/*

 Copyright (C) 2015 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The renderer class creates and draws the OpenGL shaders.

 */

#ifndef __RENDERER__

#define __RENDERER__

#import <OpenGL/gl3.h>

#import <OpenGL/gl3ext.h>

#import <GLKit/GLKMath.h>

#import <GLKit/GLKMatrixStack.h>

#include <stdint.h>

#include <stdio.h>

#include "GeoUtils.h"

const uint32_t kShaderCount = 5;

const uint32_t kNumMRT = 3; // multiple render targets (MRT)

const uint32_t kNumFBO = 1;

const uint32_t kNumTextures = 4;

enum

{

    kFinalImage,

    kPositionBuffer,

    kAlbedoBuffer,

    kNormalBuffer,

};

class OpenGLRenderer

{

    const GLubyte* rendererString;

    char* resourcePath;

    uint32_t width, height;

    mat4 cameraMatrix;

    GLint shaders[kShaderCount];

    GLint recordGBufferDataPass, deferredLightingPass, displayTextureContentsPass;

    GLuint fbos[kNumFBO];

    GLuint tex[kNumTextures];

    GLuint orientationMatrixLocation, cameraTransformLocation, colorLocation,

            normTexLocation, positionTexLocation,

            colorTexLocation,

            light1Pos, light1Color,

            light2Pos, light2Color,

            light3Pos, light3Color,

            light4Pos, light4Color;

    GLint projectionUniformIdx;

    //for visualization of the buffers

    GLint displayTexLocation;

    GLuint quadID, quadElementID;

    GLuint teapotVertexId, teapotNormalId, teapotElementId; //Lili

    GLuint cube_vertices, cube_indices;

    GLenum buffers[kNumMRT];

    uint8_t showBuffer;

    uint8_t animationStep, animate;

    float animationDelta;

    uint32_t kAnimationLoopValue;

    vec4 l1Pos, l2Pos, l3Pos, l4Pos;

    vec3 l1Color, l2Color, l3Color, l4Color;

public:

    OpenGLRenderer();

    OpenGLRenderer(const char* pathToResources, size_t len);

    ~OpenGLRenderer();

    const char* getRendererString()

    {

        return (const char*) rendererString;

    }

    bool setupQuad();

    bool setupTeapot();

    bool setupGL();

    void resizeViewport(uint32_t w, uint32_t h);

    void draw();

    void updateAnimations();

    void updateGBufferContents();

    void showPositionBuffer();

    void showNormalBuffer();

    void showAlbedoBuffer();

    void showFinalImage();

    void drawQuad();

    void attachShadersToProgram(GLint program, GLint vertShaderID, GLint fragShaderID);

    GLboolean linkAndValidateProgram(GLint program, GLint vertShaderID, GLint fragShaderID);

    GLshort loadShaders();

    GLboolean loadShaderFromFile(const char* shaderName, GLenum shaderType, GLint* shaderID);

    void setShowBuffer(uint8_t buf) 

    { 

        showBuffer = buf; 

    }

    void toggleAnimation()

    {

        animate = !animate;

    }

    void resetAnimation()

    {

        animationStep = 0;

    }

    void setAnimationDelta(float d)

    {

        animationDelta = d;

        kAnimationLoopValue = 360.0 / animationDelta;

    }

};

#endif