llviewerparceloverlay.cpp

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#include "llviewerprecompiledheaders.h"

#include "llviewerparceloverlay.h"

// indra includes
#include "llparcel.h"
#include "llgl.h"
#include "v4color.h"
#include "v2math.h"

// newview includes
#include "llviewerimage.h"
#include "llviewercontrol.h"
#include "llsurface.h"
#include "llviewerregion.h"
#include "llagent.h"
#include "llviewercamera.h"
#include "llviewerimagelist.h"
#include "llglheaders.h"

const U8  OVERLAY_IMG_COMPONENTS = 4;

LLViewerParcelOverlay::LLViewerParcelOverlay(LLViewerRegion* region, F32 region_width_meters)
:       mRegion( region ),
        mParcelGridsPerEdge( S32( region_width_meters / PARCEL_GRID_STEP_METERS ) ),
        mDirty( FALSE ),
        mTimeSinceLastUpdate(),
        mOverlayTextureIdx(-1),
        mLineImageID( gViewerArt.getString("propertyline.tga") ),
        mVertexCount(0),
        mVertexArray(NULL),
        mColorArray(NULL)
//      mTexCoordArray(NULL),
{
        // Create a texture to hold color information.
        // 4 components
        // Use mipmaps = FALSE, clamped, NEAREST filter, for sharp edges
        mTexture = new LLImageGL(FALSE);
        mImageRaw = new LLImageRaw(mParcelGridsPerEdge, mParcelGridsPerEdge, OVERLAY_IMG_COMPONENTS);
        mTexture->createGLTexture(0, mImageRaw);
        glActiveTextureARB(GL_TEXTURE0_ARB);
        mTexture->bind(0);
        mTexture->setClamp(TRUE, TRUE);
        mTexture->setMipFilterNearest(TRUE);

        //
        // Initialize the GL texture with empty data.
        //
        // Create the base texture.
        U8 *raw = mImageRaw->getData();
        const S32 COUNT = mParcelGridsPerEdge * mParcelGridsPerEdge * OVERLAY_IMG_COMPONENTS;
        for (S32 i = 0; i < COUNT; i++)
        {
                raw[i] = 0;
        }
        mTexture->setSubImage(mImageRaw, 0, 0, mParcelGridsPerEdge, mParcelGridsPerEdge);

        // Create storage for ownership information from simulator
        // and initialize it.
        mOwnership = new U8[ mParcelGridsPerEdge * mParcelGridsPerEdge ];
        for (S32 i = 0; i < mParcelGridsPerEdge * mParcelGridsPerEdge; i++)
        {
                mOwnership[i] = PARCEL_PUBLIC;
        }

        // Make sure the texture matches the ownership information.
        updateOverlayTexture();
}


LLViewerParcelOverlay::~LLViewerParcelOverlay()
{
        delete[] mOwnership;
        mOwnership = NULL;

        delete[] mVertexArray;
        mVertexArray = NULL;

        delete[] mColorArray;
        mColorArray = NULL;

// JC No textures.
//      delete mTexCoordArray;
//      mTexCoordArray = NULL;

        mImageRaw = NULL;
}

//---------------------------------------------------------------------------
// ACCESSORS
//---------------------------------------------------------------------------
BOOL LLViewerParcelOverlay::isOwned(const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        return (PARCEL_PUBLIC != ownership(row, column));
}

BOOL LLViewerParcelOverlay::isOwnedSelf(const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        return (PARCEL_SELF == ownership(row, column));
}

BOOL LLViewerParcelOverlay::isOwnedGroup(const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        return (PARCEL_GROUP == ownership(row, column));
}

BOOL LLViewerParcelOverlay::isOwnedOther(const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        U8 overlay = ownership(row, column);
        return (PARCEL_OWNED == overlay || PARCEL_FOR_SALE == overlay);
}

BOOL LLViewerParcelOverlay::isSoundLocal(const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        return PARCEL_SOUND_LOCAL & mOwnership[row * mParcelGridsPerEdge + column];
}

U8 LLViewerParcelOverlay::ownership( const LLVector3& pos) const
{
        S32 row =    S32(pos.mV[VY] / PARCEL_GRID_STEP_METERS);
        S32 column = S32(pos.mV[VX] / PARCEL_GRID_STEP_METERS);
        return ownership(row, column);
}

