/*
 * Copyright 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//--------------------------------------------------------------------------------
// MoreTeapotsRenderer.cpp
// Render teapots
//--------------------------------------------------------------------------------
//--------------------------------------------------------------------------------
// Include files
//--------------------------------------------------------------------------------
#include "MoreTeapotsRenderer.h"

//--------------------------------------------------------------------------------
// Teapot model data
//--------------------------------------------------------------------------------
#include "teapot.inl"

//--------------------------------------------------------------------------------
// Ctor
//--------------------------------------------------------------------------------
MoreTeapotsRenderer::MoreTeapotsRenderer() :
                geometry_instancing_support_( false )
{

}

//--------------------------------------------------------------------------------
// Dtor
//--------------------------------------------------------------------------------
MoreTeapotsRenderer::~MoreTeapotsRenderer()
{
    Unload();
}

//--------------------------------------------------------------------------------
// Init
//--------------------------------------------------------------------------------
void MoreTeapotsRenderer::Init( const int32_t numX,
        const int32_t numY,
        const int32_t numZ )
{
    if( ndk_helper::GLContext::GetInstance()->GetGLVersion() >= 3.0 )
    {
        geometry_instancing_support_ = true;
    }
    else if( ndk_helper::GLContext::GetInstance()->CheckExtension( "GL_NV_draw_instanced" )
            && ndk_helper::GLContext::GetInstance()->CheckExtension(
                    "GL_NV_uniform_buffer_object" ) )
    {
        LOGI( "Supported via extension!" );
        //_bGeometryInstancingSupport = true;
        //_bARBSupport = true; //Need to patch shaders
        //Currently this has been disabled
    }

    //Settings
    glFrontFace( GL_CCW );

    //Create Index buffer
    num_indices_ = sizeof(teapotIndices) / sizeof(teapotIndices[0]);
    glGenBuffers( 1, &ibo_ );
    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, ibo_ );
    glBufferData( GL_ELEMENT_ARRAY_BUFFER, sizeof(teapotIndices), teapotIndices, GL_STATIC_DRAW );
    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, 0 );

    //Create VBO
    num_vertices_ = sizeof(teapotPositions) / sizeof(teapotPositions[0]) / 3;
    int32_t iStride = sizeof(TEAPOT_VERTEX);
    int32_t iIndex = 0;
    TEAPOT_VERTEX* p = new TEAPOT_VERTEX[num_vertices_];
    for( int32_t i = 0; i < num_vertices_; ++i )
    {
        p[i].pos[0] = teapotPositions[iIndex];
        p[i].pos[1] = teapotPositions[iIndex + 1];
        p[i].pos[2] = teapotPositions[iIndex + 2];

        p[i].normal[0] = teapotNormals[iIndex];
        p[i].normal[1] = teapotNormals[iIndex + 1];
        p[i].normal[2] = teapotNormals[iIndex + 2];
        iIndex += 3;
    }
    glGenBuffers( 1, &vbo_ );
    glBindBuffer( GL_ARRAY_BUFFER, vbo_ );
    glBufferData( GL_ARRAY_BUFFER, iStride * num_vertices_, p, GL_STATIC_DRAW );
    glBindBuffer( GL_ARRAY_BUFFER, 0 );
    delete[] p;

    //Init Projection matrices
    teapot_x_ = numX;
    teapot_y_ = numY;
    teapot_z_ = numZ;
    vec_mat_models_.reserve( teapot_x_ * teapot_y_ * teapot_z_ );

    UpdateViewport();

    const float total_width = 500.f;
    float gap_x = total_width / (teapot_x_ - 1);
    float gap_y = total_width / (teapot_y_ - 1);
    float gap_z = total_width / (teapot_z_ - 1);
    float offset_x = -total_width / 2.f;
    float offset_y = -total_width / 2.f;
    float offset_z = -total_width / 2.f;

