llvosurfacepatch.cpp

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#include "llviewerprecompiledheaders.h"

#include "llvosurfacepatch.h"

#include "lldrawpoolterrain.h"

#include "lldrawable.h"
#include "llface.h"
#include "llprimitive.h"
#include "llsky.h"
#include "llsurfacepatch.h"
#include "llsurface.h"
#include "llviewerobjectlist.h"
#include "llviewerregion.h"
#include "llvlcomposition.h"
#include "llvovolume.h"
#include "pipeline.h"
#include "llspatialpartition.h"

F32 LLVOSurfacePatch::sLODFactor = 1.f;

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

class LLVertexBufferTerrain : public LLVertexBuffer
{
public:
        LLVertexBufferTerrain() :
                LLVertexBuffer(MAP_VERTEX | MAP_NORMAL | MAP_TEXCOORD | MAP_TEXCOORD2 | MAP_COLOR, GL_DYNAMIC_DRAW_ARB)
        {
        };

        // virtual
        void setupVertexBuffer(U32 data_mask) const
        {               
                if (LLDrawPoolTerrain::getDetailMode() == 0)
                {
                        LLVertexBuffer::setupVertexBuffer(data_mask);
                }
                else if (data_mask & LLVertexBuffer::MAP_TEXCOORD2)
                {
                        U8* base = useVBOs() ? NULL : mMappedData;
        
                        glVertexPointer(3,GL_FLOAT, mStride, (void*)(base + 0));
                        glNormalPointer(GL_FLOAT, mStride, (void*)(base + mOffsets[TYPE_NORMAL]));
                        glColorPointer(4, GL_UNSIGNED_BYTE, mStride, (void*)(base + mOffsets[TYPE_COLOR]));
                
                        glClientActiveTextureARB(GL_TEXTURE3_ARB);
                        glTexCoordPointer(2,GL_FLOAT, mStride, (void*)(base + mOffsets[TYPE_TEXCOORD2]));
                        glClientActiveTextureARB(GL_TEXTURE2_ARB);
                        glTexCoordPointer(2,GL_FLOAT, mStride, (void*)(base + mOffsets[TYPE_TEXCOORD2]));
                        glClientActiveTextureARB(GL_TEXTURE1_ARB);
                        glTexCoordPointer(2,GL_FLOAT, mStride, (void*)(base + mOffsets[TYPE_TEXCOORD2]));
                        glClientActiveTextureARB(GL_TEXTURE0_ARB);
                        glTexCoordPointer(2,GL_FLOAT, mStride, (void*)(base + mOffsets[TYPE_TEXCOORD2]));
                }
                else
                {
                        LLVertexBuffer::setupVertexBuffer(data_mask);
                }
                llglassertok();         
        }
};

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

LLVOSurfacePatch::LLVOSurfacePatch(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp)
        :       LLStaticViewerObject(id, LL_VO_SURFACE_PATCH, regionp),
                mDirtiedPatch(FALSE),
                mPool(NULL),
                mBaseComp(0),
                mPatchp(NULL),
                mDirtyTexture(FALSE),
                mDirtyTerrain(FALSE),
                mLastNorthStride(0),
                mLastEastStride(0),
                mLastStride(0),
                mLastLength(0)
{
        // Terrain must draw during selection passes so it can block objects behind it.
        mbCanSelect = TRUE;
        setScale(LLVector3(16.f, 16.f, 16.f)); // Hack for setting scale for bounding boxes/visibility.
}


LLVOSurfacePatch::~LLVOSurfacePatch()
{
        mPatchp = NULL;
}


void LLVOSurfacePatch::markDead()
{
        if (mPatchp)
        {
                mPatchp->clearVObj();
                mPatchp = NULL;
        }
        LLViewerObject::markDead();
}


