forked from 0ad/0ad
519 lines
13 KiB
C++
519 lines
13 KiB
C++
/**
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* =========================================================================
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* File : ShadowMap.cpp
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* Project : Pyrogenesis
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* Description : Shadow mapping related texture and matrix management
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*
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* @author Nicolai Hähnle <nicolai@wildfiregames.com>
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* =========================================================================
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*/
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#include "precompiled.h"
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#include "ogl.h"
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#include "CLogger.h"
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#include "graphics/LightEnv.h"
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#include "maths/Bound.h"
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#include "maths/MathUtil.h"
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#include "maths/Matrix3D.h"
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#include "renderer/Renderer.h"
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#include "renderer/ShadowMap.h"
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#define LOG_CATEGORY "graphics"
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// ShadowMap implementation
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/**
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* Struct ShadowMapInternals: Internal data for the ShadowMap implementation
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*/
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struct ShadowMapInternals
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{
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// whether we're using depth texture or luminance map
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bool UseDepthTexture;
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// bit depth for the depth texture, if used
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int DepthTextureBits;
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// handle of shadow map
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GLuint Texture;
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// width, height of shadow map
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u32 Width, Height;
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// transform light space into projected light space
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// in projected light space, the shadowbound box occupies the [-1..1] cube
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// calculated on BeginRender, after the final shadow bounds are known
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CMatrix3D LightProjection;
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// Transform world space into light space; calculated on SetupFrame
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CMatrix3D LightTransform;
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// Transform world space into texture space of the shadow map;
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// calculated on BeginRender, after the final shadow bounds are known
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CMatrix3D TextureMatrix;
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// transform light space into world space
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CMatrix3D InvLightTransform;
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// bounding box of shadowed objects in light space
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CBound ShadowBound;
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// Helper functions
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void CalcShadowMatrices();
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void CreateTexture();
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};
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Construction/Destruction
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ShadowMap::ShadowMap()
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{
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m = new ShadowMapInternals;
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m->Texture = 0;
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m->Width = 0;
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m->Height = 0;
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m->UseDepthTexture = false;
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m->DepthTextureBits = 16;
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}
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ShadowMap::~ShadowMap()
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{
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if (m->Texture)
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glDeleteTextures(1, &m->Texture);
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delete m;
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}
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//////////////////////////////////////////////////////////////////////////////
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// SetCameraAndLight: camera and light direction for this frame
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void ShadowMap::SetupFrame(const CCamera& camera, const CVector3D& lightdir)
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{
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if (!m->Texture)
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m->CreateTexture();
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CVector3D z = lightdir;
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CVector3D y;
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CVector3D x = camera.m_Orientation.GetIn();
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CVector3D eyepos = camera.m_Orientation.GetTranslation();
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z.Normalize();
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x -= z * z.Dot(x);
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if (x.GetLength() < 0.001)
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{
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// this is invoked if the camera and light directions almost coincide
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// assumption: light direction has a significant Z component
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x = CVector3D(1.0, 0.0, 0.0);
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x -= z * z.Dot(x);
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}
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x.Normalize();
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y = z.Cross(x);
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// X axis perpendicular to light direction, flowing along with view direction
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m->LightTransform._11 = x.X;
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m->LightTransform._12 = x.Y;
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m->LightTransform._13 = x.Z;
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// Y axis perpendicular to light and view direction
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m->LightTransform._21 = y.X;
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m->LightTransform._22 = y.Y;
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m->LightTransform._23 = y.Z;
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// Z axis is in direction of light
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m->LightTransform._31 = z.X;
