add RageDisplay::DrawSymmetricQuadStrip

stepmania/src/RageDisplay.cpp

@@ -834,6 +834,27 @@ void RageDisplay::DrawLineStrip( const RageSpriteVertex v[], int iNumVerts, floa
 	this->DrawLineStripInternal( v, iNumVerts, LineWidth );
 }
 
+/*
+ * Draw a strip of:
+ *
+ * 0..1..2
+ * . /.\ .
+ * ./ . \.
+ * 3..4..5
+ * . /.\ .
+ * ./ . \.
+ * 6..7..8
+ */
+
+void RageDisplay::DrawSymmetricQuadStrip( const RageSpriteVertex v[], int iNumVerts )
+{
+	ASSERT( iNumVerts >= 3 );
+
+	this->DrawSymmetricQuadStripInternal( v, iNumVerts );
+
+	StatsAddVerts( iNumVerts );
+}
+
 void RageDisplay::DrawCircle( const RageSpriteVertex &v, float radius )
 {
 	this->DrawCircleInternal( v, radius );

stepmania/src/RageDisplay.h

@@ -269,6 +269,7 @@ public:
 	void DrawTriangles( const RageSpriteVertex v[], int iNumVerts );
 	void DrawCompiledGeometry( const RageCompiledGeometry *p, int iMeshIndex, const vector<msMesh> &vMeshes );
 	void DrawLineStrip( const RageSpriteVertex v[], int iNumVerts, float LineWidth );
+	void DrawSymmetricQuadStrip( const RageSpriteVertex v[], int iNumVerts );
 	void DrawCircle( const RageSpriteVertex &v, float radius );
 
 	void DrawQuad( const RageSpriteVertex v[] ) { DrawQuads(v,4); } /* alias. upper-left, upper-right, lower-left, lower-right */
@@ -296,6 +297,7 @@ protected:
 	virtual void DrawTrianglesInternal( const RageSpriteVertex v[], int iNumVerts ) = 0;
 	virtual void DrawCompiledGeometryInternal( const RageCompiledGeometry *p, int iMeshIndex ) = 0;
 	virtual void DrawLineStripInternal( const RageSpriteVertex v[], int iNumVerts, float LineWidth );
+	virtual void DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts ) = 0;
 	virtual void DrawCircleInternal( const RageSpriteVertex &v, float radius );
 
 	// return RString() if mode change was successful, an error message otherwise.

stepmania/src/RageDisplay_D3D.cpp

@@ -989,6 +989,48 @@ void RageDisplay_D3D::DrawQuadStripInternal( const RageSpriteVertex v[], int iNu
 	);
 }
 
+void RageDisplay_D3D::DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts )
+{
+	int iNumPieces = (iNumVerts-3)/3;
+	int iNumTriangles = iNumPieces*4;
+	int iNumIndices = iNumTriangles*3;
+
+	// make a temporary index buffer
+	static vector<uint16_t> vIndices;
+	unsigned uOldSize = vIndices.size();
+	unsigned uNewSize = max(uOldSize,(unsigned)iNumIndices);
+	vIndices.resize( uNewSize );
+	for( uint16_t i=(uint16_t)uOldSize/12; i<(uint16_t)iNumPieces; i++ )
+	{
+		// { 1, 3, 0 } { 1, 4, 3 } { 1, 5, 4 } { 1, 2, 5 }
+		vIndices[i*12+0] = i*3+1;
+		vIndices[i*12+1] = i*3+3;
+		vIndices[i*12+2] = i*3+0;
+		vIndices[i*12+3] = i*3+1;
+		vIndices[i*12+4] = i*3+4;
+		vIndices[i*12+5] = i*3+3;
+		vIndices[i*12+6] = i*3+1;
+		vIndices[i*12+7] = i*3+5;
+		vIndices[i*12+8] = i*3+4;
+		vIndices[i*12+9] = i*3+1;
+		vIndices[i*12+10] = i*3+2;
+		vIndices[i*12+11] = i*3+5;
+	}
+
+	g_pd3dDevice->SetVertexShader( D3DFVF_RageSpriteVertex );
+	SendCurrentMatrices();
+	g_pd3dDevice->DrawIndexedPrimitiveUP(
+		D3DPT_TRIANGLELIST, // PrimitiveType
+		0, // MinIndex
+		iNumVerts, // NumVertices
+		iNumTriangles, // PrimitiveCount,
+		&vIndices[0], // pIndexData,
+		D3DFMT_INDEX16, // IndexDataFormat,
+		v, // pVertexStreamZeroData,
+		sizeof(RageSpriteVertex) // VertexStreamZeroStride
+	);
+}
+
 void RageDisplay_D3D::DrawFanInternal( const RageSpriteVertex v[], int iNumVerts )
 {
 	g_pd3dDevice->SetVertexShader( D3DFVF_RageSpriteVertex );

