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1 files changed, 183 insertions, 0 deletions

diff --git a/game/client/portal/Portal_DynamicMeshRenderingUtils.cpp b/game/client/portal/Portal_DynamicMeshRenderingUtils.cpp
new file mode 100644
index 0000000..f5b32fa
--- /dev/null
+++ b/game/client/portal/Portal_DynamicMeshRenderingUtils.cpp
@@ -0,0 +1,183 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//=============================================================================//
+
+#include "cbase.h"
+#include "Portal_DynamicMeshRenderingUtils.h"
+#include "iviewrender.h"
+
+extern ConVar mat_wireframe;
+
+
+int ClipPolyToPlane_LerpTexCoords( PortalMeshPoint_t *inVerts, int vertCount, PortalMeshPoint_t *outVerts, const Vector& normal, float dist, float fOnPlaneEpsilon )
+{
+	vec_t	*dists = (vec_t *)stackalloc( sizeof(vec_t) * vertCount * 4 ); //4x vertcount should cover all cases
+	int		*sides = (int *)stackalloc( sizeof(int) * vertCount * 4 );
+	int		counts[3];
+	vec_t	dot;
+	int		i, j;
+	Vector	mid = vec3_origin;
+	int		outCount;
+
+	counts[0] = counts[1] = counts[2] = 0;
+
+	// determine sides for each point
+	for ( i = 0; i < vertCount; i++ )
+	{
+		dot = DotProduct( inVerts[i].vWorldSpacePosition, normal) - dist;
+		dists[i] = dot;
+		if ( dot > fOnPlaneEpsilon )
+			sides[i] = SIDE_FRONT;
+		else if ( dot < -fOnPlaneEpsilon )
+			sides[i] = SIDE_BACK;
+		else
+			sides[i] = SIDE_ON;
+		counts[sides[i]]++;
+	}
+	sides[i] = sides[0];
+	dists[i] = dists[0];
+
+	if (!counts[0])
+		return 0;
+
+	if (!counts[1])
+	{
+		// Copy to output verts
+		//for ( i = 0; i < vertCount; i++ )
+		memcpy( outVerts, inVerts, sizeof( PortalMeshPoint_t ) * vertCount );
+		return vertCount;
+	}
+
+	outCount = 0;
+	for ( i = 0; i < vertCount; i++ )
+	{
+		if (sides[i] == SIDE_ON)
+		{
+			memcpy( &outVerts[outCount], &inVerts[i], sizeof( PortalMeshPoint_t ) );
+			++outCount;
+			continue;
+		}
+		if (sides[i] == SIDE_FRONT)
+		{
+			memcpy( &outVerts[outCount], &inVerts[i], sizeof( PortalMeshPoint_t ) );
+			++outCount;
+		}
+		if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
+			continue;
+
+		Vector& p1 = inVerts[i].vWorldSpacePosition;
+		
+
+		// generate a split point
+		int i2 = (i+1)%vertCount;
+		Vector& p2 = inVerts[i2].vWorldSpacePosition;
+		
+		dot = dists[i] / (dists[i]-dists[i+1]);
+		for (j=0 ; j<3 ; j++)
+		{	
+			mid[j] = p1[j] + dot*(p2[j]-p1[j]);
+		}
+
+		VectorCopy (mid, outVerts[outCount].vWorldSpacePosition);
+		
+		outVerts[outCount].texCoord.x = inVerts[i].texCoord.x + dot*(inVerts[i2].texCoord.x - inVerts[i].texCoord.x);
+		outVerts[outCount].texCoord.y = inVerts[i].texCoord.y + dot*(inVerts[i2].texCoord.y - inVerts[i].texCoord.y);
+		
+		++outCount;
+	}
+
+	return outCount;
+}
+
+void RenderPortalMeshConvexPolygon( PortalMeshPoint_t *pVerts, int iVertCount, const IMaterial *pMaterial, void *pBind )
