mesh_data_gpu.cpp

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#include "mesh_data_gpu.hpp"
#include "model.hpp"
#include "i_renderer.hpp"
#include "i_mesh_render_resources.hpp"
 
namespace rendering_engine
{
MeshDataGpu::MeshDataGpu(IRenderer* renderer)
    :
    mRenderer(renderer),
    mGpuHandle(nullptr),
    mSizeOfVerticesBytes(0),
    mSizeOfIndicesBytes(0),
    mMeshType(MeshType::None)
{
}
    MeshDataGpu::MeshDataGpu(const std::string& filename, IRenderer* renderer)
    :
    mRenderer(renderer),
    mGpuHandle(nullptr),
    mSizeOfVerticesBytes(0),
    mSizeOfIndicesBytes(0),
    mMeshType(MeshType::None)
{
    LoadModel(filename);
}
 
MeshDataGpu::MeshDataGpu(std::vector<uint8_t> const& fileBytes, IRenderer* renderer)
    :
    mRenderer(renderer),
    mGpuHandle(nullptr),
    mSizeOfVerticesBytes(0),
    mSizeOfIndicesBytes(0),
    mMeshType(MeshType::None)
{
    LoadModel(fileBytes);
}
 
MeshDataGpu::~MeshDataGpu()
{
    ReleaseFromGPU();
}
 
void MeshDataGpu::UploadToGPU()
{
    if (!mRenderer)
    {
        return;
    }
    if (mGpuHandle)
    {
        if (mGpuHandle->IsOnGPU())
        {
            ReleaseFromGPU();
        }
    }
 
    mGpuHandle = std::unique_ptr<IMeshRenderResources>(mRenderer->ProvideMeshRenderResources());
 
    switch (mMeshType)
    {
        case MeshType::None:
        {
            break;
        }
        case MeshType::Sprite2D:
        {   
            mGpuHandle->CreateVertexBuffer(ComposeVertex2DBuffer());
            mGpuHandle->CreateIndexBuffer(mIndices);
            break;
        }
        case MeshType::Billboard:
        {
            mGpuHandle->CreateVertexBuffer(ComposeUnlitBuffer());
            mGpuHandle->CreateIndexBuffer(mIndices);
            break;
        }
        case MeshType::Surface:
        {
            mGpuHandle->CreateVertexBuffer(ComposeLitBuffer());
            mGpuHandle->CreateIndexBuffer(mIndices);
            break;
        }
    }
}
 
void MeshDataGpu::ReleaseFromGPU()
{
    if (!mRenderer)
    {
        return;
    }
    if (!mGpuHandle)
    {
        return;
    }
 
    mGpuHandle->Shutdown();
    mGpuHandle.release();
    mGpuHandle = nullptr;
}
 
bool MeshDataGpu::IsOnGPU() const
{
    bool result = false;
 
    if (mGpuHandle)
    {
        result = mGpuHandle->IsOnGPU();
    }
 
    return result;
}
 
void MeshDataGpu::LoadModel(std::string path)
{
    std::unique_ptr<Model> model = std::make_unique<Model>(path, true);
 
    if (model)
    {
        if (model->HasMeshes())
        {
            mPositions = model->Meshes()[0]->Vertices();
            
            if (model->Meshes()[0]->VertexColors().size() >= 1)
                mColor = model->Meshes()[0]->VertexColors()[0];
 
            mNormals = model->Meshes()[0]->Normals();
            for (const auto& texCoord : model->Meshes()[0]->TextureCoordinates()[0])
            {
                mTexCoords.push_back(glm::vec2(texCoord.x, texCoord.y));
            }
            mTangents = model->Meshes()[0]->Tangents();
            mIndices = model->Meshes()[0]->Indices();
        }
    }
 
    CalculateMeshParameters();
 
    mMeshType = MeshType::Surface;
}
 
void MeshDataGpu::LoadModel(std::vector<uint8_t> const& fileBytes)
{
    std::unique_ptr<Model> model = std::make_unique<Model>(fileBytes, true);
 
    if (model)
    {
        if (model->HasMeshes())
        {
            mPositions = model->Meshes()[0]->Vertices();
 
            if (model->Meshes()[0]->VertexColors().size() >= 1)
                mColor = model->Meshes()[0]->VertexColors()[0];
 
            mNormals = model->Meshes()[0]->Normals();
            for (const auto& texCoord : model->Meshes()[0]->TextureCoordinates()[0])
            {
                mTexCoords.push_back(glm::vec2(texCoord.x, texCoord.y));
            }
            mTangents = model->Meshes()[0]->Tangents();
            mIndices = model->Meshes()[0]->Indices();
        }
    }
 
    CalculateMeshParameters();
 
    mMeshType = MeshType::Surface;
}
 
void MeshDataGpu::CreateQuad2D()
{
    mPositions2D = { {-0.5f, -0.5f}, { 0.5f, -0.5f}, { 0.5f,  0.5f}, {-0.5f,  0.5f} };
    