F32 LLViewerParcelOverlay::getOwnedRatio() const
{
        S32     size = mParcelGridsPerEdge * mParcelGridsPerEdge;
        S32 total = 0;

        for (S32 i = 0; i < size; i++)
        {
                if ((mOwnership[i] & PARCEL_COLOR_MASK) != PARCEL_PUBLIC)
                {
                        total++;
                }
        }

        return (F32)total / (F32)size;

}

//---------------------------------------------------------------------------
// MANIPULATORS
//---------------------------------------------------------------------------

// Color tables for owned land
// Available = index 0
// Other     = index 1
// Group     = index 2
// Self      = index 3

// Make sure the texture colors match the ownership data.
// Note: Assumes that the ownership array and 
void LLViewerParcelOverlay::updateOverlayTexture()
{
        if (mOverlayTextureIdx < 0 && mDirty)
        {
                mOverlayTextureIdx = 0;
        }
        if (mOverlayTextureIdx < 0)
        {
                return;
        }
        // Can do this because gColors are actually stored as LLColor4U
        const LLColor4U avail = gColors.getColor4U("PropertyColorAvail");
        const LLColor4U owned = gColors.getColor4U("PropertyColorOther");
        const LLColor4U group = gColors.getColor4U("PropertyColorGroup");
        const LLColor4U self  = gColors.getColor4U("PropertyColorSelf");
        const LLColor4U for_sale  = gColors.getColor4U("PropertyColorForSale");
        const LLColor4U auction  = gColors.getColor4U("PropertyColorAuction");

        // Create the base texture.
        U8 *raw = mImageRaw->getData();
        const S32 COUNT = mParcelGridsPerEdge * mParcelGridsPerEdge;
        S32 max = mOverlayTextureIdx + mParcelGridsPerEdge;
        if (max > COUNT) max = COUNT;
        S32 pixel_index = mOverlayTextureIdx*OVERLAY_IMG_COMPONENTS;
        S32 i;
        for (i = mOverlayTextureIdx; i < max; i++)
        {
                U8 ownership = mOwnership[i];

                U8 r,g,b,a;

                // Color stored in low three bits
                switch( ownership & 0x7 )
                {
                case PARCEL_PUBLIC:
                        r = avail.mV[VRED];
                        g = avail.mV[VGREEN];
                        b = avail.mV[VBLUE];
                        a = avail.mV[VALPHA];
                        break;
                case PARCEL_OWNED:
                        r = owned.mV[VRED];
                        g = owned.mV[VGREEN];
                        b = owned.mV[VBLUE];
                        a = owned.mV[VALPHA];
                        break;
                case PARCEL_GROUP:
                        r = group.mV[VRED];
                        g = group.mV[VGREEN];
                        b = group.mV[VBLUE];
                        a = group.mV[VALPHA];
                        break;
                case PARCEL_SELF:
                        r = self.mV[VRED];
                        g = self.mV[VGREEN];
                        b = self.mV[VBLUE];
                        a = self.mV[VALPHA];
                        break;
                case PARCEL_FOR_SALE:
                        r = for_sale.mV[VRED];
                        g = for_sale.mV[VGREEN];
                        b = for_sale.mV[VBLUE];
                        a = for_sale.mV[VALPHA];
                        break;
                case PARCEL_AUCTION:
                        r = auction.mV[VRED];
                        g = auction.mV[VGREEN];
                        b = auction.mV[VBLUE];
                        a = auction.mV[VALPHA];
                        break;
                default:
                        r = self.mV[VRED];
                        g = self.mV[VGREEN];
                        b = self.mV[VBLUE];
                        a = self.mV[VALPHA];
                        break;
                }

                raw[pixel_index + 0] = r;
                raw[pixel_index + 1] = g;
                raw[pixel_index + 2] = b;
                raw[pixel_index + 3] = a;

                pixel_index += OVERLAY_IMG_COMPONENTS;
        }
        
        // Copy data into GL texture from raw data
        if (i >= COUNT)
        {
                mTexture->setSubImage(mImageRaw, 0, 0, mParcelGridsPerEdge, mParcelGridsPerEdge);
                mOverlayTextureIdx = -1;
        }
        else
        {
                mOverlayTextureIdx = i;
        }
}


void LLViewerParcelOverlay::uncompressLandOverlay(S32 chunk, U8 *packed_overlay)
{
        // Unpack the message data into the ownership array
        S32     size    = mParcelGridsPerEdge * mParcelGridsPerEdge;
        S32 chunk_size = size / PARCEL_OVERLAY_CHUNKS;

        memcpy(mOwnership + chunk*chunk_size, packed_overlay, chunk_size);              /*Flawfinder: ignore*/