stepmania/src/RageDisplay_D3D.h

@@ -77,6 +77,7 @@ protected:
 	void DrawFanInternal( const RageSpriteVertex v[], int iNumVerts );
 	void DrawStripInternal( const RageSpriteVertex v[], int iNumVerts );
 	void DrawTrianglesInternal( const RageSpriteVertex v[], int iNumVerts );
+	void DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts );
 	void DrawCompiledGeometryInternal( const RageCompiledGeometry *p, int iMeshIndex );
 
 	RString TryVideoMode( const VideoModeParams &p, bool &bNewDeviceOut );

stepmania/src/RageDisplay_Null.h

@@ -76,6 +76,7 @@ protected:
 	void DrawTrianglesInternal( const RageSpriteVertex v[], int iNumVerts ) { }
 	void DrawCompiledGeometryInternal( const RageCompiledGeometry *p, int iMeshIndex ) { }
 	void DrawLineStripInternal( const RageSpriteVertex v[], int iNumVerts, float LineWidth ) { }
+	void DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts ) { }
 
 	VideoModeParams m_Params;
 	RString TryVideoMode( const VideoModeParams &p, bool &bNewDeviceOut ) { m_Params = p; return RString(); }

stepmania/src/RageDisplay_OGL.cpp

@@ -1209,6 +1209,45 @@ void RageDisplay_OGL::DrawQuadStripInternal( const RageSpriteVertex v[], int iNu
 	glDrawArrays( GL_QUAD_STRIP, 0, iNumVerts );
 }
 
+void RageDisplay_OGL::DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts )
+{
+	int iNumPieces = (iNumVerts-3)/3;
+	int iNumTriangles = iNumPieces*4;
+	int iNumIndices = iNumTriangles*3;
+
+	// make a temporary index buffer
+	static vector<uint16_t> vIndices;
+	unsigned uOldSize = vIndices.size();
+	unsigned uNewSize = max(uOldSize,(unsigned)iNumIndices);
+	vIndices.resize( uNewSize );
+	for( uint16_t i=(uint16_t)uOldSize/12; i<(uint16_t)iNumPieces; i++ )
+	{
+		// { 1, 3, 0 } { 1, 4, 3 } { 1, 5, 4 } { 1, 2, 5 }
+		vIndices[i*12+0] = i*3+1;
+		vIndices[i*12+1] = i*3+3;
+		vIndices[i*12+2] = i*3+0;
+		vIndices[i*12+3] = i*3+1;
+		vIndices[i*12+4] = i*3+4;
+		vIndices[i*12+5] = i*3+3;
+		vIndices[i*12+6] = i*3+1;
+		vIndices[i*12+7] = i*3+5;
+		vIndices[i*12+8] = i*3+4;
+		vIndices[i*12+9] = i*3+1;
+		vIndices[i*12+10] = i*3+2;
+		vIndices[i*12+11] = i*3+5;
+	}
+
+	TurnOffHardwareVBO();
+	SendCurrentMatrices();
+
+	SetupVertices( v, iNumVerts );
+	glDrawElements( 
+		GL_TRIANGLES, 
+		iNumIndices,
+		GL_UNSIGNED_SHORT, 
+		&vIndices[0] );
+}
+
 void RageDisplay_OGL::DrawFanInternal( const RageSpriteVertex v[], int iNumVerts )
 {
 	TurnOffHardwareVBO();

stepmania/src/RageDisplay_OGL.h

@@ -95,6 +95,7 @@ protected:
 	void DrawTrianglesInternal( const RageSpriteVertex v[], int iNumVerts );
 	void DrawCompiledGeometryInternal( const RageCompiledGeometry *p, int iMeshIndex );
 	void DrawLineStripInternal( const RageSpriteVertex v[], int iNumVerts, float LineWidth );
+	void DrawSymmetricQuadStripInternal( const RageSpriteVertex v[], int iNumVerts );
 
 	RString TryVideoMode( const VideoModeParams &p, bool &bNewDeviceOut );
 	RageSurface* CreateScreenshot();