source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/SkyPreetham.cpp @ 2954

#include "SkyPreetham.h"
//#include <rendering/effect/FEffect.h>
//#include <rendering/FVertexbuffer.h>




using namespace CHCDemoEngine;


SkyPreetham::SkyPreetham():
        mEffect(NULL),
        mTurbidity(4.0),
        mSunEffect(NULL),
        mSunTexture(NULL),
        mSunQuad(NULL)
{
        mEffect = D().getScene().getEffect("../effects/sky_preetham.fx");

        mVertexBuffer = D().getScene().getVertexBuffer("../models/sky.vbo");

        mSunEffect = D().getScene().getEffect("../effects/sky_sun.fx");
        mSunTexture = D().getScene().getTexture2D("../textures/sky_sun.png");

        createSunQuad();
}


SkyPreetham::~SkyPreetham()
{
        FDelete(mSunQuad);
}



void SkyPreetham::Compute()
{

        FVector2 sun_theta;
        FVector3 l_dir = D().getScene().getLight().getDirection();
        mTurbidity = D().getScene().getLight().getTurbitity();

        sun_theta.x = acos(l_dir.y);
        sun_theta.y = cos( sun_theta.x ) * cos( sun_theta.x );


#define CBQ(X)          ((X) * (X) * (X))
#define SQR(X)          ((X) * (X))

        const double PI = (double)3.1415926535897932;

        FVector3 zenithColor;

        zenithColor.x  = ( 0.00165f * CBQ(sun_theta.x) - 0.00374f  * SQR(sun_theta.x) +
                0.00208f *       sun_theta.x  +     0.0f) * SQR(mTurbidity) +
                (-0.02902f * CBQ(sun_theta.x) + 0.06377f  * SQR(sun_theta.x) -
                0.03202f *       sun_theta.x  + 0.00394f) *        mTurbidity +
                ( 0.11693f * CBQ(sun_theta.x) - 0.21196f  * SQR(sun_theta.x) +
                0.06052f *       sun_theta.x + 0.25885f);

        zenithColor.y  = ( 0.00275f * CBQ(sun_theta.x) - 0.00610f  * SQR(sun_theta.x) +
                0.00316f *       sun_theta.x +     0.0f) * SQR(mTurbidity) +
                (-0.04214f * CBQ(sun_theta.x) + 0.08970f  * SQR(sun_theta.x) -
                0.04153f *       sun_theta.x  + 0.00515f) *        mTurbidity  +
                ( 0.15346f * CBQ(sun_theta.x) - 0.26756f  * SQR(sun_theta.x) +
                0.06669f *       sun_theta.x  + 0.26688f);

        zenithColor.z  = (float)((4.0453f * mTurbidity - 4.9710f) *
                tan((4.0f / 9.0f - mTurbidity / 120.0f) * (PI - 2.0f * sun_theta.x)) -
                0.2155f * mTurbidity + 2.4192f);
        // convert kcd/m² to cd/m²
        zenithColor.z *= 1000;

        double ABCDE_x[5], ABCDE_y[5], ABCDE_Y[5];

        ABCDE_x[0] = -0.01925 * mTurbidity   - 0.25922;
        ABCDE_x[1] = -0.06651 * mTurbidity   + 0.00081;
        ABCDE_x[2] = -0.00041 * mTurbidity   + 0.21247;
        ABCDE_x[3] = -0.06409 * mTurbidity   - 0.89887;
        ABCDE_x[4] = -0.00325 * mTurbidity   + 0.04517;

        ABCDE_y[0] = -0.01669 * mTurbidity  - 0.26078;
        ABCDE_y[1] = -0.09495 * mTurbidity   + 0.00921;
        ABCDE_y[2] = -0.00792 * mTurbidity   + 0.21023;
        ABCDE_y[3] = -0.04405 * mTurbidity   - 1.65369;
        ABCDE_y[4] = -0.01092 * mTurbidity   + 0.05291;

        ABCDE_Y[0] =  0.17872 * mTurbidity   - 1.46303;
        ABCDE_Y[1] = -0.35540 * mTurbidity   + 0.42749;
        ABCDE_Y[2] = -0.02266 * mTurbidity   + 5.32505;
        ABCDE_Y[3] =  0.12064 * mTurbidity   - 2.57705;
        ABCDE_Y[4] = -0.06696 * mTurbidity   + 0.37027;


        F().getRenderDevice().setDefaultDepthStencilMode(FRenderDevice::DEPTHSTENCIL_TEST_NO_OVERWRITE);

