Strange issue with ASSIMP mesh load - opengl

Question

I have encountered an strange issue with ASSIMP mesh load.
Here is the thing, I have a complex model obj file to show a character, this model has 4 child Meshes, and in my code, I encapsulate the Mesh class to get the relevant data(vertices, indices, normals...), When I draw the 4 meshes together(in a for circle), I always get the wrong result:
But if I only load one mesh a time(hard code my assimp load class to do that), and only draw the one mesh, then I can draw the mesh correctly(but this issue only occured when I load the complex model obj file, not with the cube or plane, I can load multiple cube and plane obj files and draw them together):
Here is my ASSIMP load class code, I don't know where my issues are, please help me:
#include "AssetImport.h"
#include "Mesh.h"
#include "Model.h"
#include "ModelMgr.h"
#include "TextureMgr.h"
#include <string>
using namespace Assimp;
AssetImport::AssetImport()
{
}
AssetImport::~AssetImport()
{
}
int AssetImport::LoadModel(const char *path)
{
Importer import;
const aiScene *scene = import.ReadFile(path, aiProcess_Triangulate
| aiProcess_FlipUVs
| aiProcess_CalcTangentSpace
| aiProcess_GenNormals);
if (!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode)
{
return -1;
}
m_prePath = path;
auto index = m_prePath.lastIndexOf("/");
if (-1 != index) {
m_prePath = m_prePath.left(index + 1);
}
HandleChildNode(scene, scene->mRootNode);
return 0;
}
int AssetImport::HandleChildNode(const aiScene *scene, aiNode *node)
{
unsigned int numChild = node->mNumChildren;
for (unsigned int a = 0; a < 1; ++a)
{
**auto child = node->mChildren[3];// here is the hard code**
if (child->mNumChildren > 0) {
HandleChildNode(scene, child);
}
if (0) {
continue;
}
// create a new model for a child
Model *mod = ModelMgr::Instance().CreateNewModel();
mod->SetModelName(child->mName.C_Str());
auto numMeshes = child->mNumMeshes;
for (unsigned int i = 0; i < numMeshes; ++i)
{
// create new sub mesh, then you can add it to one model
Mesh *m = new Mesh;
auto mesh = scene->mMeshes[child->mMeshes[i]];
//handle the mesh's materials
auto mat = scene->mMaterials[mesh->mMaterialIndex];
HandleMeshMaterial(mat, m);
// add vertex info
for (unsigned int j = 0; j < mesh->mNumVertices; ++j)
{
auto vert = mesh->mVertices[j];
Mesh::VertInfo info;
info.pos = QVector3D(mesh->mVertices[j].x, mesh->mVertices[j].y, mesh->mVertices[j].z);
info.color = QVector4D(0.8f, 0.8f, 0.8f, 1);
info.normal = QVector3D(mesh->mNormals[j].x, mesh->mNormals[j].y, mesh->mNormals[j].z);
if (nullptr != mesh->mTangents)
{
info.tangent = QVector4D(mesh->mTangents[j].x, mesh->mTangents[j].y, mesh->mTangents[j].z, 0);
}
if (nullptr != mesh->mBitangents)
{
info.bitangent = QVector4D(mesh->mBitangents[j].x, mesh->mBitangents[j].y, mesh->mBitangents[j].z, 0);
}
if (nullptr != mesh->mTextureCoords[0])
{
info.uv1 = QVector2D(mesh->mTextureCoords[0][j].x, mesh->mTextureCoords[0][j].y);
}
m->AddVertInfo(info);
}
// add index info
for (unsigned int j = 0; j < mesh->mNumFaces; ++j)
{
auto face = mesh->mFaces[j];
for (unsigned int k = 0; k < face.mNumIndices; ++k)
{
m->AddIndex(face.mIndices[k]);
}
}
m->BindBuffer();
