/** 
 * @file lldrawpoolterrain.cpp
 * @brief LLDrawPoolTerrain class implementation
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "lldrawpoolterrain.h"

#include "llfasttimer.h"

#include "llagent.h"
#include "llviewercontrol.h"
#include "lldrawable.h"
#include "llface.h"
#include "llsky.h"
#include "llsurface.h"
#include "llsurfacepatch.h"
#include "llviewerregion.h"
#include "llvlcomposition.h"
#include "llviewerparcelmgr.h"		// for gRenderParcelOwnership
#include "llviewerparceloverlay.h"
#include "llvosurfacepatch.h"
#include "llviewercamera.h"
#include "llviewertexturelist.h" // To get alpha gradients
#include "llworld.h"
#include "pipeline.h"
#include "llviewershadermgr.h"
#include "llrender.h"
#include "llenvironment.h"
#include "llsettingsvo.h"

const F32 DETAIL_SCALE = 1.f/16.f;
int DebugDetailMap = 0;

S32 LLDrawPoolTerrain::sDetailMode = 1;
F32 LLDrawPoolTerrain::sDetailScale = DETAIL_SCALE;
static LLGLSLShader* sShader = NULL;
static LLTrace::BlockTimerStatHandle FTM_SHADOW_TERRAIN("Terrain Shadow");


LLDrawPoolTerrain::LLDrawPoolTerrain(LLViewerTexture *texturep) :
	LLFacePool(POOL_TERRAIN),
	mTexturep(texturep)
{
	// Hack!
	sDetailScale = 1.f/gSavedSettings.getF32("RenderTerrainScale");
	sDetailMode = gSavedSettings.getS32("RenderTerrainDetail");
	mAlphaRampImagep = LLViewerTextureManager::getFetchedTexture(IMG_ALPHA_GRAD);

	//gGL.getTexUnit(0)->bind(mAlphaRampImagep.get());
	mAlphaRampImagep->setAddressMode(LLTexUnit::TAM_CLAMP);

	m2DAlphaRampImagep = LLViewerTextureManager::getFetchedTexture(IMG_ALPHA_GRAD_2D);

	//gGL.getTexUnit(0)->bind(m2DAlphaRampImagep.get());
	m2DAlphaRampImagep->setAddressMode(LLTexUnit::TAM_CLAMP);
	
	mTexturep->setBoostLevel(LLGLTexture::BOOST_TERRAIN);
	
	//gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
}

LLDrawPoolTerrain::~LLDrawPoolTerrain()
{
	llassert( gPipeline.findPool( getType(), getTexture() ) == NULL );
}

U32 LLDrawPoolTerrain::getVertexDataMask() 
{ 
	if (LLPipeline::sShadowRender)
	{
		return LLVertexBuffer::MAP_VERTEX;
	}
	else if (LLGLSLShader::sCurBoundShaderPtr)
	{
		return VERTEX_DATA_MASK & ~(LLVertexBuffer::MAP_TEXCOORD2 | LLVertexBuffer::MAP_TEXCOORD3);
	}
	else
	{
		return VERTEX_DATA_MASK; 
	}
}

void LLDrawPoolTerrain::prerender()
{
	sDetailMode = gSavedSettings.getS32("RenderTerrainDetail");
}

//static
S32 LLDrawPoolTerrain::getDetailMode()
{
	return sDetailMode;
}

void LLDrawPoolTerrain::boostTerrainDetailTextures()
{
    // Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();
	for (S32 i = 0; i < 4; i++)
	{
        constexpr LLGLTexture::EBoostLevel level = LLGLTexture::BOOST_TERRAIN;
        constexpr float stats = 1024.f * 1024.f;

        LLPointer<LLViewerFetchedTexture>& tex = compp->mDetailTextures[i];
        llassert(tex.notNull());
		tex->setBoostLevel(level);
        tex->addTextureStats(stats);