        // Move skybox with camera.
        mPosition = D().getScene().getCamera().getPosition();

        mPosition.y -= 2.0;

        setTransform();

        mEffect->setVariableVector3("LightDirection", D().getScene().getLight().getDirection());
        mEffect->setVariableVector2("ThetaSun", sun_theta);
        mEffect->setVariableVector3("ZenithColor", zenithColor);
        mEffect->setVariableVector3("AColor",FVector3((FFloat)ABCDE_x[0], (FFloat)ABCDE_y[0], (FFloat)ABCDE_Y[0]));
        mEffect->setVariableVector3("BColor",FVector3((FFloat)ABCDE_x[1], (FFloat)ABCDE_y[1], (FFloat)ABCDE_Y[1]));
        mEffect->setVariableVector3("CColor",FVector3((FFloat)ABCDE_x[2], (FFloat)ABCDE_y[2], (FFloat)ABCDE_Y[2]));
        mEffect->setVariableVector3("DColor",FVector3((FFloat)ABCDE_x[3], (FFloat)ABCDE_y[3], (FFloat)ABCDE_Y[3]));
        mEffect->setVariableVector3("EColor",FVector3((FFloat)ABCDE_x[4], (FFloat)ABCDE_y[4], (FFloat)ABCDE_Y[4]));


        mEffect->activate();

        F().getRenderDevice().setDefaultPolygonMode(true, FRenderDevice::CULL_NONE);

        // Render sky dome.
        mVertexBuffer->render();

        // Render additively blended sun disc.
        renderSunDisk();

        F().getRenderDevice().setDefaultPolygonMode(true, FRenderDevice::CULL_BACKFACES);


        F().getRenderDevice().setDefaultDepthStencilMode(FRenderDevice::DEPTHSTENCIL_TEST_AND_OVERWRITE);
}


void SkyPreetham::renderSunDisk()
{
        F().getRenderDevice().setDefaultBlendingMode(FRenderDevice::BLENDING_ADDITIVE);

        // Set world matrix to sun disc position.
        FMatrix4 sunposition;
        sunposition.translate(D().getScene().getCamera().getPosition());
        sunposition.rotateAroundY(-D().getScene().getLight().getHorizontalOrientation() + 90.0f);
        sunposition.rotateAroundX(-D().getScene().getLight().getVerticalOrientation());
        F().getRenderDevice().getTransform().setWorldMatrix(sunposition);

        FVector3 lightdirection = D().getScene().getLight().getDirection();
        FFloat size = 0.5f + (1.0f - lightdirection.y) * 0.5f;

        mSunEffect->setVariableVector3("LightDiffuseColor", D().getScene().getLight().getDiffuseColor());
        mSunEffect->setVariableFloat("SunSize", size);
        mSunEffect->setVariableTexture2D("SunTexture", mSunTexture);

        mSunEffect->activate();
        
        mSunQuad->render();

        mSunEffect->deactivate();

        F().getRenderDevice().setDefaultBlendingMode(FRenderDevice::BLENDING_NONE);
}


void SkyPreetham::createSunQuad()
{
        mSunQuad = new FVertexBuffer();
        mSunQuad->setupPrimitiveType(FVertexBuffer::PRIMITIVES_TRIANGLES);
        mSunQuad->setupVertexFormat(3, 0, 0, true);
        mSunQuad->setupTexCoordSet(0, 2);
        mSunQuad->setVertexBufferSize(4, 6);

        mSunQuad->setVertexPosition(0, FVector3(-0.1f,  0.1f, 1.0f));
        mSunQuad->setVertexPosition(1, FVector3( 0.1f,  0.1f, 1.0f));
        mSunQuad->setVertexPosition(2, FVector3(-0.1f, -0.1f, 1.0f));
        mSunQuad->setVertexPosition(3, FVector3( 0.1f, -0.1f, 1.0f));
        mSunQuad->setVertexTexCoord(0, 0, FVector2(0.0f, 0.0f));
        mSunQuad->setVertexTexCoord(1, 0, FVector2(1.0f, 0.0f));
        mSunQuad->setVertexTexCoord(2, 0, FVector2(0.0f, 1.0f));
        mSunQuad->setVertexTexCoord(3, 0, FVector2(1.0f, 1.0f));

        mSunQuad->setIndex(0, 0);
        mSunQuad->setIndex(1, 1);
        mSunQuad->setIndex(2, 2);
        mSunQuad->setIndex(3, 2);
        mSunQuad->setIndex(4, 1);
        mSunQuad->setIndex(5, 3);
}