        // Force property lines and overlay texture to update
        setDirty();
}


void LLViewerParcelOverlay::updatePropertyLines()
{
        if (!gSavedSettings.getBOOL("ShowPropertyLines"))
                return;
        
        S32 row, col;

        // Can do this because gColors are actually stored as LLColor4U
        const LLColor4U self_coloru  = gColors.getColor4U("PropertyColorSelf");
        const LLColor4U other_coloru = gColors.getColor4U("PropertyColorOther");
        const LLColor4U group_coloru = gColors.getColor4U("PropertyColorGroup");
        const LLColor4U for_sale_coloru = gColors.getColor4U("PropertyColorForSale");
        const LLColor4U auction_coloru = gColors.getColor4U("PropertyColorAuction");

        // Build into dynamic arrays, then copy into static arrays.
        LLDynamicArray<LLVector3, 256> new_vertex_array;
        LLDynamicArray<LLColor4U, 256> new_color_array;
        LLDynamicArray<LLVector2, 256> new_coord_array;

        U8 overlay = 0;
        BOOL add_edge = FALSE;
        const F32 GRID_STEP = PARCEL_GRID_STEP_METERS;
        const S32 GRIDS_PER_EDGE = mParcelGridsPerEdge;

        for (row = 0; row < GRIDS_PER_EDGE; row++)
        {
                for (col = 0; col < GRIDS_PER_EDGE; col++)
                {
                        overlay = mOwnership[row*GRIDS_PER_EDGE+col];

                        F32 left = col*GRID_STEP;
                        F32 right = left+GRID_STEP;

                        F32 bottom = row*GRID_STEP;
                        F32 top = bottom+GRID_STEP;

                        // West edge
                        if (overlay & PARCEL_WEST_LINE)
                        {
                                switch(overlay & PARCEL_COLOR_MASK)
                                {
                                case PARCEL_SELF:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, WEST, self_coloru);
                                        break;
                                case PARCEL_GROUP:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, WEST, group_coloru);
                                        break;
                                case PARCEL_OWNED:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, WEST, other_coloru);
                                        break;
                                case PARCEL_FOR_SALE:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, WEST, for_sale_coloru);
                                        break;
                                case PARCEL_AUCTION:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, WEST, auction_coloru);
                                        break;
                                default:
                                        break;
                                }
                        }

                        // East edge
                        if (col < GRIDS_PER_EDGE-1)
                        {
                                U8 east_overlay = mOwnership[row*GRIDS_PER_EDGE+col+1];
                                add_edge = east_overlay & PARCEL_WEST_LINE;
                        }
                        else
                        {
                                add_edge = TRUE;
                        }

                        if (add_edge)
                        {
                                switch(overlay & PARCEL_COLOR_MASK)
                                {
                                case PARCEL_SELF:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                right, bottom, EAST, self_coloru);
                                        break;
                                case PARCEL_GROUP:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                right, bottom, EAST, group_coloru);
                                        break;
                                case PARCEL_OWNED:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                right, bottom, EAST, other_coloru);
                                        break;
                                case PARCEL_FOR_SALE:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                right, bottom, EAST, for_sale_coloru);
                                        break;
                                case PARCEL_AUCTION:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                right, bottom, EAST, auction_coloru);
                                        break;
                                default:
                                        break;
                                }
                        }

                        // South edge
                        if (overlay & PARCEL_SOUTH_LINE)
                        {
                                switch(overlay & PARCEL_COLOR_MASK)
                                {
                                case PARCEL_SELF:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, SOUTH, self_coloru);
                                        break;
                                case PARCEL_GROUP:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, SOUTH, group_coloru);
                                        break;
                                case PARCEL_OWNED:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, SOUTH, other_coloru);
                                        break;
                                case PARCEL_FOR_SALE:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, SOUTH, for_sale_coloru);
                                        break;
                                case PARCEL_AUCTION:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, bottom, SOUTH, auction_coloru);
                                        break;
                                default:
                                        break;
                                }
                        }