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m->LightTransform._32 = z.Y;
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m->LightTransform._33 = z.Z;
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// eye is at the origin of the coordinate system
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m->LightTransform._14 = -x.Dot(eyepos);
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m->LightTransform._24 = -y.Dot(eyepos);
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m->LightTransform._34 = -z.Dot(eyepos);
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m->LightTransform._41 = 0.0;
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m->LightTransform._42 = 0.0;
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m->LightTransform._43 = 0.0;
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m->LightTransform._44 = 1.0;
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m->LightTransform.GetInverse(m->InvLightTransform);
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m->ShadowBound.SetEmpty();
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}
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//////////////////////////////////////////////////////////////////////////////
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// AddShadowedBound: add a world-space bounding box to the bounds of shadowed
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// objects
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void ShadowMap::AddShadowedBound(const CBound& bounds)
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{
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CBound lightspacebounds;
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bounds.Transform(m->LightTransform, lightspacebounds);
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m->ShadowBound += lightspacebounds;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// CalcShadowMatrices: calculate required matrices for shadow map generation - the light's
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// projection and transformation matrices
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void ShadowMapInternals::CalcShadowMatrices()
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{
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CRenderer& renderer = g_Renderer;
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// Setup orthogonal projection (lightspace -> clip space) for shadowmap rendering
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CVector3D scale = ShadowBound[1] - ShadowBound[0];
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CVector3D shift = (ShadowBound[1] + ShadowBound[0]) * -0.5;
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if (scale.X < 1.0)
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scale.X = 1.0;
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if (scale.Y < 1.0)
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scale.Y = 1.0;
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if (scale.Z < 1.0)
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scale.Z = 1.0;
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scale.X = 2.0 / scale.X;
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scale.Y = 2.0 / scale.Y;
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scale.Z = 2.0 / scale.Z;
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LightProjection.SetZero();
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LightProjection._11 = scale.X;
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LightProjection._14 = shift.X * scale.X;
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LightProjection._22 = scale.Y;
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LightProjection._24 = shift.Y * scale.Y;
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LightProjection._33 = scale.Z;
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LightProjection._34 = shift.Z * scale.Z + renderer.m_ShadowZBias;
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LightProjection._44 = 1.0;
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// Calculate texture matrix by creating the clip space to texture coordinate matrix
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// and then concatenating all matrices that have been calculated so far
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CMatrix3D lightToTex;
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float texscalex = (float)renderer.GetWidth() / (float)Width;
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float texscaley = (float)renderer.GetHeight() / (float)Height;
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float texscalez = 1.0;
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texscalex = texscalex / (ShadowBound[1].X - ShadowBound[0].X);
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texscaley = texscaley / (ShadowBound[1].Y - ShadowBound[0].Y);
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texscalez = texscalez / (ShadowBound[1].Z - ShadowBound[0].Z);
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lightToTex.SetZero();
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lightToTex._11 = texscalex;
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lightToTex._14 = -ShadowBound[0].X * texscalex;
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lightToTex._22 = texscaley;
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lightToTex._24 = -ShadowBound[0].Y * texscaley;
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lightToTex._33 = texscalez;
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lightToTex._34 = -ShadowBound[0].Z * texscalez;
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lightToTex._44 = 1.0;
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TextureMatrix = lightToTex * LightTransform;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Create the shadow map
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void ShadowMapInternals::CreateTexture()
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{
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if (Texture)
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glDeleteTextures(1, &Texture);
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// get shadow map size as next power of two up from view width and height
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Width = g_Renderer.GetWidth();
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Width = RoundUpToPowerOf2(Width);
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Height = g_Renderer.GetHeight();
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Height = RoundUpToPowerOf2(Height);
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const char* formatname = "LUMINANCE";
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if (UseDepthTexture)
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{
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switch(DepthTextureBits) {
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case 16: formatname = "DEPTH_COMPONENT16"; break;
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case 24: formatname = "DEPTH_COMPONENT24"; break;
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case 32: formatname = "DEPTH_COMPONENT32"; break;
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default: formatname = "DEPTH_COMPONENT"; break;
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}
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}
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LOG(NORMAL, LOG_CATEGORY, "Creating shadow texture (size %ix%i) (format = %s)",
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Width, Height, formatname);
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// create texture object
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glGenTextures(1, &Texture);
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g_Renderer.BindTexture(0, Texture);
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u32 size = Width*Height;
