Merge 'remotes/trunk'

[0ad.git] / source / renderer / ShadowMap.cpp

/* Copyright (C) 2017 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Shadow mapping related texture and matrix management
 */

#include "precompiled.h"

#include "gui/GUIutil.h"
#include "lib/bits.h"
#include "lib/ogl.h"
#include "ps/CLogger.h"
#include "ps/ConfigDB.h"
#include "ps/Profile.h"

#include "graphics/LightEnv.h"
#include "graphics/ShaderManager.h"

#include "maths/BoundingBoxAligned.h"
#include "maths/Brush.h"
#include "maths/MathUtil.h"
#include "maths/Matrix3D.h"

#include "renderer/Renderer.h"
#include "renderer/ShadowMap.h"


///////////////////////////////////////////////////////////////////////////////////////////////////
// ShadowMap implementation

/**
 * Struct ShadowMapInternals: Internal data for the ShadowMap implementation
 */
struct ShadowMapInternals
{
        // bit depth for the depth texture
        int DepthTextureBits;
        // the EXT_framebuffer_object framebuffer
        GLuint Framebuffer;
        // handle of shadow map
        GLuint Texture;
        // width, height of shadow map
        int Width, Height;
        // Shadow map quality (-2 - Very Low, -1 - Low, 0 - Medium, 1 - High, 2 - Very High)
        int QualityLevel;
        // used width, height of shadow map
        int EffectiveWidth, EffectiveHeight;
        // transform light space into projected light space
        // in projected light space, the shadowbound box occupies the [-1..1] cube
        // calculated on BeginRender, after the final shadow bounds are known
        CMatrix3D LightProjection;
        // Transform world space into light space; calculated on SetupFrame
        CMatrix3D LightTransform;
        // Transform world space into texture space of the shadow map;
        // calculated on BeginRender, after the final shadow bounds are known
        CMatrix3D TextureMatrix;

        // transform light space into world space
        CMatrix3D InvLightTransform;
        // bounding box of shadowed objects in light space
        CBoundingBoxAligned ShadowCasterBound;
        CBoundingBoxAligned ShadowReceiverBound;

        CBoundingBoxAligned ShadowRenderBound;

        // Camera transformed into light space
        CCamera LightspaceCamera;

        // Some drivers (at least some Intel Mesa ones) appear to handle alpha testing
        // incorrectly when the FBO has only a depth attachment.
        // When m_ShadowAlphaFix is true, we use DummyTexture to store a useless
        // alpha texture which is attached to the FBO as a workaround.
        GLuint DummyTexture;

        // Copy of renderer's standard view camera, saved between
        // BeginRender and EndRender while we replace it with the shadow camera
        CCamera SavedViewCamera;

        // Save the caller's FBO so it can be restored
        GLint SavedViewFBO;

        // Helper functions
        void CalcShadowMatrices();
        void CreateTexture();
};


///////////////////////////////////////////////////////////////////////////////////////////////////
// Construction/Destruction
ShadowMap::ShadowMap()
{
        m = new ShadowMapInternals;
        m->Framebuffer = 0;
        m->Texture = 0;
        m->DummyTexture = 0;
        m->Width = 0;
        m->Height = 0;
        m->QualityLevel = 0;
        m->EffectiveWidth = 0;
        m->EffectiveHeight = 0;
        m->DepthTextureBits = 0;
        // DepthTextureBits: 24/32 are very much faster than 16, on GeForce 4 and FX;
        // but they're very much slower on Radeon 9800.
        // In both cases, the default (no specified depth) is fast, so we just use
        // that by default and hope it's alright. (Otherwise, we'd probably need to
        // do some kind of hardware detection to work out what to use.)

