source: ps/trunk/source/renderer/ShadowMap.cpp@ 25269

/* Copyright (C) 2021 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/>.
 */

#include "precompiled.h"

#include "ShadowMap.h"

#include "graphics/Camera.h"
#include "graphics/LightEnv.h"
#include "graphics/ShaderManager.h"
#include "gui/GUIMatrix.h"
#include "lib/bits.h"
#include "lib/ogl.h"
#include "maths/BoundingBoxAligned.h"
#include "maths/Brush.h"
#include "maths/Frustum.h"
#include "maths/MathUtil.h"
#include "maths/Matrix3D.h"
#include "ps/CLogger.h"
#include "ps/ConfigDB.h"
#include "ps/Profile.h"
#include "renderer/DebugRenderer.h"
#include "renderer/Renderer.h"
#include "renderer/RenderingOptions.h"

/**
 * 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;

    CBoundingBoxAligned FixedFrustumBounds;
    bool FixedShadowsEnabled;
    float FixedShadowsDistance;

    // 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();
};

void CalculateBoundsForFixedShadows(
    const CCamera& camera, const CMatrix3D& lightTransform,
    const float nearPlane, const float farPlane, CBoundingBoxAligned* bbaa)
{
    // We need to calculate a circumscribed sphere for the camera to
    // create a rotation stable bounding box.
    const CVector3D cameraIn = camera.m_Orientation.GetIn();
    const CVector3D cameraTranslation = camera.m_Orientation.GetTranslation();
    const CVector3D centerNear = cameraTranslation + cameraIn * nearPlane;
    const CVector3D centerDist = cameraTranslation + cameraIn * farPlane;

    // We can solve 3D problem in 2D space, because the frustum is
    // symmetric by 2 planes. Than means we can use only one corner
    // to find a circumscribed sphere.
    CCamera::Quad corners;
    camera.GetViewQuad(nearPlane, corners);
    const CVector3D cornerNear = camera.GetOrientation().Transform(corners[0]);
    camera.GetViewQuad(farPlane, corners);
    const CVector3D cornerDist = camera.GetOrientation().Transform(corners[0]);

    // We solve 2D case for the right trapezoid.
    const float firstBase = (cornerNear - centerNear).Length();
    const float secondBase = (cornerDist - centerDist).Length();
    const float height = (centerDist - centerNear).Length();
    const float distanceToCenter =
        (height * height + secondBase * secondBase - firstBase * firstBase) * 0.5f / height;

    CVector3D position = cameraTranslation + cameraIn * (camera.GetNearPlane() + distanceToCenter);
    const float radius = (cornerNear - position).Length();

    // We need to convert the bounding box to the light space.
    position = lightTransform.Rotate(position);

    const float insets = 0.2f;
    *bbaa = CBoundingBoxAligned(position, position);
    bbaa->Expand(radius);
    bbaa->Expand(insets);
}

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();

    m->FixedShadowsEnabled = false;
    m->FixedShadowsDistance = 300.0f;
    CFG_GET_VAL("shadowsfixed", m->FixedShadowsEnabled);
    CFG_GET_VAL("shadowsfixeddistance", m->FixedShadowsDistance);
}

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 x, eyepos;
    if (!m->FixedShadowsEnabled)
    {
        x = camera.m_Orientation.GetIn();
        eyepos = camera.m_Orientation.GetTranslation();
    }
    else
        x = CVector3D(0, 1, 0);

    CVector3D z = lightdir;
    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();
    CVector3D 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();

    if (m->FixedShadowsEnabled)
        CalculateBoundsForFixedShadows(camera, m->LightTransform, camera.GetNearPlane(), m->FixedShadowsDistance, &m->FixedFrustumBounds);
}

// 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()
{
    if (FixedShadowsEnabled)
    {
        ShadowRenderBound = FixedFrustumBounds;

        // 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;
    }
    else
    {
        // 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);

    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;

    GLenum format;
    const char* formatName;
#if CONFIG2_GLES
    format = GL_DEPTH_COMPONENT;
    formatName = "DEPTH_COMPONENT";
#else
    switch ( DepthTextureBits )
    {
    case 16: format = GL_DEPTH_COMPONENT16; formatName = "DEPTH_COMPONENT16"; break;
    case 24: format = GL_DEPTH_COMPONENT24; formatName = "DEPTH_COMPONENT24"; break;
    case 32: format = GL_DEPTH_COMPONENT32; formatName = "DEPTH_COMPONENT32"; break;
    default: format = GL_DEPTH_COMPONENT; formatName = "DEPTH_COMPONENT"; break;
    }
#endif
    ENSURE(formatName);

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

    if (g_RenderingOptions.GetShadowAlphaFix())
    {
        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);

    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_RenderingOptions.GetShadowAlphaFix())
    {
        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_RenderingOptions.SetShadows(false);
    }
}

// Set up to render into shadow map texture
void ShadowMap::BeginRender()
{
    // 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, 0);
    }

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

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

void ShadowMap::BindTo(const CShaderProgramPtr& shader) const
{
    if (!shader->GetTextureBinding(str_shadowTex).Active())
        return;

    shader->BindTexture(str_shadowTex, m->Texture);
    shader->Uniform(str_shadowTransform, m->TextureMatrix);
    shader->Uniform(str_shadowScale, m->Width, m->Height, 1.0f / m->Width, 1.0f / m->Height);
}

// 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;
    }
}

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);
    g_Renderer.GetDebugRenderer().DrawBoundingBoxOutline(m->ShadowReceiverBound, shader);

    shader->Uniform(str_color, 0.0f, 1.0f, 0.0f, 1.0f);
    g_Renderer.GetDebugRenderer().DrawBoundingBoxOutline(m->ShadowCasterBound, 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);
    g_Renderer.GetDebugRenderer().DrawBoundingBox(m->ShadowRenderBound, shader);
    glDisable(GL_BLEND);

    shader->Uniform(str_color, 0.0f, 0.0f, 1.0f, 1.0f);
    g_Renderer.GetDebugRenderer().DrawBoundingBoxOutline(m->ShadowRenderBound, 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);
    g_Renderer.GetDebugRenderer().DrawBrush(frustumBrush, shader);
    glDisable(GL_BLEND);

    shader->Uniform(str_color, 1.0f, 0.0f, 0.0f, 1.0f);
    g_Renderer.GetDebugRenderer().DrawBrushOutline(frustumBrush, 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);

    ogl_WarnIfError();
}

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);

    ogl_WarnIfError();
}