axmol/cocos/vr/CCVRGenericRenderer.cpp

/****************************************************************************
 Copyright (c) 2016 Chukong Technologies Inc.

 http://www.cocos2d-x.org

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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 THE SOFTWARE.
 ****************************************************************************/

#include "platform/CCPlatformMacros.h"
#include "vr/CCVRGenericRenderer.h"
#include "vr/CCVRDistortionMesh.h"
#include "vr/CCVRDistortion.h"
#include "vr/CCVRGenericHeadTracker.h"
#include "renderer/CCRenderer.h"
#include "renderer/CCGLProgramState.h"
#include "renderer/ccGLStateCache.h"
#include "base/CCDirector.h"
#include "2d/CCScene.h"
#include "2d/CCCamera.h"
#include "2d/CCSprite.h"
#include "platform/CCGLView.h"


NS_CC_BEGIN

VRGenericRenderer::VRGenericRenderer()
: _vignetteEnabled(true)
, _distortion(nullptr)
, _leftDistortionMesh(nullptr)
, _rightDistortionMesh(nullptr)
, _glProgramState(nullptr)
{
    _headTracker = new VRGenericHeadTracker;
}

VRGenericRenderer::~VRGenericRenderer()
{
    CC_SAFE_DELETE(_headTracker);
    CC_SAFE_RELEASE(_glProgramState);
    CC_SAFE_RELEASE(_fb);
    CC_SAFE_DELETE(_distortion);
    CC_SAFE_DELETE(_leftDistortionMesh);
    CC_SAFE_DELETE(_rightDistortionMesh);
}

void VRGenericRenderer::setup(GLView* glview)
{
//    CC_UNUSED(glview);

    // set origin to 0,0 in case origin is not 0,0
    auto vp = Camera::getDefaultViewport();

    _leftEye.viewport._bottom = vp._bottom/2 + vp._height/4;
    _leftEye.viewport._left = vp._left/4;
    _leftEye.viewport._width = vp._width/2;
    _leftEye.viewport._height = vp._height/2;

    _rightEye.viewport._bottom = vp._bottom/2 + vp._height/4;
    _rightEye.viewport._left = _leftEye.viewport._width + vp._left/2;
    _rightEye.viewport._width = vp._width/2;
    _rightEye.viewport._height = vp._height/2;


    _texSize = Size(vp._width, vp._height);

    _fb = experimental::FrameBuffer::create(1, _texSize.width, _texSize.height);
    _fb->retain();
    auto rt = experimental::RenderTarget::create(_texSize.width, _texSize.height);
    auto ds = experimental::RenderTargetDepthStencil::create(_texSize.width, _texSize.height);
    _fb->attachRenderTarget(rt);
    _fb->attachDepthStencilTarget(ds);
    _fb->setClearColor(Color4F(0,0,0,1));

    _distortion = new Distortion;
    _leftDistortionMesh = createDistortionMesh(VREye::EyeType::LEFT);
    _rightDistortionMesh = createDistortionMesh(VREye::EyeType::RIGHT);

    setupGLProgram();
}

void VRGenericRenderer::cleanup()
{
}

VRIHeadTracker* VRGenericRenderer::getHeadTracker()
{
    return _headTracker;
}

void VRGenericRenderer::render(Scene* scene, Renderer* renderer)
{
    // FIXME: Use correct eye displacement
    const float eyeOffset = 0.5;

    auto headRotation = _headTracker->getLocalRotation();
    Mat4 leftTransform;
    Mat4::createTranslation(eyeOffset, 0, 0, &leftTransform);
    leftTransform *= headRotation;

    Mat4 rightTransform;
    Mat4::createTranslation(-eyeOffset, 0, 0, &rightTransform);
    rightTransform *= headRotation;

    _fb->applyFBO();
    auto defaultVP = Camera::getDefaultViewport();
    Camera::setDefaultViewport(_leftEye.viewport);
    scene->render(renderer, leftTransform, nullptr);
    Camera::setDefaultViewport(_rightEye.viewport);
    scene->render(renderer, rightTransform, nullptr);
    Camera::setDefaultViewport(defaultVP);
    _fb->restoreFBO();

    auto texture = _fb->getRenderTarget()->getTexture();
    GL::bindTexture2D(texture->getName());
    _glProgramState->apply(Mat4::IDENTITY);

