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app/legion/heightfield.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: Heightfield class
+//
+// $Revision: $
+// $NoKeywords: $
+//===========================================================================//
+
+#include "heightfield.h"
+#include "materialsystem/imaterial.h"
+#include "legion.h"
+#include "materialsystem/imaterialsystem.h"
+#include "materialsystem/imesh.h"
+#include "tier2/tier2.h"
+#include "tier2/utlstreambuffer.h"
+#include "bitmap/bitmap.h"
+#include "bitmap/psd.h"
+#include "tier1/KeyValues.h"
+
+
+//-----------------------------------------------------------------------------
+// Utility macro
+//-----------------------------------------------------------------------------
+#define HEIGHT( _x, _y )	m_pHeightField[ ( (_y) << m_nPowX ) + (_x) ]
+#define ROW( _y )			&m_pHeightField[ (_y) << m_nPowX ]
+
+
+//-----------------------------------------------------------------------------
+// Constructor, destructor
+//-----------------------------------------------------------------------------
+CHeightField::CHeightField( int nPowX, int nPowY, int nPowScale )
+{
+	m_nPowX = nPowX;
+	m_nPowY = nPowY;
+	m_nPowScale = nPowScale;
+	m_nWidth = ( 1 << nPowX );
+	m_nHeight = ( 1 << nPowY );
+	m_nScale = ( 1 << nPowScale );
+	m_flOOScale = 1.0f / m_nScale;
+	m_pHeightField = (float*)malloc( m_nWidth * m_nHeight * sizeof(float) );
+	memset( m_pHeightField, 0, m_nWidth * m_nHeight * sizeof(float) );
+
+	KeyValues *pKeyValues = new KeyValues( "Wireframe" );
+	pKeyValues->SetInt( "$nocull", 1 );
+	m_Material.Init( "__Temp", pKeyValues );
+}
+
+CHeightField::~CHeightField()
+{
+	free( m_pHeightField );
+}
+
+
+//-----------------------------------------------------------------------------
+// Bilinearly filters a sample out of a bitmap at a particular (x,y)
+// NOTE: x,y are not normalized and are expected to go in the range of (0->w-1, 0->h-1)
+//-----------------------------------------------------------------------------
+float BilerpBitmap( Bitmap_t &bitmap, float x, float y )
+{
+	Assert( bitmap.m_ImageFormat == IMAGE_FORMAT_RGBA8888 );
+
+    float w = (float)bitmap.m_nWidth;
+    float h = (float)bitmap.m_nHeight;
+
+    // Clamp to a valid range
+	x = clamp( x, 0, w - 1.0f );
+	y = clamp( y, 0, h - 1.0f );
+
+    // pick bilerp coordinates
+	int i0 = (int)floor( x );
+	int i1 = i0 + 1;
+	int j0 = (int)floor( y );
+	int j1 = j0 + 1;
+	if ( i1 >= bitmap.m_nWidth )
+	{
+		i1 = bitmap.m_nWidth - 1;
+	}
+	if ( j1 >= bitmap.m_nHeight )
+	{
+		j1 = bitmap.m_nHeight - 1;
+	}
+
+	float fx = x - i0;
+	float fy = y - j0;
+
+	RGBA8888_t* pPixel00 = (RGBA8888_t*)bitmap.GetPixel( i0, j0 );
+	RGBA8888_t* pPixel10 = (RGBA8888_t*)bitmap.GetPixel( i1, j0 );
+	RGBA8888_t* pPixel01 = (RGBA8888_t*)bitmap.GetPixel( i0, j1 );
+	RGBA8888_t* pPixel11 = (RGBA8888_t*)bitmap.GetPixel( i1, j1 );
+
+	float v00 = pPixel00->r / 255.0f;
+    float v10 = pPixel10->r / 255.0f;
+    float v01 = pPixel01->r / 255.0f;
+    float v11 = pPixel11->r / 255.0f;
+
+    // do the bilerp
+    return (1-fx)*(1-fy)*v00 + fx*(1-fy)*v10 + (1-fx)*fy*v01 + fx*fy*v11;
+}
+
+
+//-----------------------------------------------------------------------------
+// Loads the heightfield from a file
+//-----------------------------------------------------------------------------
+bool CHeightField::LoadHeightFromFile( const char *pFileName )
+{
+	Bitmap_t bitmap;
+	CUtlStreamBuffer buf( pFileName, "GAME", CUtlBuffer::READ_ONLY );
+	if ( IsPSDFile( buf ) )
+	{
+		if ( !PSDReadFileRGBA8888( buf, bitmap ) )
+			return false;
+	}
+
+    // map from height field into map, ensuring corner pixel centers line up
+    // hfx -> mapx:  0 -> 0.5, hfw-1 -> mapw-0.5
+    // x (mapw - 1)/(hfw - 1) + 0.5
+    // mapx -> worldx: 0 -> 0, mapw -> worldw
+    float fx = (float)( bitmap.m_nWidth - 1) / (float)( m_nWidth - 1 );
+    float fy = (float)( bitmap.m_nHeight - 1) / (float)( m_nHeight - 1 );
+
+    for( int i = 0; i < m_nHeight; ++i ) 
+	{
+		float *pRow = ROW( i );
+        for( int j = 0; j < m_nWidth; ++j, ++pRow ) 
+		{