mod->AddMesh(m);
}
}
return 0;
}
int AssetImport::HandleMeshMaterial(aiMaterial *mat, Mesh *mesh)
{
auto diffuseTexCount = mat->GetTextureCount(aiTextureType_DIFFUSE);
auto specularTexCount = mat->GetTextureCount(aiTextureType_SPECULAR);
for (unsigned int i = 0; i < diffuseTexCount; ++i)
{
aiString path;
mat->GetTexture(aiTextureType_DIFFUSE, i, &path);
QString strPath = path.C_Str();
strPath.replace("/", "\\");
auto index = strPath.lastIndexOf("\\");
if (-1 != index) {
strPath = strPath.right(strPath.length() - index - 1);
strPath.prepend(m_prePath);
}
auto texID = TextureMgr::Instance().LoadTexture(strPath.toLocal8Bit());
mesh->SetDiffuseTexID(texID);
}
for (unsigned int i = 0; i < specularTexCount; ++i)
{
aiString strPath;
mat->GetTexture(aiTextureType_SPECULAR, i, &strPath);
}
return 0;
}
Here is my Mesh Class(with Draw Function):
#include "Mesh.h"
#include "TextureMgr.h"
#include "ShaderHelper.h"
#include "PreDef.h"
#include "QMatrix4x4"
Mesh::Mesh()
:m_vao(0), m_vbo(0), m_vaeo(0), m_instanceBufferId(0), m_tbo1(0)
, m_drawType(Triangle)
, m_skyboxTexID(0), m_projTexID(0), m_normalmapTexID(0)
, m_diffuseTex1ID(0)
{
initializeOpenGLFunctions();
m_normalmapTexID = TextureMgr::Instance().LoadTexture("./models/brickwall_normal.jpg");
}
Mesh::~Mesh()
{
}
void Mesh::AddVertex(QVector3D vert)
{
m_vertices.push_back(vert.x());
m_vertices.push_back(vert.y());
m_vertices.push_back(vert.z());
}
const float* Mesh::GetVertices() const
{
return m_vertices.data();
}
int Mesh::GetVerticesMemSize() const
{
return m_vertices.size() * sizeof(float);
}
int Mesh::GetVerticesNum() const
{
return m_vertices.size() / 3;
}
void Mesh::AddColor(QVector4D color)
{
m_colors.push_back(color.x());
m_colors.push_back(color.y());
m_colors.push_back(color.z());
m_colors.push_back(color.w());
}
const float* Mesh::GetColors() const
{
return m_colors.data();
}
int Mesh::GetColorsMemSize() const
{
return m_colors.size() * sizeof(float);
}
void Mesh::AddNormal(QVector3D normal)
{
m_normals.append(normal.x());
m_normals.append(normal.y());
m_normals.append(normal.z());
}
const float* Mesh::GetNormals() const
{
return m_normals.data();
}
int Mesh::GetNormalsMemSize() const
{
return m_normals.size() * sizeof(float);
}
int Mesh::GetNormalsNum() const
{
return m_normals.size() / 3;
}
void Mesh::AddTangent(QVector4D tangent)
{
m_tangents.append(tangent.x());
m_tangents.append(tangent.y());
m_tangents.append(tangent.z());
m_tangents.append(tangent.w());
}
const float* Mesh::GetTangents() const
{
return m_tangents.data();
}
int Mesh::GetTangentsMemSize() const
{
return m_tangents.size() * sizeof(float);
}
int Mesh::GetTangentsNum() const
{
return m_tangents.size() / 4;
}
void Mesh::AddBitangent(QVector4D binormal)
{
m_binormals.append(binormal.x());
m_binormals.append(binormal.y());
m_binormals.append(binormal.z());
m_binormals.append(binormal.w());
}
const float* Mesh::GetBitangents() const
{
return m_binormals.data();
}
int Mesh::GetBitangentsMemSize() const
{
return m_binormals.size() * sizeof(float);
}
int Mesh::GetBitangentsNum() const
{
return m_binormals.size() / 4;
}
void Mesh::AddUv1(QVector2D uv)
{
m_uvs1.append(uv.x());
m_uvs1.append(uv.y());
}
