Added vegetation impostors to OpenGL renderer

This is currently an unoptimized and broken version, to be improved

src/basics/Color.h

@@ -27,6 +27,7 @@ class BASICSSHARED_EXPORT Color {
 
     void mask(const Color &mask);
     double normalize();
+    Color normalized();
     double getValue() const;
     double getPower() const;
     void limitPower(double max_power);

src/basics/Color.inline.cpp

@@ -118,6 +118,12 @@ METHSPEC double Color::normalize() {
     return max;*/
 }
 
+METHSPEC Color Color::normalized() {
+    Color col = *this;
+    col.normalize();
+    return col;
+}
+
 METHSPEC double Color::getValue() const {
     double max;
 

src/definition/VegetationPresenceDefinition.cpp

@@ -42,11 +42,14 @@ bool VegetationPresenceDefinition::collectInstances(std::vector<VegetationInstan
                 double size =
                     0.1 + 0.2 * fabs(generator->get2DTotal(z * 10.0, x * 10.0)) * (noise_presence * 0.5 + 0.5);
                 double angle = 3.0 * generator->get2DTotal(-x * 20.0, z * 20.0); // TODO balanced distribution
-                double xoffset = fabs(generator->get2DTotal(x * 12.0, -z * 12.0));
+                double xo = x + fabs(generator->get2DTotal(x * 12.0, -z * 12.0));
-                double zoffset = fabs(generator->get2DTotal(-x * 27.0, -z * 27.0));
+                double zo = z + fabs(generator->get2DTotal(-x * 27.0, -z * 27.0));
-                double y = getScenery()->getTerrain()->getInterpolatedHeight(x + xoffset, z + zoffset, true, true);
+                if (xo >= xmin and xo < xmax and zo >= zmin and zo < zmax)
-                result->push_back(VegetationInstance(model, Vector3(x + xoffset, y, z + zoffset), size, angle));
+                {
-                added++;
+                    double y = getScenery()->getTerrain()->getInterpolatedHeight(xo, zo, true, true);
+                    result->push_back(VegetationInstance(model, Vector3(xo, y, zo), size, angle));
+                    added++;
+                }
             }
         }
     }

src/interface/commandline/commandline.pro

@@ -32,3 +32,9 @@ else:win32:CONFIG(debug, debug|release): LIBS += -L$$OUT_PWD/../../render/softwa
 else:unix: LIBS += -L$$OUT_PWD/../../render/software/ -lpaysages_render_software
 INCLUDEPATH += $$PWD/../../render/software
 DEPENDPATH += $$PWD/../../render/software
+
+win32:CONFIG(release, debug|release): LIBS += -L$$OUT_PWD/../../render/opengl/release/ -lpaysages_render_opengl
+else:win32:CONFIG(debug, debug|release): LIBS += -L$$OUT_PWD/../../render/opengl/debug/ -lpaysages_render_opengl
+else:unix: LIBS += -L$$OUT_PWD/../../render/opengl/ -lpaysages_render_opengl
+INCLUDEPATH += $$PWD/../../render/opengl
+DEPENDPATH += $$PWD/../../render/opengl

src/interface/commandline/tests.cpp

@@ -23,12 +23,15 @@
 #include "VegetationInstance.h"
 #include "VegetationRenderer.h"
 #include "RayCastingResult.h"
+#include "OpenGLVegetationImpostor.h"
+#include "Texture2D.h"
 
 #include <sstream>
+#include <iostream>
 
 void startRender(SoftwareCanvasRenderer *renderer, const char *outputpath);
 
-static void startTestRender(SoftwareCanvasRenderer *renderer, const std::string &name, int iteration = -1) {
+static std::string getFileName(const std::string &name, int iteration = -1) {
     std::ostringstream stream;
 
     stream << "pic_test_" << name;
@@ -40,7 +43,11 @@ static void startTestRender(SoftwareCanvasRenderer *renderer, const std::string
     }
     stream << ".png";
 
-    startRender(renderer, stream.str().data());
+    return stream.str();
+}
+
+static void startTestRender(SoftwareCanvasRenderer *renderer, const std::string &name, int iteration = -1) {
+    startRender(renderer, getFileName(name, iteration).data());
 }
 
 static void testGroundShadowQuality() {
@@ -288,6 +295,19 @@ static void testVegetationModels() {
     }
 }
 
+static void testOpenGLVegetationImpostor() {
+    std::string filename = getFileName("opengl_vegetation_impostor");
+    std::cout << "Rendering " << filename << "..." << std::endl;
+
+    Scenery scenery;
+    scenery.autoPreset(1);
+    OpenGLVegetationImpostor impostor(200);
+    VegetationModelDefinition model(NULL);
+    bool interrupted = false;
+    impostor.prepareTexture(model, scenery, &interrupted);
+    impostor.getTexture()->saveToFile(filename);
+}
+
 void runTestSuite() {
     testGroundShadowQuality();
     testRasterizationQuality();
@@ -297,4 +317,5 @@ void runTestSuite() {
     testCloudsNearGround();
     testSunNearHorizon();
     testVegetationModels();
+    testOpenGLVegetationImpostor();
 }

src/render/opengl/OpenGLPart.cpp

@@ -40,3 +40,13 @@ void OpenGLPart::updateScenery(bool onlyCommon) {
         update();
     }
 }
+
+Scenery *OpenGLPart::getScenery() const
+{
+    return renderer->getScenery();
+}
+
+OpenGLFunctions *OpenGLPart::getOpenGlFunctions() const
+{
+    return renderer->getOpenGlFunctions();
+}

src/render/opengl/OpenGLPart.h

@@ -30,6 +30,16 @@ class OPENGLSHARED_EXPORT OpenGLPart {
 
     void updateScenery(bool onlyCommon = false);
 