                        // North edge
                        if (row < GRIDS_PER_EDGE-1)
                        {
                                U8 north_overlay = mOwnership[(row+1)*GRIDS_PER_EDGE+col];
                                add_edge = north_overlay & PARCEL_SOUTH_LINE;
                        }
                        else
                        {
                                add_edge = TRUE;
                        }

                        if (add_edge)
                        {
                                switch(overlay & PARCEL_COLOR_MASK)
                                {
                                case PARCEL_SELF:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, top, NORTH, self_coloru);
                                        break;
                                case PARCEL_GROUP:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, top, NORTH, group_coloru);
                                        break;
                                case PARCEL_OWNED:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, top, NORTH, other_coloru);
                                        break;
                                case PARCEL_FOR_SALE:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, top, NORTH, for_sale_coloru);
                                        break;
                                case PARCEL_AUCTION:
                                        addPropertyLine(new_vertex_array, new_color_array, new_coord_array,
                                                left, top, NORTH, auction_coloru);
                                        break;
                                default:
                                        break;
                                }
                        }
                }
        }

        // Now copy into static arrays for faster rendering.
        // Attempt to recycle old arrays if possible to avoid memory
        // shuffling.
        S32 new_vertex_count = new_vertex_array.count();
        
        if (!(mVertexArray && mColorArray && new_vertex_count == mVertexCount))
        {
                // ...need new arrays
                delete[] mVertexArray;
                mVertexArray = NULL;
                delete[] mColorArray;
                mColorArray = NULL;

                mVertexCount = new_vertex_count;

                if (new_vertex_count > 0)
                {
                        mVertexArray   = new F32[3 * mVertexCount];
                        mColorArray    = new U8 [4 * mVertexCount];
                }
        }

        // Copy the new data into the arrays
        S32 i;
        F32* vertex = mVertexArray;
        for (i = 0; i < mVertexCount; i++)
        {
                const LLVector3& point = new_vertex_array.get(i);
                *vertex = point.mV[VX];
                vertex++;
                *vertex = point.mV[VY];
                vertex++;
                *vertex = point.mV[VZ];
                vertex++;
        }

        U8* colorp = mColorArray;
        for (i = 0; i < mVertexCount; i++)
        {
                const LLColor4U& color = new_color_array.get(i);
                *colorp = color.mV[VRED];
                colorp++;
                *colorp = color.mV[VGREEN];
                colorp++;
                *colorp = color.mV[VBLUE];
                colorp++;
                *colorp = color.mV[VALPHA];
                colorp++;
        }
        
        // Everything's clean now
        mDirty = FALSE;
}


void LLViewerParcelOverlay::addPropertyLine(
                                LLDynamicArray<LLVector3, 256>& vertex_array,
                                LLDynamicArray<LLColor4U, 256>& color_array,
                                LLDynamicArray<LLVector2, 256>& coord_array,
                                const F32 start_x, const F32 start_y, 
                                const U32 edge,
                                const LLColor4U& color)
{
        LLColor4U underwater( color );
        underwater.mV[VALPHA] /= 2;

        LLSurface& land = mRegion->getLand();

        F32 dx;
        F32 dy;
        F32 tick_dx;
        F32 tick_dy;
        //const F32 LINE_WIDTH = 0.125f;
        const F32 LINE_WIDTH = 0.0625f;

        switch(edge)
        {
        case WEST:
                dx = 0.f;
                dy = 1.f;
                tick_dx = LINE_WIDTH;
                tick_dy = 0.f;
                break;

        case EAST:
                dx = 0.f;
                dy = 1.f;
                tick_dx = -LINE_WIDTH;
                tick_dy = 0.f;
                break;

        case NORTH:
                dx = 1.f;
                dy = 0.f;
                tick_dx = 0.f;
                tick_dy = -LINE_WIDTH;
                break;

        case SOUTH:
                dx = 1.f;
                dy = 0.f;
                tick_dx = 0.f;
                tick_dy = LINE_WIDTH;
                break;

        default:
                llerrs << "Invalid edge in addPropertyLine" << llendl;
                return;
        }

        F32 outside_x = start_x;
        F32 outside_y = start_y;
        F32 outside_z = 0.f;
        F32 inside_x  = start_x + tick_dx;
        F32 inside_y  = start_y + tick_dy;
        F32 inside_z  = 0.f;

