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lightpreview: Frustum culling and cull freeze.
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@dsvensson
dsvensson committed Dec 8, 2023
1 parent 3eb5cb7 commit f03d315
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Showing 3 changed files with 233 additions and 14 deletions.
223 changes: 211 additions & 12 deletions lightpreview/glview.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -56,12 +56,16 @@ GLView::GLView(QWidget *parent)
m_moveSpeed(1000),
m_displayAspect(1),
m_cameraOrigin(0, 0, 0),
m_cullOrigin(0, 0, 0),
m_cameraFwd(0, 1, 0),
m_vao(),
m_indexBuffer(QOpenGLBuffer::IndexBuffer),
m_leakVao(),
m_portalVao(),
m_portalIndexBuffer(QOpenGLBuffer::IndexBuffer)
m_portalIndexBuffer(QOpenGLBuffer::IndexBuffer),
m_frustumVao(),
m_frustumFacesIndexBuffer(QOpenGLBuffer::IndexBuffer),
m_frustumEdgesIndexBuffer(QOpenGLBuffer::IndexBuffer)
{
for (auto &hullVao : m_hullVaos) {
hullVao.indexBuffer = QOpenGLBuffer(QOpenGLBuffer::IndexBuffer);
Expand Down Expand Up @@ -89,6 +93,11 @@ GLView::~GLView()
m_portalIndexBuffer.destroy();
m_portalVao.destroy();

m_frustumVbo.destroy();
m_frustumFacesIndexBuffer.destroy();
m_frustumEdgesIndexBuffer.destroy();
m_frustumVao.destroy();

for (auto &hullVao : m_hullVaos) {
hullVao.vbo.destroy();
hullVao.indexBuffer.destroy();
Expand Down Expand Up @@ -370,9 +379,10 @@ GLView::face_visibility_key_t GLView::desiredFaceVisibility() const
if (m_visCulling) {
const mbsp_t &bsp = *m_bsp;
const auto &world = bsp.dmodels.at(0);
const auto &origin = m_keepCullOrigin ? m_cullOrigin : m_cameraOrigin;

auto *leaf =
BSP_FindLeafAtPoint(&bsp, &world, qvec3d{m_cameraOrigin.x(), m_cameraOrigin.y(), m_cameraOrigin.z()});
BSP_FindLeafAtPoint(&bsp, &world, qvec3d{origin.x(), origin.y(), origin.z()});

int leafnum = leaf - bsp.dleafs.data();

Expand All @@ -390,7 +400,26 @@ GLView::face_visibility_key_t GLView::desiredFaceVisibility() const
return result;
}

void GLView::updateFaceVisibility()
bool isLeafInFrustum(const std::array<QVector4D, 4>& frustum, const qvec3f& mins, const qvec3f& maxs) {
for (auto &plane : frustum) {
// Select the p-vertex (positive vertex) - the vertex of the bounding
// box most aligned with the plane normal
qvec3f pVertex = qvec3f(
plane.x() > 0 ? maxs[0] : mins[0],
plane.y() > 0 ? maxs[1] : mins[1],
plane.z() > 0 ? maxs[2] : mins[2]
);

// Check if the p-vertex is outside the plane
if (plane.x() * pVertex[0] + plane.y() * pVertex[1] + plane.z() * pVertex[2] + plane.w() < 0) {
return false;
}
}

return true;
}

void GLView::updateFaceVisibility(const std::array<QVector4D, 4>& frustum)
{
if (!m_bsp)
return;
Expand All @@ -403,7 +432,7 @@ void GLView::updateFaceVisibility()
if (m_uploaded_face_visibility &&
*m_uploaded_face_visibility == desired) {
//qDebug() << "reusing last frame visdata";
return;
//return;
}

qDebug() << "looking up pvs for clusternum " << desired.clusternum;
Expand Down Expand Up @@ -433,7 +462,7 @@ void GLView::updateFaceVisibility()

// visit all world leafs: if they're visible, mark the appropriate faces
BSP_VisitAllLeafs(bsp, bsp.dmodels[0], [&](const mleaf_t &leaf) {
if (Pvs_LeafVisible(&bsp, pvs, &leaf)) {
if (Pvs_LeafVisible(&bsp, pvs, &leaf) && isLeafInFrustum(frustum, leaf.mins, leaf.maxs)) {
for (int ms = 0; ms < leaf.nummarksurfaces; ++ms) {
int fnum = bsp.dleaffaces[leaf.firstmarksurface + ms];
face_flags[fnum] = 16;
Expand All @@ -460,6 +489,7 @@ void GLView::updateFaceVisibility()
}
}