+    /**
+     * Get access to rendered scenery.
+     */
+    Scenery *getScenery() const;
+
+    /**
+     * Get access to OpenGL functions.
+     */
+    OpenGLFunctions *getOpenGlFunctions() const;
+
   protected:
     // Create a shader program
     OpenGLShaderProgram *createShader(QString name);

src/render/opengl/OpenGLRenderer.cpp

@@ -6,6 +6,7 @@
 #include "OpenGLSkybox.h"
 #include "OpenGLWater.h"
 #include "OpenGLTerrain.h"
+#include "OpenGLVegetation.h"
 #include "CloudsRenderer.h"
 #include "VegetationRenderer.h"
 #include "Color.h"
@@ -40,9 +41,11 @@ OpenGLRenderer::OpenGLRenderer(Scenery *scenery) : SoftwareRenderer(scenery) {
     skybox = new OpenGLSkybox(this);
     water = new OpenGLWater(this);
     terrain = new OpenGLTerrain(this);
+    vegetation = new OpenGLVegetation(this);
 }
 
 OpenGLRenderer::~OpenGLRenderer() {
+    vegetation->interrupt();
     terrain->interrupt();
     water->interrupt();
     skybox->interrupt();
@@ -54,6 +57,7 @@ OpenGLRenderer::~OpenGLRenderer() {
     delete skybox;
     delete water;
     delete terrain;
+    delete vegetation;
 
     delete functions;
     delete shared_state;
@@ -69,9 +73,9 @@ void OpenGLRenderer::prepare() {
 }
 
 void OpenGLRenderer::initialize() {
-    ready = functions->initializeOpenGLFunctions();
+    bool init = functions->initializeOpenGLFunctions();
 
-    if (ready) {
+    if (init) {
         prepareOpenGLState();
 
         prepare();
@@ -85,7 +89,12 @@ void OpenGLRenderer::initialize() {
         terrain->initialize();
         terrain->updateScenery();
 
+        vegetation->initialize();
+        vegetation->updateScenery();
+
         cameraChangeEvent(render_camera);
+
+        ready = true;
     } else {
         Logs::error() << "Failed to initialize OpenGL bindings" << std::endl;
     }
@@ -100,7 +109,7 @@ void OpenGLRenderer::prepareOpenGLState() {
         functions->glEnable(GL_CULL_FACE);
 
         functions->glDepthFunc(GL_LESS);
-        functions->glDepthMask(1);
+        functions->glDepthMask(GL_TRUE);
         functions->glEnable(GL_DEPTH_TEST);
 
         functions->glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
@@ -145,6 +154,7 @@ void OpenGLRenderer::paint() {
         skybox->render();
         terrain->render();
         water->render();
+        vegetation->render();
 
         if (mouse_tracking) {
             updateMouseProjection();
@@ -164,6 +174,7 @@ void OpenGLRenderer::reset() {
         skybox->updateScenery();
         water->updateScenery();
         terrain->updateScenery();
+        vegetation->updateScenery();
 
         cameraChangeEvent(render_camera);
     }
@@ -210,6 +221,9 @@ void OpenGLRenderer::cameraChangeEvent(CameraDefinition *camera) {
     // Set in shaders
     shared_state->set("cameraLocation", location);
     shared_state->set("viewMatrix", *view_matrix);
+
+    // Broadcast to parts
+    vegetation->cameraChanged(camera);
 }
 
 double OpenGLRenderer::getPrecision(const Vector3 &) {

src/render/opengl/OpenGLRenderer.h

@@ -27,6 +27,9 @@ class OPENGLSHARED_EXPORT OpenGLRenderer : public SoftwareRenderer {
     inline OpenGLTerrain *getTerrain() const {
         return terrain;
     }
+    inline OpenGLVegetation *getVegetation() const {
+        return vegetation;
+    }
     inline bool isDisplayed() const {
         return displayed;
     }
@@ -106,6 +109,7 @@ class OPENGLSHARED_EXPORT OpenGLRenderer : public SoftwareRenderer {
     OpenGLSkybox *skybox;
     OpenGLWater *water;
     OpenGLTerrain *terrain;
+    OpenGLVegetation *vegetation;
 };
 }
 }

src/render/opengl/OpenGLShaderProgram.cpp

@@ -15,11 +15,13 @@ OpenGLShaderProgram::OpenGLShaderProgram(const std::string &name, OpenGLRenderer
     : renderer(renderer), name(name) {
     program = new QOpenGLShaderProgram();
     functions = renderer->getOpenGlFunctions();
+    state = new OpenGLSharedState();
     compiled = false;
 }
 
 OpenGLShaderProgram::~OpenGLShaderProgram() {
     delete program;
+    delete state;
 }
 
 void OpenGLShaderProgram::addVertexSource(QString path) {
@@ -63,6 +65,7 @@ void OpenGLShaderProgram::bind() {
 
     int texture_unit = 0;
     renderer->getSharedState()->apply(this, texture_unit);
+    state->apply(this, texture_unit);
 }
 
 void OpenGLShaderProgram::release() {

src/render/opengl/OpenGLShaderProgram.h

@@ -30,6 +30,9 @@ class OPENGLSHARED_EXPORT OpenGLShaderProgram {
     inline OpenGLRenderer *getRenderer() const {
         return renderer;
     }
+    inline OpenGLSharedState *getState() const {
+        return state;
+    }
 
   protected:
     friend class OpenGLVariable;
@@ -45,6 +48,8 @@ class OPENGLSHARED_EXPORT OpenGLShaderProgram {
     QOpenGLShaderProgram *program;
     OpenGLFunctions *functions;
 