+{
+	CMatRenderContextPtr pRenderContext( materials );
+	pRenderContext->Bind( (IMaterial *)pMaterial, pBind );
+
+	//PortalMeshPoint_t *pMidVerts = (PortalMeshPoint_t *)stackalloc( sizeof( PortalMeshPoint_t ) * iVertCount );
+
+	CMeshBuilder meshBuilder;
+	IMesh* pMesh = pRenderContext->GetDynamicMesh( true );
+	meshBuilder.Begin( pMesh, MATERIAL_TRIANGLE_STRIP, iVertCount - 2 );
+
+	//any convex polygon can be rendered with a triangle strip by starting at a vertex and alternating vertices from each side
+	int iForwardCounter = 0;
+	int iReverseCounter = iVertCount - 1; //guaranteed to be >= 2 to start
+
+	do
+	{
+		PortalMeshPoint_t *pVertex = &pVerts[iForwardCounter];
+		meshBuilder.Position3fv( &pVertex->vWorldSpacePosition.x );
+		meshBuilder.TexCoord2fv( 0, &pVertex->texCoord.x );
+		meshBuilder.AdvanceVertex();
+		++iForwardCounter;
+
+		if( iForwardCounter > iReverseCounter )
+			break;
+
+		pVertex = &pVerts[iReverseCounter];
+		meshBuilder.Position3fv( &pVertex->vWorldSpacePosition.x );
+		meshBuilder.TexCoord2fv( 0, &pVertex->texCoord.x );
+		meshBuilder.AdvanceVertex();
+		--iReverseCounter;
+	} while( iForwardCounter <= iReverseCounter );
+
+	meshBuilder.End();
+	pMesh->Draw();
+}
+
+
+void Clip_And_Render_Convex_Polygon( PortalMeshPoint_t *pVerts, int iVertCount, const IMaterial *pMaterial, void *pBind )
+{
+	PortalMeshPoint_t *pInVerts = (PortalMeshPoint_t *)stackalloc( iVertCount * 4 * sizeof( PortalMeshPoint_t ) ); //really only should need 2x points, but I'm paranoid
+	PortalMeshPoint_t *pOutVerts = (PortalMeshPoint_t *)stackalloc( iVertCount * 4 * sizeof( PortalMeshPoint_t ) );
+	PortalMeshPoint_t *pTempVerts;
+
+
+	//clip by the viewing frustum
+	{
+		VPlane *pFrustum = view->GetFrustum();
+		
+		//clip by first plane and put output into pInVerts
+		iVertCount = ClipPolyToPlane_LerpTexCoords( pVerts, iVertCount, pInVerts, pFrustum[0].m_Normal, pFrustum[0].m_Dist, 0.01f );
+
+		//clip by other planes and flipflop in and out pointers
+		for( int i = 1; i != FRUSTUM_NUMPLANES; ++i )
+		{
+			if( iVertCount < 3 )
+				return; //nothing to draw
+
+			iVertCount = ClipPolyToPlane_LerpTexCoords( pInVerts, iVertCount, pOutVerts, pFrustum[i].m_Normal, pFrustum[i].m_Dist, 0.01f );
+			pTempVerts = pInVerts; pInVerts = pOutVerts; pOutVerts = pTempVerts; //swap vertex pointers
+		}
+
+		if( iVertCount < 3 )
+			return; //nothing to draw
+	}
+
+	CMatRenderContextPtr pRenderContext( materials );
+	
+	RenderPortalMeshConvexPolygon( pOutVerts, iVertCount, pMaterial, pBind );
+	if( mat_wireframe.GetBool() )
+		RenderPortalMeshConvexPolygon( pOutVerts, iVertCount, materials->FindMaterial( "shadertest/wireframe", TEXTURE_GROUP_CLIENT_EFFECTS, false ), pBind );
+
+	stackfree( pOutVerts );
+	stackfree( pInVerts );
+}
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