    for( int32_t iX = 0; iX < teapot_x_; ++iX )
        for( int32_t iY = 0; iY < teapot_y_; ++iY )
            for( int32_t iZ = 0; iZ < teapot_z_; ++iZ )
            {
                vec_mat_models_.push_back(
                        ndk_helper::Mat4::Translation( iX * gap_x + offset_x, iY * gap_y + offset_y,
                                iZ * gap_z + offset_z ) );
                vec_colors_.push_back(
                        ndk_helper::Vec3( random() / float( RAND_MAX * 1.1 ),
                                random() / float( RAND_MAX * 1.1 ),
                                random() / float( RAND_MAX * 1.1 ) ) );

                float fX = random() / float( RAND_MAX ) - 0.5f;
                float fY = random() / float( RAND_MAX ) - 0.5f;
                vec_rotations_.push_back( ndk_helper::Vec2( fX * 0.05f, fY * 0.05f ) );
                vec_current_rotations_.push_back( ndk_helper::Vec2( fX * M_PI, fY * M_PI ) );
            }

    if( geometry_instancing_support_ )
    {
        //
        //Create parameter dictionary for shader patch
        std::map<std::string, std::string> param;
        param[std::string( "%NUM_TEAPOT%" )] = ToString( teapot_x_ * teapot_y_ * teapot_z_ );
        param[std::string( "%LOCATION_VERTEX%" )] = ToString( ATTRIB_VERTEX );
        param[std::string( "%LOCATION_NORMAL%" )] = ToString( ATTRIB_NORMAL );
        if( arb_support_ )
            param[std::string( "%ARB%" )] = std::string( "ARB" );
        else
            param[std::string( "%ARB%" )] = std::string( "" );

        //Load shader
        bool b = LoadShadersES3( &shader_param_, "Shaders/VS_ShaderPlainES3.vsh",
                "Shaders/ShaderPlainES3.fsh", param );
        if( b )
        {
            //
            //Create uniform buffer
            //
            GLuint bindingPoint = 1;
            GLuint blockIndex;
            blockIndex = glGetUniformBlockIndex( shader_param_.program_, "ParamBlock" );
            glUniformBlockBinding( shader_param_.program_, blockIndex, bindingPoint );

            //Retrieve array stride value
            int32_t iNumIndices;
            glGetActiveUniformBlockiv( shader_param_.program_, blockIndex,
                    GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, &iNumIndices );
            GLint i[iNumIndices];
            GLint stride[iNumIndices];
            glGetActiveUniformBlockiv( shader_param_.program_, blockIndex,
                    GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, i );
            glGetActiveUniformsiv( shader_param_.program_, iNumIndices, (GLuint*) i,
                    GL_UNIFORM_ARRAY_STRIDE, stride );

            ubo_matrix_stride_ = stride[0] / sizeof(float);
            ubo_vector_stride_ = stride[2] / sizeof(float);

            glGenBuffers( 1, &ubo_ );
            glBindBuffer( GL_UNIFORM_BUFFER, ubo_ );
            glBindBufferBase( GL_UNIFORM_BUFFER, bindingPoint, ubo_ );

            //Store color value which wouldn't be updated every frame
            int32_t iSize = teapot_x_ * teapot_y_ * teapot_z_
                    * (ubo_matrix_stride_ + ubo_matrix_stride_ + ubo_vector_stride_); //Mat4 + Mat4 + Vec3 + 1 stride
            float* pBuffer = new float[iSize];
            float* pColor = pBuffer + teapot_x_ * teapot_y_ * teapot_z_ * ubo_matrix_stride_ * 2;
            for( int32_t i = 0; i < teapot_x_ * teapot_y_ * teapot_z_; ++i )
            {
                memcpy( pColor, &vec_colors_[i], 3 * sizeof(float) );
                pColor += ubo_vector_stride_; //Assuming std140 layout which is 4 DWORD stride for vectors
            }

            glBufferData( GL_UNIFORM_BUFFER, iSize * sizeof(float), pBuffer, GL_DYNAMIC_DRAW );
            delete[] pBuffer;
        }
        else
        {
            LOGI( "Shader compilation failed!! Falls back to ES2.0 pass" );
            //This happens some devices.
            geometry_instancing_support_ = false;
            //Load shader for GLES2.0
            LoadShaders( &shader_param_, "Shaders/VS_ShaderPlain.vsh", "Shaders/ShaderPlain.fsh" );
        }
    }
    else
    {
        //Load shader for GLES2.0
        LoadShaders( &shader_param_, "Shaders/VS_ShaderPlain.vsh", "Shaders/ShaderPlain.fsh" );
    }
}