+    OpenGLSharedState *state;
+
     std::string source_vertex;
     std::string source_fragment;
 };

src/render/opengl/OpenGLSharedState.cpp

@@ -3,7 +3,7 @@
 OpenGLSharedState::OpenGLSharedState() {
 }
 
-paysages::opengl::OpenGLSharedState::~OpenGLSharedState()
+OpenGLSharedState::~OpenGLSharedState()
 {
     for (const auto &pair : variables) {
         delete pair.second;

src/render/opengl/OpenGLSharedState.h

@@ -28,6 +28,12 @@ class OPENGLSHARED_EXPORT OpenGLSharedState {
     OpenGLVariable *get(const std::string &name);
 
     // Shortcuts
+    inline void setInt(const std::string &name, int value) {
+        get(name)->set(value);
+    }
+    inline void set(const std::string &name, float value) {
+        get(name)->set(value);
+    }
     inline void set(const std::string &name, const Texture2D *texture, bool repeat = false, bool color = true) {
         get(name)->set(texture, repeat, color);
     }
@@ -37,9 +43,6 @@ class OPENGLSHARED_EXPORT OpenGLSharedState {
     inline void set(const std::string &name, const Texture4D *texture, bool repeat = false, bool color = true) {
         get(name)->set(texture, repeat, color);
     }
-    inline void set(const std::string &name, float value) {
-        get(name)->set(value);
-    }
     inline void set(const std::string &name, const Vector3 &vector) {
         get(name)->set(vector);
     }

src/render/opengl/OpenGLVariable.cpp

@@ -28,6 +28,9 @@ void OpenGLVariable::apply(OpenGLShaderProgram *program, int &texture_unit) {
     }
 
     switch (type) {
+    case TYPE_INTEGER:
+        pr->setUniformValue(name.c_str(), value_int);
+        break;
     case TYPE_FLOAT:
         pr->setUniformValue(name.c_str(), value_float);
         break;
@@ -88,6 +91,14 @@ void OpenGLVariable::set(const Texture4D *texture, bool repeat, bool color) {
     texture_color = color;
 }
 
+void OpenGLVariable::set(int value)
+{
+    assert(type == TYPE_NONE or type == TYPE_INTEGER);
+
+    type = TYPE_INTEGER;
+    value_int = value;
+}
+
 void OpenGLVariable::set(float value) {
     assert(type == TYPE_NONE or type == TYPE_FLOAT);
 

src/render/opengl/OpenGLVariable.h

@@ -20,6 +20,7 @@ class OpenGLVariable {
         TYPE_TEXTURE_2D,
         TYPE_TEXTURE_3D,
         TYPE_TEXTURE_4D,
+        TYPE_INTEGER,
         TYPE_FLOAT,
         TYPE_VECTOR3,
         TYPE_MATRIX4,
@@ -34,6 +35,7 @@ class OpenGLVariable {
     void set(const Texture2D *texture, bool repeat = false, bool color = true);
     void set(const Texture3D *texture, bool repeat = false, bool color = true);
     void set(const Texture4D *texture, bool repeat = false, bool color = true);
+    void set(int value);
     void set(float value);
     void set(const Vector3 &vector);
     void set(const QVector3D &vector);
@@ -48,6 +50,7 @@ class OpenGLVariable {
     std::string name;
     OpenGLVariableType type;
 
+    int value_int;
     float value_float;
     QColor value_color;
     QVector3D value_vector3;

src/render/opengl/OpenGLVegetation.cpp

@@ -0,0 +1,155 @@
+#include "OpenGLVegetation.h"
+
+#include "OpenGLRenderer.h"
+#include "OpenGLShaderProgram.h"
+#include "OpenGLVegetationLayer.h"
+#include "Thread.h"
+#include "Mutex.h"
+#include "Scenery.h"
+#include "VegetationDefinition.h"
+#include "VegetationLayerDefinition.h"
+
+class paysages::opengl::VegetationUpdater : public Thread {
+  public:
+    VegetationUpdater(OpenGLVegetation *vegetation) : vegetation(vegetation) {
+        interrupted = false;
+    }
+
+    void interrupt(bool wait = true) {
+        interrupted = true;
+        if (wait) {
+            join();
+        }
+    }
+
+  protected:
+    virtual void run() override {
+        while (not interrupted) {
+            std::vector<OpenGLVegetationLayer *> layers;
+            vegetation->acquireLayers(layers);
+            for (auto layer: layers) {
+                layer->threadedUpdate();
+            }
+            vegetation->releaseLayers(layers);
+            timeSleepMs(100);
+        }
+    }
+
+  private:
+    bool interrupted;
+    OpenGLVegetation *vegetation;
+};
+
+OpenGLVegetation::OpenGLVegetation(OpenGLRenderer *renderer) : OpenGLPart(renderer) {
+    layers_lock = new Mutex();
+    updater = new VegetationUpdater(this);
+    enabled = true;
+
+    // Watch scenery changes
+    renderer->getScenery()->getVegetation()->addWatcher(this, true);
+}
+
+OpenGLVegetation::~OpenGLVegetation() {
+    for (auto layer: layers) {
+        delete layer;
+    }
+    layers.clear();
+
+    delete layers_lock;
+
+    updater->interrupt();
+    delete updater;
+}
+
+void OpenGLVegetation::initialize() {
+    // Start the threaded updater
+    updater->start();
+
+    // Prepare shader programs
+    program = createShader("vegetation");
+    program->addVertexSource("vegetation");
+    program->addFragmentSource("atmosphere");
+    program->addFragmentSource("tonemapping");
+    program->addFragmentSource("ui");
+    program->addFragmentSource("vegetation");
+}
+
+void OpenGLVegetation::update() {
+}
+
+void OpenGLVegetation::render() {
+    if (enabled) {
+        std::vector<OpenGLVegetationLayer *> layers;
+        acquireLayers(layers);
+        for (auto layer: layers) {
+            layer->render();
+        }
+        releaseLayers(layers);
+    }
+}
+
+void OpenGLVegetation::nodeChanged(const DefinitionNode *node, const DefinitionDiff *) {
+    if (node->getPath() == "/vegetation") {
+        updateLayers();
+    }
+}
+
+Scenery *OpenGLVegetation::getScenery() const
+{
+    return renderer->getScenery();
+}
+
+void OpenGLVegetation::cameraChanged(const CameraDefinition *camera)
+{
+    std::vector<OpenGLVegetationLayer *> layers;
+    acquireLayers(layers);
+    for (auto layer: layers) {
+        layer->setCamera(camera);
+    }
+    releaseLayers(layers);
+}
+
+void OpenGLVegetation::acquireLayers(std::vector<OpenGLVegetationLayer *> &layers) {
+    layers_lock->acquire();
+
+    for (auto layer : this->layers) {
+        // TODO Reference count
+        layers.push_back(layer);
+    }
+
+    layers_lock->release();
+}
+
+void OpenGLVegetation::releaseLayers(const std::vector<OpenGLVegetationLayer *> &layers) {
+    // TODO Reference count
+}
+
+OpenGLVegetationLayer *OpenGLVegetation::findLayer(VegetationLayerDefinition *layer) {
+    for (auto &l : layers) {
+        if (l->getDefinition() == layer) {
+            return l;
+        }
+    }
+    return NULL;
+}
+
+void OpenGLVegetation::setEnabled(bool enabled) {
+    this->enabled = enabled;
+}
+
+void OpenGLVegetation::updateLayers() {
+    layers_lock->acquire();
+
+    // Add missing layers
+    int n = renderer->getScenery()->getVegetation()->getLayerCount();
+    for (int i = 0; i < n; i++) {
+        VegetationLayerDefinition *layer = renderer->getScenery()->getVegetation()->getVegetationLayer(i);
+        if (!findLayer(layer)) {
+            layers.push_back(new OpenGLVegetationLayer(this, layer));
+        }
+    }
+
+    // TODO Mark extraneous layers for deletion
+
+    layers_lock->release();
+}

