/*
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Open Asset Import Library (assimp)
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*/
#include "UnitTestPCH.h"

#include <assimp/scene.h>

#include "PostProcessing/JoinVerticesProcess.h"

using namespace std;
using namespace Assimp;

class utJoinVertices : public ::testing::Test {
public:
    utJoinVertices() :
            Test(), piProcess(nullptr), pcMesh(nullptr) {
        // empty
    }

protected:
    virtual void SetUp();
    virtual void TearDown();

protected:
    JoinVerticesProcess *piProcess;
    aiMesh *pcMesh;
};

// ------------------------------------------------------------------------------------------------
void utJoinVertices::SetUp() {
    // construct the process
    piProcess = new JoinVerticesProcess();

    // create a quite small mesh for testing purposes -
    // the mesh itself is *something* but it has redundant vertices
    pcMesh = new aiMesh();

    pcMesh->mNumVertices = 900;
    aiVector3D *&pv = pcMesh->mVertices = new aiVector3D[900];
    for (unsigned int i = 0; i < 3; ++i) {
        const unsigned int base = i * 300;
        for (unsigned int a = 0; a < 300; ++a) {
            pv[base + a].x = pv[base + a].y = pv[base + a].z = (float)a;
        }
    }

    // generate faces - each vertex is referenced once
    pcMesh->mNumFaces = 300;
    pcMesh->mFaces = new aiFace[300];
    for (unsigned int i = 0, p = 0; i < 300; ++i) {
        aiFace &face = pcMesh->mFaces[i];
        face.mIndices = new unsigned int[face.mNumIndices = 3];
        for (unsigned int a = 0; a < 3; ++a) {
            face.mIndices[a] = p++;
        }
    }

    // generate extra members - set them to zero to make sure they're identical
    pcMesh->mTextureCoords[0] = new aiVector3D[900];
    pcMesh->mBitangents = new aiVector3D[900];
    pcMesh->mNormals = new aiVector3D[900];
    pcMesh->mTangents = new aiVector3D[900];
    for (unsigned int i = 0; i < 900; ++i) {
        pcMesh->mTextureCoords[0][i] = aiVector3D(0.f);
        pcMesh->mNormals[i] = aiVector3D(0.f);
        pcMesh->mTangents[i] = aiVector3D(0.f);
        pcMesh->mBitangents[i] = aiVector3D(0.f);
    }
}

// ------------------------------------------------------------------------------------------------
void utJoinVertices::TearDown() {
    delete this->pcMesh;
    pcMesh = nullptr;
    delete this->piProcess;
    piProcess = nullptr;
}

// ------------------------------------------------------------------------------------------------
TEST_F(utJoinVertices, testProcess) {
    // execute the step on the given data
    piProcess->ProcessMesh(pcMesh, 0);

    // the number of faces shouldn't change
    ASSERT_EQ(300U, pcMesh->mNumFaces);
    ASSERT_EQ(300U, pcMesh->mNumVertices);

    ASSERT_TRUE(nullptr != pcMesh->mNormals);
    ASSERT_TRUE(nullptr != pcMesh->mTangents);
    ASSERT_TRUE(nullptr != pcMesh->mBitangents);
    ASSERT_TRUE(nullptr != pcMesh->mTextureCoords[0]);

    // the order doesn't care
    float fSum = 0.f;
    for (unsigned int i = 0; i < 300; ++i) {
        aiVector3D &v = pcMesh->mVertices[i];
        fSum += v.x + v.y + v.z;

        EXPECT_FALSE(pcMesh->mNormals[i].x);
        EXPECT_FALSE(pcMesh->mTangents[i].x);
        EXPECT_FALSE(pcMesh->mBitangents[i].x);
        EXPECT_FALSE(pcMesh->mTextureCoords[0][i].x);
    }
    EXPECT_EQ(150.f * 299.f * 3.f, fSum); // gaussian sum equation
}