BOOL LLVOSurfacePatch::isActive() const
{
        return FALSE;
}


void LLVOSurfacePatch::setPixelAreaAndAngle(LLAgent &agent)
{
        mAppAngle = 50;
        mPixelArea = 500*500;
}


void LLVOSurfacePatch::updateTextures(LLAgent &agent)
{
}


LLFacePool *LLVOSurfacePatch::getPool()
{
        mPool = (LLDrawPoolTerrain*) gPipeline.getPool(LLDrawPool::POOL_TERRAIN, mPatchp->getSurface()->getSTexture());

        return mPool;
}


LLDrawable *LLVOSurfacePatch::createDrawable(LLPipeline *pipeline)
{
        pipeline->allocDrawable(this);

        mDrawable->setRenderType(LLPipeline::RENDER_TYPE_TERRAIN);
        
        mBaseComp = llfloor(mPatchp->getMinComposition());
        S32 min_comp, max_comp, range;
        min_comp = llfloor(mPatchp->getMinComposition());
        max_comp = llceil(mPatchp->getMaxComposition());
        range = (max_comp - min_comp);
        range++;
        if (range > 3)
        {
                if ((mPatchp->getMinComposition() - min_comp) > (max_comp - mPatchp->getMaxComposition()))
                {
                        // The top side runs over more
                        mBaseComp++;
                }
                range = 3;
        }

        LLFacePool *poolp = getPool();

        mDrawable->addFace(poolp, NULL);

        return mDrawable;
}


BOOL LLVOSurfacePatch::updateGeometry(LLDrawable *drawable)
{
        LLFastTimer ftm(LLFastTimer::FTM_UPDATE_TERRAIN);

        dirtySpatialGroup();
        
        S32 min_comp, max_comp, range;
        min_comp = lltrunc(mPatchp->getMinComposition());
        max_comp = lltrunc(ceil(mPatchp->getMaxComposition()));
        range = (max_comp - min_comp);
        range++;
        S32 new_base_comp = lltrunc(mPatchp->getMinComposition());
        if (range > 3)
        {
                if ((mPatchp->getMinComposition() - min_comp) > (max_comp - mPatchp->getMaxComposition()))
                {
                        // The top side runs over more
                        new_base_comp++;
                }
                range = 3;
        }

        // Pick the two closest detail textures for this patch...
        // Then create the draw pool for it.
        // Actually, should get the average composition instead of the center.
        mBaseComp = new_base_comp;

        //
        // Figure out the strides
        //
        //

        U32 patch_width, render_stride, north_stride, east_stride, length;
        render_stride = mPatchp->getRenderStride();
        patch_width = mPatchp->getSurface()->getGridsPerPatchEdge();

        length = patch_width / render_stride;

        if (mPatchp->getNeighborPatch(NORTH))
        {
                north_stride = mPatchp->getNeighborPatch(NORTH)->getRenderStride();
        }
        else
        {
                north_stride = render_stride;
        }

        if (mPatchp->getNeighborPatch(EAST))
        {
                east_stride = mPatchp->getNeighborPatch(EAST)->getRenderStride();
        }
        else
        {
                east_stride = render_stride;
        }

        mLastLength = length;
        mLastStride = render_stride;
        mLastNorthStride = north_stride;
        mLastEastStride = east_stride;

        return TRUE;
}

void LLVOSurfacePatch::updateFaceSize(S32 idx)
{
        if (idx != 0)
        {
                llwarns << "Terrain partition requested invalid face!!!" << llendl;
                return;
        }

        LLFace* facep = mDrawable->getFace(idx);

        S32 num_vertices = 0;
        S32 num_indices = 0;
        
        if (mLastStride)
        {
                getGeomSizesMain(mLastStride, num_vertices, num_indices);
                getGeomSizesNorth(mLastStride, mLastNorthStride, num_vertices, num_indices);
                getGeomSizesEast(mLastStride, mLastEastStride, num_vertices, num_indices);
        }

        facep->setSize(num_vertices, num_indices);      
}

BOOL LLVOSurfacePatch::updateLOD()
{
        return TRUE;
}

void LLVOSurfacePatch::getGeometry(LLStrider<LLVector3> &verticesp,
                                                                LLStrider<LLVector3> &normalsp,
                                                                LLStrider<LLColor4U> &colorsp,
                                                                LLStrider<LLVector2> &texCoords0p,
                                                                LLStrider<LLVector2> &texCoords1p,
                                                                LLStrider<U16> &indicesp)
{
        LLFace* facep = mDrawable->getFace(0);