        // First part, only one vertex
        outside_z = land.resolveHeightRegion( outside_x, outside_y );

        if (outside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        vertex_array.put( LLVector3(outside_x, outside_y, outside_z) );
        coord_array.put(  LLVector2(outside_x - start_x, 0.f) );

        inside_x += dx * LINE_WIDTH;
        inside_y += dy * LINE_WIDTH;

        outside_x += dx * LINE_WIDTH;
        outside_y += dy * LINE_WIDTH;

        // Then the "actual edge"
        inside_z = land.resolveHeightRegion( inside_x, inside_y );
        outside_z = land.resolveHeightRegion( outside_x, outside_y );

        if (inside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        if (outside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        vertex_array.put( LLVector3(inside_x, inside_y, inside_z) );
        vertex_array.put( LLVector3(outside_x, outside_y, outside_z) );

        coord_array.put(  LLVector2(outside_x - start_x, 1.f) );
        coord_array.put(  LLVector2(outside_x - start_x, 0.f) );

        inside_x += dx * (dx - LINE_WIDTH);
        inside_y += dy * (dy - LINE_WIDTH);

        outside_x += dx * (dx - LINE_WIDTH);
        outside_y += dy * (dy - LINE_WIDTH);

        // Middle part, full width
        S32 i;
        const S32 GRID_STEP = S32( PARCEL_GRID_STEP_METERS );
        for (i = 1; i < GRID_STEP; i++)
        {
                inside_z = land.resolveHeightRegion( inside_x, inside_y );
                outside_z = land.resolveHeightRegion( outside_x, outside_y );

                if (inside_z > 20.f) color_array.put( color );
                else color_array.put( underwater );

                if (outside_z > 20.f) color_array.put( color );
                else color_array.put( underwater );

                vertex_array.put( LLVector3(inside_x, inside_y, inside_z) );
                vertex_array.put( LLVector3(outside_x, outside_y, outside_z) );

                coord_array.put(  LLVector2(outside_x - start_x, 1.f) );
                coord_array.put(  LLVector2(outside_x - start_x, 0.f) );

                inside_x += dx;
                inside_y += dy;

                outside_x += dx;
                outside_y += dy;
        }

        // Extra buffer for edge
        inside_x -= dx * LINE_WIDTH;
        inside_y -= dy * LINE_WIDTH;

        outside_x -= dx * LINE_WIDTH;
        outside_y -= dy * LINE_WIDTH;

        inside_z = land.resolveHeightRegion( inside_x, inside_y );
        outside_z = land.resolveHeightRegion( outside_x, outside_y );

        if (inside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        if (outside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        vertex_array.put( LLVector3(inside_x, inside_y, inside_z) );
        vertex_array.put( LLVector3(outside_x, outside_y, outside_z) );

        coord_array.put(  LLVector2(outside_x - start_x, 1.f) );
        coord_array.put(  LLVector2(outside_x - start_x, 0.f) );

        inside_x += dx * LINE_WIDTH;
        inside_y += dy * LINE_WIDTH;

        outside_x += dx * LINE_WIDTH;
        outside_y += dy * LINE_WIDTH;

        // Last edge is not drawn to the edge
        outside_z = land.resolveHeightRegion( outside_x, outside_y );

        if (outside_z > 20.f) color_array.put( color );
        else color_array.put( underwater );

        vertex_array.put( LLVector3(outside_x, outside_y, outside_z) );
        coord_array.put(  LLVector2(outside_x - start_x, 0.f) );
}


void LLViewerParcelOverlay::setDirty()
{
        mDirty = TRUE;
}

void LLViewerParcelOverlay::idleUpdate(bool force_update)
{
        if (gGLManager.mIsDisabled)
        {
                return;
        }
        if (mOverlayTextureIdx >= 0 && (!(mDirty && force_update)))
        {
                // We are in the middle of updating the overlay texture
                updateOverlayTexture();
                return;
        }
        // Only if we're dirty and it's been a while since the last update.
        if (mDirty)
        {
                if (force_update || mTimeSinceLastUpdate.getElapsedTimeF32() > 4.0f)
                {
                        updateOverlayTexture();
                        updatePropertyLines();
                        mTimeSinceLastUpdate.reset();
                }
        }
}