        // Avoid using uninitialised values in AddShadowedBound if SetupFrame wasn't called first
        m->LightTransform.SetIdentity();
}


ShadowMap::~ShadowMap()
{
        if (m->Texture)
                glDeleteTextures(1, &m->Texture);
        if (m->DummyTexture)
                glDeleteTextures(1, &m->DummyTexture);
        if (m->Framebuffer)
                pglDeleteFramebuffersEXT(1, &m->Framebuffer);

        delete m;
}

///////////////////////////////////////////////////////////////////////////////////////////////////
// Force the texture/buffer/etc to be recreated, particularly when the renderer's
// size has changed
void ShadowMap::RecreateTexture()
{
        if (m->Texture)
                glDeleteTextures(1, &m->Texture);
        if (m->DummyTexture)
                glDeleteTextures(1, &m->DummyTexture);
        if (m->Framebuffer)
                pglDeleteFramebuffersEXT(1, &m->Framebuffer);

        m->Texture = 0;
        m->DummyTexture = 0;
        m->Framebuffer = 0;

        // (Texture will be constructed in next SetupFrame)
}

//////////////////////////////////////////////////////////////////////////////
// SetupFrame: camera and light direction for this frame
void ShadowMap::SetupFrame(const CCamera& camera, const CVector3D& lightdir)
{
        if (!m->Texture)
                m->CreateTexture();

        CVector3D z = lightdir;
        CVector3D y;
        CVector3D x = camera.m_Orientation.GetIn();
        CVector3D eyepos = camera.m_Orientation.GetTranslation();

        z.Normalize();
        x -= z * z.Dot(x);
        if (x.Length() < 0.001)
        {
                // this is invoked if the camera and light directions almost coincide
                // assumption: light direction has a significant Z component
                x = CVector3D(1.0, 0.0, 0.0);
                x -= z * z.Dot(x);
        }
        x.Normalize();
        y = z.Cross(x);

        // X axis perpendicular to light direction, flowing along with view direction
        m->LightTransform._11 = x.X;
        m->LightTransform._12 = x.Y;
        m->LightTransform._13 = x.Z;

        // Y axis perpendicular to light and view direction
        m->LightTransform._21 = y.X;
        m->LightTransform._22 = y.Y;
        m->LightTransform._23 = y.Z;

        // Z axis is in direction of light
        m->LightTransform._31 = z.X;
        m->LightTransform._32 = z.Y;
        m->LightTransform._33 = z.Z;

        // eye is at the origin of the coordinate system
        m->LightTransform._14 = -x.Dot(eyepos);
        m->LightTransform._24 = -y.Dot(eyepos);
        m->LightTransform._34 = -z.Dot(eyepos);

        m->LightTransform._41 = 0.0;
        m->LightTransform._42 = 0.0;
        m->LightTransform._43 = 0.0;
        m->LightTransform._44 = 1.0;

        m->LightTransform.GetInverse(m->InvLightTransform);
        m->ShadowCasterBound.SetEmpty();
        m->ShadowReceiverBound.SetEmpty();

        //
        m->LightspaceCamera = camera;
        m->LightspaceCamera.m_Orientation = m->LightTransform * camera.m_Orientation;
        m->LightspaceCamera.UpdateFrustum();
}


//////////////////////////////////////////////////////////////////////////////
// AddShadowedBound: add a world-space bounding box to the bounds of shadowed
// objects
void ShadowMap::AddShadowCasterBound(const CBoundingBoxAligned& bounds)
{
        CBoundingBoxAligned lightspacebounds;

        bounds.Transform(m->LightTransform, lightspacebounds);
        m->ShadowCasterBound += lightspacebounds;
}

void ShadowMap::AddShadowReceiverBound(const CBoundingBoxAligned& bounds)
{
        CBoundingBoxAligned lightspacebounds;

        bounds.Transform(m->LightTransform, lightspacebounds);
        m->ShadowReceiverBound += lightspacebounds;
}

CFrustum ShadowMap::GetShadowCasterCullFrustum()
{
        // Get the bounds of all objects that can receive shadows
        CBoundingBoxAligned bound = m->ShadowReceiverBound;

        // Intersect with the camera frustum, so the shadow map doesn't have to get
        // stretched to cover the off-screen parts of large models
        bound.IntersectFrustumConservative(m->LightspaceCamera.GetFrustum());

        // ShadowBound might have been empty to begin with, producing an empty result
        if (bound.IsEmpty())
        {
                // CFrustum can't easily represent nothingness, so approximate it with
                // a single point which won't match many objects
                bound += CVector3D(0.0f, 0.0f, 0.0f);
                return bound.ToFrustum();
        }

        // Extend the bounds a long way towards the light source, to encompass
        // all objects that might cast visible shadows.
        // (The exact constant was picked entirely arbitrarily.)
        bound[0].Z -= 1000.f;

        CFrustum frustum = bound.ToFrustum();
        frustum.Transform(m->InvLightTransform);
        return frustum;
}

