Spite中初始化

TrianglesCommand _trianglesCommand;     
_trianglesCommand.init(_globalZOrder,
                           _texture,
                           getGLProgramState(),
                           _blendFunc,
                           _polyInfo.triangles, // 类型为Triangles
                           transform,
                           flags);

struct Triangles
{
    /**Vertex data pointer.*/
    V3F_C4B_T2F* verts; // 注意这里是V3F
    /**Index data pointer.*/
    unsigned short* indices;
    /**The number of vertices.*/
    int vertCount;
    /**The number of indices.*/
    int indexCount;
};

填充顶点数据的逻辑

void Renderer::fillVerticesAndIndices(const TrianglesCommand* cmd)
{
    memcpy(&_verts[_filledVertex], cmd->getVertices(), sizeof(V3F_C4B_T2F) * cmd->getVertexCount());

    // fill vertex, and convert them to world coordinates
    const Mat4& modelView = cmd->getModelView();
    for(ssize_t i=0; i < cmd->getVertexCount(); ++i)
    {
        modelView.transformPoint(&(_verts[i + _filledVertex].vertices));
    }

    // fill index
    const unsigned short* indices = cmd->getIndices();
    for(ssize_t i=0; i< cmd->getIndexCount(); ++i)
    {
        _indices[_filledIndex + i] = _filledVertex + indices[i];
    }

    _filledVertex += cmd->getVertexCount();
    _filledIndex += cmd->getIndexCount();
}

setupVBOAndVAO函数规定了如何解析顶点数据， 数据结构类型就是V3F_C4B_T2F

void Renderer::setupVBOAndVAO()
{
    //generate vbo and vao for trianglesCommand
    glGenVertexArrays(1, &_buffersVAO);
    GL::bindVAO(_buffersVAO);

    glGenBuffers(2, &_buffersVBO[0]);

    glBindBuffer(GL_ARRAY_BUFFER, _buffersVBO[0]);

    // vertices
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_POSITION);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 3, GL_FLOAT, GL_FALSE, sizeof(V3F_C4B_T2F), (GLvoid*) offsetof( V3F_C4B_T2F, vertices));

    // colors
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_COLOR);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(V3F_C4B_T2F), (GLvoid*) offsetof( V3F_C4B_T2F, colors));

    // tex coords
    glEnableVertexAttribArray(GLProgram::VERTEX_ATTRIB_TEX_COORD);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD, 2, GL_FLOAT, GL_FALSE, sizeof(V3F_C4B_T2F), (GLvoid*) offsetof( V3F_C4B_T2F, texCoords));

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _buffersVBO[1]);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(_indices[0]) * INDEX_VBO_SIZE, _indices, GL_STATIC_DRAW);

    // Must unbind the VAO before changing the element buffer.
    GL::bindVAO(0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    CHECK_GL_ERROR_DEBUG();
}

顶点数据布局

可以使用Vec3的Z进行纹理单元的设置