    GLint origViewport[4];
    glGetIntegerv(GL_VIEWPORT, origViewport);
    glViewport(0, 0, _texSize.width, _texSize.height);

    renderDistortionMesh(_leftDistortionMesh, texture->getName());
    renderDistortionMesh(_rightDistortionMesh, texture->getName());


    glViewport(origViewport[0], origViewport[1], origViewport[2], origViewport[3]);

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

    CHECK_GL_ERROR_DEBUG();
}

void VRGenericRenderer::renderDistortionMesh(DistortionMesh *mesh, GLint textureID)
{
    glBindBuffer(GL_ARRAY_BUFFER, mesh->_arrayBufferID);

    _glProgramState->setVertexAttribPointer("a_position", 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(0 * sizeof(float)));
    _glProgramState->setVertexAttribPointer("a_textureCoord", 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(2 * sizeof(float)));
    _glProgramState->setVertexAttribPointer("a_vignette", 1, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(4 * sizeof(float)));
    _glProgramState->setUniformTexture("u_textureSampler", textureID);

    _glProgramState->apply(Mat4::IDENTITY);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->_elementBufferID);
    glDrawElements(GL_TRIANGLE_STRIP, mesh->_indices, GL_UNSIGNED_SHORT, 0);

    CHECK_GL_ERROR_DEBUG();
}

DistortionMesh* VRGenericRenderer::createDistortionMesh(VREye::EyeType eyeType)
{
    auto vp = Camera::getDefaultViewport();

    const float screenWidth = _texSize.width;
    const float screenHeight = _texSize.height;
    const float xEyeOffsetScreen = (eyeType == VREye::EyeType::LEFT) ? screenWidth/4 + vp._left : screenWidth*3/4 + vp._left;
    const float yEyeOffsetScreen = screenHeight/2 + vp._bottom;

    const float textureWidth = _texSize.width;
    const float textureHeight = _texSize.height;
    const float xEyeOffsetTexture = (eyeType == VREye::EyeType::LEFT) ? _texSize.width/4 : _texSize.width*3/4;
    const float yEyeOffsetTexture = _texSize.height/2;

    const float viewportX = (eyeType == VREye::EyeType::LEFT) ? 0 : textureWidth/2;
    const float viewportY = 0;
    const float viewportW = textureWidth/2;
    const float viewportH = textureHeight;

    return new DistortionMesh(_distortion,
                              screenWidth, screenHeight,
                              xEyeOffsetScreen, yEyeOffsetScreen,
                              textureWidth, textureHeight,
                              xEyeOffsetTexture, yEyeOffsetTexture,
                              viewportX, viewportY,
                              viewportW, viewportH,
                              _vignetteEnabled);
}

void VRGenericRenderer::setupGLProgram()
{
    const GLchar *vertexShader =
    "\
    attribute vec2 a_position;\n\
    attribute vec2 a_textureCoord;\n\
    attribute float a_vignette;\n\
    varying vec2 v_textureCoord;\n\
    varying float v_vignette;\n\
    void main() {\n\
    gl_Position = vec4(a_position, 0.0, 1.0);\n\
    v_textureCoord = a_textureCoord.xy;\n\
    v_vignette = a_vignette;\n\
    }\n";

    const GLchar *fragmentShader =
    "\
    #ifdef GL_ES\n\
    precision mediump float;\n\
    #endif\n\
    varying vec2 v_textureCoord;\n\
    varying float v_vignette;\n\
    uniform sampler2D u_textureSampler;\n\
    void main() {\n\
    gl_FragColor = v_vignette * texture2D(u_textureSampler, v_textureCoord);\n\
    }\n";

    auto program = GLProgram::createWithByteArrays(vertexShader, fragmentShader);
    _glProgramState = GLProgramState::getOrCreateWithGLProgram(program);

    _glProgramState->retain();
}

NS_CC_END