src/render/opengl/OpenGLVegetation.h

@@ -0,0 +1,89 @@
+#ifndef OPENGLVEGETATION_H
+#define OPENGLVEGETATION_H
+
+#include "opengl_global.h"
+
+#include "OpenGLPart.h"
+#include "DefinitionWatcher.h"
+
+#include <map>
+
+namespace paysages {
+namespace opengl {
+
+class VegetationUpdater;
+
+class OPENGLSHARED_EXPORT OpenGLVegetation : public OpenGLPart, public DefinitionWatcher {
+  public:
+    OpenGLVegetation(OpenGLRenderer *renderer);
+    virtual ~OpenGLVegetation();
+
+    inline int getLayerCount() {
+        return layers.size();
+    }
+    inline OpenGLVegetationLayer *getLayer(int i) {
+        return layers[i];
+    }
+    inline OpenGLShaderProgram *getProgram() {
+        return program;
+    }
+
+    virtual void initialize() override;
+    virtual void update() override;
+    virtual void render() override;
+
+    virtual void nodeChanged(const DefinitionNode *node, const DefinitionDiff *diff) override;
+
+    /**
+     * Get the currently rendered scenery.
+     */
+    Scenery *getScenery() const;
+
+    /**
+     * Call this when the dynamic camera (not the scenery one) changed.
+     */
+    void cameraChanged(const CameraDefinition *camera);
+
+    /**
+     * Acquire the current layers for processing.
+     *
+     * Don't forget to call releaseLayers once done with them.
+     *
+     * This will not hold a lock on them, but increment a reference counter to not delete them while in use.
+     */
+    void acquireLayers(std::vector<OpenGLVegetationLayer *> &layers);
+
+    /**
+     * Release the layers acquired by acquireLayers.
+     */
+    void releaseLayers(const std::vector<OpenGLVegetationLayer *> &layers);
+
+    /**
+     * Find a rendering layer, by the matching definition layer.
+     */
+    OpenGLVegetationLayer *findLayer(VegetationLayerDefinition *layer);
+
+    /**
+     * Enable or disable the whole vegetation rendering.
+     */
+    void setEnabled(bool enabled);
+
+    /**
+     * Update the *layers* member from the scenery.
+     *
+     * This will create missing layers, and mark extraneous ones for deletion.
+     * This will not update existing layers (they should update themselves by watching their definition).
+     */
+    void updateLayers();
+
+  private:
+    OpenGLShaderProgram *program;
+    bool enabled;
+    std::vector<OpenGLVegetationLayer *> layers;
+    Mutex *layers_lock;
+    VegetationUpdater *updater;
+};
+}
+}
+
+#endif // OPENGLVEGETATION_H