// TODO: Come up with some way of checking if vis has changed
setFaceVisibilityArray(face_flags.data());

m_uploaded_face_visibility = desired;
Expand Down Expand Up @@ -571,6 +601,20 @@ void GLView::initializeGL()
glFrontFace(GL_CW);
}

std::array<QVector4D, 4> GLView::getFrustumPlanes(const QMatrix4x4& MVP)
{
return {
// left
(MVP.row(3) + MVP.row(0)).normalized(),
// right
(MVP.row(3) - MVP.row(0)).normalized(),
// top
(MVP.row(3) - MVP.row(1)).normalized(),
// bottom
(MVP.row(3) + MVP.row(1)).normalized(),
};
}

void GLView::paintGL()
{
// calculate frame time + update m_lastFrame
Expand All @@ -588,13 +632,6 @@ void GLView::paintGL()
applyMouseMotion();
applyFlyMovement(duration_seconds);

// update vis culling if needed
updateFaceVisibility();

// draw
glClearColor(0.1, 0.1, 0.1, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

QMatrix4x4 modelMatrix;
QMatrix4x4 viewMatrix;
QMatrix4x4 projectionMatrix;
Expand All @@ -603,6 +640,16 @@ void GLView::paintGL()

QMatrix4x4 MVP = projectionMatrix * viewMatrix * modelMatrix;

const auto frustum = m_keepCullOrigin ?
getFrustumPlanes(projectionMatrix * m_cullViewMatrix * modelMatrix) : getFrustumPlanes(MVP);

// update vis culling if needed
updateFaceVisibility(frustum);

// draw
glClearColor(0.1, 0.1, 0.1, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

QOpenGLShaderProgram *active_program = nullptr;

m_program->bind();
Expand Down Expand Up @@ -750,6 +797,40 @@ void GLView::paintGL()
m_program_wireframe->release();
}

if (m_visCulling && m_keepCullOrigin) {
const QMatrix4x4 cullMVP = projectionMatrix * viewMatrix * m_cullModelMatrix;

m_program_simple->bind();
m_program_simple->setUniformValue(m_program_simple_mvp_location, cullMVP);

QOpenGLVertexArrayObject::Binder vaoBinder(&m_frustumVao);

glEnable(GL_PRIMITIVE_RESTART);
glPrimitiveRestartIndex((GLuint)-1);

m_frustumEdgesIndexBuffer.bind();
m_program_simple->setUniformValue(m_program_simple_color_location, QVector4D{1.0, 1.0, 1.0, 1.0});
glDrawElements(GL_LINE_LOOP, 30, GL_UNSIGNED_INT, 0);
m_frustumEdgesIndexBuffer.release();

glDisable(GL_PRIMITIVE_RESTART);

glDisable(GL_CULL_FACE);
glEnable(GL_BLEND);

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

m_frustumFacesIndexBuffer.bind();
m_program_simple->setUniformValue(m_program_simple_color_location, QVector4D{1.0, 1.0, 1.0, 0.05});
glDrawElements(GL_TRIANGLES, 24, GL_UNSIGNED_INT, 0);
m_frustumFacesIndexBuffer.release();

glDisable(GL_BLEND);
glEnable(GL_CULL_FACE);

m_program_simple->release();
}

if (m_drawLeak && num_leak_points) {
m_program_simple->bind();
m_program_simple->setUniformValue(m_program_simple_mvp_location, MVP);
Expand Down Expand Up @@ -872,6 +953,27 @@ void GLView::setVisCulling(bool viscull)
update();
}

void GLView::setKeepCullOrigin(bool keepcullorigin)
{
m_keepCullOrigin = keepcullorigin;
if (keepcullorigin) {
m_cullOrigin = m_cameraOrigin;

QMatrix4x4 rotation, position;

m_cullViewMatrix.setToIdentity();
m_cullViewMatrix.lookAt(m_cameraOrigin, m_cameraOrigin + m_cameraFwd, QVector3D(0, 0, 1));

rotation = m_cullViewMatrix.inverted();
rotation.setColumn(3, QVector4D(0, 0, 0, 1));

position.translate(m_cameraOrigin);

m_cullModelMatrix = position * rotation;
}
update();
}

void GLView::setDrawFlat(bool drawflat)
{
m_drawFlat = drawflat;
Expand Down Expand Up @@ -987,6 +1089,36 @@ void GLView::setFaceVisibilityArray(uint8_t *data)
logging::print("uploaded {} bytes face visibility texture", face_visibility_width);
}

std::vector<QVector3D> GLView::getFrustumCorners(float displayAspect) {
QMatrix4x4 projectionMatrix;
projectionMatrix.perspective(90, displayAspect, 1.0f, 8192.0f);

const QMatrix4x4 invProjectionMatrix = projectionMatrix.inverted();

const std::vector ndcCorners = {
QVector4D(-1.0f, -1.0f, -1.0f, 1.0f), // 0: near bottom left
QVector4D( 1.0f, -1.0f, -1.0f, 1.0f), // 1: near bottom right
QVector4D (1.0f, 1.0f, -1.0f, 1.0f), // 2: near top right
QVector4D(-1.0f, 1.0f, -1.0f, 1.0f), // 3: near top left