///////////////////////////////////////////////////////////////////////////////////////////////////
// CalcShadowMatrices: calculate required matrices for shadow map generation - the light's
// projection and transformation matrices
void ShadowMapInternals::CalcShadowMatrices()
{
        // Start building the shadow map to cover all objects that will receive shadows
        CBoundingBoxAligned receiverBound = ShadowReceiverBound;

        // Intersect with the camera frustum, so the shadow map doesn't have to get
        // stretched to cover the off-screen parts of large models
        receiverBound.IntersectFrustumConservative(LightspaceCamera.GetFrustum());

        // Intersect with the shadow caster bounds, because there's no point
        // wasting space around the edges of the shadow map that we're not going
        // to draw into
        ShadowRenderBound[0].X = std::max(receiverBound[0].X, ShadowCasterBound[0].X);
        ShadowRenderBound[0].Y = std::max(receiverBound[0].Y, ShadowCasterBound[0].Y);
        ShadowRenderBound[1].X = std::min(receiverBound[1].X, ShadowCasterBound[1].X);
        ShadowRenderBound[1].Y = std::min(receiverBound[1].Y, ShadowCasterBound[1].Y);

        // Set the near and far planes to include just the shadow casters,
        // so we make full use of the depth texture's range. Add a bit of a
        // delta so we don't accidentally clip objects that are directly on
        // the planes.
        ShadowRenderBound[0].Z = ShadowCasterBound[0].Z - 2.f;
        ShadowRenderBound[1].Z = ShadowCasterBound[1].Z + 2.f;

        // ShadowBound might have been empty to begin with, producing an empty result
        if (ShadowRenderBound.IsEmpty())
        {
                // no-op
                LightProjection.SetIdentity();
                TextureMatrix = LightTransform;
                return;
        }

        // round off the shadow boundaries to sane increments to help reduce swim effect
        float boundInc = 16.0f;
        ShadowRenderBound[0].X = floor(ShadowRenderBound[0].X / boundInc) * boundInc;
        ShadowRenderBound[0].Y = floor(ShadowRenderBound[0].Y / boundInc) * boundInc;
        ShadowRenderBound[1].X = ceil(ShadowRenderBound[1].X / boundInc) * boundInc;
        ShadowRenderBound[1].Y = ceil(ShadowRenderBound[1].Y / boundInc) * boundInc;

        // Setup orthogonal projection (lightspace -> clip space) for shadowmap rendering
        CVector3D scale = ShadowRenderBound[1] - ShadowRenderBound[0];
        CVector3D shift = (ShadowRenderBound[1] + ShadowRenderBound[0]) * -0.5;

        if (scale.X < 1.0)
                scale.X = 1.0;
        if (scale.Y < 1.0)
                scale.Y = 1.0;
        if (scale.Z < 1.0)
                scale.Z = 1.0;

        scale.X = 2.0 / scale.X;
        scale.Y = 2.0 / scale.Y;
        scale.Z = 2.0 / scale.Z;

        // make sure a given world position falls on a consistent shadowmap texel fractional offset
        float offsetX = fmod(ShadowRenderBound[0].X - LightTransform._14, 2.0f/(scale.X*EffectiveWidth));
        float offsetY = fmod(ShadowRenderBound[0].Y - LightTransform._24, 2.0f/(scale.Y*EffectiveHeight));

        LightProjection.SetZero();
        LightProjection._11 = scale.X;
        LightProjection._14 = (shift.X + offsetX) * scale.X;
        LightProjection._22 = scale.Y;
        LightProjection._24 = (shift.Y + offsetY) * scale.Y;
        LightProjection._33 = scale.Z;
        LightProjection._34 = shift.Z * scale.Z;
        LightProjection._44 = 1.0;

        // Calculate texture matrix by creating the clip space to texture coordinate matrix
        // and then concatenating all matrices that have been calculated so far

        float texscalex = scale.X * 0.5f * (float)EffectiveWidth / (float)Width;
        float texscaley = scale.Y * 0.5f * (float)EffectiveHeight / (float)Height;
        float texscalez = scale.Z * 0.5f;

