From 03de2f3ea7db92e948035d2b87bb66ec8c86b897 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Mon, 5 Aug 2013 11:41:42 -0700
Subject: [PATCH] Render a green plane with fog, per Grayson's request.

---
 interface/src/Application.cpp            | 17 ++++++
 interface/src/renderer/GeometryCache.cpp | 70 +++++++++++++++++++++++-
 interface/src/renderer/GeometryCache.h   |  6 +-
 3 files changed, 90 insertions(+), 3 deletions(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 6087a4493e..5399c274e4 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2893,6 +2893,23 @@ void Application::displaySide(Camera& whichCamera) {
 
     //draw a grid ground plane....
     if (_renderGroundPlaneOn->isChecked()) {
+        // draw grass plane with fog
+        glEnable(GL_FOG);
+        const float FOG_COLOR[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+        glFogfv(GL_FOG_COLOR, FOG_COLOR);
+        glFogi(GL_FOG_MODE, GL_EXP2);
+        glFogf(GL_FOG_DENSITY, 0.025f);
+        glPushMatrix();
+            const float GRASS_PLANE_SIZE = 256.0f;
+            glTranslatef(-GRASS_PLANE_SIZE * 0.5f, -0.01f, GRASS_PLANE_SIZE * 0.5f);
+            glScalef(GRASS_PLANE_SIZE, 1.0f, GRASS_PLANE_SIZE);
+            glRotatef(-90.0f, 1.0f, 0.0f, 0.0f);
+            glColor3ub(70, 134, 74);
+            const int GRASS_DIVISIONS = 40;
+            _geometryCache.renderSquare(GRASS_DIVISIONS, GRASS_DIVISIONS);
+        glPopMatrix();
+        glDisable(GL_FOG);
+        
         renderGroundPlaneGrid(EDGE_SIZE_GROUND_PLANE, _audio.getCollisionSoundMagnitude());
     } 
     //  Draw voxels
diff --git a/interface/src/renderer/GeometryCache.cpp b/interface/src/renderer/GeometryCache.cpp
index 971f18706e..8331a5deb9 100644
--- a/interface/src/renderer/GeometryCache.cpp
+++ b/interface/src/renderer/GeometryCache.cpp
@@ -18,7 +18,7 @@ GeometryCache::~GeometryCache() {
 }
 
 void GeometryCache::renderHemisphere(int slices, int stacks) {
-    VerticesIndices& vbo = _hemisphereVBOs[SlicesStacks(slices, stacks)];
+    VerticesIndices& vbo = _hemisphereVBOs[IntPair(slices, stacks)];
     int vertices = slices * (stacks - 1) + 1;
     int indices = slices * 2 * 3 * (stacks - 2) + slices * 3;
     if (vbo.first == 0) {    
@@ -95,3 +95,71 @@ void GeometryCache::renderHemisphere(int slices, int stacks) {
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 }
+
+void GeometryCache::renderSquare(int xDivisions, int yDivisions) {
+    VerticesIndices& vbo = _squareVBOs[IntPair(xDivisions, yDivisions)];
+    int xVertices = xDivisions + 1;
+    int yVertices = yDivisions + 1;
+    int vertices = xVertices * yVertices;
+    int indices = 2 * 3 * xDivisions * yDivisions;
+    if (vbo.first == 0) {
+        GLfloat* vertexData = new GLfloat[vertices * 3];
+        GLfloat* vertex = vertexData;
+        for (int i = 0; i <= yDivisions; i++) {
+            float y = (float)i / yDivisions;
+            
+            for (int j = 0; j <= xDivisions; j++) {
+                *(vertex++) = (float)j / xDivisions;
+                *(vertex++) = y;
+                *(vertex++) = 0.0f;
+            }
+        }
+        
+        glGenBuffers(1, &vbo.first);
+        glBindBuffer(GL_ARRAY_BUFFER, vbo.first);
+        const int BYTES_PER_VERTEX = 3 * sizeof(GLfloat);
+        glBufferData(GL_ARRAY_BUFFER, vertices * BYTES_PER_VERTEX, vertexData, GL_STATIC_DRAW);
+        delete[] vertexData;
+        
+        GLushort* indexData = new GLushort[indices];
+        GLushort* index = indexData;
+        for (int i = 0; i < yDivisions; i++) {
+            GLushort bottom = i * xVertices;
+            GLushort top = bottom + xVertices;
+            for (int j = 0; j < xDivisions; j++) {
+                int next = j + 1;
+                
+                *(index++) = bottom + j;
+                *(index++) = top + next;
+                *(index++) = top + j;
+                
+                *(index++) = bottom + j;
+                *(index++) = bottom + next;
+                *(index++) = top + next;
+            }
+        }
+        
+        glGenBuffers(1, &vbo.second);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbo.second);
+        const int BYTES_PER_INDEX = sizeof(GLushort);
+        glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices * BYTES_PER_INDEX, indexData, GL_STATIC_DRAW);
+        delete[] indexData;
+        
+    } else {
+        glBindBuffer(GL_ARRAY_BUFFER, vbo.first);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbo.second);
+    }
+    glEnableClientState(GL_VERTEX_ARRAY);
+ 
+    // all vertices have the same normal
+    glNormal3f(0.0f, 0.0f, 1.0f);
+    
+    glVertexPointer(3, GL_FLOAT, 0, 0);
+        
+    glDrawRangeElementsEXT(GL_TRIANGLES, 0, vertices - 1, indices, GL_UNSIGNED_SHORT, 0);
+        
+    glDisableClientState(GL_VERTEX_ARRAY);
+    
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+}
diff --git a/interface/src/renderer/GeometryCache.h b/interface/src/renderer/GeometryCache.h
index 0c5ccea06f..bfce642554 100644
--- a/interface/src/renderer/GeometryCache.h
+++ b/interface/src/renderer/GeometryCache.h
@@ -19,13 +19,15 @@ public:
     ~GeometryCache();
     
     void renderHemisphere(int slices, int stacks);
+    void renderSquare(int xDivisions, int yDivisions);
 
 private:
     
-    typedef QPair<int, int> SlicesStacks;
+    typedef QPair<int, int> IntPair;
     typedef QPair<GLuint, GLuint> VerticesIndices;
     
-    QHash<SlicesStacks, VerticesIndices> _hemisphereVBOs;
+    QHash<IntPair, VerticesIndices> _hemisphereVBOs;
+    QHash<IntPair, VerticesIndices> _squareVBOs;
 };
 
 #endif /* defined(__interface__GeometryCache__) */