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if (UseDepthTexture)
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{
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GLenum format;
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switch(DepthTextureBits) {
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case 16: format = GL_DEPTH_COMPONENT16; break;
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case 24: format = GL_DEPTH_COMPONENT24; break;
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case 32: format = GL_DEPTH_COMPONENT32; break;
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default: format = GL_DEPTH_COMPONENT; break;
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}
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float* buf = new float[size];
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for(uint i = 0; i < size; i++) buf[i] = 1.0;
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glTexImage2D(GL_TEXTURE_2D, 0, format, Width, Height, 0,
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GL_DEPTH_COMPONENT, GL_FLOAT, buf);
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delete[] buf;
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glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
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}
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else
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{
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u32* buf=new u32[size];
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for (uint i=0;i<size;i++) buf[i]=0x00ffffff;
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glTexImage2D(GL_TEXTURE_2D,0,GL_LUMINANCE8,Width,Height,0,GL_RGBA,GL_UNSIGNED_BYTE,buf);
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delete[] buf;
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}
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// set texture parameters
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Set up to render into shadow map texture
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void ShadowMap::BeginRender()
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{
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// HACK HACK: this depends in non-obvious ways on the behaviour of the caller
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CRenderer& renderer = g_Renderer;
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int renderWidth = renderer.GetWidth();
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int renderHeight = renderer.GetHeight();
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// Calc remaining shadow matrices
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m->CalcShadowMatrices();
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// clear buffers
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if (m->UseDepthTexture)
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{
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glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
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glColorMask(0,0,0,0);
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}
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else
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{
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glClearColor(1,1,1,0);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
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}
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// setup viewport
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glViewport(0, 0, renderWidth, renderHeight);
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glLoadMatrixf(&m->LightProjection._11);
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glMatrixMode(GL_MODELVIEW);
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glPushMatrix();
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glLoadMatrixf(&m->LightTransform._11);
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glEnable(GL_SCISSOR_TEST);
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glScissor(1,1, renderWidth-2, renderHeight-2);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Finish rendering into shadow map texture
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void ShadowMap::EndRender()
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{
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glDisable(GL_SCISSOR_TEST);
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// copy result into shadow map texture
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if (!g_Renderer.GetDisableCopyShadow())
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{
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g_Renderer.BindTexture(0, m->Texture);
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glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, g_Renderer.GetWidth(), g_Renderer.GetHeight());
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}
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if (m->UseDepthTexture)
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{
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glColorMask(1,1,1,1);
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}
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// restore matrix stack
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glPopMatrix();
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glMatrixMode(GL_PROJECTION);
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glPopMatrix();
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glMatrixMode(GL_MODELVIEW);
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Retrieve the texture handle and texture matrix for shadowing
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GLuint ShadowMap::GetTexture()
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{
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return m->Texture;
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}
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const CMatrix3D& ShadowMap::GetTextureMatrix()
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{
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return m->TextureMatrix;
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Using depth textures vs. a simple luminance map
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bool ShadowMap::GetUseDepthTexture()
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{
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return m->UseDepthTexture;
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}
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void ShadowMap::SetUseDepthTexture(bool depthTexture)
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{
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if (depthTexture)
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{
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if (!g_Renderer.GetCapabilities().m_DepthTextureShadows)
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{
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LOG(WARNING, LOG_CATEGORY, "Depth textures are not supported by your graphics card/driver. Fallback to luminance map (no self-shadowing)!");
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depthTexture = false;
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}
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}
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if (depthTexture != m->UseDepthTexture)
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{
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if (m->Texture)
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{
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glDeleteTextures(1, &m->Texture);
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m->Texture = 0;
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}
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m->Width = m->Height = 0;