src/render/opengl/OpenGLVegetationImpostor.cpp

@@ -0,0 +1,106 @@
+#include "OpenGLVegetationImpostor.h"
+
+#include "OpenGLShaderProgram.h"
+#include "OpenGLSharedState.h"
+#include "OpenGLVegetationInstance.h"
+#include "Texture2D.h"
+#include "SoftwareRenderer.h"
+#include "Scenery.h"
+#include "AtmosphereDefinition.h"
+#include "GodRaysSampler.h"
+#include "VegetationRenderer.h"
+#include "VegetationInstance.h"
+#include "RayCastingResult.h"
+#include "SpaceSegment.h"
+#include "Matrix4.h"
+#include "LightingManager.h"
+#include "CameraDefinition.h"
+
+OpenGLVegetationImpostor::OpenGLVegetationImpostor(int partsize) {
+    vertices = new float[4 * 3];
+    texture_size = partsize * 4;
+    texture = new Texture2D(texture_size, texture_size);
+    texture_changed = true;
+
+    setVertex(0, 0.0f, 0.0f, 0.0f);
+    setVertex(1, 0.0f, 0.0f, 1.0f);
+    setVertex(2, 0.0f, 1.0f, 0.0f);
+    setVertex(3, 0.0f, 1.0f, 1.0f);
+}
+
+OpenGLVegetationImpostor::~OpenGLVegetationImpostor() {
+    delete[] vertices;
+    delete texture;
+}
+
+void OpenGLVegetationImpostor::render(OpenGLShaderProgram *program, const OpenGLVegetationInstance *instance,
+                                      int index) {
+    if (index == 0 or texture_changed) {
+        texture_changed = false;
+        program->getState()->set("impostorTexture", texture);
+    }
+    program->getState()->setInt("index", 15); // TODO
+    program->getState()->set("offset", instance->getBase());
+    program->getState()->set("size", instance->getSize());
+    program->drawTriangleStrip(vertices, 4);
+}
+
+void OpenGLVegetationImpostor::prepareTexture(const VegetationModelDefinition &model, const Scenery &environment,
+                                              bool *interrupt) {
+    Scenery scenery;
+    environment.getAtmosphere()->copy(scenery.getAtmosphere());
+    SoftwareRenderer renderer(&scenery);
+    // FIXME Self light filtering
+    renderer.getLightingManager()->clearFilters();
+    renderer.getGodRaysSampler()->setEnabled(false);
+    VegetationRenderer *vegetation = renderer.getVegetationRenderer();
+    VegetationInstance instance(model, VECTOR_ZERO);
+
+    int parts = 4;
+    int partsize = texture_size / parts;
+    Matrix4 rotation;
+    for (int py = 0; py < parts; py++) {
+        for (int px = 0; px < parts; px++) {
+            int index = py * parts + px;
+            if (index == 0) {
+                rotation = Matrix4::newRotateX(-M_PI_2);
+            } else if (index < 6) {
+                rotation = Matrix4::newRotateY(M_2PI * (double)(index - 1) * 0.2).mult(Matrix4::newRotateX(-M_PI_4));
+            } else {
+                rotation = Matrix4::newRotateY(M_2PI * (double)(index - 6) * 0.1);
+            }
+
+            Vector3 cam(0.0, 0.0, 5.0);
+            scenery.getCamera()->setLocation(rotation.multPoint(cam));
+            scenery.getCamera()->setTarget(VECTOR_ZERO);
+            renderer.prepare();
+
+            int startx = px * partsize;
+            int starty = py * partsize;
+
+            for (int x = 0; x < partsize; x++) {
+                double dx = (double)x / (double)partsize;
+                for (int y = 0; y < partsize; y++) {
+                    double dy = (double)y / (double)partsize;
+
+                    Vector3 near(dx - 0.5, dy - 0.5, 5.0);
+                    Vector3 far(dx - 0.5, dy - 0.5, -5.0);
+                    SpaceSegment segment(rotation.multPoint(near.scale(1.3)).add(VECTOR_UP.scale(0.5)),
+                                         rotation.multPoint(far.scale(1.3)).add(VECTOR_UP.scale(0.5)));
+
+                    RayCastingResult result = vegetation->renderInstance(segment, instance, false, true);
+                    texture->setPixel(startx + x, starty + y,
+                                      result.hit ? result.hit_color.normalized() : COLOR_TRANSPARENT);
+                }
+            }
+        }
+    }
+
+    texture_changed = true;
+}
+
+void OpenGLVegetationImpostor::setVertex(int i, float x, float y, float z) {
+    vertices[i * 3] = x;
+    vertices[i * 3 + 1] = y;
+    vertices[i * 3 + 2] = z;
+}

src/render/opengl/OpenGLVegetationImpostor.h

@@ -0,0 +1,43 @@
+#ifndef OPENGLVEGETATIONIMPOSTOR_H
+#define OPENGLVEGETATIONIMPOSTOR_H
+
+#include "opengl_global.h"
+
+namespace paysages {
+namespace opengl {
+
+/**
+ * A tool to render an "impostor" of a vegetation layer.
+ */
+class OPENGLSHARED_EXPORT OpenGLVegetationImpostor {
+  public:
+    OpenGLVegetationImpostor(int partsize = 64);
+    ~OpenGLVegetationImpostor();
+
+    inline const Texture2D *getTexture() const {
+        return texture;
+    }
+
+    /**
+     * Render a single instance using this impostor.
+     */
+    void render(OpenGLShaderProgram *program, const OpenGLVegetationInstance *instance, int index);
+
+    /**
+     * Prepare the texture grid for a given model.
+     */
+    void prepareTexture(const VegetationModelDefinition &model, const Scenery &environment, bool *interrupt);
+
+  private:
+    void setVertex(int i, float x, float y, float z);
+
+  private:
+    float *vertices;
+    int texture_size;
+    bool texture_changed;
+    Texture2D *texture;
+};
+}
+}
+
+#endif // OPENGLVEGETATIONIMPOSTOR_H

src/render/opengl/OpenGLVegetationInstance.cpp

@@ -0,0 +1,11 @@
+#include "OpenGLVegetationInstance.h"
+
+#include "VegetationInstance.h"
+
+OpenGLVegetationInstance::OpenGLVegetationInstance(const VegetationInstance &wrapped) : wrapped(wrapped) {
+}
+
+void OpenGLVegetationInstance::setDistance(double distance)
+{
+    this->distance = distance;
+}