        LLPointer<LLFetchedGLTFMaterial>& mat = compp->mDetailMaterials[i];
        llassert(mat.notNull());
        if (mat->mBaseColorTexture)
        {
            mat->mBaseColorTexture->setBoostLevel(level);
            mat->mBaseColorTexture->addTextureStats(stats);
        }
        if (mat->mNormalTexture)
        {
            mat->mNormalTexture->setBoostLevel(level);
            mat->mNormalTexture->addTextureStats(stats);
        }
        if (mat->mMetallicRoughnessTexture)
        {
            mat->mMetallicRoughnessTexture->setBoostLevel(level);
            mat->mMetallicRoughnessTexture->addTextureStats(stats);
        }
        if (mat->mEmissiveTexture)
        {
            mat->mEmissiveTexture->setBoostLevel(level);
            mat->mEmissiveTexture->addTextureStats(stats);
        }
	}
}

void LLDrawPoolTerrain::beginDeferredPass(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_RENDER_TERRAIN);
	LLFacePool::beginRenderPass(pass);
}

void LLDrawPoolTerrain::endDeferredPass(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_RENDER_TERRAIN);
	LLFacePool::endRenderPass(pass);
	sShader->unbind();
}

void LLDrawPoolTerrain::renderDeferred(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_RENDER_TERRAIN);
	if (mDrawFace.empty())
	{
		return;
	}

    boostTerrainDetailTextures();

	renderFullShader();

	// Special-case for land ownership feedback
	if (gSavedSettings.getBOOL("ShowParcelOwners"))
	{
		hilightParcelOwners();
	}

}

void LLDrawPoolTerrain::beginShadowPass(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_SHADOW_TERRAIN);
	LLFacePool::beginRenderPass(pass);
	gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
	gDeferredShadowProgram.bind();

    LLEnvironment& environment = LLEnvironment::instance();
    gDeferredShadowProgram.uniform1i(LLShaderMgr::SUN_UP_FACTOR, environment.getIsSunUp() ? 1 : 0);
}

void LLDrawPoolTerrain::endShadowPass(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_SHADOW_TERRAIN);
	LLFacePool::endRenderPass(pass);
	gDeferredShadowProgram.unbind();
}

void LLDrawPoolTerrain::renderShadow(S32 pass)
{
	LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; //LL_RECORD_BLOCK_TIME(FTM_SHADOW_TERRAIN);
	if (mDrawFace.empty())
	{
		return;
	}
	//LLGLEnable offset(GL_POLYGON_OFFSET);
	//glCullFace(GL_FRONT);
	drawLoop();
	//glCullFace(GL_BACK);
}


void LLDrawPoolTerrain::drawLoop()
{
	if (!mDrawFace.empty())
	{
		for (std::vector<LLFace*>::iterator iter = mDrawFace.begin();
			 iter != mDrawFace.end(); iter++)
		{
			LLFace *facep = *iter;

			LLMatrix4* model_matrix = &(facep->getDrawable()->getRegion()->mRenderMatrix);

			if (model_matrix != gGLLastMatrix)
			{
				llassert(gGL.getMatrixMode() == LLRender::MM_MODELVIEW);
				gGLLastMatrix = model_matrix;
				gGL.loadMatrix(gGLModelView);
				if (model_matrix)
				{
					gGL.multMatrix((GLfloat*) model_matrix->mMatrix);
				}
				gPipeline.mMatrixOpCount++;
			}

			facep->renderIndexed();
		}
	}
}

void LLDrawPoolTerrain::renderFullShader()
{
	// Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();
    const BOOL use_textures = compp->useTextures();
    
    if (use_textures)
    {
        // Use textures
        sShader = &gDeferredTerrainProgram;
        sShader->bind();
        renderFullShaderTextures();
    }
    else
    {
        // Use materials
        sShader = &gDeferredPBRTerrainProgram;
        sShader->bind();
        renderFullShaderPBR();
    }
}

void LLDrawPoolTerrain::renderFullShaderTextures()
{
	// Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();

