source-engine/vguimatsurface/Clip2D.cpp

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2020-04-22 16:56:21 +00:00
//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: Contains 2D clipping routines
//
// $Revision: $
// $NoKeywords: $
//=============================================================================//
#include <vgui/ISurface.h>
#include "Clip2D.h"
#include "tier0/dbg.h"
#include "utlvector.h"
#if defined( _X360 )
#include "materialsystem/imaterialsystem.h"
#endif
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
//-----------------------------------------------------------------------------
// Stretch texture to fit window ( before scissoring )
//-----------------------------------------------------------------------------
static bool g_bStretchTexture = false;
//-----------------------------------------------------------------------------
// Max # of vertices for clipping
//-----------------------------------------------------------------------------
enum
{
VGUI_VERTEX_TEMP_COUNT = 48,
};
//-----------------------------------------------------------------------------
// For simulated scissor tests...
//-----------------------------------------------------------------------------
struct ScissorRect_t
{
int left;
int top;
int right;
int bottom;
};
static ScissorRect_t g_ScissorRect;
static bool g_bScissor = false;
static bool g_bFullScreenScissor = false;
//-----------------------------------------------------------------------------
// Enable/disable scissoring...
//-----------------------------------------------------------------------------
void EnableScissor( bool enable )
{
g_bScissor = enable;
}
void SetScissorRect( int left, int top, int right, int bottom )
{
// Check for a valid rectangle...
Assert( left <= right );
Assert( top <= bottom );
if ( g_ScissorRect.left == left && g_ScissorRect.right == right &&
g_ScissorRect.top == top && g_ScissorRect.bottom == bottom )
return;
g_ScissorRect.left = left;
g_ScissorRect.top = top;
g_ScissorRect.right = right;
g_ScissorRect.bottom = bottom;
#if defined( _X360 )
// no reason to waste cpu on full screen scissor, gpu does it
CMatRenderContextPtr pRenderContext( g_pMaterialSystem );
int vx, vy, vw, vh;
pRenderContext->GetViewport( vx, vy, vw, vh );
g_bFullScreenScissor = (left <= vx && top <= vy && right >= vw && bottom >= vh );
#endif
}
void GetScissorRect( int &left, int &top, int &right, int &bottom, bool &enabled )
{
left = g_ScissorRect.left;
top = g_ScissorRect.top;
right = g_ScissorRect.right;
bottom = g_ScissorRect.bottom;
enabled = g_bScissor;
}
//-----------------------------------------------------------------------------
// Used to clip the shadow decals
//-----------------------------------------------------------------------------
struct PolygonClipState_t
{
int m_CurrVert;
int m_TempCount;
int m_ClipCount;
vgui::Vertex_t m_pTempVertices[VGUI_VERTEX_TEMP_COUNT];
vgui::Vertex_t* m_ppClipVertices[2][VGUI_VERTEX_TEMP_COUNT];
};
//-----------------------------------------------------------------------------
// Clipping methods for 2D
//-----------------------------------------------------------------------------
class CClipTop
{
public:
static inline bool Inside( vgui::Vertex_t const& vert )
{
return vert.m_Position.y >= g_ScissorRect.top;
}
static inline float Clip( const Vector2D& one, const Vector2D& two )
{
return (g_ScissorRect.top - one.y) / (two.y - one.y);
}
};
class CClipLeft
{
public:
static inline bool Inside( vgui::Vertex_t const& vert )
{
return vert.m_Position.x >= g_ScissorRect.left;
}
static inline float Clip( const Vector2D& one, const Vector2D& two )
{
return (one.x - g_ScissorRect.left) / (one.x - two.x);
}
};
class CClipRight
{
public:
static inline bool Inside( vgui::Vertex_t const& vert )
{
return vert.m_Position.x < g_ScissorRect.right;
}
static inline float Clip( const Vector2D& one, const Vector2D& two )
{
return (g_ScissorRect.right - one.x) / (two.x - one.x);
}
};
class CClipBottom
{
public:
static inline bool Inside( vgui::Vertex_t const& vert )
{
return vert.m_Position.y < g_ScissorRect.bottom;
}
static inline float Clip( const Vector2D& one, const Vector2D& two )
{
return (one.y - g_ScissorRect.bottom) / (one.y - two.y);
}
};
template <class Clipper>
static inline void Intersect( const vgui::Vertex_t& start, const vgui::Vertex_t& end, vgui::Vertex_t* pOut, Clipper& clipper )
{
// Clip to the scissor rectangle
float t = Clipper::Clip( start.m_Position, end.m_Position );
Vector2DLerp( start.m_Position, end.m_Position, t, pOut->m_Position );
Vector2DLerp( start.m_TexCoord, end.m_TexCoord, t, pOut->m_TexCoord );
}
//-----------------------------------------------------------------------------
// Clips a line segment to a single plane
//-----------------------------------------------------------------------------
template< class Clipper >
bool ClipLineToPlane( Clipper &clipper, const vgui::Vertex_t *pInVerts, vgui::Vertex_t* pOutVerts )
{
bool startInside = Clipper::Inside( pInVerts[0] );
bool endInside = Clipper::Inside( pInVerts[1] );
// Cull
if (!startInside && !endInside)
return false;
if (startInside && endInside)
{
pOutVerts[0] = pInVerts[0];
pOutVerts[1] = pInVerts[1];
}
else
{
int inIndex = startInside ? 0 : 1;
pOutVerts[inIndex] = pInVerts[inIndex];
Intersect( pInVerts[0], pInVerts[1], &pOutVerts[1 - inIndex], clipper );
}
return true;
}
//-----------------------------------------------------------------------------
// Clips a line segment to the current scissor rectangle
//-----------------------------------------------------------------------------
bool ClipLine( const vgui::Vertex_t *pInVerts, vgui::Vertex_t* pOutVerts )
{
if ( g_bScissor && !g_bFullScreenScissor )
{
// Clippers...