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m->UseDepthTexture = depthTexture;
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}
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}
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// Depth texture bits
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int ShadowMap::GetDepthTextureBits() const
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{
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return m->DepthTextureBits;
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}
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void ShadowMap::SetDepthTextureBits(int bits)
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{
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if (bits != m->DepthTextureBits)
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{
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if (m->Texture)
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{
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glDeleteTextures(1, &m->Texture);
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m->Texture = 0;
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}
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m->Width = m->Height = 0;
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m->DepthTextureBits = bits;
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}
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}
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//////////////////////////////////////////////////////////////////////////////
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// RenderDebugDisplay: debug visualizations
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// - blue: objects in shadow
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void ShadowMap::RenderDebugDisplay()
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{
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glDepthMask(0);
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glDisable(GL_CULL_FACE);
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// Render shadow bound
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glMatrixMode(GL_MODELVIEW);
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glPushMatrix();
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glMultMatrixf(&m->InvLightTransform._11);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glColor4ub(0,0,255,64);
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m->ShadowBound.Render();
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glDisable(GL_BLEND);
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glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
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glColor3ub(0,0,255);
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m->ShadowBound.Render();
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glBegin(GL_LINES);
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glVertex3f(0.0, 0.0, 0.0);
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glVertex3f(0.0, 0.0, 50.0);
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glEnd();
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glBegin(GL_POLYGON);
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glVertex3f(0.0, 0.0, 50.0);
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glVertex3f(50.0, 0.0, 50.0);
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glVertex3f(0.0, 50.0, 50.0);
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glEnd();
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glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
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glPopMatrix();
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#if 0
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CMatrix3D InvTexTransform;
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m->TextureMatrix.GetInverse(InvTexTransform);
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// Render representative texture rectangle
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glPushMatrix();
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glMultMatrixf(&InvTexTransform._11);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glColor4ub(255,0,0,64);
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glBegin(GL_QUADS);
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glVertex3f(0.0, 0.0, 0.0);
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glVertex3f(1.0, 0.0, 0.0);
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glVertex3f(1.0, 1.0, 0.0);
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glVertex3f(0.0, 1.0, 0.0);
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glEnd();
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glDisable(GL_BLEND);
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glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
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glColor3ub(255,0,0);
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glBegin(GL_QUADS);
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glVertex3f(0.0, 0.0, 0.0);
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glVertex3f(1.0, 0.0, 0.0);
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glVertex3f(1.0, 1.0, 0.0);
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glVertex3f(0.0, 1.0, 0.0);
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glEnd();
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glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
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glPopMatrix();
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#endif
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// Render the shadow map
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glLoadIdentity();
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glOrtho(0.0, 1.0, 1.0, 0.0, -1.0, 1.0);
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glMatrixMode(GL_MODELVIEW);
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glPushMatrix();
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glLoadIdentity();
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glDisable(GL_DEPTH_TEST);
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g_Renderer.BindTexture(0, m->Texture);
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if (m->UseDepthTexture)
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{
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_NONE);
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}
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glColor3f(1.0f, 1.0f, 1.0f);
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glBegin(GL_QUADS);
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glTexCoord2f(0.0f, 0.0f); glVertex2f(0.0f, 0.0f);
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glTexCoord2f(1.0f, 0.0f); glVertex2f(0.2f, 0.0f);
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glTexCoord2f(1.0f, 1.0f); glVertex2f(0.2f, 0.2f);
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glTexCoord2f(0.0f, 1.0f); glVertex2f(0.0f, 0.2f);
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glEnd();
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if (m->UseDepthTexture)
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{
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
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}
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glEnable(GL_CULL_FACE);
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glMatrixMode(GL_PROJECTION);
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glPopMatrix();
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glMatrixMode(GL_MODELVIEW);
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glPopMatrix();
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glEnable(GL_DEPTH_TEST);
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glDepthMask(1);
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}
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