	LLViewerTexture *detail_texture0p = compp->mDetailTextures[0];
	LLViewerTexture *detail_texture1p = compp->mDetailTextures[1];
	LLViewerTexture *detail_texture2p = compp->mDetailTextures[2];
	LLViewerTexture *detail_texture3p = compp->mDetailTextures[3];

	LLVector3d region_origin_global = gAgent.getRegion()->getOriginGlobal();
	F32 offset_x = (F32)fmod(region_origin_global.mdV[VX], 1.0/(F64)sDetailScale)*sDetailScale;
	F32 offset_y = (F32)fmod(region_origin_global.mdV[VY], 1.0/(F64)sDetailScale)*sDetailScale;

	LLVector4 tp0, tp1;
	
	tp0.setVec(sDetailScale, 0.0f, 0.0f, offset_x);
	tp1.setVec(0.0f, sDetailScale, 0.0f, offset_y);

	//
	// detail texture 0
	//
	S32 detail0 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL0);
	gGL.getTexUnit(detail0)->bind(detail_texture0p);
    gGL.getTexUnit(detail0)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail0)->activate();

	LLGLSLShader* shader = LLGLSLShader::sCurBoundShaderPtr;
	llassert(shader);
		
	shader->uniform4fv(LLShaderMgr::OBJECT_PLANE_S, 1, tp0.mV);
	shader->uniform4fv(LLShaderMgr::OBJECT_PLANE_T, 1, tp1.mV);

    LLSettingsWater::ptr_t pwater = LLEnvironment::instance().getCurrentWater();

	//
	// detail texture 1
	//
	S32 detail1 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL1); 
	gGL.getTexUnit(detail1)->bind(detail_texture1p);
	gGL.getTexUnit(detail1)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail1)->activate();
	
	// detail texture 2
	//
	S32 detail2 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL2);
	gGL.getTexUnit(detail2)->bind(detail_texture2p);
    gGL.getTexUnit(detail2)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail2)->activate();
	

	// detail texture 3
	//
	S32 detail3 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL3);
	gGL.getTexUnit(detail3)->bind(detail_texture3p);
	gGL.getTexUnit(detail3)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail3)->activate();

	//
	// Alpha Ramp 
	//
	S32 alpha_ramp = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_ALPHARAMP);
	gGL.getTexUnit(alpha_ramp)->bind(m2DAlphaRampImagep);
    gGL.getTexUnit(alpha_ramp)->setTextureAddressMode(LLTexUnit::TAM_CLAMP);

	// GL_BLEND disabled by default
	drawLoop();

	// Disable multitexture
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_ALPHARAMP);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL0);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL1);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL2);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL3);

	gGL.getTexUnit(alpha_ramp)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(alpha_ramp)->disable();
	gGL.getTexUnit(alpha_ramp)->activate();
	
	gGL.getTexUnit(detail3)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail3)->disable();
	gGL.getTexUnit(detail3)->activate();

	gGL.getTexUnit(detail2)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail2)->disable();
	gGL.getTexUnit(detail2)->activate();

	gGL.getTexUnit(detail1)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail1)->disable();
	gGL.getTexUnit(detail1)->activate();
	
	//----------------------------------------------------------------------------
	// Restore Texture Unit 0 defaults
	
	gGL.getTexUnit(detail0)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail0)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail0)->activate();
}

void LLDrawPoolTerrain::renderFullShaderPBR()
{
	// Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();

	LLViewerTexture *detail_texture0p = compp->mDetailMaterials[0]->mBaseColorTexture;
	LLViewerTexture *detail_texture1p = compp->mDetailMaterials[1]->mBaseColorTexture;
	LLViewerTexture *detail_texture2p = compp->mDetailMaterials[2]->mBaseColorTexture;
	LLViewerTexture *detail_texture3p = compp->mDetailMaterials[3]->mBaseColorTexture;
    LLViewerTexture* blank = LLViewerFetchedTexture::sWhiteImagep;
    if (!detail_texture0p) { detail_texture0p = blank; }
    if (!detail_texture1p) { detail_texture1p = blank; }
    if (!detail_texture2p) { detail_texture2p = blank; }
    if (!detail_texture3p) { detail_texture3p = blank; }