CClipTop top;
CClipBottom bottom;
CClipLeft left;
CClipRight right;
// Sutherland-hodgman clip, not particularly efficient but that's ok for now
vgui::Vertex_t tempVerts[2];
if (!ClipLineToPlane( top, pInVerts, tempVerts ))
return false;
if (!ClipLineToPlane( bottom, tempVerts, pOutVerts ))
return false;
if (!ClipLineToPlane( left, pOutVerts, tempVerts ))
return false;
if (!ClipLineToPlane( right, tempVerts, pOutVerts ))
return false;
return true;
}
else
{
pOutVerts[0] = pInVerts[0];
pOutVerts[1] = pInVerts[1];
return true;
}
}
//-----------------------------------------------------------------------------
// Methods associated with clipping 2D polygons
//-----------------------------------------------------------------------------
struct ScreenClipState_t
{
int m_iCurrVert;
int m_iTempCount;
int m_iClipCount;
CUtlVector<vgui::Vertex_t> m_pTempVertices;
CUtlVector<vgui::Vertex_t*> m_ppClipVertices[2];
};
template <class Clipper>
static void ScreenClip( ScreenClipState_t& clip, Clipper& clipper )
{
if (clip.m_iClipCount < 3)
return;
// Ye Olde Sutherland-Hodgman clipping algorithm
int numOutVerts = 0;
vgui::Vertex_t** pSrcVert = clip.m_ppClipVertices[clip.m_iCurrVert].Base();
vgui::Vertex_t** pDestVert = clip.m_ppClipVertices[!clip.m_iCurrVert].Base();
int numVerts = clip.m_iClipCount;
vgui::Vertex_t* pStart = pSrcVert[numVerts-1];
bool startInside = Clipper::Inside( *pStart );
for (int i = 0; i < numVerts; ++i)
{
vgui::Vertex_t* pEnd = pSrcVert[i];
bool endInside = Clipper::Inside( *pEnd );
if (endInside)
{
if (!startInside)
{
// Started outside, ended inside, need to clip the edge
Assert( clip.m_iTempCount <= clip.m_pTempVertices.Count() );
// Allocate a new clipped vertex
pDestVert[numOutVerts] = &clip.m_pTempVertices[clip.m_iTempCount++];
// Clip the edge to the clip plane
Intersect( *pStart, *pEnd, pDestVert[numOutVerts], clipper );
++numOutVerts;
}
pDestVert[numOutVerts++] = pEnd;
}
else
{
if (startInside)
{
// Started inside, ended outside, need to clip the edge
Assert( clip.m_iTempCount <= clip.m_pTempVertices.Count() );
// Allocate a new clipped vertex
pDestVert[numOutVerts] = &clip.m_pTempVertices[clip.m_iTempCount++];
// Clip the edge to the clip plane
Intersect( *pStart, *pEnd, pDestVert[numOutVerts], clipper );
++numOutVerts;
}
}
pStart = pEnd;
startInside = endInside;
}
// Switch source lists
clip.m_iCurrVert = 1 - clip.m_iCurrVert;
clip.m_iClipCount = numOutVerts;
}
//-----------------------------------------------------------------------------
// Clips a polygon to the screen area
//-----------------------------------------------------------------------------
int ClipPolygon( int iCount, vgui::Vertex_t *pVerts, int iTranslateX, int iTranslateY, vgui::Vertex_t ***pppOutVertex )
{
static ScreenClipState_t clip;
// Allocate enough room in the clip state...