        CMatrix3D lightToTex;
        lightToTex.SetZero();
        lightToTex._11 = texscalex;
        lightToTex._14 = (offsetX - ShadowRenderBound[0].X) * texscalex;
        lightToTex._22 = texscaley;
        lightToTex._24 = (offsetY - ShadowRenderBound[0].Y) * texscaley;
        lightToTex._33 = texscalez;
        lightToTex._34 = -ShadowRenderBound[0].Z * texscalez;
        lightToTex._44 = 1.0;

        TextureMatrix = lightToTex * LightTransform;
}



//////////////////////////////////////////////////////////////////////////
// Create the shadow map
void ShadowMapInternals::CreateTexture()
{
        // Cleanup
        if (Texture)
        {
                glDeleteTextures(1, &Texture);
                Texture = 0;
        }
        if (DummyTexture)
        {
                glDeleteTextures(1, &DummyTexture);
                DummyTexture = 0;
        }
        if (Framebuffer)
        {
                pglDeleteFramebuffersEXT(1, &Framebuffer);
                Framebuffer = 0;
        }

        // save the caller's FBO
        glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &SavedViewFBO);

        pglGenFramebuffersEXT(1, &Framebuffer);

        if (g_Renderer.m_ShadowMapSize != 0)
        {
                // non-default option to override the size
                Width = Height = g_Renderer.m_ShadowMapSize;
        }
        else
        {
                CFG_GET_VAL("shadowquality", QualityLevel);

                // get shadow map size as next power of two up from view width/height
                int shadow_map_size = (int)round_up_to_pow2((unsigned)std::max(g_Renderer.GetWidth(), g_Renderer.GetHeight()));
                switch (QualityLevel)
                {
                // Very Low
                case -2:
                        shadow_map_size /= 4;
                        break;
                // Low
                case -1:
                        shadow_map_size /= 2;
                        break;
                // High
                case 1:
                        shadow_map_size *= 2;
                        break;
                // Ultra
                case 2:
                        shadow_map_size *= 4;
                        break;
                // Medium as is
                default:
                        break;
                }
                Width = Height = shadow_map_size;
        }
        // Clamp to the maximum texture size
        Width = std::min(Width, (int)ogl_max_tex_size);
        Height = std::min(Height, (int)ogl_max_tex_size);

        // Since we're using a framebuffer object, the whole texture is available
        EffectiveWidth = Width;
        EffectiveHeight = Height;

        const char* formatname;

        switch(DepthTextureBits)
        {
        case 16: formatname = "DEPTH_COMPONENT16"; break;
        case 24: formatname = "DEPTH_COMPONENT24"; break;
        case 32: formatname = "DEPTH_COMPONENT32"; break;
        default: formatname = "DEPTH_COMPONENT"; break;
        }

        LOGMESSAGE("Creating shadow texture (size %dx%d) (format = %s)",
                Width, Height, formatname);


        if (g_Renderer.m_Options.m_ShadowAlphaFix)
        {
                glGenTextures(1, &DummyTexture);
                g_Renderer.BindTexture(0, DummyTexture);
                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Width, Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
        }

        glGenTextures(1, &Texture);
        g_Renderer.BindTexture(0, Texture);

        GLenum format;

#if CONFIG2_GLES
        format = GL_DEPTH_COMPONENT;
#else
        switch (DepthTextureBits)
        {
        case 16: format = GL_DEPTH_COMPONENT16; break;
        case 24: format = GL_DEPTH_COMPONENT24; break;
        case 32: format = GL_DEPTH_COMPONENT32; break;
        default: format = GL_DEPTH_COMPONENT; break;
        }
#endif

        glTexImage2D(GL_TEXTURE_2D, 0, format, Width, Height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, NULL);
        // GLES requires type == UNSIGNED_SHORT or UNSIGNED_INT

        // set texture parameters
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

#if CONFIG2_GLES
        // GLES doesn't do depth comparisons, so treat it as a
        // basic unfiltered depth texture
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
#else
        // Enable automatic depth comparisons
        glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_INTENSITY);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);

        // Use GL_LINEAR to trigger automatic PCF on some devices
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
#endif

        ogl_WarnIfError();

        // bind to framebuffer object
        glBindTexture(GL_TEXTURE_2D, 0);
        pglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, Framebuffer);

        pglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_2D, Texture, 0);

        if (g_Renderer.m_Options.m_ShadowAlphaFix)
        {
                pglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, DummyTexture, 0);
        }
        else
        {
#if CONFIG2_GLES
#warning TODO: figure out whether the glDrawBuffer/glReadBuffer stuff is needed, since it is not supported by GLES
#else
                glDrawBuffer(GL_NONE);
#endif
        }