    // TOP-LEFT origin UVs
    mTexCoords = {
        {0.0f, 0.0f}, // bottom-left
        {1.0f, 0.0f}, // bottom-right
        {1.0f, 1.0f}, // top-right
        {0.0f, 1.0f}  // top-left
    };
 
    mColor = { {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, 0.0f, 1.0f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f} };
 
    mIndices = {
            0, 1, 2,  // first triangle
            2, 3, 0   // second triangle
    };
 
    CalculateMeshParameters();
 
    mMeshType = MeshType::Sprite2D;
}
 
void MeshDataGpu::LoadCustomMesh(std::vector<glm::vec2> positions2D, std::vector<glm::vec2> texCoords, std::vector<glm::vec4> colors, std::vector<std::uint32_t> indices)
{
    mPositions2D = positions2D;
    mTexCoords = texCoords;
    mColor = colors;
    mIndices = indices;
 
    CalculateMeshParameters();
 
    mMeshType = MeshType::Sprite2D;
}
 
size_t MeshDataGpu::GetGpuVertexBufferSize() const
{
    size_t result = 0;
 
    if (mGpuHandle)
    {
        result = mGpuHandle->GetVertexBufferSize();
    }
 
    return result;
}
 
size_t MeshDataGpu::GetGpuIndexBufferSize() const
{
    size_t result = 0;
 
    if (mGpuHandle)
    {
        result = mGpuHandle->GetIndexBufferSize();
    }
 
    return result;
}
 
size_t MeshDataGpu::GetCpuVertexBufferSize() const
{
    return mSizeOfVerticesBytes;
}
 
size_t MeshDataGpu::GetCpuIndexBufferSize() const
{
    return mSizeOfIndicesBytes;
}
 
IMeshRenderResources* MeshDataGpu::GetMeshRenderResources()
{
    if (!IsOnGPU())
    {
        UploadToGPU();
    }
    return mGpuHandle.get();
}
 
void MeshDataGpu::CalculateMeshParameters()
{
    size_t sizeOfVerticesBytes = 0;
    size_t sizeOfIndicesBytes = 0;
 
    sizeOfVerticesBytes += (mPositions2D.size() * sizeof(glm::vec2));
    sizeOfVerticesBytes += (mPositions.size() * sizeof(glm::vec3));
    sizeOfVerticesBytes += (mColor.size() * sizeof(glm::vec4));
    sizeOfVerticesBytes += (mNormals.size() * sizeof(glm::vec3));
    sizeOfVerticesBytes += (mTexCoords.size() * sizeof(glm::vec2));
    sizeOfVerticesBytes += (mTangents.size() * sizeof(glm::vec3));
    
    sizeOfIndicesBytes += (mIndices.size() * sizeof(uint32_t));
 
    mSizeOfVerticesBytes = sizeOfVerticesBytes;
    mSizeOfIndicesBytes = sizeOfIndicesBytes;
}
 
std::vector<Vertex2D> MeshDataGpu::ComposeVertex2DBuffer()
{
    std::vector<Vertex2D> result;
 
    unsigned int index = 0;
    for (const auto& position : mPositions2D)
    {
        Vertex2D vert;
        vert.position = position;
        vert.color = mColor.empty() ? glm::vec4(1.0f) : mColor[index];
        vert.textureCoordinates = mTexCoords.empty() ? glm::vec2(0.0f) : mTexCoords[index];
 
        result.push_back(vert);
        ++index;
    }
 
    return result;
}
 
std::vector<VertexPositionColorTexture> MeshDataGpu::ComposeUnlitBuffer()
{
    std::vector<VertexPositionColorTexture> result;
 
    unsigned int index = 0;
    for (const auto& position : mPositions)
    {
        VertexPositionColorTexture vert;
        vert.position = position;
        vert.color = mColor.empty() ? glm::vec4(1) : mColor[index];
        vert.textureCoordinates = mTexCoords.empty() ? glm::vec2(0.0f) : mTexCoords[index];
 
        result.push_back(vert);
        ++index;
    }
 
    return result;
}
 
std::vector<VertexPositionColorTextureNormalTangent> MeshDataGpu::ComposeLitBuffer()
{
    std::vector<VertexPositionColorTextureNormalTangent> result;
 
    unsigned int index = 0;
    for (const auto& position : mPositions)
    {
        VertexPositionColorTextureNormalTangent vert;
        vert.position = position;
        vert.color = mColor.empty() ? glm::vec4(1.0f) : mColor[index];
        vert.textureCoordinates = mTexCoords.empty() ? glm::vec2(0.0f) : mTexCoords[index];
        vert.normal = mNormals.empty() ? glm::vec3(0.0f, 0.0f, 1.0f) : mNormals[index];
        vert.tangent = mTangents.empty() ? glm::vec3(1.0f, 0.0f, 0.0f) : mTangents[index];
 
        result.push_back(vert);
        ++index;
    }
 
    return result;
}
 
} // namespace rendering_engine