void MoreTeapotsRenderer::UpdateViewport()
{
    int32_t viewport[4];
    glGetIntegerv( GL_VIEWPORT, viewport );
    float fAspect = (float) viewport[2] / (float) viewport[3];

    const float CAM_NEAR = 5.f;
    const float CAM_FAR = 10000.f;
    bool bRotate = false;
    mat_projection_ = ndk_helper::Mat4::Perspective( fAspect, 1.f, CAM_NEAR, CAM_FAR );
}

//--------------------------------------------------------------------------------
// Unload
//--------------------------------------------------------------------------------
void MoreTeapotsRenderer::Unload()
{
    if( vbo_ )
    {
        glDeleteBuffers( 1, &vbo_ );
        vbo_ = 0;
    }
    if( ubo_ )
    {
        glDeleteBuffers( 1, &ubo_ );
        ubo_ = 0;
    }
    if( ibo_ )
    {
        glDeleteBuffers( 1, &ibo_ );
        ibo_ = 0;
    }
    if( shader_param_.program_ )
    {
        glDeleteProgram( shader_param_.program_ );
        shader_param_.program_ = 0;
    }
}

//--------------------------------------------------------------------------------
// Update
//--------------------------------------------------------------------------------
void MoreTeapotsRenderer::Update( float fTime )
{
    const float CAM_X = 0.f;
    const float CAM_Y = 0.f;
    const float CAM_Z = 2000.f;

    mat_view_ = ndk_helper::Mat4::LookAt( ndk_helper::Vec3( CAM_X, CAM_Y, CAM_Z ),
            ndk_helper::Vec3( 0.f, 0.f, 0.f ), ndk_helper::Vec3( 0.f, 1.f, 0.f ) );

    if( camera_ )
    {
        camera_->Update();
        mat_view_ = camera_->GetTransformMatrix() * mat_view_ * camera_->GetRotationMatrix();
    }
}

//--------------------------------------------------------------------------------
// Render
//--------------------------------------------------------------------------------
void MoreTeapotsRenderer::Render()
{
    // Bind the VBO
    glBindBuffer( GL_ARRAY_BUFFER, vbo_ );

    int32_t iStride = sizeof(TEAPOT_VERTEX);
    // Pass the vertex data
    glVertexAttribPointer( ATTRIB_VERTEX, 3, GL_FLOAT, GL_FALSE, iStride, BUFFER_OFFSET( 0 ) );
    glEnableVertexAttribArray( ATTRIB_VERTEX );

    glVertexAttribPointer( ATTRIB_NORMAL, 3, GL_FLOAT, GL_FALSE, iStride,
            BUFFER_OFFSET( 3 * sizeof(GLfloat) ) );
    glEnableVertexAttribArray( ATTRIB_NORMAL );

    // Bind the IB
    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, ibo_ );

    glUseProgram( shader_param_.program_ );

    TEAPOT_MATERIALS material = { { 1.0f, 1.0f, 1.0f, 10.f }, { 0.1f, 0.1f, 0.1f }, };

    //Update uniforms
    //
    //using glUniform3fv here was troublesome..
    //
    glUniform4f( shader_param_.material_specular_, material.specular_color[0],
            material.specular_color[1], material.specular_color[2], material.specular_color[3] );
    glUniform3f( shader_param_.material_ambient_, material.ambient_color[0],
            material.ambient_color[1], material.ambient_color[2] );

    glUniform3f( shader_param_.light0_, 100.f, -200.f, -600.f );

    if( geometry_instancing_support_ )
    {
        //
        //Geometry instancing, new feature in GLES3.0
        //