        U32 index_offset = facep->getGeomIndex();

        updateMainGeometry(facep, 
                                        verticesp,
                                        normalsp,
                                        colorsp,
                                        texCoords0p,
                                        texCoords1p,
                                        indicesp,
                                        index_offset);
        updateNorthGeometry(facep, 
                                                verticesp,
                                                normalsp,
                                                colorsp,
                                                texCoords0p,
                                                texCoords1p,
                                                indicesp,
                                                index_offset);
        updateEastGeometry(facep, 
                                                verticesp,
                                                normalsp,
                                                colorsp,
                                                texCoords0p,
                                                texCoords1p,
                                                indicesp,
                                                index_offset);
}

void LLVOSurfacePatch::updateMainGeometry(LLFace *facep,
                                                                                LLStrider<LLVector3> &verticesp,
                                                                                LLStrider<LLVector3> &normalsp,
                                                                                LLStrider<LLColor4U> &colorsp,
                                                                                LLStrider<LLVector2> &texCoords0p,
                                                                                LLStrider<LLVector2> &texCoords1p,
                                                                                LLStrider<U16> &indicesp,
                                                                                U32 &index_offset)
{
        S32 i, j, x, y;

        U32 patch_size, render_stride;
        S32 num_vertices, num_indices;
        U32 index;

        render_stride = mLastStride;
        patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();
        S32 vert_size = patch_size / render_stride;

        //
        // Render the main patch
        //
        //

        num_vertices = 0;
        num_indices = 0;
        // First, figure out how many vertices we need...
        getGeomSizesMain(render_stride, num_vertices, num_indices);

        if (num_vertices > 0)
        {
                facep->mCenterAgent = mPatchp->getPointAgent(8, 8);

                // Generate patch points first
                for (j = 0; j < vert_size; j++)
                {
                        for (i = 0; i < vert_size; i++)
                        {
                                x = i * render_stride;
                                y = j * render_stride;
                                mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                                *colorsp++ = LLColor4U::white;
                                verticesp++;
                                normalsp++;
                                texCoords0p++;
                                texCoords1p++;
                        }
                }

                for (j = 0; j < (vert_size - 1); j++)
                {
                        if (j % 2)
                        {
                                for (i = (vert_size - 1); i > 0; i--)
                                {
                                        index = (i - 1)+ j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = i + (j+1)*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = (i - 1) + (j+1)*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = (i - 1) + j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = i + j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = i + (j+1)*vert_size;
                                        *(indicesp++) = index_offset + index;
                                }
                        }
                        else
                        {
                                for (i = 0; i < (vert_size - 1); i++)
                                {
                                        index = i + j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = (i + 1) + (j+1)*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = i + (j+1)*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = i + j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = (i + 1) + j*vert_size;
                                        *(indicesp++) = index_offset + index;

                                        index = (i + 1) + (j + 1)*vert_size;
                                        *(indicesp++) = index_offset + index;
                                }
                        }
                }
        }
        index_offset += num_vertices;
}


void LLVOSurfacePatch::updateNorthGeometry(LLFace *facep,
                                                                                LLStrider<LLVector3> &verticesp,
                                                                                LLStrider<LLVector3> &normalsp,
                                                                                LLStrider<LLColor4U> &colorsp,
                                                                                LLStrider<LLVector2> &texCoords0p,
                                                                                LLStrider<LLVector2> &texCoords1p,
                                                                                LLStrider<U16> &indicesp,
                                                                                U32 &index_offset)
{
        S32 vertex_count = 0;
        S32 i, x, y;

        S32 num_vertices, num_indices;

        U32 render_stride = mLastStride;
        S32 patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();
        S32 length = patch_size / render_stride;
        S32 half_length = length / 2;
        U32 north_stride = mLastNorthStride;
        
        //
        // Render the north strip
        //
        //

        // Stride lengths are the same
        if (north_stride == render_stride)
        {
                num_vertices = 2 * length + 1;
                num_indices = length * 6 - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(8, 15) + mPatchp->getPointAgent(8, 16))*0.5f;

                // Main patch
                for (i = 0; i < length; i++)
                {
                        x = i * render_stride;
                        y = 16 - render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        *colorsp++ = LLColor4U::white;
                        verticesp++;
                        normalsp++;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }

                // North patch
                for (i = 0; i <= length; i++)
                {
                        x = i * render_stride;
                        y = 16;
                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }


                for (i = 0; i < length; i++)
                {
                        // Generate indices
                        *(indicesp++) = index_offset + i;
                        *(indicesp++) = index_offset + length + i + 1;
                        *(indicesp++) = index_offset + length + i;

