renderer: render scene to a texture

And then render the texture onto a quad that fills the screen
The screen-filled quad upon which the texture is rendered must never be rendered in wireframe. Rendering in wireframe only makes sense when rendering the world on the texture

include/renderer.hpp

@@ -11,8 +11,9 @@
 namespace renderer{
     typedef oneapi::tbb::concurrent_unordered_set<Chunk::Chunk*> RenderSet;
 
-    void init();
+    void init(GLFWwindow* window);
-    void render();
+    void render(GLFWwindow* window);
+    void framebuffer_size_callback(GLFWwindow *window, int width, int height);
     void destroy();
     Shader* getRenderShader();
     RenderSet& getChunksToRender();

intervalmap.hpp

@@ -0,0 +1,143 @@
+#ifndef INTERVALMAP_H
+#define INTERVALMAP_H
+
+#include <iostream>
+#include <iterator> //std::prev
+#include <limits>   // std::numeric_limits
+#include <memory>   //std::shared_ptr
+#include <map>
+
+template <typename K, typename V>
+class IntervalMap
+{
+
+public:
+    ~IntervalMap(){
+	treemap.clear();
+    }
+
+    void insert(K start, K end, V value)
+    {
+        if (start >= end)
+            return;
+
+	// The entry just before the end index
+	auto tmp = treemap.upper_bound(end);
+	auto end_prev_entry = tmp == treemap.end() ? tmp : --tmp;
+	auto added_end = treemap.end();
+
+	// If it doesn't exist (empty map)
+	if(end_prev_entry == treemap.end()){
+	    V v{};
+	    added_end = treemap.insert_or_assign(treemap.begin(), end, v);
+	}
+	// Or if it has value different from the insertion
+	else if(end_prev_entry->second != value)
+	    // Add it back at the end
+	    added_end = treemap.insert_or_assign(end_prev_entry, end, end_prev_entry->second);
+	
+	// The entry just before the start index
+	tmp = treemap.upper_bound(start);
+	auto start_prev_entry = tmp == treemap.end() ? tmp : --tmp;
+	auto added_start = treemap.end();
+	// If it has value different from the insertion
+	if(start_prev_entry == treemap.end() || start_prev_entry->second != value)
+	    // Add the start node of the insertion
+	    added_start = treemap.insert_or_assign(start_prev_entry, start, value);
+
+	// Delete everything else inside
+	// map.erase(start, end) deletes every node with key in the range [start, end)
+
+	// The key to start deleting from is the key after the start node we added
+	// (We don't want to delete a node we just added)
+	auto del_start = added_start == treemap.end() ? std::next(start_prev_entry) : std::next(added_start);
+	auto del_end = added_end == treemap.end() ? end_prev_entry : added_end;
+	auto del_end_next = std::next(del_end);
+
+	// If the node after the end is of the same type of the end, delete it
+	// We cannot just expand del_end (++del_end) otherwise interval limits get messed up
+	if(del_end != treemap.end() && del_end_next != treemap.end() && del_end->second ==
+		del_end_next->second) treemap.erase(del_end_next);
+
+	// Delete everything in between
+	if(del_start != treemap.end() && (del_end==treemap.end() || del_start->first <
+		    del_end->first)) treemap.erase(del_start, del_end);
+    }
+
+    void remove(K at)
+    {
+        treemap.erase(at);
+    }
+
+    auto at(K index)
+    {
+	const auto tmp = treemap.lower_bound(index);
+	const auto r = tmp != treemap.begin() && tmp->first!=index ? std::prev(tmp) : tmp;
+	return r;
+    }
+
+    void print()
+    {
+        for (auto i = treemap.begin(); i != treemap.end(); i++)
+            std::cout << i->first << ": " << (int)(i->second) << "\n";
+	if(!treemap.empty()) std::cout << "end key: " << std::prev(treemap.end())->first << "\n";
+    }
+
+    std::unique_ptr<V[]> toArray(int *length)
+    {
+        if (treemap.empty())
+        {
+            *length = 0;
+            return nullptr;
+        }
+
+        const auto &end = std::prev(treemap.end());
+        *length = end->first;
+        if(*length == 0) return nullptr;
+        
+	std::unique_ptr<V[]> arr(new V[*length]);
+        auto start = treemap.begin();
+        for (auto i = std::next(treemap.begin()); i != treemap.end(); i++)
+        {
+            for (int k = start->first; k < i->first; k++)
+                arr[k] = start->second;
+            start = i;
+        }
+
+        return arr;
+    }
+
+    void fromArray(V *arr, int length)
+    {
+        treemap.clear();
+
+        if (length == 0)
+            return;
+
+        V prev = arr[0];
+        unsigned int prev_start = 0;
+        for (unsigned int i = 1; i < length; i++)
+        {
+            if (prev != arr[i])
+            {
+                insert(prev_start, i, prev);
+                prev_start = i;
+            }
+            prev = arr[i];
+        }
+        insert(prev_start, length, prev);
+    }
+
+    auto begin(){
+	return treemap.begin();
+    }
+    
+    auto end(){
+	return treemap.end();
+    }
+
+private:
+    std::map<K, V> treemap{};
+};
+
+#endif