// Having no reallocations during clipping
clip.m_pTempVertices.EnsureCount( iCount * 4 );
clip.m_ppClipVertices[0].EnsureCount( iCount * 4 );
clip.m_ppClipVertices[1].EnsureCount( iCount * 4 );
// Copy the initial verts in...
for (int i = 0; i < iCount; ++i)
{
// NOTE: This only works because we EnsuredCount above
clip.m_pTempVertices[i] = pVerts[i];
clip.m_pTempVertices[i].m_Position.x += iTranslateX;
clip.m_pTempVertices[i].m_Position.y += iTranslateY;
clip.m_ppClipVertices[0][i] = &clip.m_pTempVertices[i];
}
if ( !g_bScissor || g_bFullScreenScissor )
{
Assert(pppOutVertex);
*pppOutVertex = clip.m_ppClipVertices[0].Base();
return iCount;
}
clip.m_iClipCount = iCount;
clip.m_iTempCount = iCount;
clip.m_iCurrVert = 0;
// Clippers...
CClipTop top;
CClipBottom bottom;
CClipLeft left;
CClipRight right;
// Sutherland-hodgman clip
ScreenClip( clip, top );
ScreenClip( clip, bottom );
ScreenClip( clip, left );
ScreenClip( clip, right );
if (clip.m_iClipCount < 3)
return 0;
// Return a pointer to the array of clipped vertices...
Assert(pppOutVertex);
*pppOutVertex = clip.m_ppClipVertices[clip.m_iCurrVert].Base();
return clip.m_iClipCount;
}
//-----------------------------------------------------------------------------
// Purpose: Used for clipping, produces an interpolated texture coordinate
//-----------------------------------------------------------------------------
inline float InterpTCoord(float val, float mins, float maxs, float tMin, float tMax)
{
float flPercent;
if (mins != maxs)
flPercent = (float)(val - mins) / (maxs - mins);
else
flPercent = 0.5f;
return tMin + (tMax - tMin) * flPercent;
}
//-----------------------------------------------------------------------------
// Purpose: Does a scissor clip of the input rectangle.
// Returns false if it is completely clipped off.
//-----------------------------------------------------------------------------
bool ClipRect( const vgui::Vertex_t &inUL, const vgui::Vertex_t &inLR,
vgui::Vertex_t *pOutUL, vgui::Vertex_t *pOutLR )
{
// Check for a valid rectangle...
// Assert( inUL.m_Position.x <= inLR.m_Position.x );
// Assert( inUL.m_Position.y <= inLR.m_Position.y );
if ( IsX360() && ( !g_bScissor || g_bFullScreenScissor ||
( inUL.m_Position.x >= g_ScissorRect.left && inLR.m_Position.x <= g_ScissorRect.right && inUL.m_Position.y >= g_ScissorRect.top && inLR.m_Position.y <= g_ScissorRect.bottom ) ) )
{
// clipping is not needed
// either full screen, and hw will do it or rect is inscribed, and operation is meaningless
*pOutUL = inUL;
*pOutLR = inLR;
return true;
}
if ( g_bScissor )
{
// Pick whichever left side is larger
if (g_ScissorRect.left > inUL.m_Position.x)
pOutUL->m_Position.x = g_ScissorRect.left;
else
pOutUL->m_Position.x = inUL.m_Position.x;
// Pick whichever right side is smaller
if (g_ScissorRect.right <= inLR.m_Position.x)
pOutLR->m_Position.x = g_ScissorRect.right;
else
pOutLR->m_Position.x = inLR.m_Position.x;
// Pick whichever top side is larger
if (g_ScissorRect.top > inUL.m_Position.y)
pOutUL->m_Position.y = g_ScissorRect.top;
else
pOutUL->m_Position.y = inUL.m_Position.y;
// Pick whichever bottom side is smaller
if (g_ScissorRect.bottom <= inLR.m_Position.y)
pOutLR->m_Position.y = g_ScissorRect.bottom;
else
pOutLR->m_Position.y = inLR.m_Position.y;
// Check for non-intersecting
if ( (pOutUL->m_Position.x > pOutLR->m_Position.x) ||
(pOutUL->m_Position.y > pOutLR->m_Position.y) )
{
return false;
}
if ( !g_bStretchTexture )
{
pOutUL->m_TexCoord.x = InterpTCoord(pOutUL->m_Position.x,
inUL.m_Position.x, inLR.m_Position.x, inUL.m_TexCoord.x, inLR.m_TexCoord.x);
pOutLR->m_TexCoord.x = InterpTCoord(pOutLR->m_Position.x,
inUL.m_Position.x, inLR.m_Position.x, inUL.m_TexCoord.x, inLR.m_TexCoord.x);
pOutUL->m_TexCoord.y = InterpTCoord(pOutUL->m_Position.y,
inUL.m_Position.y, inLR.m_Position.y, inUL.m_TexCoord.y, inLR.m_TexCoord.y);
pOutLR->m_TexCoord.y = InterpTCoord(pOutLR->m_Position.y,
inUL.m_Position.y, inLR.m_Position.y, inUL.m_TexCoord.y, inLR.m_TexCoord.y);
}
else
{
// FIXME, this isn't right
pOutUL->m_TexCoord = inUL.m_TexCoord;
pOutLR->m_TexCoord = inLR.m_TexCoord;
}
}
else
{
*pOutUL = inUL;
*pOutLR = inLR;
}
return true;
}