src/render/opengl/OpenGLVegetationInstance.h

@@ -0,0 +1,43 @@
+#ifndef OPENGLVEGETATIONINSTANCE_H
+#define OPENGLVEGETATIONINSTANCE_H
+
+#include "opengl_global.h"
+
+#include "VegetationInstance.h"
+
+namespace paysages {
+namespace opengl {
+
+/**
+ * A single instance of vegetation.
+ */
+class OPENGLSHARED_EXPORT OpenGLVegetationInstance {
+  public:
+    OpenGLVegetationInstance(const VegetationInstance &wrapped);
+
+    inline const VegetationModelDefinition &getModel() const {
+        return wrapped.getModel();
+    }
+    inline const Vector3 &getBase() const {
+        return wrapped.getBase();
+    }
+    inline double getSize() const {
+        return wrapped.getSize();
+    }
+    inline double getDistance() const {
+        return distance;
+    }
+
+    /**
+     * Set the distance to camera, mainly for sorting.
+     */
+    void setDistance(double distance);
+
+private:
+    VegetationInstance wrapped;
+    double distance;
+};
+}
+}
+
+#endif // OPENGLVEGETATIONINSTANCE_H

src/render/opengl/OpenGLVegetationLayer.cpp

@@ -0,0 +1,141 @@
+#include "OpenGLVegetationLayer.h"
+
+#include OPENGL_FUNCTIONS_INCLUDE
+#include <algorithm>
+#include "Vector3.h"
+#include "CameraDefinition.h"
+#include "Mutex.h"
+#include "OpenGLVegetation.h"
+#include "OpenGLVegetationInstance.h"
+#include "OpenGLVegetationImpostor.h"
+#include "VegetationLayerDefinition.h"
+#include "VegetationPresenceDefinition.h"
+
+OpenGLVegetationLayer::OpenGLVegetationLayer(OpenGLVegetation *parent, VegetationLayerDefinition *definition,
+                                             bool own_instances)
+    : parent(parent), definition(definition), own_instances(own_instances) {
+    lock_instances = new Mutex;
+    camera_location = new Vector3(0.0, 0.0, 0.0);
+    impostor = new OpenGLVegetationImpostor();
+    range = 10.0;
+
+    reset();
+}
+
+OpenGLVegetationLayer::~OpenGLVegetationLayer() {
+    delete camera_location;
+    delete lock_instances;
+    delete impostor;
+}
+
+void OpenGLVegetationLayer::produceInstancesInArea(double xmin, double xmax, double zmin, double zmax,
+                                                   std::vector<OpenGLVegetationInstance *> *instances) const {
+    std::vector<VegetationInstance> result;
+    definition->getPresence()->collectInstances(&result, *definition->getModel(), xmin, zmin, xmax, zmax, false);
+    for (auto raw_instance : result) {
+        instances->push_back(new OpenGLVegetationInstance(raw_instance));
+    }
+}
+
+static bool isNull(void *ptr) {
+    return ptr == NULL;
+}
+
+static bool compareInstances(OpenGLVegetationInstance *instance1, OpenGLVegetationInstance *instance2) {
+    return instance1->getDistance() > instance2->getDistance();
+}
+
+void OpenGLVegetationLayer::removeInstancesOutsideArea(double xmin, double xmax, double zmin, double zmax,
+                                                       std::vector<OpenGLVegetationInstance *> *instances) const {
+    for (auto &instance : *instances) {
+        Vector3 base = instance->getBase();
+        if (base.x < xmin or base.x >= xmax or base.z < zmin or base.z >= zmax) {
+            if (own_instances) {
+                delete instance;
+            }
+            instance = NULL;
+        }
+    }
+    instances->erase(std::remove_if(instances->begin(), instances->end(), isNull), instances->end());
+}
+
+void OpenGLVegetationLayer::threadedUpdate() {
+    if (camera_changed) {
+        camera_changed = false;
+
+        // Compute new area around camera
+        double newxmin, newxmax, newzmin, newzmax;
+        newxmin = camera_location->x - range;
+        newxmax = camera_location->x + range;
+        newzmin = camera_location->z - range;
+        newzmax = camera_location->z + range;
+
+        // Prepare instances where area grew
+        std::vector<OpenGLVegetationInstance *> new_instances;
+        if (newxmin < xmin) {
+            produceInstancesInArea(newxmin, xmin, newzmin, newzmax, &new_instances);
+        }
+        if (newxmax > xmax) {
+            produceInstancesInArea(xmax, newxmax, newzmin, newzmax, &new_instances);
+        }
+        if (newzmin < zmin) {
+            produceInstancesInArea(xmin, xmax, newzmin, zmin, &new_instances);
+        }
+        if (newzmax > zmax) {
+            produceInstancesInArea(xmin, xmax, zmax, newzmax, &new_instances);
+        }
+
+        // Apply the changes
+        lock_instances->acquire();
+        xmin = newxmin;
+        xmax = newxmax;
+        zmin = newzmin;
+        zmax = newzmax;
+        removeInstancesOutsideArea(xmin, xmax, zmin, zmax, &instances);
+        instances.insert(instances.end(), new_instances.begin(), new_instances.end());
+        for (auto instance: instances) {
+            instance->setDistance(instance->getBase().sub(*camera_location).getNorm());
+        }
+        std::sort(instances.begin(), instances.end(), compareInstances);
+        lock_instances->release();
+
+        // Update impostor texture
+        bool interrupted = false;
+        impostor->prepareTexture(*definition->getModel(), *parent->getScenery(), &interrupted);
+    }
+}
+
+void OpenGLVegetationLayer::render() {
+    lock_instances->acquire();
+
+    // TODO Instanced rendering
+    int index = 0;
+    for (auto instance : instances) {
+        impostor->render(parent->getProgram(), instance, index++);
+    }
+
+    lock_instances->release();
+}
+
+void OpenGLVegetationLayer::reset() {
+    lock_instances->acquire();
+    camera_changed = true;
+    xmin = 0.0;
+    xmax = 0.0;
+    zmin = 0.0;
+    zmax = 0.0;
+    if (own_instances) {
+        for (auto instance : instances) {
+            delete instance;
+        }
+    }
+    instances.clear();
+    lock_instances->release();
+}
+
+void OpenGLVegetationLayer::setCamera(const CameraDefinition *camera) {
+    if (camera_location->sub(camera->getLocation()).getNorm() > 1.0) {
+        *camera_location = camera->getLocation();
+        camera_changed = true;
+    }
+}