                        if (i != length - 1)
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + i + 1;
                                *(indicesp++) = index_offset + length + i + 1;
                        }
                }
        }
        else if (north_stride > render_stride)
        {
                // North stride is longer (has less vertices)
                num_vertices = length + length/2 + 1;
                num_indices = half_length*9 - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(7, 15) + mPatchp->getPointAgent(8, 16))*0.5f;

                // Iterate through this patch's points
                for (i = 0; i < length; i++)
                {
                        x = i * render_stride;
                        y = 16 - render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }

                // Iterate through the north patch's points
                for (i = 0; i <= length; i+=2)
                {
                        x = i * render_stride;
                        y = 16;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }


                for (i = 0; i < length; i++)
                {
                        if (!(i % 2))
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + i + 1;
                                *(indicesp++) = index_offset + length + (i/2);

                                *(indicesp++) = index_offset + i + 1;
                                *(indicesp++) = index_offset + length + (i/2) + 1;
                                *(indicesp++) = index_offset + length + (i/2);
                        }
                        else if (i < (length - 1))
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + i + 1;
                                *(indicesp++) = index_offset + length + (i/2) + 1;
                        }
                }
        }
        else
        {
                // North stride is shorter (more vertices)
                length = patch_size / north_stride;
                half_length = length / 2;
                num_vertices = length + half_length + 1;
                num_indices = 9*half_length - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(15, 7) + mPatchp->getPointAgent(16, 8))*0.5f;

                // Iterate through this patch's points
                for (i = 0; i < length; i+=2)
                {
                        x = i * north_stride;
                        y = 16 - render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        *colorsp++ = LLColor4U::white;
                        verticesp++;
                        normalsp++;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }

                // Iterate through the north patch's points
                for (i = 0; i <= length; i++)
                {
                        x = i * north_stride;
                        y = 16;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                        vertex_count++;
                }

                for (i = 0; i < length; i++)
                {
                        if (!(i%2))
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + i/2;
                                *(indicesp++) = index_offset + half_length + i + 1;
                        }
                        else if (i < (length - 2))
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + i/2;
                                *(indicesp++) = index_offset + i/2 + 1;

                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + i/2 + 1;
                                *(indicesp++) = index_offset + half_length + i + 1;
                        }
                        else
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + i/2;
                                *(indicesp++) = index_offset + half_length + i + 1;
                        }
                }
        }
        index_offset += num_vertices;
}

void LLVOSurfacePatch::updateEastGeometry(LLFace *facep,
                                                                                  LLStrider<LLVector3> &verticesp,
                                                                                  LLStrider<LLVector3> &normalsp,
                                                                                  LLStrider<LLColor4U> &colorsp,
                                                                                  LLStrider<LLVector2> &texCoords0p,
                                                                                  LLStrider<LLVector2> &texCoords1p,
                                                                                  LLStrider<U16> &indicesp,
                                                                                  U32 &index_offset)
{
        S32 i, x, y;

        S32 num_vertices, num_indices;

        U32 render_stride = mLastStride;
        S32 patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();
        S32 length = patch_size / render_stride;
        S32 half_length = length / 2;

        U32 east_stride = mLastEastStride;

        // Stride lengths are the same
        if (east_stride == render_stride)
        {
                num_vertices = 2 * length + 1;
                num_indices = length * 6 - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(8, 15) + mPatchp->getPointAgent(8, 16))*0.5f;

                // Main patch
                for (i = 0; i < length; i++)
                {
                        x = 16 - render_stride;
                        y = i * render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }

                // East patch
                for (i = 0; i <= length; i++)
                {
                        x = 16;
                        y = i * render_stride;
                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }


                for (i = 0; i < length; i++)
                {
                        // Generate indices
                        *(indicesp++) = index_offset + i;
                        *(indicesp++) = index_offset + length + i;
                        *(indicesp++) = index_offset + length + i + 1;

                        if (i != length - 1)
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + length + i + 1;
                                *(indicesp++) = index_offset + i + 1;
                        }
                }
        }
        else if (east_stride > render_stride)
        {
                // East stride is longer (has less vertices)
                num_vertices = length + half_length + 1;
                num_indices = half_length*9 - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(7, 15) + mPatchp->getPointAgent(8, 16))*0.5f;

