/** 
 * @file lldrawpoolwlsky.cpp
 * @brief LLDrawPoolWLSky class implementation
 *
 * $LicenseInfo:firstyear=2007&license=viewergpl$
 * 
 * Copyright (c) 2007-2007, Linden Research, Inc.
 * 
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
 * the GPL can be found in doc/GPL-license.txt in this distribution, or
 * online at http://secondlife.com/developers/opensource/gplv2
 * 
 * There are special exceptions to the terms and conditions of the GPL as
 * it is applied to this Source Code. View the full text of the exception
 * in the file doc/FLOSS-exception.txt in this software distribution, or
 * online at http://secondlife.com/developers/opensource/flossexception
 * 
 * By copying, modifying or distributing this software, you acknowledge
 * that you have read and understood your obligations described above,
 * and agree to abide by those obligations.
 * 
 * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
 * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
 * COMPLETENESS OR PERFORMANCE.
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "lldrawpoolwlsky.h"

#include "llerror.h"
#include "llgl.h"
#include "pipeline.h"
#include "llviewercamera.h"
#include "llimage.h"
#include "llwlparammanager.h"
#include "llsky.h"
#include "llvowlsky.h"
#include "llagent.h"
#include "llviewerregion.h"
#include "llface.h"
#include "llglimmediate.h"

LLPointer<LLImageGL> LLDrawPoolWLSky::sCloudNoiseTexture = NULL;

LLPointer<LLImageRaw> LLDrawPoolWLSky::sCloudNoiseRawImage = NULL;



LLDrawPoolWLSky::LLDrawPoolWLSky(void) :
	LLDrawPool(POOL_WL_SKY)
{
	const LLString cloudNoiseFilename(gDirUtilp->getExpandedFilename(LL_PATH_APP_SETTINGS, "windlight", "clouds2.tga"));
	llinfos << "loading WindLight cloud noise from " << cloudNoiseFilename << llendl;

	LLPointer<LLImageFormatted> cloudNoiseFile(LLImageFormatted::createFromExtension(cloudNoiseFilename));

	if(cloudNoiseFile.isNull()) {
		llerrs << "Error: Failed to load cloud noise image " << cloudNoiseFilename << llendl;
	}

	cloudNoiseFile->load(cloudNoiseFilename);

	sCloudNoiseRawImage = new LLImageRaw();

	cloudNoiseFile->decode(sCloudNoiseRawImage, 0.0f);

	LLImageGL::create(sCloudNoiseTexture, sCloudNoiseRawImage, TRUE);

	LLWLParamManager::instance()->propagateParameters();
}

LLDrawPoolWLSky::~LLDrawPoolWLSky()
{
	//llinfos << "destructing wlsky draw pool." << llendl;
	sCloudNoiseTexture = 0;
}

LLViewerImage *LLDrawPoolWLSky::getDebugTexture()
{
	return NULL;
}

void LLDrawPoolWLSky::beginRenderPass( S32 pass )
{
}

void LLDrawPoolWLSky::endRenderPass( S32 pass )
{
}

void LLDrawPoolWLSky::renderDome(F32 camHeightLocal, LLGLSLShader * shader) const
{
	LLVector3 const & origin = LLViewerCamera::getInstance()->getOrigin();

	llassert_always(NULL != shader);

	glPushMatrix();

	//chop off translation
	if (LLPipeline::sReflectionRender && origin.mV[2] > 256.f)
	{
		glTranslatef(origin.mV[0], origin.mV[1], 256.f-origin.mV[2]*0.5f);
	}
	else
	{
		glTranslatef(origin.mV[0], origin.mV[1], origin.mV[2]);
	}
		

	// the windlight sky dome works most conveniently in a coordinate system
	// where Y is up, so permute our basis vectors accordingly.
	glRotatef(120.f, 1.f / F_SQRT3, 1.f / F_SQRT3, 1.f / F_SQRT3);

	glScalef(0.333f, 0.333f, 0.333f);

	glTranslatef(0.f,-camHeightLocal, 0.f);
	
	// Draw WL Sky	
	shader->uniform3f("camPosLocal", 0.f, camHeightLocal, 0.f);

	gSky.mVOWLSkyp->drawDome();

	glPopMatrix();
}

void LLDrawPoolWLSky::renderSkyHaze(F32 camHeightLocal) const
{
	if (gPipeline.canUseWindLightShaders() && gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_SKY))
	{
		LLGLSLShader* shader =
			LLPipeline::sUnderWaterRender ?
				&gObjectSimpleWaterProgram :
				&gWLSkyProgram;

		LLGLDisable blend(GL_BLEND);

		shader->bind();

		/// Render the skydome
		renderDome(camHeightLocal, shader);	

		shader->unbind();
	}
}

void LLDrawPoolWLSky::renderStars(void) const
{
	LLGLSPipelineSkyBox gls_sky;
	LLGLEnable blend(GL_BLEND);
	gGL.blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	
	// *NOTE: have to have bound the cloud noise texture already since register
	// combiners blending below requires something to be bound
	// and we might as well only bind once.
	//LLGLEnable gl_texture_2d(GL_TEXTURE_2D);
	
	gPipeline.disableLights();

	if (!LLPipeline::sReflectionRender)
	{
		glPointSize(2.f);
	}

	// *NOTE: we divide by two here and GL_ALPHA_SCALE by two below to avoid
	// clamping and allow the star_alpha param to brighten the stars.
	bool error;
	LLColor4 star_alpha(LLColor4::black);
	star_alpha.mV[3] = LLWLParamManager::instance()->mCurParams.getFloat("star_brightness", error) / 2.f;
	llassert_always(!error);