src/render/opengl/OpenGLVegetationLayer.h

@@ -0,0 +1,82 @@
+#ifndef OPENGLVEGETATIONLAYER_H
+#define OPENGLVEGETATIONLAYER_H
+
+#include "opengl_global.h"
+
+#include <vector>
+
+namespace paysages {
+namespace opengl {
+
+class OPENGLSHARED_EXPORT OpenGLVegetationLayer {
+  public:
+    OpenGLVegetationLayer(OpenGLVegetation *parent, VegetationLayerDefinition *definition, bool own_instances = true);
+    virtual ~OpenGLVegetationLayer();
+
+    inline auto getDefinition() const {
+        return definition;
+    }
+    inline int getInstanceCount() const {
+        return (int)instances.size();
+    }
+
+    /**
+     * Collect instances in a given area, and add them to the array *instances*.
+     *
+     * The array is not checked for already present instances.
+     */
+    virtual void produceInstancesInArea(double xmin, double xmax, double zmin, double zmax,
+                                        std::vector<OpenGLVegetationInstance *> *instances) const;
+
+    /**
+     * Remove instances outside of a given area.
+     */
+    virtual void removeInstancesOutsideArea(double xmin, double xmax, double zmin, double zmax,
+                                            std::vector<OpenGLVegetationInstance *> *instances) const;
+
+    /**
+     * Perform maintenance tasks that can be perform in a thread.
+     *
+     * This will be called from a thread separate from the main GUI thread,
+     * so it should not call OpenGL functions.
+     */
+    void threadedUpdate();
+
+    /**
+     * Render the vegetation layer.
+     *
+     * This is called from the GUI thread.
+     */
+    void render();
+
+    /**
+     * Reset to an initial state.
+     *
+     * It is only useful (and safe) from unit testing.
+     */
+    void reset();
+
+    /**
+     * Set the current camera in use.
+     */
+    void setCamera(const CameraDefinition *camera);
+
+  private:
+    OpenGLVegetation *parent;
+    VegetationLayerDefinition *definition;
+    double xmin;
+    double xmax;
+    double zmin;
+    double zmax;
+    double range;
+    bool own_instances;
+    std::vector<OpenGLVegetationInstance *> instances;
+    Mutex *lock_instances;
+    OpenGLVegetationImpostor *impostor;
+    Vector3 *camera_location;
+    bool camera_changed;
+};
+}
+}
+
+#endif // OPENGLVEGETATIONLAYER_H

src/render/opengl/opengl.pro

@@ -55,3 +55,7 @@ RESOURCES += \
 OTHER_FILES += \
     shaders/*.frag \
     shaders/*.vert
+
+DISTFILES += \
+    shaders/vegetation.frag \
+    shaders/vegetation.vert

src/render/opengl/opengl_global.h

@@ -19,6 +19,10 @@ class OpenGLVariable;
 class OpenGLSkybox;
 class OpenGLWater;
 class OpenGLTerrain;
+class OpenGLVegetation;
+class OpenGLVegetationLayer;
+class OpenGLVegetationInstance;
+class OpenGLVegetationImpostor;
 class ExplorerChunkTerrain;
 template <typename Vertex> class VertexArray;
 }

src/render/opengl/shaders/resources.qrc

@@ -11,5 +11,7 @@
         <file>fadeout.frag</file>
         <file>noise.frag</file>
         <file>ui.frag</file>
+        <file>vegetation.vert</file>
+        <file>vegetation.frag</file>
     </qresource>
 </RCC>

src/render/opengl/shaders/vegetation.frag

@@ -0,0 +1,15 @@
+varying vec2 texcoord;
+uniform sampler2D impostorTexture;
+
+void main(void)
+{
+    gl_FragColor = texture2D(impostorTexture, texcoord);
+    float alpha = gl_FragColor.a;
+
+    gl_FragColor = applyAerialPerspective(gl_FragColor);
+
+    gl_FragColor = applyToneMapping(gl_FragColor);
+
+    gl_FragColor = applyMouseTracking(unprojected, gl_FragColor);
+    gl_FragColor.a = alpha;
+}

src/render/opengl/shaders/vegetation.vert

@@ -0,0 +1,16 @@
+attribute highp vec4 vertex;
+uniform highp mat4 viewMatrix;
+uniform highp vec3 offset;
+uniform float size;
+uniform int index;
+varying vec3 unprojected;
+varying vec2 texcoord;
+uniform float waterOffset;
+
+void main(void)
+{
+    vec3 final = offset + size * (vertex.xyz - vec3(0.0, 0.0, 0.5));  // + vec3(0, waterOffset, 0)
+    unprojected = final.xyz;
+    texcoord = vec2(0.25 * (vertex.z + float(mod(index, 4))), 0.25 * (vertex.y + float(index / 4)));
+    gl_Position = viewMatrix * vec4(final.xyz, 1.0);
+}

src/render/software/SoftwareRenderer.cpp

@@ -64,6 +64,7 @@ SoftwareRenderer::~SoftwareRenderer() {
     delete clouds_renderer;
     delete terrain_renderer;
     delete textures_renderer;
+    delete vegetation_renderer;
     delete water_renderer;
 }
 

src/render/software/VegetationModelRenderer.cpp

@@ -10,6 +10,13 @@
 #include "VegetationModelDefinition.h"
 #include "VegetationResult.h"
 