#if !CONFIG2_GLES
        glReadBuffer(GL_NONE);
#endif

        ogl_WarnIfError();

        GLenum status = pglCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

        pglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, SavedViewFBO);

        if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
        {
                LOGWARNING("Framebuffer object incomplete: 0x%04X", status);

                // Disable shadow rendering (but let the user try again if they want)
                g_Renderer.m_Options.m_Shadows = false;
        }
}


///////////////////////////////////////////////////////////////////////////////////////////////////
// Set up to render into shadow map texture
void ShadowMap::BeginRender()
{
        // HACK HACK: this depends in non-obvious ways on the behaviour of the caller

        // save caller's FBO
        glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &m->SavedViewFBO);

        // Calc remaining shadow matrices
        m->CalcShadowMatrices();

        {
                PROFILE("bind framebuffer");
                glBindTexture(GL_TEXTURE_2D, 0);
                pglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m->Framebuffer);
        }

        // clear buffers
        {
                PROFILE("clear depth texture");
                // In case we used m_ShadowAlphaFix, we ought to clear the unused
                // color buffer too, else Mali 400 drivers get confused.
                // Might as well clear stencil too for completeness.
                glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
                glColorMask(0,0,0,0);
        }

        // setup viewport
        const SViewPort vp = { 0, 0, m->EffectiveWidth, m->EffectiveHeight };
        g_Renderer.SetViewport(vp);

        m->SavedViewCamera = g_Renderer.GetViewCamera();

        CCamera c = m->SavedViewCamera;
        c.SetProjection(m->LightProjection);
        c.GetOrientation() = m->InvLightTransform;
        g_Renderer.SetViewCamera(c);

#if !CONFIG2_GLES
        glMatrixMode(GL_PROJECTION);
        glLoadMatrixf(&m->LightProjection._11);
        glMatrixMode(GL_MODELVIEW);
        glLoadMatrixf(&m->LightTransform._11);
#endif

        glEnable(GL_SCISSOR_TEST);
        glScissor(1,1, m->EffectiveWidth-2, m->EffectiveHeight-2);
}


///////////////////////////////////////////////////////////////////////////////////////////////////
// Finish rendering into shadow map texture
void ShadowMap::EndRender()
{
        glDisable(GL_SCISSOR_TEST);

        g_Renderer.SetViewCamera(m->SavedViewCamera);

        {
                PROFILE("unbind framebuffer");
                pglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m->SavedViewFBO);
        }

        const SViewPort vp = { 0, 0, g_Renderer.GetWidth(), g_Renderer.GetHeight() };
        g_Renderer.SetViewport(vp);

        glColorMask(1,1,1,1);
}


///////////////////////////////////////////////////////////////////////////////////////////////////
// Retrieve the texture handle and texture matrix for shadowing
GLuint ShadowMap::GetTexture() const
{
        return m->Texture;
}

const CMatrix3D& ShadowMap::GetTextureMatrix() const
{
        return m->TextureMatrix;
}


///////////////////////////////////////////////////////////////////////////////////////////////////
// Depth texture bits
int ShadowMap::GetDepthTextureBits() const
{
        return m->DepthTextureBits;
}

void ShadowMap::SetDepthTextureBits(int bits)
{
        if (bits != m->DepthTextureBits)
        {
                if (m->Texture)
                {
                        glDeleteTextures(1, &m->Texture);
                        m->Texture = 0;
                }
                m->Width = m->Height = 0;

                m->DepthTextureBits = bits;
        }
}

///////////////////////////////////////////////////////////////////////////////////////////////////
// Depth texture size
int ShadowMap::GetWidth() const
{
        return m->Width;
}

int ShadowMap::GetHeight() const
{
        return m->Height;
}

//////////////////////////////////////////////////////////////////////////////

void ShadowMap::RenderDebugBounds()
{
        CShaderTechniquePtr shaderTech = g_Renderer.GetShaderManager().LoadEffect(str_gui_solid);
        shaderTech->BeginPass();
        CShaderProgramPtr shader = shaderTech->GetShader();

        glDepthMask(0);
        glDisable(GL_CULL_FACE);

