source-engine/engine/decal_clip.cpp

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2020-04-22 16:56:21 +00:00
//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#include "decal_clip.h"
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
// --------------------------------------------------------------------------- //
// Template classes for the clipper.
// --------------------------------------------------------------------------- //
class CPlane_Top
{
public:
static inline bool Inside( CDecalVert *pVert ) {return pVert->m_ctCoords.y < 1;}
static inline float Clip( CDecalVert *one, CDecalVert *two ) {return (1 - one->m_ctCoords.y) / (two->m_ctCoords.y - one->m_ctCoords.y);}
};
class CPlane_Left
{
public:
static inline bool Inside( CDecalVert *pVert ) {return pVert->m_ctCoords.x > 0;}
static inline float Clip( CDecalVert *one, CDecalVert *two ) {return one->m_ctCoords.x / (one->m_ctCoords.x - two->m_ctCoords.x);}
};
class CPlane_Right
{
public:
static inline bool Inside( CDecalVert *pVert ) {return pVert->m_ctCoords.x < 1;}
static inline float Clip( CDecalVert *one, CDecalVert *two ) {return (1 - one->m_ctCoords.x) / (two->m_ctCoords.x - one->m_ctCoords.x);}
};
class CPlane_Bottom
{
public:
static inline bool Inside( CDecalVert *pVert ) {return pVert->m_ctCoords.y > 0;}
static inline float Clip( CDecalVert *one, CDecalVert *two ) {return one->m_ctCoords.y / (one->m_ctCoords.y - two->m_ctCoords.y);}
};
// --------------------------------------------------------------------------- //
// Globals.
// --------------------------------------------------------------------------- //
CDecalVert ALIGN16 g_DecalClipVerts[MAX_DECALCLIPVERT] ALIGN16_POST;
static CDecalVert ALIGN16 g_DecalClipVerts2[MAX_DECALCLIPVERT] ALIGN16_POST;
template< class Clipper >
static inline void Intersect( Clipper &clip, CDecalVert *one, CDecalVert *two, CDecalVert *out )
{
float t = Clipper::Clip( one, two );
VectorLerp( one->m_vPos, two->m_vPos, t, out->m_vPos );
Vector2DLerp( one->m_cLMCoords, two->m_cLMCoords, t, out->m_cLMCoords );
Vector2DLerp( one->m_ctCoords, two->m_ctCoords, t, out->m_ctCoords );
}
template< class Clipper >
static inline int SHClip( CDecalVert *pDecalClipVerts, int vertCount, CDecalVert *out, Clipper &clip )
{
int j, outCount;
CDecalVert *s, *p;
Assert( vertCount <= MAX_DECALCLIPVERT );
outCount = 0;
s = &pDecalClipVerts[ vertCount-1 ];
for ( j = 0; j < vertCount; j++ )
{
p = &pDecalClipVerts[ j ];
if ( Clipper::Inside( p ) )
{
if ( Clipper::Inside( s ) )
{
*out = *p;
outCount++;
out++;
}
else
{
Intersect( clip, s, p, out );
out++;
outCount++;
*out = *p;
outCount++;
out++;
}
}
else
{
if ( Clipper::Inside( s ) )
{
Intersect( clip, p, s, out );
out++;
outCount++;
}
}
s = p;
}
return outCount;
}
const float DECAL_CLIP_EPSILON = 0.01f;
CDecalVert* R_DoDecalSHClip( CDecalVert *pInVerts, CDecalVert *pOutVerts, decal_t *pDecal, int nStartVerts, const Vector &vecNormal )
{
if ( pOutVerts == NULL )
pOutVerts = &g_DecalClipVerts[0];
CPlane_Top top;
CPlane_Left left;
CPlane_Right right;
CPlane_Bottom bottom;
// Clip the polygon to the decal texture space
int outCount = SHClip( pInVerts, nStartVerts, &g_DecalClipVerts2[0], top );
outCount = SHClip( &g_DecalClipVerts2[0], outCount, &g_DecalClipVerts[0], left );
outCount = SHClip( &g_DecalClipVerts[0], outCount, &g_DecalClipVerts2[0], right );
outCount = SHClip( &g_DecalClipVerts2[0], outCount, pOutVerts, bottom );
pDecal->clippedVertCount = outCount;
if ( !outCount )
return NULL;
// FIXME: This is a brutally hack workaround for the fact that we get massive decal flicker
// when looking at a decal at a glancing angle while standing right next to it.