        //Update UBO
        glBindBuffer( GL_UNIFORM_BUFFER, ubo_ );
        float* p = (float*) glMapBufferRange( GL_UNIFORM_BUFFER, 0,
                teapot_x_ * teapot_y_ * teapot_z_ * (ubo_matrix_stride_ * 2) * sizeof(float),
                GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_RANGE_BIT );
        float* pMVPMat = p;
        float* pMVMat = p + teapot_x_ * teapot_y_ * teapot_z_ * ubo_matrix_stride_;
        for( int32_t i = 0; i < teapot_x_ * teapot_y_ * teapot_z_; ++i )
        {
            //Rotation
            float fX, fY;
            vec_current_rotations_[i] += vec_rotations_[i];
            vec_current_rotations_[i].Value( fX, fY );
            ndk_helper::Mat4 mat_rotation = ndk_helper::Mat4::RotationX( fX )
                    * ndk_helper::Mat4::RotationY( fY );

            // Feed Projection and Model View matrices to the shaders
            ndk_helper::Mat4 mat_v = mat_view_ * vec_mat_models_[i] * mat_rotation;
            ndk_helper::Mat4 mat_vp = mat_projection_ * mat_v;

            memcpy( pMVPMat, mat_vp.Ptr(), sizeof(mat_v) );
            pMVPMat += ubo_matrix_stride_;

            memcpy( pMVMat, mat_v.Ptr(), sizeof(mat_v) );
            pMVMat += ubo_matrix_stride_;
        }
        glUnmapBuffer( GL_UNIFORM_BUFFER );

        //Instanced rendering
        glDrawElementsInstanced( GL_TRIANGLES, num_indices_, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0),
                teapot_x_ * teapot_y_ * teapot_z_ );

    }
    else
    {
        //Regular rendering pass
        for( int32_t i = 0; i < teapot_x_ * teapot_y_ * teapot_z_; ++i )
        {
            //Set diffuse
            float x, y, z;
            vec_colors_[i].Value( x, y, z );
            glUniform4f( shader_param_.material_diffuse_, x, y, z, 1.f );

            //Rotation
            vec_current_rotations_[i] += vec_rotations_[i];
            vec_current_rotations_[i].Value( x, y );
            ndk_helper::Mat4 mat_rotation = ndk_helper::Mat4::RotationX( x )
                    * ndk_helper::Mat4::RotationY( y );

            // Feed Projection and Model View matrices to the shaders
            ndk_helper::Mat4 mat_v = mat_view_ * vec_mat_models_[i] * mat_rotation;
            ndk_helper::Mat4 mat_vp = mat_projection_ * mat_v;
            glUniformMatrix4fv( shader_param_.matrix_projection_, 1, GL_FALSE, mat_vp.Ptr() );
            glUniformMatrix4fv( shader_param_.matrix_view_, 1, GL_FALSE, mat_v.Ptr() );

            glDrawElements( GL_TRIANGLES, num_indices_, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0) );

        }
    }

    glBindBuffer( GL_ARRAY_BUFFER, 0 );
    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, 0 );
}

//--------------------------------------------------------------------------------
// LoadShaders
//--------------------------------------------------------------------------------
bool MoreTeapotsRenderer::LoadShaders( SHADER_PARAMS* params,
        const char* strVsh,
        const char* strFsh )
{
    //
    //Shader load for GLES2
    //In GLES2.0, shader attribute locations need to be explicitly specified before linking
    //
    GLuint program;
    GLuint vertShader, fragShader;
    char *vertShaderPathname, *fragShaderPathname;

    // Create shader program
    program = glCreateProgram();
    LOGI( "Created Shader %d", program );

    // Create and compile vertex shader
    if( !ndk_helper::shader::CompileShader( &vertShader, GL_VERTEX_SHADER, strVsh ) )
    {
        LOGI( "Failed to compile vertex shader" );
        glDeleteProgram( program );
        return false;
    }

    // Create and compile fragment shader
    if( !ndk_helper::shader::CompileShader( &fragShader, GL_FRAGMENT_SHADER, strFsh ) )
    {
        LOGI( "Failed to compile fragment shader" );
        glDeleteProgram( program );
        return false;
    }

    // Attach vertex shader to program
    glAttachShader( program, vertShader );

    // Attach fragment shader to program
    glAttachShader( program, fragShader );

