Hide trees and grass in the path of the car

src/renderlogic.cpp

@@ -144,6 +144,8 @@ void renderNode(SceneNode* node, Gloom::Shader* parent_shader, vector<NodeDistSh
     static Gloom::Shader* s = nullptr; // The currently active shader
     static Gloom::Shader* prev_s = nullptr; // The last shader to glDrawElements
     
+    if (node->isHidden) return;
+    
     // activate the correct shader
     Gloom::Shader* node_shader = (node->shader != nullptr)
         ? node->shader
@@ -173,6 +175,7 @@ void renderNode(SceneNode* node, Gloom::Shader* parent_shader, vector<NodeDistSh
                 //transparent_nodes->push_back({node, node_shader, glm::length(vec3(node->MVP*vec4(0,0,0,1)))});
             }
             else if(node->vertexArrayObjectID != -1) {
+                if (node->opacity <= 0.05) break;
                 // load uniforms
                 um4fv(MVP);
                 um4fv(MV);

src/scene.cpp

@@ -244,7 +244,7 @@ void step_scene(double timeDelta) {
         vec3 o = carNode->position;
         o.x += plainNode->uvOffset.x*1000/3;
         o.y += plainNode->uvOffset.y*1000/3;
-        float t = carNode->rotation.z + 3*3.1415926535/2.0;
+        float t/*heta*/ = carNode->rotation.z + 3*3.1415926535/2.0;
         
         vec3 fr =  o + vec3(60*glm::cos(t), 60*glm::sin(t), 0) + vec3(30*glm::sin(t), -30*glm::cos(t), 0);
         vec3 fl =  o + vec3(60*glm::cos(t), 60*glm::sin(t), 0) - vec3(30*glm::sin(t), -30*glm::cos(t), 0);
@@ -273,6 +273,12 @@ void step_scene(double timeDelta) {
         if (node->position.x > 1000.0) node->position.x -= 1000.0;
         if (node->position.y > 1000.0) node->position.y -= 1000.0;
         //node->position.z = DISPLACEMENT * (t_perlin.at_bilinear(node->position.x*3/1000, node->position.y*3/1000).x * 2 - 1) - 0.5;
+        
+        // cull objects in the cars path
+        vec2 PQ = vec2(node->position - carNode->position);
+        vec2 N = flip(plane_movement)*vec2(1, -1);
+        float dist_from_path = glm::length(glm::dot(PQ, N)) / glm::length(N);
+        node->isHidden = dist_from_path < 60;
     }
 
     /*

src/sceneGraph.hpp

@@ -99,6 +99,7 @@ struct SceneNode {
 	bool isInverted = false;
 
 	// rendering
+	bool isHidden = false;
 	Gloom::Shader* shader = nullptr;
 	mat4 MVP; // MVP
 	mat4 MV; // MV