+            *pRow = 50.0f * BilerpBitmap( bitmap, i * fx, j * fy );
+        }
+    }
+	return true;
+}
+
+
+//-----------------------------------------------------------------------------
+// Returns the height at a particular point
+//-----------------------------------------------------------------------------
+float CHeightField::GetHeight( float x, float y )
+{
+	x *= m_flOOScale;
+	y *= m_flOOScale;
+
+	int gx = (int)floor( x );
+	int gy = (int)floor( y );
+	x -= gx;
+	y -= gy;
+
+	// Check for out of range
+	if ( gx < -1 || gy < -1 || gx >= m_nWidth || gy >= m_nHeight ) 
+		return 0.0f;
+
+	float h00 = ( gx >= 0 && gy >= 0 )					? HEIGHT(gx  , gy  ) : 0.0f;
+	float h01 = ( gx < (m_nWidth-1) && gy >= 0 )		? HEIGHT(gx+1, gy  ) : 0.0f;
+	float h10 = ( gx >= 0 && gy < (m_nHeight-1) )		? HEIGHT(gx  , gy+1) : 0.0f;
+	float h11 = ( gx<(m_nWidth-1) && gy<(m_nHeight-1) )	? HEIGHT(gx+1, gy+1) : 0.0f;
+
+	// This fixup accounts for the triangularization of the mesh
+	if (x > y) 
+	{
+		h10 = h00 + h11 - h01;
+	} 
+	else 
+	{
+		h01 = h00 + h11 - h10;
+	}
+
+	// Bilinear filter
+	float h0 = h00 + ( h01 - h00 ) * x;
+	float h1 = h10 + ( h11 - h10 ) * x;
+	float h = h0 + (h1-h0)*y;
+
+	return h;
+}
+
+
+//-----------------------------------------------------------------------------
+// Returns the height + slope at a particular point
+//-----------------------------------------------------------------------------
+float CHeightField::GetHeightAndSlope( float x, float y, float *dx, float *dy )
+{
+	x *= m_flOOScale;
+	y *= m_flOOScale;
+
+	int gx = (int)floor(x);
+	int gy = (int)floor(y);
+	x -= gx;
+	y -= gy;
+
+	if ( gx < -1 || gy < -1 || gx >= m_nWidth || gy >= m_nHeight )
+	{
+		*dx = 0;
+		*dy = 0;
+		return 0.0f;
+	}
+
+	float h00 = ( gx >= 0 && gy >= 0 )					? HEIGHT(gx  , gy  ) : 0.0f;
+	float h01 = ( gx < (m_nWidth-1) && gy >= 0 )		? HEIGHT(gx+1, gy  ) : 0.0f;
+	float h10 = ( gx >= 0 && gy < (m_nHeight-1) )		? HEIGHT(gx  , gy+1) : 0.0f;
+	float h11 = ( gx<(m_nWidth-1) && gy<(m_nHeight-1) )	? HEIGHT(gx+1, gy+1) : 0.0f;
+
+	if (x > y) 
+	{
+		h10 = h00 + h11 - h01;
+	} 
+	else 
+	{
+		h01 = h00 + h11 - h10;
+	}
+
+	*dx = ( h01 - h00 ) * m_flOOScale;
+	*dy = ( h10 - h00 ) * m_flOOScale;
+
+	// Bilinear filter
+	float h0 = h00 + ( h01 - h00 ) * x;
+	float h1 = h10 + ( h11 - h10 ) * x;
+	float h = h0 + ( h1 - h0 )* y;
+
+	return h;
+}
+
+
+//-----------------------------------------------------------------------------
+// Draws the height field
+//-----------------------------------------------------------------------------
+void CHeightField::Draw( )
+{
+	int nVertexCount = m_nWidth * m_nHeight;
+	int nIndexCount = 6 * ( m_nWidth - 1 ) * ( m_nHeight - 1 );
+
+	float flOOTexWidth = 1.0f / m_Material->GetMappingWidth();
+	float flOOTexHeight = 1.0f / m_Material->GetMappingHeight();
+	float iu = 0.5f  * flOOTexWidth;
+	float iv = 1.0f - ( 0.5f * flOOTexHeight );
+	float du = ( 1.0f - flOOTexWidth ) / ( m_nWidth - 1 );
+	float dv = -( 1.0f - flOOTexHeight ) / ( m_nHeight - 1 );
+
+	CMatRenderContextPtr pRenderContext( g_pMaterialSystem );
+	pRenderContext->Bind( m_Material );
+	IMesh *pMesh = pRenderContext->GetDynamicMesh( );
+
+	CMeshBuilder meshBuilder;
+	meshBuilder.Begin( pMesh, MATERIAL_TRIANGLES, nVertexCount, nIndexCount );
+
+	// Deal with vertices
+	float v = iv;
+	float y = 0.0f;
+	for ( int i = 0; i < m_nHeight; ++i, y += m_nScale, v += dv )
+	{
+		float u = iu;
+		float x = 0.0f;
+		for ( int j = 0; j < m_nWidth; ++j, x += m_nScale, u += du )
+		{
+			meshBuilder.Position3f( x, y, HEIGHT( j, i ) );
+			meshBuilder.TexCoord2f( 0, u, v );
+			meshBuilder.AdvanceVertex();
+		}
+	}
+
+	// Deal with indices
+	for ( int i = 0; i < (m_nHeight - 1); ++i )
+	{
+		int nRow0 = m_nWidth * i; 
+		int nRow1 = nRow0 + m_nWidth; 
+		for ( int j = 0; j < (m_nWidth - 1); ++j )
+		{
+			meshBuilder.FastIndex( nRow0+j );
+			meshBuilder.FastIndex( nRow0+j+1 );
+			meshBuilder.FastIndex( nRow1+j+1 );
+
+			meshBuilder.FastIndex( nRow0+j );
+			meshBuilder.FastIndex( nRow1+j+1 );
+			meshBuilder.FastIndex( nRow1+j );
+		}
+	}
+
+	meshBuilder.End();
+	pMesh->Draw();
+}