    // Bind attribute locations
    // this needs to be done prior to linking
    glBindAttribLocation( program, ATTRIB_VERTEX, "myVertex" );
    glBindAttribLocation( program, ATTRIB_NORMAL, "myNormal" );

    // Link program
    if( !ndk_helper::shader::LinkProgram( program ) )
    {
        LOGI( "Failed to link program: %d", program );

        if( vertShader )
        {
            glDeleteShader( vertShader );
            vertShader = 0;
        }
        if( fragShader )
        {
            glDeleteShader( fragShader );
            fragShader = 0;
        }
        if( program )
        {
            glDeleteProgram( program );
        }
        return false;
    }

    // Get uniform locations
    params->matrix_projection_ = glGetUniformLocation( program, "uPMatrix" );
    params->matrix_view_ = glGetUniformLocation( program, "uMVMatrix" );

    params->light0_ = glGetUniformLocation( program, "vLight0" );
    params->material_diffuse_ = glGetUniformLocation( program, "vMaterialDiffuse" );
    params->material_ambient_ = glGetUniformLocation( program, "vMaterialAmbient" );
    params->material_specular_ = glGetUniformLocation( program, "vMaterialSpecular" );

    // Release vertex and fragment shaders
    if( vertShader )
        glDeleteShader( vertShader );
    if( fragShader )
        glDeleteShader( fragShader );

    params->program_ = program;
    return true;
}

bool MoreTeapotsRenderer::LoadShadersES3( SHADER_PARAMS* params,
        const char* strVsh,
        const char* strFsh,
        std::map<std::string, std::string>&shaderParams )
{
    //
    //Shader load for GLES3
    //In GLES3.0, shader attribute index can be described in a shader code directly with layout() attribute
    //
    GLuint program;
    GLuint vertShader, fragShader;
    char *vertShaderPathname, *fragShaderPathname;

    // Create shader program
    program = glCreateProgram();
    LOGI( "Created Shader %d", program );

    // Create and compile vertex shader
    if( !ndk_helper::shader::CompileShader( &vertShader, GL_VERTEX_SHADER, strVsh, shaderParams ) )
    {
        LOGI( "Failed to compile vertex shader" );
        glDeleteProgram( program );
        return false;
    }

    // Create and compile fragment shader
    if( !ndk_helper::shader::CompileShader( &fragShader, GL_FRAGMENT_SHADER, strFsh,
            shaderParams ) )
    {
        LOGI( "Failed to compile fragment shader" );
        glDeleteProgram( program );
        return false;
    }

    // Attach vertex shader to program
    glAttachShader( program, vertShader );

    // Attach fragment shader to program
    glAttachShader( program, fragShader );

    // Link program
    if( !ndk_helper::shader::LinkProgram( program ) )
    {
        LOGI( "Failed to link program: %d", program );

        if( vertShader )
        {
            glDeleteShader( vertShader );
            vertShader = 0;
        }
        if( fragShader )
        {
            glDeleteShader( fragShader );
            fragShader = 0;
        }
        if( program )
        {
            glDeleteProgram( program );
        }

        return false;
    }

    // Get uniform locations
    params->light0_ = glGetUniformLocation( program, "vLight0" );
    params->material_ambient_ = glGetUniformLocation( program, "vMaterialAmbient" );
    params->material_specular_ = glGetUniformLocation( program, "vMaterialSpecular" );

    // Release vertex and fragment shaders
    if( vertShader )
        glDeleteShader( vertShader );
    if( fragShader )
        glDeleteShader( fragShader );

    params->program_ = program;
    return true;
}

//--------------------------------------------------------------------------------
// Bind
//--------------------------------------------------------------------------------
bool MoreTeapotsRenderer::Bind( ndk_helper::TapCamera* camera )
{
    camera_ = camera;
    return true;
}

//--------------------------------------------------------------------------------
// Helper functions
//--------------------------------------------------------------------------------
std::string MoreTeapotsRenderer::ToString( const int32_t i )
{
    char str[64];
    snprintf( str, sizeof(str), "%d", i );
    return std::string( str );
}