+#ifndef NDEBUG
+//#define DEBUG_VEGETATION_CONTAINERS 1
+#endif
+#ifdef DEBUG_VEGETATION_CONTAINERS
+SurfaceMaterial DEBUG_MATERIAL1(Color(1.0, 0.0, 0.0));
+#endif
+
 VegetationModelRenderer::VegetationModelRenderer(SoftwareRenderer *parent, const VegetationModelDefinition *model)
     : parent(parent), model(model) {
 }
@@ -98,6 +105,16 @@ VegetationResult VegetationModelRenderer::getResult(const SpaceSegment &segment,
                     }
                 }
             }
+#ifdef DEBUG_VEGETATION_CONTAINERS
+            if (!hit) {
+                Vector3 near, far;
+                intersections = foliage.findRayIntersection(ray, &near, &far);
+                location = near;
+                normal = VECTOR_ZERO;
+                material = &DEBUG_MATERIAL1;
+                hit = true;
+            }
+#endif
         }
     }
 

src/render/software/VegetationRenderer.cpp

@@ -44,6 +44,9 @@ VegetationRenderer::VegetationRenderer(SoftwareRenderer *parent) : parent(parent
     enabled = true;
 }
 
+VegetationRenderer::~VegetationRenderer() {
+}
+
 void VegetationRenderer::setEnabled(bool enabled) {
     this->enabled = enabled;
 }

src/render/software/VegetationRenderer.h

@@ -11,6 +11,7 @@ namespace software {
 class SOFTWARESHARED_EXPORT VegetationRenderer : public LightFilter {
   public:
     VegetationRenderer(SoftwareRenderer *parent);
+    virtual ~VegetationRenderer();
 
     /**
      * Totally enable or disable the vegetation layers rendering.

src/tests/OpenGLVegetationLayer_Test.cpp

@@ -0,0 +1,67 @@
+#include "BaseTestCase.h"
+#include "OpenGLVegetationLayer.h"
+
+#include "VegetationLayerDefinition.h"
+#include "VegetationModelDefinition.h"
+#include "VegetationInstance.h"
+#include "OpenGLVegetationInstance.h"
+#include "CameraDefinition.h"
+
+class FakeLayerRenderer : public OpenGLVegetationLayer {
+  public:
+    FakeLayerRenderer(VegetationLayerDefinition *definition) : OpenGLVegetationLayer(NULL, definition, false) {
+    }
+    virtual ~FakeLayerRenderer() {
+        for (auto instance : static_instances) {
+            delete instance;
+        }
+    }
+    virtual void produceInstancesInArea(double xmin, double xmax, double zmin, double zmax,
+                                        std::vector<OpenGLVegetationInstance *> *instances) const override {
+        for (auto instance : static_instances) {
+            Vector3 location = instance->getBase();
+            if (location.x >= xmin and location.z >= zmin and location.x < xmax and location.z < zmax) {
+                instances->push_back(instance);
+            }
+        }
+    }
+    std::vector<OpenGLVegetationInstance *> static_instances;
+};
+
+TEST(OpenGLVegetationLayer, threadedUpdate) {
+    CameraDefinition camera;
+    VegetationLayerDefinition definition(NULL, "test");
+    FakeLayerRenderer rendering(&definition);
+    VegetationModelDefinition model(NULL);
+
+    EXPECT_EQ(0, rendering.getInstanceCount());
+
+    rendering.threadedUpdate();
+    EXPECT_EQ(0, rendering.getInstanceCount());
+
+    rendering.static_instances.push_back(
+        new OpenGLVegetationInstance(VegetationInstance(model, Vector3(0.0, 0.0, 0.0))));
+    rendering.reset();
+    rendering.threadedUpdate();
+    EXPECT_EQ(1, rendering.getInstanceCount());
+
+    camera.setLocation(Vector3(-5.0, 0.0, 0.0));
+    rendering.setCamera(&camera);
+    rendering.threadedUpdate();
+    EXPECT_EQ(1, rendering.getInstanceCount());
+
+    camera.setLocation(Vector3(-11.0, 0.0, 0.0));
+    rendering.setCamera(&camera);
+    rendering.threadedUpdate();
+    EXPECT_EQ(0, rendering.getInstanceCount());
+
+    camera.setLocation(Vector3(0.0, 0.0, 5.0));
+    rendering.setCamera(&camera);
+    rendering.threadedUpdate();
+    EXPECT_EQ(1, rendering.getInstanceCount());
+
+    camera.setLocation(Vector3(0.0, 0.0, 15.0));
+    rendering.setCamera(&camera);
+    rendering.threadedUpdate();
+    EXPECT_EQ(0, rendering.getInstanceCount());
+}

src/tests/OpenGLVegetation_Test.cpp

@@ -0,0 +1,19 @@
+#include "BaseTestCase.h"
+#include "OpenGLVegetation.h"
+
+#include "Scenery.h"
+#include "VegetationDefinition.h"
+#include "VegetationLayerDefinition.h"
+#include "OpenGLRenderer.h"
+
+TEST(OpenGLVegetation, updateLayers) {
+    Scenery scenery;
+    OpenGLRenderer renderer(&scenery);
+    OpenGLVegetation glvegetation(&renderer);
+
+    EXPECT_EQ(0, glvegetation.getLayerCount());
+
+    scenery.getVegetation()->addLayer("test");
+
+    EXPECT_EQ(1, glvegetation.getLayerCount());
+}

src/tests/OverlayRasterizer_Test.cpp

@@ -40,8 +40,9 @@ TEST(OverlayRasterizer, pixelProcessing) {
 
     Scenery scenery;
     SoftwareCanvasRenderer renderer(&scenery);
+    MockOverlayRasterizer rasterizer(&renderer);
     renderer.setSize(4, 3);
-    renderer.setSoloRasterizer(new MockOverlayRasterizer(&renderer));
+    renderer.setSoloRasterizer(&rasterizer);
     renderer.render();
 
     ASSERT_EQ(12, (int)calls.size());