	LLVector3d region_origin_global = gAgent.getRegion()->getOriginGlobal();
	F32 offset_x = (F32)fmod(region_origin_global.mdV[VX], 1.0/(F64)sDetailScale)*sDetailScale;
	F32 offset_y = (F32)fmod(region_origin_global.mdV[VY], 1.0/(F64)sDetailScale)*sDetailScale;

	LLVector4 tp0, tp1;
	
	tp0.setVec(sDetailScale, 0.0f, 0.0f, offset_x);
	tp1.setVec(0.0f, sDetailScale, 0.0f, offset_y);

	//
	// detail texture 0
	//
	S32 detail0 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL0);
	gGL.getTexUnit(detail0)->bind(detail_texture0p);
    gGL.getTexUnit(detail0)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail0)->activate();

	LLGLSLShader* shader = LLGLSLShader::sCurBoundShaderPtr;
	llassert(shader);
		
	shader->uniform4fv(LLShaderMgr::OBJECT_PLANE_S, 1, tp0.mV);
	shader->uniform4fv(LLShaderMgr::OBJECT_PLANE_T, 1, tp1.mV);

    LLSettingsWater::ptr_t pwater = LLEnvironment::instance().getCurrentWater();

	//
	// detail texture 1
	//
	S32 detail1 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL1); 
	gGL.getTexUnit(detail1)->bind(detail_texture1p);
	gGL.getTexUnit(detail1)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail1)->activate();
	
	// detail texture 2
	//
	S32 detail2 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL2);
	gGL.getTexUnit(detail2)->bind(detail_texture2p);
    gGL.getTexUnit(detail2)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail2)->activate();
	

	// detail texture 3
	//
	S32 detail3 = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_DETAIL3);
	gGL.getTexUnit(detail3)->bind(detail_texture3p);
	gGL.getTexUnit(detail3)->setTextureAddressMode(LLTexUnit::TAM_WRAP);
	gGL.getTexUnit(detail3)->activate();

	//
	// Alpha Ramp 
	//
	S32 alpha_ramp = sShader->enableTexture(LLViewerShaderMgr::TERRAIN_ALPHARAMP);
	gGL.getTexUnit(alpha_ramp)->bind(m2DAlphaRampImagep);
    gGL.getTexUnit(alpha_ramp)->setTextureAddressMode(LLTexUnit::TAM_CLAMP);

	// GL_BLEND disabled by default
	drawLoop();

	// Disable multitexture
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_ALPHARAMP);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL0);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL1);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL2);
	sShader->disableTexture(LLViewerShaderMgr::TERRAIN_DETAIL3);

	gGL.getTexUnit(alpha_ramp)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(alpha_ramp)->disable();
	gGL.getTexUnit(alpha_ramp)->activate();
	
	gGL.getTexUnit(detail3)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail3)->disable();
	gGL.getTexUnit(detail3)->activate();

	gGL.getTexUnit(detail2)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail2)->disable();
	gGL.getTexUnit(detail2)->activate();

	gGL.getTexUnit(detail1)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail1)->disable();
	gGL.getTexUnit(detail1)->activate();
	
	//----------------------------------------------------------------------------
	// Restore Texture Unit 0 defaults
	
	gGL.getTexUnit(detail0)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail0)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(detail0)->activate();
}

void LLDrawPoolTerrain::hilightParcelOwners()
{
	{ //use fullbright shader for highlighting
		LLGLSLShader* old_shader = sShader;
		sShader->unbind();
		sShader = &gDeferredHighlightProgram;
		sShader->bind();
		gGL.diffuseColor4f(1, 1, 1, 1);
		LLGLEnable polyOffset(GL_POLYGON_OFFSET_FILL);
		glPolygonOffset(-1.0f, -1.0f);
		renderOwnership();
		sShader = old_shader;
		sShader->bind();
	}
	