                // Iterate through this patch's points
                for (i = 0; i < length; i++)
                {
                        x = 16 - render_stride;
                        y = i * render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }
                // Iterate through the east patch's points
                for (i = 0; i <= length; i+=2)
                {
                        x = 16;
                        y = i * render_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }

                for (i = 0; i < length; i++)
                {
                        if (!(i % 2))
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + length + (i/2);
                                *(indicesp++) = index_offset + i + 1;

                                *(indicesp++) = index_offset + i + 1;
                                *(indicesp++) = index_offset + length + (i/2);
                                *(indicesp++) = index_offset + length + (i/2) + 1;
                        }
                        else if (i < (length - 1))
                        {
                                *(indicesp++) = index_offset + i;
                                *(indicesp++) = index_offset + length + (i/2) + 1;
                                *(indicesp++) = index_offset + i + 1;
                        }
                }
        }
        else
        {
                // East stride is shorter (more vertices)
                length = patch_size / east_stride;
                half_length = length / 2;
                num_vertices = length + length/2 + 1;
                num_indices = 9*(length/2) - 3;

                facep->mCenterAgent = (mPatchp->getPointAgent(15, 7) + mPatchp->getPointAgent(16, 8))*0.5f;

                // Iterate through this patch's points
                for (i = 0; i < length; i+=2)
                {
                        x = 16 - render_stride;
                        y = i * east_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }
                // Iterate through the east patch's points
                for (i = 0; i <= length; i++)
                {
                        x = 16;
                        y = i * east_stride;

                        mPatchp->eval(x, y, render_stride, verticesp.get(), normalsp.get(), texCoords0p.get(), texCoords1p.get());
                        verticesp++;
                        normalsp++;
                        *colorsp++ = LLColor4U::white;
                        texCoords0p++;
                        texCoords1p++;
                }

                for (i = 0; i < length; i++)
                {
                        if (!(i%2))
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + half_length + i + 1;
                                *(indicesp++) = index_offset + i/2;
                        }
                        else if (i < (length - 2))
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + i/2 + 1;
                                *(indicesp++) = index_offset + i/2;

                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + half_length + i + 1;
                                *(indicesp++) = index_offset + i/2 + 1;
                        }
                        else
                        {
                                *(indicesp++) = index_offset + half_length + i;
                                *(indicesp++) = index_offset + half_length + i + 1;
                                *(indicesp++) = index_offset + i/2;
                        }
                }
        }
        index_offset += num_vertices;
}

void LLVOSurfacePatch::setPatch(LLSurfacePatch *patchp)
{
        mPatchp = patchp;

        dirtyPatch();
};


void LLVOSurfacePatch::dirtyPatch()
{
        mDirtiedPatch = TRUE;
        dirtyGeom();
        mDirtyTerrain = TRUE;
        LLVector3 center = mPatchp->getCenterRegion();
        LLSurface *surfacep = mPatchp->getSurface();

        setPositionRegion(center);

        F32 scale_factor = surfacep->getGridsPerPatchEdge() * surfacep->getMetersPerGrid();
        setScale(LLVector3(scale_factor, scale_factor, mPatchp->getMaxZ() - mPatchp->getMinZ()));
}

void LLVOSurfacePatch::dirtyGeom()
{
        if (mDrawable)
        {
                gPipeline.markRebuild(mDrawable, LLDrawable::REBUILD_ALL, TRUE);
                mDrawable->getFace(0)->mVertexBuffer = NULL;
                mDrawable->movePartition();
        }
}

void LLVOSurfacePatch::getGeomSizesMain(const S32 stride, S32 &num_vertices, S32 &num_indices)
{
        S32 patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();