for ( int i = 0; i < outCount; ++i )
{
VectorMA( pOutVerts[i].m_vPos, OVERLAY_AVOID_FLICKER_NORMAL_OFFSET, vecNormal, pOutVerts[i].m_vPos );
}
if ( outCount && pDecal->material->InMaterialPage() )
{
float offset[2], scale[2];
pDecal->material->GetMaterialOffset( offset );
pDecal->material->GetMaterialScale( scale );
for ( int i = 0; i < outCount; ++i )
{
pOutVerts[i].m_ctCoords.x = offset[0] + (pOutVerts[i].m_ctCoords.x * scale[0]);
pOutVerts[i].m_ctCoords.y = offset[1] + (pOutVerts[i].m_ctCoords.y * scale[1]);
}
}
return pOutVerts;
}
// Build the initial list of vertices from the surface verts into the global array, 'verts'.
void R_SetupDecalVertsForMSurface(
decal_t * RESTRICT pDecal,
SurfaceHandle_t surfID,
Vector * RESTRICT pTextureSpaceBasis,
CDecalVert * RESTRICT pVerts )
{
unsigned short * RESTRICT pIndices = &host_state.worldbrush->vertindices[MSurf_FirstVertIndex( surfID )];
int count = MSurf_VertCount( surfID );
float uOffset = 0.5f - pDecal->dx;
float vOffset = 0.5f - pDecal->dy;
for ( int j = 0; j < count; j++ )
{
int vertIndex = pIndices[j];
pVerts[j].m_vPos = host_state.worldbrush->vertexes[vertIndex].position; // Copy model space coordinates
// garymcthack - what about m_ParentTexCoords?
pVerts[j].m_ctCoords.x = DotProduct( pVerts[j].m_vPos, pTextureSpaceBasis[0] ) + uOffset;
pVerts[j].m_ctCoords.y = DotProduct( pVerts[j].m_vPos, pTextureSpaceBasis[1] ) + vOffset;
pVerts[j].m_cLMCoords.Init();
}
}
//-----------------------------------------------------------------------------
// compute the decal basis based on surface normal, and preferred saxis
//-----------------------------------------------------------------------------
#define SIN_45_DEGREES ( 0.70710678118654752440084436210485f )
void R_DecalComputeBasis( Vector const& surfaceNormal, Vector const* pSAxis,
Vector* textureSpaceBasis )
{
/*
// s, t, textureSpaceNormal (T cross S = textureSpaceNormal(N))
// N
// \
// \
// \
// |---->S
// |
// |
// |T
// S = textureSpaceBasis[0]
// T = textureSpaceBasis[1]
// N = textureSpaceBasis[2]
*/
// Get the surface normal.
VectorCopy( surfaceNormal, textureSpaceBasis[2] );
if (pSAxis)
{
// T = S cross N
CrossProduct( *pSAxis, textureSpaceBasis[2], textureSpaceBasis[1] );
// Name sure they aren't parallel or antiparallel
// In that case, fall back to the normal algorithm.
if ( DotProduct( textureSpaceBasis[1], textureSpaceBasis[1] ) > 1e-6 )
{
// S = N cross T
CrossProduct( textureSpaceBasis[2], textureSpaceBasis[1], textureSpaceBasis[0] );
VectorNormalizeFast( textureSpaceBasis[0] );
VectorNormalizeFast( textureSpaceBasis[1] );
return;
}
// Fall through to the standard algorithm for parallel or antiparallel
}
// floor/ceiling?
