
if(!attribName)
throw std::runtime_error("attribName was NULL");
GLint attrib = glGetAttribLocation(_object, attribName);
if(attrib == -1)
throw std::runtime_error(std::string("Program attribute not found: ") + attribName);
return attrib;
}
GLint shprogram::uniform(const GLchar* uniformName) const {
if(!uniformName)
throw std::runtime_error("uniformName was NULL");
GLint uniform = glGetUniformLocation(_object, uniformName);
if(uniform == -1)
throw std::runtime_error(std::string("Program uniform not found: ") + uniformName);
return uniform;
}
void shprogram::setUniformMatrix2(const GLchar* name, const GLfloat* v, GLsizei count, GLboolean transpose) {
assert(isInUse());
glUniformMatrix2fv(uniform(name), count, transpose, v);
}
void shprogram::setUniformMatrix3(const GLchar* name, const GLfloat* v, GLsizei count, GLboolean transpose) {
assert(isInUse());
glUniformMatrix3fv(uniform(name), count, transpose, v);
}
void shprogram::setUniformMatrix4(const GLchar* name, const GLfloat* v, GLsizei count, GLboolean transpose) {
assert(isInUse());
glUniformMatrix4fv(uniform(name), count, transpose, v);
}
void shprogram::setUniform(const GLchar* name, const glm::mat2& m, GLboolean transpose) {
assert(isInUse());
glUniformMatrix2fv(uniform(name), 1, transpose, glm::value_ptr(m));
}
void shprogram::setUniform(const GLchar* name, const glm::mat3& m, GLboolean transpose) {
assert(isInUse());
glUniformMatrix3fv(uniform(name), 1, transpose, glm::value_ptr(m));
}
void shprogram::setUniform(const GLchar* name, const glm::mat4& m, GLboolean transpose) {
assert(isInUse());
glUniformMatrix4fv(uniform(name), 1, transpose, glm::value_ptr(m));
}
void shprogram::setUniform(const GLchar* uniformName, const glm::vec3& v) {
setUniform3v(uniformName, glm::value_ptr(v));
}
void shprogram::setUniform(const GLchar* uniformName, const glm::vec4& v) {
setUniform4v(uniformName, glm::value_ptr(v));
}
setting up uniforms
//bind shader program
gProgram->use();
//set the "camera" uniform
gProgram->setUniform("camera", gCamera.matrix());
//set the "model" uniform in the vertex shader, based on the gDegreesRotated global
gProgram->setUniform("model", glm::rotate(glm::mat4(), 150.0f ,glm::vec3(0,1,0)));
gProgram->setUniform("light.position", gLight.position);
gProgram->setUniform("light.intensities", gLight.intensities);

Answer 1

You neither explicitely set the attribute locations in the shader source, nor bind them before linking the shader, nor query them. The GL is free to use any valid attribute index for any active input attribute.
You just assume that 0 is position, 1 is texcoord and 2 is normal. It might work by accident for the position+texcoord case, but when you add the normal, the indices might get all mixed up. Either use layout(location=...) (see GL_ARB_explicit_attrib_location for details) in the GLSL code, or use glBindAttribLocation() to specify the mapping you want.