        // First, figure out how many vertices we need...
        S32 vert_size = patch_size / stride;
        if (vert_size >= 2)
        {
                num_vertices += vert_size * vert_size;
                num_indices += 6 * (vert_size - 1)*(vert_size - 1);
        }
}

void LLVOSurfacePatch::getGeomSizesNorth(const S32 stride, const S32 north_stride,
                                                                                 S32 &num_vertices, S32 &num_indices)
{
        S32 patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();
        S32 length = patch_size / stride;
        // Stride lengths are the same
        if (north_stride == stride)
        {
                num_vertices += 2 * length + 1;
                num_indices += length * 6 - 3;
        }
        else if (north_stride > stride)
        {
                // North stride is longer (has less vertices)
                num_vertices += length + (length/2) + 1;
                num_indices += (length/2)*9 - 3;
        }
        else
        {
                // North stride is shorter (more vertices)
                length = patch_size / north_stride;
                num_vertices += length + (length/2) + 1;
                num_indices += 9*(length/2) - 3;
        }
}

void LLVOSurfacePatch::getGeomSizesEast(const S32 stride, const S32 east_stride,
                                                                                S32 &num_vertices, S32 &num_indices)
{
        S32 patch_size = mPatchp->getSurface()->getGridsPerPatchEdge();
        S32 length = patch_size / stride;
        // Stride lengths are the same
        if (east_stride == stride)
        {
                num_vertices += 2 * length + 1;
                num_indices += length * 6 - 3;
        }
        else if (east_stride > stride)
        {
                // East stride is longer (has less vertices)
                num_vertices += length + (length/2) + 1;
                num_indices += (length/2)*9 - 3;
        }
        else
        {
                // East stride is shorter (more vertices)
                length = patch_size / east_stride;
                num_vertices += length + (length/2) + 1;
                num_indices += 9*(length/2) - 3;
        }
}

void LLVOSurfacePatch::updateSpatialExtents(LLVector3& newMin, LLVector3 &newMax)
{
        LLVector3 posAgent = getPositionAgent();
        LLVector3 scale = getScale();
        newMin = posAgent-scale*0.5f; // Changing to 2.f makes the culling a -little- better, but still wrong
        newMax = posAgent+scale*0.5f;
        mDrawable->setPositionGroup((newMin+newMax)*0.5f);
}

U32 LLVOSurfacePatch::getPartitionType() const
{ 
        return LLViewerRegion::PARTITION_TERRAIN; 
}

LLTerrainPartition::LLTerrainPartition()
: LLSpatialPartition(LLDrawPoolTerrain::VERTEX_DATA_MASK)
{
        mOcclusionEnabled = FALSE;
        mRenderByGroup = FALSE;
        mInfiniteFarClip = TRUE;
        mBufferUsage = GL_DYNAMIC_DRAW_ARB;
        mDrawableType = LLPipeline::RENDER_TYPE_TERRAIN;
        mPartitionType = LLViewerRegion::PARTITION_TERRAIN;
}

LLVertexBuffer* LLTerrainPartition::createVertexBuffer(U32 type_mask, U32 usage)
{
        return new LLVertexBufferTerrain();
}

void LLTerrainPartition::getGeometry(LLSpatialGroup* group)
{
        LLFastTimer ftm(LLFastTimer::FTM_REBUILD_TERRAIN_VB);

        LLVertexBuffer* buffer = group->mVertexBuffer;

        //get vertex buffer striders
        LLStrider<LLVector3> vertices;
        LLStrider<LLVector3> normals;
        LLStrider<LLVector2> texcoords2;
        LLStrider<LLVector2> texcoords;
        LLStrider<LLColor4U> colors;
        LLStrider<U16> indices;

        buffer->getVertexStrider(vertices);
        buffer->getNormalStrider(normals);
        buffer->getTexCoordStrider(texcoords);
        buffer->getTexCoord2Strider(texcoords2);
        buffer->getColorStrider(colors);
        buffer->getIndexStrider(indices);

        U32 indices_index = 0;
        U32 index_offset = 0;

        for (std::vector<LLFace*>::iterator i = mFaceList.begin(); i != mFaceList.end(); ++i)
        {
                LLFace* facep = *i;

                facep->setIndicesIndex(indices_index);
                facep->setGeomIndex(index_offset);
                facep->mVertexBuffer = buffer;

                LLVOSurfacePatch* patchp = (LLVOSurfacePatch*) facep->getViewerObject();
                patchp->getGeometry(vertices, normals, colors, texcoords, texcoords2, indices);

                indices_index += facep->getIndicesCount();
                index_offset += facep->getGeomCount();
        }

        buffer->setBuffer(0);
        mFaceList.clear();
}

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