QVector4D(-1.0f, -1.0f, 1.0f, 1.0f), // far bottom left
QVector4D( 1.0f, -1.0f, 1.0f, 1.0f), // far bottom right
QVector4D( 1.0f, 1.0f, 1.0f, 1.0f), // far top left
QVector4D(-1.0f, 1.0f, 1.0f, 1.0f) // far top right
};

std::vector<QVector3D> corners(8);

// Transform to world space
for (int i = 0; i < 8; i++) {
QVector4D worldSpaceCorner = invProjectionMatrix * ndcCorners[i];
worldSpaceCorner /= worldSpaceCorner.w(); // Perspective divide
corners[i] = worldSpaceCorner.toVector3D();
}

return corners;
}

void GLView::renderBSP(const QString &file, const mbsp_t &bsp, const bspxentries_t &bspx,
const std::vector<entdict_t> &entities, const full_atlas_t &lightmap, const settings::common_settings &settings,
bool use_bspx_normals)
Expand Down Expand Up @@ -1035,6 +1167,13 @@ void GLView::renderBSP(const QString &file, const mbsp_t &bsp, const bspxentries
hullVao.indexBuffer.allocate(0);
}

m_frustumVbo.bind();
m_frustumVbo.allocate(0);
m_frustumFacesIndexBuffer.bind();
m_frustumFacesIndexBuffer.allocate(0);
m_frustumEdgesIndexBuffer.bind();
m_frustumEdgesIndexBuffer.allocate(0);

num_leak_points = 0;
num_portal_indices = 0;
m_uploaded_face_visibility = std::nullopt;
Expand Down Expand Up @@ -1457,6 +1596,55 @@ void GLView::renderBSP(const QString &file, const mbsp_t &bsp, const bspxentries
qvec3f pos;
};

{
QOpenGLVertexArrayObject::Binder vaoBinder(&m_frustumVao);

auto corners = getFrustumCorners(m_displayAspect);

m_frustumVbo.create();
m_frustumVbo.bind();
m_frustumVbo.allocate(corners.data(), corners.size() * sizeof(QVector3D));

glEnableVertexAttribArray(0 /* attrib */);
glVertexAttribPointer(0 /* attrib */, 3, GL_FLOAT, GL_FALSE, sizeof(QVector3D), 0);

// Near Plane: Far Plane:
// 3----2 7----6
// | | | |
// | | | |
// 0----1 4----5
GLuint faceIndices[] = {
// Left face
0, 4, 7, 0, 7, 3,
// Right face
1, 2, 6, 1, 6, 5,
// Top face
2, 3, 7, 2, 7, 6,
// Bottom face
0, 1, 5, 0, 5, 4
};

GLuint edgeIndices[] = {
// Front face
0, 1, 1, 2, 2, 3, 3, 0, (GLuint)-1,
// Back face
4, 5, 5, 6, 6, 7, 7, 4, (GLuint)-1,
// Connecting edges
0, 4, (GLuint)-1,
1, 5, (GLuint)-1,
2, 6, (GLuint)-1,
3, 7, (GLuint)-1
};

m_frustumFacesIndexBuffer.create();
m_frustumFacesIndexBuffer.bind();
m_frustumFacesIndexBuffer.allocate(faceIndices, sizeof(faceIndices));

m_frustumEdgesIndexBuffer.create();
m_frustumEdgesIndexBuffer.bind();
m_frustumEdgesIndexBuffer.allocate(edgeIndices, sizeof(edgeIndices));
}

if (fs::exists(leakFile)) {
QOpenGLVertexArrayObject::Binder leakVaoBinder(&m_leakVao);

Expand Down Expand Up @@ -1608,9 +1796,20 @@ void GLView::renderBSP(const QString &file, const mbsp_t &bsp, const bspxentries
update();
}

void GLView::updateFrustumVBO()
{
if (m_frustumVbo.isCreated()) {
const std::vector<QVector3D> corners = getFrustumCorners(m_displayAspect);
m_frustumVbo.bind();
glBufferData(GL_ARRAY_BUFFER, sizeof(QVector3D) * corners.size(), corners.data(), GL_DYNAMIC_DRAW);
m_frustumVbo.release();
}
}

void GLView::resizeGL(int width, int height)
{
m_displayAspect = static_cast<float>(width) / static_cast<float>(height);
updateFrustumVBO();
}

void GLView::applyMouseMotion()
Expand Down
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