shaders/shader-quad.fs

@@ -0,0 +1,10 @@
+#version 330 core
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D renderTex;
+
+void main(){
+    FragColor = texture(renderTex, TexCoord);
+}

shaders/shader-quad.vs

@@ -0,0 +1,12 @@
+#version 330 core
+
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec2 aTexCoord;
+
+out vec2 TexCoord;
+
+void main()
+{
+    TexCoord = aTexCoord;
+    gl_Position = vec4(aPos, 1.0);
+}

src/main.cpp

@@ -57,7 +57,6 @@ int main()
     glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
     glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
     glfwSetCursorPosCallback(window, mouse_callback);
-    glEnable(GL_DEPTH_TEST);
     //glEnable(GL_FRAMEBUFFER_SRGB); //gamma correction done in fragment shader
     //glEnable(GL_CULL_FACE); //GL_BACK GL_CCW by default
 
@@ -70,7 +69,7 @@ int main()
     }
     SpaceFilling::initLUT();
     chunkmanager::init();
-    renderer::init();
+    renderer::init(window);
 
     while (!glfwWindowShouldClose(window))
     {
@@ -100,7 +99,7 @@ int main()
 	if(glfwGetTime() - lastBlockPick > 0.1) blockpick = false;
 
 	// Render pass
-	renderer::render();
+	renderer::render(window);
 
         // Swap buffers to avoid tearing
         glfwSwapBuffers(window);
@@ -122,6 +121,7 @@ void framebuffer_size_callback(GLFWwindow *window, int width, int height)
 {
     glViewport(0, 0, width, height);
     theCamera.viewPortCallBack(window, width, height);
+    renderer::framebuffer_size_callback(window, width, height);
 }
 
 void mouse_callback(GLFWwindow *window, double xpos, double ypos)

src/renderer.cpp

@@ -13,18 +13,73 @@ namespace renderer{
     oneapi::tbb::concurrent_vector<Chunk::Chunk*> render_todelete;
     oneapi::tbb::concurrent_queue<chunkmesher::MeshData*> MeshDataQueue;
 
-    Shader* theShader;
+    Shader* theShader, *quadShader;
     GLuint chunkTexture;
 
     Shader* getRenderShader() { return theShader; }
     RenderSet& getChunksToRender(){ return chunks_torender; }
     oneapi::tbb::concurrent_queue<chunkmesher::MeshData*>& getMeshDataQueue(){ return MeshDataQueue; }
 
+    GLuint renderTexFrameBuffer, renderTex, renderTexDepthBuffer, quadVAO, quadVBO;
+    int screenWidth, screenHeight;
 