const float* Mesh::GetUvs1() const
{
return m_uvs1.data();
}
int Mesh::GetUvs1MemSize() const
{
return m_uvs1.size() * sizeof(float);
}
int Mesh::GetUvs1Num() const
{
return m_uvs1.size() / 2;
}
void Mesh::AddVertInfo(const VertInfo &info)
{
m_vertInfoVec.push_back(info);
AddVertex(info.pos);
AddColor(info.color);
AddNormal(info.normal);
AddTangent(info.tangent);
AddBitangent(info.bitangent);
AddUv1(info.uv1);
}
void Mesh::BindBuffer()
{
// init the shaders first
ShaderHelper::Instance();
BindVertexRelevantBuffer();
}
void Mesh::BindVertexRelevantBuffer()
{
const GLuint *vertex_indices = GetIndices();
const GLfloat *vertex_positions = GetVertices();
const GLfloat *vertex_uvs = GetUvs1();
const GLfloat *vertex_tangents = GetTangents();
const GLfloat *vertex_bitangents = GetBitangents();
const GLfloat *vertex_normals = GetNormals();
// set element array(index array) buffer
glGenBuffers(1, &m_vaeo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vaeo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, GetIndicesMemSize(), vertex_indices, GL_STATIC_DRAW);
// set vertex array object
glGenVertexArrays(1, &m_vao);
glBindVertexArray(m_vao);
glVertexArrayElementBuffer(m_vao, m_vaeo);
glGenBuffers(1, &m_vbo);
glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
glBufferData(GL_ARRAY_BUFFER, GetVerticesMemSize() + GetUvs1MemSize()
+ GetTangentsMemSize() + GetBitangentsMemSize() + GetNormalsMemSize() /*+ 16 * sizeof(GLfloat) * 10*/, NULL, GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, 0, GetVerticesMemSize(), vertex_positions);
glBufferSubData(GL_ARRAY_BUFFER, GetVerticesMemSize(), GetUvs1MemSize(), vertex_uvs);
glBufferSubData(GL_ARRAY_BUFFER, GetVerticesMemSize() + GetUvs1MemSize(), GetTangentsMemSize(), vertex_tangents);
glBufferSubData(GL_ARRAY_BUFFER, GetVerticesMemSize() + GetUvs1MemSize() + GetTangentsMemSize(),
GetBitangentsMemSize(), vertex_bitangents);
glBufferSubData(GL_ARRAY_BUFFER, GetVerticesMemSize() + GetUvs1MemSize()
+ GetTangentsMemSize() + GetBitangentsMemSize(),
GetNormalsMemSize(), vertex_normals);
GLint positionLoc = 0;
GLint uvLoc = 1;
GLint tangentLoc = 2;
GLint bitangentLoc = 3;
GLint normalLoc = 4;
GLint modelMatLoc = -1;
glVertexAttribPointer(positionLoc, 3, GL_FLOAT, GL_FALSE, 0, (0));
glEnableVertexAttribArray(positionLoc);
glVertexAttribPointer(uvLoc, 2, GL_FLOAT, GL_FALSE, 0, (void*)(GetVerticesMemSize()));
glEnableVertexAttribArray(uvLoc);
glVertexAttribPointer(tangentLoc, 3, GL_FLOAT, GL_FALSE, 0, (void*)(GetVerticesMemSize() + GetUvs1MemSize()));
glEnableVertexAttribArray(tangentLoc);
glVertexAttribPointer(bitangentLoc, 3, GL_FLOAT, GL_FALSE, 0,
(void*)(GetVerticesMemSize() + GetUvs1MemSize() + GetTangentsMemSize()));
glEnableVertexAttribArray(bitangentLoc);
glVertexAttribPointer(normalLoc, 3, GL_FLOAT, GL_FALSE, 0,
(void*)(GetVerticesMemSize() + GetUvs1MemSize() + GetTangentsMemSize() + GetBitangentsMemSize()));
glEnableVertexAttribArray(normalLoc);
// multi instances model matrix
if (-1 != modelMatLoc) {
// generate the new buffer for instances
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &m_instanceBufferId);
glBindBuffer(GL_ARRAY_BUFFER, m_instanceBufferId);
glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * 16 * 10, nullptr, GL_STATIC_DRAW);
// m_instanceBufferId = m_vbo;
// mat4 type take space of 4 vec4, so we should circle 4 times
for (int i = 0; i < 4; ++i)
{
glVertexAttribPointer(modelMatLoc + i, 4, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 16,
(void*)(/*GetVerticesMemSize() + GetUvs1MemSize() + GetTangentsMemSize() + GetBitangentsMemSize() + GetNormalsMemSize() +*/ sizeof(GLfloat) * 4 * i));
glEnableVertexAttribArray(modelMatLoc + i);
// implement the multi instances
glVertexAttribDivisor(modelMatLoc + i, 1);
}
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
// sampler buffer bind
glGenBuffers(1, &m_tbo1);
glBindBuffer(GL_TEXTURE_BUFFER, m_tbo1);
glBufferData(GL_TEXTURE_BUFFER, sizeof(GLfloat) * 16 * 10, nullptr, GL_STATIC_DRAW);
GLuint tex1;
glCreateTextures(GL_TEXTURE_BUFFER, 1, &tex1);
glTextureBuffer(tex1, GL_RGBA32F, m_tbo1);
glBindTextureUnit(0, m_tbo1);
glBindBuffer(GL_TEXTURE_BUFFER, 0);
}
GLuint Mesh::GetVao()
{
return m_vao;
}
void Mesh::AddIndex(unsigned int index)
{
m_indices.push_back(index);
}
void Mesh::AddIndexVec(QVector<unsigned int> &indexVec)
{
m_indices = indexVec;
}
const unsigned int* Mesh::GetIndices() const
{
return m_indices.data();
}
int Mesh::GetIndicesMemSize() const
{
return m_indices.size() * sizeof(unsigned int);
}
int Mesh::GetIndicesNum() const
{
return m_indices.size();
}
GLuint Mesh::GetMultiInstanceModelMatrixOffset() const
{
return (GetVerticesMemSize() + GetUvs1MemSize() + GetTangentsMemSize()
+ GetBitangentsMemSize() + GetNormalsMemSize());
}
GLuint Mesh::GetInstancesBufferId() const
{
return m_instanceBufferId;
}
void Mesh::SetDiffuseTexID(GLuint id)
{
m_diffuseTex1ID = id;
}
void Mesh::AddSpecularTexture(GLuint id)
{
m_specularTex1ID = id;
}
GLuint Mesh::GetTextureBuffer1() const
{
return m_tbo1;
}
void Mesh::InitSkybox()
{
m_skyboxTexID = TextureMgr::Instance().LoadTexture("skybox");
}
void Mesh::InitProjTex()
{
m_projTexID = TextureMgr::Instance().LoadTexture("./textures/proj.jpg");
}
void Mesh::SetDrawType(eDrawType type)
{
m_drawType = type;
}
void Mesh::Draw(QMatrix4x4 matVP, QMatrix4x4 matModel, QVector3D camPos, QMatrix4x4 matProj, QMatrix4x4 matView,
QMatrix4x4 matOrtho)
{
if (0 != m_diffuseTex1ID)
{
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, m_diffuseTex1ID);
}
if (0 != m_normalmapTexID)
{
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, m_normalmapTexID);
}
if (0 != m_skyboxTexID) {
glBindTexture(GL_TEXTURE_CUBE_MAP, m_skyboxTexID);
matModel.translate(camPos);
matModel.scale(10000);
glCullFace(GL_FRONT);
glDepthMask(0);
ShaderHelper::Instance().SetShaderType(ShaderHelper::Skybox);
}
else if (0 != m_projTexID) {
glActiveTexture(GL_TEXTURE10);
glBindTexture(GL_TEXTURE_2D, m_projTexID);
ShaderHelper::Instance().SetShaderType(ShaderHelper::Decal);
}
glBindVertexArray(GetVao());
matVP = matVP * matModel;
ShaderHelper::Instance().SetMVPMatrix(matVP);
ShaderHelper::Instance().SetWorldMatrix(matModel);
ShaderHelper::Instance().SetCamWorldPos(camPos);
ShaderHelper::Instance().SetProjMat(matProj);
ShaderHelper::Instance().SetViewMat(matView);
ShaderHelper::Instance().SetOrthoMat(matOrtho);
// Draw element(with indices)