S32 LLViewerParcelOverlay::renderPropertyLines  () 
{
        if (!gSavedSettings.getBOOL("ShowPropertyLines"))
        {
                return 0;
        }
        if (!mVertexArray || !mColorArray)
        {
                return 0;
        }

        LLSurface& land = mRegion->getLand();

        LLGLSUIDefault gls_ui; // called from pipeline
        LLGLSNoTexture gls_no_texture;
        LLGLDepthTest mDepthTest(GL_TRUE);

        // JC - This doesn't work.
        //gGLSUITextureDepth.set();
        //LLViewerImage* image = gImageList.getImage( mLineImageID );
        //image->bindTexture();

        // Find camera height off the ground (not from zero)
        F32 ground_height_at_camera = land.resolveHeightGlobal( gAgent.getCameraPositionGlobal() );
        F32 camera_z = gCamera->getOrigin().mV[VZ];
        F32 camera_height = camera_z - ground_height_at_camera;

        camera_height = llclamp(camera_height, 0.f, 100.f);

        // Pull lines toward camera by 1 cm per meter off the ground.
        const LLVector3& CAMERA_AT = gCamera->getAtAxis();
        F32 pull_toward_camera_scale = 0.01f * camera_height;
        LLVector3 pull_toward_camera = CAMERA_AT;
        pull_toward_camera *= -pull_toward_camera_scale;

        // Always fudge a little vertically.
        pull_toward_camera.mV[VZ] += 0.01f;

        glMatrixMode( GL_MODELVIEW );
        glPushMatrix();

        // Move to appropriate region coords
        LLVector3 origin = mRegion->getOriginAgent();
        glTranslatef( origin.mV[VX], origin.mV[VY], origin.mV[VZ] );

        glTranslatef(pull_toward_camera.mV[VX], pull_toward_camera.mV[VY],
                pull_toward_camera.mV[VZ]);

        // Include +1 because vertices are fenceposts.
        // *2 because it's a quad strip
        const S32 GRID_STEP = S32( PARCEL_GRID_STEP_METERS );
        const S32 vertex_per_edge = 3 + 2 * (GRID_STEP-1) + 3;

        // Stomp the camera into two dimensions
        LLVector3 camera_region = mRegion->getPosRegionFromGlobal( gAgent.getCameraPositionGlobal() );

        // Set up a cull plane 2 * PARCEL_GRID_STEP_METERS behind
        // the camera.  The cull plane normal is the camera's at axis.
        LLVector3 cull_plane_point = gCamera->getAtAxis();
        cull_plane_point *= -2.f * PARCEL_GRID_STEP_METERS;
        cull_plane_point += camera_region;

        LLVector3 vertex;

        const S32 BYTES_PER_COLOR = 4;
        const S32 FLOATS_PER_VERTEX = 3;
        //const S32 FLOATS_PER_TEX_COORD = 2;
        S32 i, j;
        S32 drawn = 0;
        F32* vertexp;
        U8* colorp;

        const F32 PROPERTY_LINE_CLIP_DIST = 256.f;

        for (i = 0; i < mVertexCount; i += vertex_per_edge)
        {
                colorp  = mColorArray  + BYTES_PER_COLOR   * i;
                vertexp = mVertexArray + FLOATS_PER_VERTEX * i;

                vertex.mV[VX] = *(vertexp);
                vertex.mV[VY] = *(vertexp+1);
                vertex.mV[VZ] = *(vertexp+2);

                if (dist_vec_squared2D(vertex, camera_region) > PROPERTY_LINE_CLIP_DIST*PROPERTY_LINE_CLIP_DIST)
                {
                        continue;
                }

                // Destroy vertex, transform to plane-local.
                vertex -= cull_plane_point;

                // negative dot product means it is in back of the plane
                if ( vertex * CAMERA_AT < 0.f )
                {
                        continue;
                }

                glBegin(GL_TRIANGLE_STRIP);

                for (j = 0; j < vertex_per_edge; j++)
                {
                        // JC - This doesn't work
                        //glTexCoord2fv(mTexCoordArray + FLOATS_PER_TEX_COORD*offset);
                        glColor4ubv(colorp);
                        glVertex3fv(vertexp);

                        colorp  += BYTES_PER_COLOR;
                        vertexp += FLOATS_PER_VERTEX;                   
                }

                drawn += vertex_per_edge;

                glEnd();
        }

        glPopMatrix();

        return drawn;
}

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