        // Render various shadow bounds:
        //  Yellow = bounds of objects in view frustum that receive shadows
        //  Red = culling frustum used to find potential shadow casters
        //  Green = bounds of objects in culling frustum that cast shadows
        //  Blue = frustum used for rendering the shadow map

        shader->Uniform(str_transform, g_Renderer.GetViewCamera().GetViewProjection() * m->InvLightTransform);

        shader->Uniform(str_color, 1.0f, 1.0f, 0.0f, 1.0f);
        m->ShadowReceiverBound.RenderOutline(shader);

        shader->Uniform(str_color, 0.0f, 1.0f, 0.0f, 1.0f);
        m->ShadowCasterBound.RenderOutline(shader);

        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        shader->Uniform(str_color, 0.0f, 0.0f, 1.0f, 0.25f);
        m->ShadowRenderBound.Render(shader);
        glDisable(GL_BLEND);

        shader->Uniform(str_color, 0.0f, 0.0f, 1.0f, 1.0f);
        m->ShadowRenderBound.RenderOutline(shader);

        // Render light frustum

        shader->Uniform(str_transform, g_Renderer.GetViewCamera().GetViewProjection());

        CFrustum frustum = GetShadowCasterCullFrustum();
        // We don't have a function to create a brush directly from a frustum, so use
        // the ugly approach of creating a large cube and then intersecting with the frustum
        CBoundingBoxAligned dummy(CVector3D(-1e4, -1e4, -1e4), CVector3D(1e4, 1e4, 1e4));
        CBrush brush(dummy);
        CBrush frustumBrush;
        brush.Intersect(frustum, frustumBrush);

        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        shader->Uniform(str_color, 1.0f, 0.0f, 0.0f, 0.25f);
        frustumBrush.Render(shader);
        glDisable(GL_BLEND);

        shader->Uniform(str_color, 1.0f, 0.0f, 0.0f, 1.0f);
        frustumBrush.RenderOutline(shader);


        shaderTech->EndPass();

#if 0
        CMatrix3D InvTexTransform;

        m->TextureMatrix.GetInverse(InvTexTransform);

        // Render representative texture rectangle
        glPushMatrix();
        glMultMatrixf(&InvTexTransform._11);

        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        glColor4ub(255,0,0,64);
        glBegin(GL_QUADS);
                glVertex3f(0.0, 0.0, 0.0);
                glVertex3f(1.0, 0.0, 0.0);
                glVertex3f(1.0, 1.0, 0.0);
                glVertex3f(0.0, 1.0, 0.0);
        glEnd();
        glDisable(GL_BLEND);

        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
        glColor3ub(255,0,0);
        glBegin(GL_QUADS);
                glVertex3f(0.0, 0.0, 0.0);
                glVertex3f(1.0, 0.0, 0.0);
                glVertex3f(1.0, 1.0, 0.0);
                glVertex3f(0.0, 1.0, 0.0);
        glEnd();
        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
        glPopMatrix();
#endif

        glEnable(GL_CULL_FACE);
        glDepthMask(1);
}

void ShadowMap::RenderDebugTexture()
{
        glDepthMask(0);

        glDisable(GL_DEPTH_TEST);

#if !CONFIG2_GLES
        g_Renderer.BindTexture(0, m->Texture);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_NONE);
#endif

        CShaderTechniquePtr texTech = g_Renderer.GetShaderManager().LoadEffect(str_gui_basic);
        texTech->BeginPass();
        CShaderProgramPtr texShader = texTech->GetShader();

        texShader->Uniform(str_transform, GetDefaultGuiMatrix());
        texShader->BindTexture(str_tex, m->Texture);

        float s = 256.f;
        float boxVerts[] = {
                0,0, 0,s, s,0,
                s,0, 0,s, s,s
        };
        float boxUV[] = {
                0,0, 0,1, 1,0,
                1,0, 0,1, 1,1
        };

        texShader->VertexPointer(2, GL_FLOAT, 0, boxVerts);
        texShader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, 0, boxUV);
        texShader->AssertPointersBound();
        glDrawArrays(GL_TRIANGLES, 0, 6);

        texTech->EndPass();

#if !CONFIG2_GLES
        g_Renderer.BindTexture(0, m->Texture);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
#endif

        glEnable(GL_DEPTH_TEST);
        glDepthMask(1);
}