if( fabs( surfaceNormal[2] ) > SIN_45_DEGREES )
{
textureSpaceBasis[0][0] = 1.0f;
textureSpaceBasis[0][1] = 0.0f;
textureSpaceBasis[0][2] = 0.0f;
// T = S cross N
CrossProduct( textureSpaceBasis[0], textureSpaceBasis[2], textureSpaceBasis[1] );
// S = N cross T
CrossProduct( textureSpaceBasis[2], textureSpaceBasis[1], textureSpaceBasis[0] );
}
// wall
else
{
textureSpaceBasis[1][0] = 0.0f;
textureSpaceBasis[1][1] = 0.0f;
textureSpaceBasis[1][2] = -1.0f;
// S = N cross T
CrossProduct( textureSpaceBasis[2], textureSpaceBasis[1], textureSpaceBasis[0] );
// T = S cross N
CrossProduct( textureSpaceBasis[0], textureSpaceBasis[2], textureSpaceBasis[1] );
}
VectorNormalizeFast( textureSpaceBasis[0] );
VectorNormalizeFast( textureSpaceBasis[1] );
}
#define MAX_PLAYERSPRAY_SIZE 64
void R_SetupDecalTextureSpaceBasis( decal_t *pDecal, Vector &vSurfNormal, IMaterial *pMaterial, Vector textureSpaceBasis[3], float decalWorldScale[2] )
{
// Compute the non-scaled decal basis
R_DecalComputeBasis( vSurfNormal, (pDecal->flags & FDECAL_USESAXIS) ? &pDecal->saxis : 0, textureSpaceBasis );
// world width of decal = ptexture->width / pDecal->scale
// world height of decal = ptexture->height / pDecal->scale
// scale is inverse, scales world space to decal u/v space [0,1]
// OPTIMIZE: Get rid of these divides
if ( pDecal->flags & FDECAL_PLAYERSPRAY )
{
int nWidthScale = pMaterial->GetMappingWidth() / MAX_PLAYERSPRAY_SIZE;
int nHeightScale = pMaterial->GetMappingHeight() / MAX_PLAYERSPRAY_SIZE;
float flScale = static_cast<float>( max( nWidthScale, nHeightScale ) );
decalWorldScale[0] = pDecal->scale / pMaterial->GetMappingWidth();
decalWorldScale[1] = pDecal->scale / pMaterial->GetMappingHeight();
if ( flScale > 1.0f )
{
decalWorldScale[0] *= flScale;
decalWorldScale[1] *= flScale;
}
}
else
{
decalWorldScale[0] = pDecal->scale / pMaterial->GetMappingWidth();
decalWorldScale[1] = pDecal->scale / pMaterial->GetMappingHeight();
}
VectorScale( textureSpaceBasis[0], decalWorldScale[0], textureSpaceBasis[0] );
VectorScale( textureSpaceBasis[1], decalWorldScale[1], textureSpaceBasis[1] );
}
// Figure out where the decal maps onto the surface.
void R_SetupDecalClip( CDecalVert* &pOutVerts, decal_t *pDecal, Vector &vSurfNormal, IMaterial *pMaterial, Vector textureSpaceBasis[3], float decalWorldScale[2] )
{
// if ( pOutVerts == NULL )
// pOutVerts = &g_DecalClipVerts[0];
R_SetupDecalTextureSpaceBasis( pDecal, vSurfNormal, pMaterial, textureSpaceBasis, decalWorldScale );
// Generate texture coordinates for each vertex in decal s,t space
// probably should pre-generate this, store it and use it for decal-decal collisions
// as in R_DecalsIntersect()
pDecal->dx = DotProduct( pDecal->position, textureSpaceBasis[0] );
pDecal->dy = DotProduct( pDecal->position, textureSpaceBasis[1] );
}
//-----------------------------------------------------------------------------
// Generate clipped vertex list for decal pdecal projected onto polygon psurf
//-----------------------------------------------------------------------------
CDecalVert* R_DecalVertsClip( CDecalVert *pOutVerts, decal_t *pDecal, SurfaceHandle_t surfID, IMaterial *pMaterial )
{
float decalWorldScale[2];
Vector textureSpaceBasis[3];
// Figure out where the decal maps onto the surface.
R_SetupDecalClip( pOutVerts, pDecal, MSurf_Plane( surfID ).normal, pMaterial, textureSpaceBasis, decalWorldScale );
// Build the initial list of vertices from the surface verts.
R_SetupDecalVertsForMSurface( pDecal, surfID, textureSpaceBasis, g_DecalClipVerts );
return R_DoDecalSHClip( g_DecalClipVerts, pOutVerts, pDecal, MSurf_VertCount( surfID ), MSurf_Plane( surfID ).normal );
}