	// gl_FragColor.rgb = gl_Color.rgb;
	// gl_FragColor.a = gl_Color.a * star_alpha.a;
	glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
	glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE);
	glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_MODULATE);
	glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS);
	glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
	glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS);
	glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA_ARB, GL_SRC_ALPHA);
	glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_ALPHA_ARB, GL_CONSTANT);
	glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA_ARB, GL_SRC_ALPHA);
	glTexEnvf(GL_TEXTURE_ENV, GL_ALPHA_SCALE, 2.0f);
	glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, star_alpha.mV);

	gSky.mVOWLSkyp->drawStars();

	glPointSize(1.f);

	// and disable the combiner states
	glTexEnvf(GL_TEXTURE_ENV, GL_ALPHA_SCALE, 1.0f);
	glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
}

void LLDrawPoolWLSky::renderSkyClouds(F32 camHeightLocal) const
{
	if (gPipeline.canUseWindLightShaders() && gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_CLOUDS))
	{
		LLGLSLShader* shader =
			LLPipeline::sUnderWaterRender ?
				&gObjectSimpleWaterProgram :
				&gWLCloudProgram;

		LLGLEnable blend(GL_BLEND);
		LLGLSBlendFunc blendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		glAlphaFunc(GL_GREATER, 0.01f);

		sCloudNoiseTexture->bind();
		shader->bind();

		/// Render the skydome
		renderDome(camHeightLocal, shader);

		shader->unbind();
	}
}

void LLDrawPoolWLSky::renderHeavenlyBodies()
{
	LLGLSPipelineSkyBox gls_skybox;
	LLGLEnable blend_on(GL_BLEND);
	gPipeline.disableLights();

#if 0 // when we want to re-add a texture sun disc, here's where to do it.
	LLFace * face = gSky.mVOSkyp->mFace[LLVOSky::FACE_SUN];
	if (gSky.mVOSkyp->getSun().getDraw() && face->getGeomCount())
	{
		LLImageGL * tex  = face->getTexture();
		tex->bind();
		LLColor4 color(gSky.mVOSkyp->getSun().getInterpColor());
		LLFacePool::LLOverrideFaceColor color_override(this, color);
		face->renderIndexed();
	}
#endif

	LLFace * face = gSky.mVOSkyp->mFace[LLVOSky::FACE_MOON];

	if (gSky.mVOSkyp->getMoon().getDraw() && face->getGeomCount())
	{
		// *NOTE: even though we already bound this texture above for the
		// stars register combiners, we bind again here for defensive reasons,
		// since LLImageGL::bind detects that it's a noop, and optimizes it out.
		LLImageGL * tex  = face->getTexture();
		tex->bind();
		LLColor4 color(gSky.mVOSkyp->getMoon().getInterpColor());
		F32 a = gSky.mVOSkyp->getMoon().getDirection().mV[2];
		if (a > 0.f)
		{
			a = a*a*4.f;
		}
			
		color.mV[3] = llclamp(a, 0.f, 1.f);
		
		LLFacePool::LLOverrideFaceColor color_override(this, color);
		face->renderIndexed();
	}
}

void LLDrawPoolWLSky::render(S32 pass)
{
	if (!gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_SKY))
	{
		return;
	}
	LLFastTimer ftm(LLFastTimer::FTM_RENDER_WL_SKY);

	const F32 camHeightLocal = LLWLParamManager::instance()->getDomeOffset() * LLWLParamManager::instance()->getDomeRadius();

	LLGLSNoFog disableFog;
	LLGLDepthTest depth(GL_TRUE, GL_FALSE);
	LLGLDisable clip(GL_CLIP_PLANE0);

	LLGLClampToFarClip far_clip(glh_get_current_projection());

	renderSkyHaze(camHeightLocal);

	LLVector3 const & origin = LLViewerCamera::getInstance()->getOrigin();
	glPushMatrix();

		glTranslatef(origin.mV[0], origin.mV[1], origin.mV[2]);

		// *NOTE: have to bind a texture here since register combiners blending in
		// renderStars() requires something to be bound and we might as well only
		// bind the moon's texture once.
		LLImageGL * tex  = gSky.mVOSkyp->mFace[LLVOSky::FACE_MOON]->getTexture();
		tex->bind();

		renderHeavenlyBodies();

		renderStars();
		

	glPopMatrix();

	renderSkyClouds(camHeightLocal);

	LLImageGL::unbindTexture(0);
}

void LLDrawPoolWLSky::prerender()
{
	//llinfos << "wlsky prerendering pass." << llendl;
}

LLDrawPoolWLSky *LLDrawPoolWLSky::instancePool()
{
	return new LLDrawPoolWLSky();
}

LLViewerImage* LLDrawPoolWLSky::getTexture()
{
	return NULL;
}

void LLDrawPoolWLSky::resetDrawOrders()
{
}

//static
void LLDrawPoolWLSky::cleanupGL()
{
	sCloudNoiseTexture = NULL;
}

//static
void LLDrawPoolWLSky::restoreGL()
{
	LLImageGL::create(sCloudNoiseTexture, sCloudNoiseRawImage, TRUE);
}