-    void init(){
+
+    void init(GLFWwindow* window){
+	// Setup rendering
+	// We will render the image to a texture, then display the texture on a quad that fills the
+	// entire screen.
+	// This makes it easy to capture screenshots or apply filters to the final image (e.g.
+	// over-impress HUD elements like a crosshair)
+	glfwGetWindowSize(window, &screenWidth, &screenHeight);
+
+	glGenFramebuffers(1, &renderTexFrameBuffer);
+	glBindFramebuffer(GL_FRAMEBUFFER, renderTexFrameBuffer);
+
+	// Depth buffer
+	glGenRenderbuffers(1, &renderTexDepthBuffer);
+	glBindRenderbuffer(GL_RENDERBUFFER, renderTexDepthBuffer);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, screenWidth, screenHeight); //Support up to
+										//full-hd for now
+	// Attach it to the frame buffer
+	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
+		renderTexDepthBuffer);
+	// Create texture to render to
+	// The texture we're going to render to
+	glGenTextures(1, &renderTex);
+	glBindTexture(GL_TEXTURE_2D, renderTex);
+	glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, screenWidth, screenHeight, 0,GL_RGB, GL_UNSIGNED_BYTE, 0); // Support
+											 // up to
+											 // full-hd
+											 // for now
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	// Set the texture as a render attachment for the framebuffer
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, renderTex, 0);
+
+	// Create the quad to render the texture to
+	float vertices[] = {
+	    -1.0f, -1.0f, 0.0f, 0.0f, 0.0f,
+	    -1.0f, 1.0f, 0.0f, 0.0f, 1.0f,
+	    1.0f, -1.0f, 0.0f, 1.0f, 0.0f,
+	    1.0f, 1.0f, 0.0f, 1.0f, 1.0f
+	};
+	glGenBuffers(1, &quadVBO);
+	glGenVertexArrays(1, &quadVAO);
+	glBindVertexArray(quadVAO);
+	glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void*)0);
+	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void*)(3*sizeof(float)));
+	glEnableVertexAttribArray(0);
+	glEnableVertexAttribArray(1);
+	glBindVertexArray(0);
+
+	// Rendering of the world
 	// Create Shader
 	theShader = new Shader{"shaders/shader-texture.gs", "shaders/shader-texture.vs", "shaders/shader-texture.fs"};
+	quadShader = new Shader{nullptr, "shaders/shader-quad.vs", "shaders/shader-quad.fs"};
 
+	// Block textures
 	// Create 3d array texture
 	constexpr int layerCount = 5;
 	glGenTextures(1, &chunkTexture);
@@ -49,7 +104,18 @@ namespace renderer{
 	glTexParameteri(GL_TEXTURE_2D_ARRAY,GL_TEXTURE_WRAP_T,GL_REPEAT);
     }
 
-    void render(){
+
+    void render(GLFWwindow* window){
+	// Bind the frame buffer to render to the texture
+	glBindFramebuffer(GL_FRAMEBUFFER, renderTexFrameBuffer);
+	glEnable(GL_DEPTH_TEST);
+	if(wireframe) glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+	else glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+	// Clear the screen
+        glClearColor(0.431f, 0.694f, 1.0f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
 	int total{0}, toGpu{0};
 	glm::vec4 frustumPlanes[6];
 	theCamera.getFrustumPlanes(frustumPlanes, true);
@@ -65,9 +131,6 @@ namespace renderer{
 	    chunkmesher::getMeshDataQueue().push(m);
 	}
 
-	if(wireframe) glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
-	else glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
-
 	for(auto& c : chunks_torender){
 	    float dist = glm::distance(c->getPosition(), cameraChunkPos);
 	    if(dist <= static_cast<float>(RENDER_DISTANCE)){
@@ -139,6 +202,32 @@ namespace renderer{
 	    chunkmanager::getDeleteVector().push(c);
 	}
 	render_todelete.clear();
+
+
+	// Now to render the quad, with the texture on top
+	// Switch to the default frame buffer
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+        glClearColor(0.431f, 0.694f, 1.0f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+	glBindVertexArray(quadVAO);
+	glDisable(GL_DEPTH_TEST);
+	glBindTexture(GL_TEXTURE_2D, renderTex);
+	quadShader->use();
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+	glBindVertexArray(0);
+    }
+
+    void framebuffer_size_callback(GLFWwindow *window, int width, int height){
+	screenWidth = width;
+	screenHeight = height;
+
+	glBindTexture(GL_TEXTURE_2D, renderTex);
+	glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, screenWidth, screenHeight, 0,GL_RGB, GL_UNSIGNED_BYTE, 0); // Support
+
+	glBindRenderbuffer(GL_RENDERBUFFER, renderTexDepthBuffer);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, screenWidth, screenHeight); //Support up to
     }
 
     void destroy(){