From e0c0a9f3816facd0fc4066a50479f823447e03f6 Mon Sep 17 00:00:00 2001
From: Jon Bergli Heier <snakebite@jvnv.net>
Date: Sun, 10 Apr 2011 14:51:47 +0200
Subject: Simple raise/lower implementation.

---
 quadtree.cpp | 110 +++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 81 insertions(+), 29 deletions(-)

(limited to 'quadtree.cpp')

diff --git a/quadtree.cpp b/quadtree.cpp
index c60fd27..65c60ae 100644
--- a/quadtree.cpp
+++ b/quadtree.cpp
@@ -220,6 +220,8 @@ float Quadtree::QuadChunk::distance(float px, float pz) {
 void Quadtree::QuadChunk::make_vbo() {
 	node_count = width*height;
 	vertices = node_count*12;
+	if(vbo_object)
+		glDeleteBuffers(1, &vbo_object);
 	glGenBuffers(1, &vbo_object);
 	glBindBuffer(GL_ARRAY_BUFFER, vbo_object);
 
@@ -325,15 +327,16 @@ Quadtree::QuadNode* Quadtree::QuadChunk::find(float x, float y) {
 	if(!nodes) {
 		float mx = this->x + width / 2;
 		float my = this->y + height / 2;
-		int i = 2*(y > my);
-		if(i < 2 && x > mx)
+		int i = 2*(y >= my);
+		if(i < 2 && x >= mx)
 			i = 1;
 		else if(i == 2 && x < mx)
 			i = 3;
 		return children[i]->find(x, y);
 	}
-	if(!(x >= this->x && x < this->x+width && y >= this->y && y < this->y+height))
+	if(!(x >= this->x && x < this->x+width && y >= this->y && y < this->y+height)) {
 		return NULL;
+	}
 	return nodes[(int)(x-this->x)*(int)height + (int)(y - this->y)];
 }
 
@@ -349,32 +352,7 @@ Quadtree::Quadtree(int width, int height, float *heightmap) {
 	normals = new Vector3[width*height];
 	for(int x = 0; x < width; x++) {
 		for(int y = 0; y < height; y++) {
-			Vector3 p(x, heights[x*height + y], y);
-			Vector3 N;
-
-			if(x > 0) {
-				Vector3 U = Vector3(x-1, heights[(x-1)*height + y], y) - p;
-				if(y > 0) {
-					Vector3 V = Vector3(x, heights[x*height + y - 1], y-1) - p;
-					N += V.cross(U);
-				}
-				if(y < height-1) {
-					Vector3 V = Vector3(x, heights[x*height + y + 1], y+1) - p;
-					N += U.cross(V);
-				}
-			}
-			if(x < width-1) {
-				Vector3 U = Vector3(x+1, heights[(x+1)*height + y], y) - p;
-				if(y > 0) {
-					Vector3 V = Vector3(x, heights[x*height + y - 1], y-1) - p;
-					N += U.cross(V);
-				}
-				if(y < height-1) {
-					Vector3 V = Vector3(x, heights[x*height + y + 1], y+1) - p;
-					N += V.cross(U);
-				}
-			}
-			normals[x*height + y] = N / N.length();
+			calc_normal(x, y);
 		}
 	}
 }
@@ -385,6 +363,80 @@ Quadtree::~Quadtree() {
 	delete[] normals;
 }
 
+void Quadtree::raise(float x, float z, float radius, float focus, float strength) {
+	if(x < 0 || x >= width-1 || z < 0 || z >= height-1)
+		return;
+
+	/* adjust heights */
+	QuadNode *node = find(x, z);
+	for(int i = x-radius; i < x+radius; i++) {
+		if(i < 0 || i >= width-1)
+			continue;
+		for(int j = z-radius; j < z+radius; j++) {
+			if(j < 0 || j >= height-1)
+				continue;
+			heights[i*height + j] += strength / max(powf((Vector2(x, z) - Vector2(i, j)).length(), focus), 1.0f);
+		}
+	}
+
+	/* recalculate normals */
+	for(int i = x-radius-1; i < x+radius; i++) {
+		if(i < 0 || i >= width-1)
+			continue;
+		for(int j = z-radius-1; j < z+radius; j++) {
+			if(j < 0 || j >= height-1)
+				continue;
+			calc_normal(i, j);
+		}
+	}
+
+	/* refill nodes and remake VBOs */
+	for(int nx = x-radius-1; nx < x+chunk_size; nx+=chunk_size) {
+		if(nx < 0 || nx >= width-1)
+			continue;
+		for(int nz = z-radius-1; nz < z+chunk_size; nz+=chunk_size) {
+			if(nz < 0 || nz >= height-1)
+				continue;
+			QuadNode *node = find(nx, nz);
+			for(int i = 0; i < node->chunk->node_count; i++) {
+				node->chunk->nodes[i]->fill();
+			}
+			node->chunk->make_vbo();
+		}
+	}
+}
+
+Vector3 Quadtree::calc_normal(int x, int y) {
+	Vector3 p(x, heights[x*height + y], y);
+	Vector3 N;
+
+	if(x > 0) {
+		Vector3 U = Vector3(x-1, heights[(x-1)*height + y], y) - p;
+		if(y > 0) {
+			Vector3 V = Vector3(x, heights[x*height + y - 1], y-1) - p;
+			N += V.cross(U);
+		}
+		if(y < height-1) {
+			Vector3 V = Vector3(x, heights[x*height + y + 1], y+1) - p;
+			N += U.cross(V);
+		}
+	}
+	if(x < width-1) {
+		Vector3 U = Vector3(x+1, heights[(x+1)*height + y], y) - p;
+		if(y > 0) {
+			Vector3 V = Vector3(x, heights[x*height + y - 1], y-1) - p;
+			N += U.cross(V);
+		}
+		if(y < height-1) {
+			Vector3 V = Vector3(x, heights[x*height + y + 1], y+1) - p;
+			N += V.cross(U);
+		}
+	}
+	N /= N.length();
+	normals[x*height + y] = N;
+	return N;
+}
+
 void Quadtree::update(float x, float z) {
 	std::queue<QuadChunk*> q;
 	q.push(root);
-- 
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