}

void LLDrawPoolTerrain::renderFull4TU()
{
	// Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();
	LLViewerTexture *detail_texture0p = compp->mDetailTextures[0];
	LLViewerTexture *detail_texture1p = compp->mDetailTextures[1];
	LLViewerTexture *detail_texture2p = compp->mDetailTextures[2];
	LLViewerTexture *detail_texture3p = compp->mDetailTextures[3];

	LLVector3d region_origin_global = gAgent.getRegion()->getOriginGlobal();
	F32 offset_x = (F32)fmod(region_origin_global.mdV[VX], 1.0/(F64)sDetailScale)*sDetailScale;
	F32 offset_y = (F32)fmod(region_origin_global.mdV[VY], 1.0/(F64)sDetailScale)*sDetailScale;

	LLVector4 tp0, tp1;
	
	tp0.setVec(sDetailScale, 0.0f, 0.0f, offset_x);
	tp1.setVec(0.0f, sDetailScale, 0.0f, offset_y);

	gGL.blendFunc(LLRender::BF_ONE_MINUS_SOURCE_ALPHA, LLRender::BF_SOURCE_ALPHA);
	
	//----------------------------------------------------------------------------
	// Pass 1/1

	//
	// Stage 0: detail texture 0
	//
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->bind(detail_texture0p);
	
	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);

	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	//
	// Stage 1: Generate alpha ramp for detail0/detail1 transition
	//

	gGL.getTexUnit(1)->bind(m2DAlphaRampImagep.get());
	gGL.getTexUnit(1)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->activate();
	
	//
	// Stage 2: Interpolate detail1 with existing based on ramp
	//
	gGL.getTexUnit(2)->bind(detail_texture1p);
	gGL.getTexUnit(2)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(2)->activate();

	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	//
	// Stage 3: Modulate with primary (vertex) color for lighting
	//
	gGL.getTexUnit(3)->bind(detail_texture1p);
	gGL.getTexUnit(3)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(3)->activate();
	
	gGL.getTexUnit(0)->activate();
	
	// GL_BLEND disabled by default
	drawLoop();

	//----------------------------------------------------------------------------
	// Second pass

	// Stage 0: Write detail3 into base
	//
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->bind(detail_texture3p);

	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	//
	// Stage 1: Generate alpha ramp for detail2/detail3 transition
	//
	gGL.getTexUnit(1)->bind(m2DAlphaRampImagep);
	gGL.getTexUnit(1)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->activate();

	// Set the texture matrix
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.translatef(-2.f, 0.f, 0.f);

	//
	// Stage 2: Interpolate detail2 with existing based on ramp
	//
	gGL.getTexUnit(2)->bind(detail_texture2p);
	gGL.getTexUnit(2)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(2)->activate();

	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	//
	// Stage 3: Generate alpha ramp for detail1/detail2 transition
	//
	gGL.getTexUnit(3)->bind(m2DAlphaRampImagep);
	gGL.getTexUnit(3)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(3)->activate();

	// Set the texture matrix
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.translatef(-1.f, 0.f, 0.f);
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	gGL.getTexUnit(0)->activate();
	{
		LLGLEnable blend(GL_BLEND);
		drawLoop();
	}

	LLVertexBuffer::unbind();
	// Disable multitexture
	gGL.getTexUnit(3)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(3)->disable();
	gGL.getTexUnit(3)->activate();
	
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	gGL.getTexUnit(2)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(2)->disable();
	gGL.getTexUnit(2)->activate();
	
	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	gGL.getTexUnit(1)->unbind(LLTexUnit::TT_TEXTURE);	
	gGL.getTexUnit(1)->disable();
	gGL.getTexUnit(1)->activate();
 	
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	// Restore blend state
	gGL.setSceneBlendType(LLRender::BT_ALPHA);
	
	//----------------------------------------------------------------------------
	// Restore Texture Unit 0 defaults
	
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);

