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106 lines
3.4 KiB
C++
106 lines
3.4 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// Purpose:
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//
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//=============================================================================
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#include "tier2/camerautils.h"
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#include "tier0/dbg.h"
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#include "mathlib/vector.h"
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#include "mathlib/vmatrix.h"
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#include "tier2/tier2.h"
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// memdbgon must be the last include file in a .cpp file!!!
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#include "tier0/memdbgon.h"
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//-----------------------------------------------------------------------------
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// accessors for generated matrices
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//-----------------------------------------------------------------------------
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void ComputeViewMatrix( matrix3x4_t *pWorldToCamera, const Camera_t &camera )
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{
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matrix3x4_t transform;
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AngleMatrix( camera.m_angles, camera.m_origin, transform );
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VMatrix matRotate( transform );
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VMatrix matRotateZ;
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MatrixBuildRotationAboutAxis( matRotateZ, Vector(0,0,1), -90 );
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MatrixMultiply( matRotate, matRotateZ, matRotate );
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VMatrix matRotateX;
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MatrixBuildRotationAboutAxis( matRotateX, Vector(1,0,0), 90 );
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MatrixMultiply( matRotate, matRotateX, matRotate );
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transform = matRotate.As3x4();
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MatrixInvert( transform, *pWorldToCamera );
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}
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void ComputeViewMatrix( VMatrix *pWorldToCamera, const Camera_t &camera )
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{
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matrix3x4_t transform, invTransform;
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AngleMatrix( camera.m_angles, camera.m_origin, transform );
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VMatrix matRotate( transform );
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VMatrix matRotateZ;
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MatrixBuildRotationAboutAxis( matRotateZ, Vector(0,0,1), -90 );
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MatrixMultiply( matRotate, matRotateZ, matRotate );
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VMatrix matRotateX;
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MatrixBuildRotationAboutAxis( matRotateX, Vector(1,0,0), 90 );
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MatrixMultiply( matRotate, matRotateX, matRotate );
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transform = matRotate.As3x4();
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MatrixInvert( transform, invTransform );
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*pWorldToCamera = invTransform;
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}
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void ComputeProjectionMatrix( VMatrix *pCameraToProjection, const Camera_t &camera, int width, int height )
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{
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float flFOV = camera.m_flFOV;
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float flZNear = camera.m_flZNear;
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float flZFar = camera.m_flZFar;
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float flApsectRatio = (float)width / (float)height;
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// MatrixBuildPerspective( proj, flFOV, flFOV * flApsectRatio, flZNear, flZFar );
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#if 1
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float halfWidth = tan( flFOV * M_PI / 360.0 );
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float halfHeight = halfWidth / flApsectRatio;
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#else
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float halfHeight = tan( flFOV * M_PI / 360.0 );
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float halfWidth = flApsectRatio * halfHeight;
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#endif
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pCameraToProjection->Init(
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0.f, 0.f, 0.f, 0.f,
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0.f, 0.f, 0.f, 0.f,
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0.f, 0.f, 0.f, 0.f,
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0.f, 0.f, 0.f, 0.f
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);
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pCameraToProjection->m[0][0] = 1.0f / halfWidth;
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pCameraToProjection->m[1][1] = 1.0f / halfHeight;
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pCameraToProjection->m[2][2] = flZFar / ( flZNear - flZFar );
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pCameraToProjection->m[3][2] = -1.0f;
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pCameraToProjection->m[2][3] = flZNear * flZFar / ( flZNear - flZFar );
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}
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//-----------------------------------------------------------------------------
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// Computes the screen space position given a screen size
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//-----------------------------------------------------------------------------
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void ComputeScreenSpacePosition( Vector2D *pScreenPosition, const Vector &vecWorldPosition,
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const Camera_t &camera, int width, int height )
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{
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VMatrix view, proj, viewproj;
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ComputeViewMatrix( &view, camera );
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ComputeProjectionMatrix( &proj, camera, width, height );
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MatrixMultiply( proj, view, viewproj );
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Vector vecScreenPos;
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Vector3DMultiplyPositionProjective( viewproj, vecWorldPosition, vecScreenPos );
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pScreenPosition->x = ( vecScreenPos.x + 1.0f ) * width / 2.0f;
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pScreenPosition->y = ( -vecScreenPos.y + 1.0f ) * height / 2.0f;
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}
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