if (Triangle == m_drawType)
{
glDrawElements(GL_TRIANGLES, GetIndicesNum(), GL_UNSIGNED_INT, 0);
}
else if (Point == m_drawType)
{
glDrawArrays(GL_POINTS, 0, GetVerticesNum());
}
if (0 != m_skyboxTexID) {
glCullFace(GL_BACK);
glDepthMask(1);
}
glBindVertexArray(0);
}
Here is the main draw function:
void OpenWidget::paintGL()
{
static int i = 0;
if (0 == i){
++i;
CreateOffScreenFrameBufferTexture();
}
glBindFramebuffer(GL_FRAMEBUFFER, m_fb);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
return;
}
paintClearAndReset();
QMatrix4x4 matVP = m_cam->GetVPMatrix();
QMatrix4x4 matProj = m_cam->GetProjectionMatrix();
QMatrix4x4 matOrtho = m_cam->GetOrthographicMatrix();
QMatrix4x4 matView = m_cam->GetViewMatrix();
QVector3D camPos = m_cam->GetCamPos().toVector3D();
auto modelNum = ModelMgr::Instance().GetModelNum();
for (unsigned int i = 0; i < modelNum; ++i)
{
Model *mod = ModelMgr::Instance().GetModel(i);
SwitchShader(ShaderHelper::Default);
QMatrix4x4 matModel = mod->GetWorldMat();
mod->Draw(matVP, matModel, camPos, matProj, matView, matOrtho);
if (modelNum - 1 == i) {
Model *pBox = ModelMgr::Instance().FindModelByName("Box001");
// SwitchShader(ShaderHelper::PlaneClip);
// glFrontFace(GL_CW);
// glEnable(GL_CLIP_PLANE0);
// glStencilMask(0xff);
// glStencilFunc(GL_ALWAYS, 1, 0xff);
// glColorMask(0, 0, 0, 0);
//
// pBox->Draw(matVP, pBox->GetWorldMat(), camPos);
// glFrontFace(GL_CCW);
// glDisable(GL_CLIP_PLANE0);
// glColorMask(1, 1, 1, 1);
//
// glStencilMask(0);
// glStencilFunc(GL_EQUAL, 1, 0xff);
// SwitchShader(ShaderHelper::PureColor);
// pBox->Draw(matVP, pBox->GetWorldMat(), camPos);
}
}
//-----------------------------------------------
// test the frame buffer
DrawOffScreenTexture();
}

Answer 1

Finally, I found where the problem is, I give up on this issue for a while, but today, I encountered another problem with my skybox(cubemap), I can only draw my skybox correctly at the last of my draw queue, otherwise the cubemap only show one face, so, no shortcut for me anymore, I decided to resolve this issue, after many hours debug, I found this issue caused by the create sequence of VAO and ElementBuffer, here is the wrong code:
// set element array(index array) buffer
glGenBuffers(1, &m_vaeo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vaeo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, GetIndicesMemSize(), vertex_indices, GL_STATIC_DRAW);
// set vertex array object
glGenVertexArrays(1, &m_vao);
glBindVertexArray(m_vao);
glVertexArrayElementBuffer(m_vao, m_vaeo);
you should always create and bind VAO first:
// set vertex array object
glGenVertexArrays(1, &m_vao);
glBindVertexArray(m_vao);
// set element array(index array) buffer
glGenBuffers(1, &m_vaeo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vaeo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, GetIndicesMemSize(), vertex_indices, GL_STATIC_DRAW);
glVertexArrayElementBuffer(m_vao, m_vaeo);
But, after all, I think it's so implicit, because of you can bind the element to vao after you create the element buffer, it seems like when you gen the element buffer it's nothing to do with the vao, what I can do, only be careful next time.