	
	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);
}

void LLDrawPoolTerrain::renderFull2TU()
{
	// Hack! Get the region that this draw pool is rendering from!
	LLViewerRegion *regionp = mDrawFace[0]->getDrawable()->getVObj()->getRegion();
	LLVLComposition *compp = regionp->getComposition();
	LLViewerTexture *detail_texture0p = compp->mDetailTextures[0];
	LLViewerTexture *detail_texture1p = compp->mDetailTextures[1];
	LLViewerTexture *detail_texture2p = compp->mDetailTextures[2];
	LLViewerTexture *detail_texture3p = compp->mDetailTextures[3];

	LLVector3d region_origin_global = gAgent.getRegion()->getOriginGlobal();
	F32 offset_x = (F32)fmod(region_origin_global.mdV[VX], 1.0/(F64)sDetailScale)*sDetailScale;
	F32 offset_y = (F32)fmod(region_origin_global.mdV[VY], 1.0/(F64)sDetailScale)*sDetailScale;

	LLVector4 tp0, tp1;
	
	tp0.setVec(sDetailScale, 0.0f, 0.0f, offset_x);
	tp1.setVec(0.0f, sDetailScale, 0.0f, offset_y);

	gGL.blendFunc(LLRender::BF_ONE_MINUS_SOURCE_ALPHA, LLRender::BF_SOURCE_ALPHA);
	
	//----------------------------------------------------------------------------
	// Pass 1/4

	//
	// Stage 0: Render detail 0 into base
	//
	gGL.getTexUnit(0)->bind(detail_texture0p);
	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);

	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	drawLoop();

	//----------------------------------------------------------------------------
	// Pass 2/4
	
	//
	// Stage 0: Generate alpha ramp for detail0/detail1 transition
	//
	gGL.getTexUnit(0)->bind(m2DAlphaRampImagep);
	
	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	
	//
	// Stage 1: Write detail1
	//
	gGL.getTexUnit(1)->bind(detail_texture1p);
	gGL.getTexUnit(1)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->activate();

	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	gGL.getTexUnit(0)->activate();
	{
		LLGLEnable blend(GL_BLEND);
		drawLoop();
	}
	//----------------------------------------------------------------------------
	// Pass 3/4
	
	//
	// Stage 0: Generate alpha ramp for detail1/detail2 transition
	//
	gGL.getTexUnit(0)->bind(m2DAlphaRampImagep);

	// Set the texture matrix
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.translatef(-1.f, 0.f, 0.f);
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	//
	// Stage 1: Write detail2
	//
	gGL.getTexUnit(1)->bind(detail_texture2p);
	gGL.getTexUnit(1)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->activate();
	
	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	{
		LLGLEnable blend(GL_BLEND);
		drawLoop();
	}
	
	//----------------------------------------------------------------------------
	// Pass 4/4
	
	//
	// Stage 0: Generate alpha ramp for detail2/detail3 transition
	//
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->bind(m2DAlphaRampImagep);
	// Set the texture matrix
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.translatef(-2.f, 0.f, 0.f);
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	// Stage 1: Write detail3
	gGL.getTexUnit(1)->bind(detail_texture3p);
	gGL.getTexUnit(1)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->activate();

	glEnable(GL_TEXTURE_GEN_S);
	glEnable(GL_TEXTURE_GEN_T);
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
	glTexGenfv(GL_S, GL_OBJECT_PLANE, tp0.mV);
	glTexGenfv(GL_T, GL_OBJECT_PLANE, tp1.mV);

	gGL.getTexUnit(0)->activate();
	{
		LLGLEnable blend(GL_BLEND);
		drawLoop();
	}
	
	// Restore blend state
	gGL.setSceneBlendType(LLRender::BT_ALPHA);
	
	// Disable multitexture
	
	gGL.getTexUnit(1)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(1)->disable();
	gGL.getTexUnit(1)->activate();

	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);

	//----------------------------------------------------------------------------
	// Restore Texture Unit 0 defaults
	
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);

	glDisable(GL_TEXTURE_GEN_S);
	glDisable(GL_TEXTURE_GEN_T);
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);
}


void LLDrawPoolTerrain::renderSimple()
{
	LLVector4 tp0, tp1;

	//----------------------------------------------------------------------------
	// Pass 1/1

	// Stage 0: Base terrain texture pass
	mTexturep->addTextureStats(1024.f*1024.f);

	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->enable(LLTexUnit::TT_TEXTURE);
	gGL.getTexUnit(0)->bind(mTexturep);
	
	LLVector3 origin_agent = mDrawFace[0]->getDrawable()->getVObj()->getRegion()->getOriginAgent();
	F32 tscale = 1.f/256.f;
	tp0.setVec(tscale, 0.f, 0.0f, -1.f*(origin_agent.mV[0]/256.f));
	tp1.setVec(0.f, tscale, 0.0f, -1.f*(origin_agent.mV[1]/256.f));
	
	sShader->uniform4fv(LLShaderMgr::OBJECT_PLANE_S, 1, tp0.mV);
	sShader->uniform4fv(LLShaderMgr::OBJECT_PLANE_T, 1, tp1.mV);

	drawLoop();

	//----------------------------------------------------------------------------
	// Restore Texture Unit 0 defaults
	
	gGL.getTexUnit(0)->activate();
	gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.loadIdentity();
	gGL.matrixMode(LLRender::MM_MODELVIEW);
}

//============================================================================

void LLDrawPoolTerrain::renderOwnership()
{
	LLGLSPipelineAlpha gls_pipeline_alpha;

	llassert(!mDrawFace.empty());

	// Each terrain pool is associated with a single region.
	// We need to peek back into the viewer's data to find out
	// which ownership overlay texture to use.
	LLFace					*facep				= mDrawFace[0];
	LLDrawable				*drawablep			= facep->getDrawable();
	const LLViewerObject	*objectp				= drawablep->getVObj();
	const LLVOSurfacePatch	*vo_surface_patchp	= (LLVOSurfacePatch *)objectp;
	LLSurfacePatch			*surface_patchp		= vo_surface_patchp->getPatch();
	LLSurface				*surfacep			= surface_patchp->getSurface();
	LLViewerRegion			*regionp			= surfacep->getRegion();
	LLViewerParcelOverlay	*overlayp			= regionp->getParcelOverlay();
	LLViewerTexture			*texturep			= overlayp->getTexture();

	gGL.getTexUnit(0)->bind(texturep);

	// *NOTE: Because the region is 256 meters wide, but has 257 pixels, the 
	// texture coordinates for pixel 256x256 is not 1,1. This makes the
	// ownership map not line up with the selection. We address this with
	// a texture matrix multiply.
	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.pushMatrix();

	const F32 TEXTURE_FUDGE = 257.f / 256.f;
	gGL.scalef( TEXTURE_FUDGE, TEXTURE_FUDGE, 1.f );
	for (std::vector<LLFace*>::iterator iter = mDrawFace.begin();
		 iter != mDrawFace.end(); iter++)
	{
		LLFace *facep = *iter;
		facep->renderIndexed();
	}

	gGL.matrixMode(LLRender::MM_TEXTURE);
	gGL.popMatrix();
	gGL.matrixMode(LLRender::MM_MODELVIEW);
}


void LLDrawPoolTerrain::dirtyTextures(const std::set<LLViewerFetchedTexture*>& textures)
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL;
	LLViewerFetchedTexture* tex = LLViewerTextureManager::staticCastToFetchedTexture(mTexturep) ;
	if (tex && textures.find(tex) != textures.end())
	{
		for (std::vector<LLFace*>::iterator iter = mReferences.begin();
			 iter != mReferences.end(); iter++)
		{
			LLFace *facep = *iter;
			gPipeline.markTextured(facep->getDrawable());
		}
	}
}

LLViewerTexture *LLDrawPoolTerrain::getTexture()
{
	return mTexturep;
}

LLViewerTexture *LLDrawPoolTerrain::getDebugTexture()
{
	return mTexturep;
}


LLColor3 LLDrawPoolTerrain::getDebugColor() const
{
	return LLColor3(0.f, 0.f, 1.f);
}