From 0fbb5345666429b008ec8d3b169b63dbbe9aaab7 Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Wed, 6 Mar 2013 12:04:27 -0800
Subject: [PATCH] randomly draw 50000 voxels for glDrawElements test

---
 interface/src/VoxelSystem.cpp | 80 +++++++++++++++++++++++++++++++++--
 interface/src/VoxelSystem.h   |  4 ++
 interface/src/main.cpp        | 15 +------
 3 files changed, 82 insertions(+), 17 deletions(-)

diff --git a/interface/src/VoxelSystem.cpp b/interface/src/VoxelSystem.cpp
index d654f71a5e..c20eb30fbd 100644
--- a/interface/src/VoxelSystem.cpp
+++ b/interface/src/VoxelSystem.cpp
@@ -8,6 +8,28 @@
 
 #include "VoxelSystem.h"
 
+const float MAX_UNIT_ANY_AXIS = 20.0f;
+const float CUBE_WIDTH = 0.05f;
+const int VERTICES_PER_VOXEL = 8;
+const int VERTEX_POINTS_PER_VOXEL = 3 * VERTICES_PER_VOXEL;
+const int INDICES_PER_VOXEL = 3 * 12;
+
+GLfloat identityVertices[] = { -1, -1, 1,
+                               1, -1, 1,
+                               1, -1, -1,
+                               -1, -1, -1,
+                               1, 1, 1,
+                              -1, 1, 1,
+                              -1, 1, -1,
+                               1, 1, -1 };
+
+GLubyte identityIndices[] = { 0,1,2, 0,2,3,
+                              0,4,1, 0,4,5,
+                              0,3,6, 0,5,6,
+                              1,2,4, 2,4,7,
+                              2,3,6, 2,6,7,
+                              4,5,6, 4,6,7 };
+
 
 bool onSphereShell(float radius, float scale, glm::vec3 * position) {
     float vRadius = glm::length(*position);
@@ -18,6 +40,49 @@ void VoxelSystem::init() {
     root = new Voxel;
 }
 
+void VoxelSystem::init(int numberOfRandomVoxels) {
+    // create the arrays needed to pass to glDrawElements later
+    // position / color are random for now
+    
+    voxelsRendered = numberOfRandomVoxels;
+    
+    // there are 3 points for each vertices, 24 vertices in each cube
+    verticesArray = new GLfloat[VERTEX_POINTS_PER_VOXEL * numberOfRandomVoxels];
+    
+    // there are 12 triangles in each cube, with three indices for each triangle
+    indicesArray = new GLuint[INDICES_PER_VOXEL * numberOfRandomVoxels];
+    
+    // new seed based on time now so voxels are different each time
+    srand((unsigned)time(0));
+    
+    for (int n = 0; n < numberOfRandomVoxels; n++) {        
+        // pick a random point for the center of the cube
+        glm::vec3 position = glm::vec3(
+            ((float) rand() / ((float) RAND_MAX / MAX_UNIT_ANY_AXIS)),
+            ((float) rand() / ((float) RAND_MAX / MAX_UNIT_ANY_AXIS)),
+            ((float) rand() / ((float) RAND_MAX / MAX_UNIT_ANY_AXIS))
+        );
+        
+        GLfloat *currentVerticesPos = verticesArray + (n * VERTEX_POINTS_PER_VOXEL);
+        
+        // fill the vertices array
+        for (int v = 0; v < VERTEX_POINTS_PER_VOXEL; v++) {
+            currentVerticesPos[v] = position[v % 3] + (identityVertices[v] * CUBE_WIDTH);
+        }
+
+        // fill the indices array
+        int voxelIndexOffset = n * INDICES_PER_VOXEL;
+        GLuint *currentIndicesPos = indicesArray + voxelIndexOffset;
+        int startIndex = (n * VERTICES_PER_VOXEL);
+        
+        for (int i = 0; i < INDICES_PER_VOXEL; i++) {
+            // add indices for this side of the cube
+            currentIndicesPos[i] = startIndex + identityIndices[i];
+        }
+    }
+    
+}
+
 //
 //  Recursively initialize the voxel tree
 //
@@ -118,11 +183,18 @@ int VoxelSystem::render(Voxel * voxel, float scale, glm::vec3 * distance) {
     return vRendered;
 }
 
+void VoxelSystem::render() {
+    glEnableClientState(GL_VERTEX_ARRAY);
+    glVertexPointer(3, GL_FLOAT, 0, verticesArray);
+    
+    // draw a cube
+    glDrawElements(GL_TRIANGLES, 36 * voxelsRendered, GL_UNSIGNED_INT, indicesArray);
+    
+    // deactivate vertex arrays after drawing
+    glDisableClientState(GL_VERTEX_ARRAY);
+}
+
 void VoxelSystem::simulate(float deltaTime) {
     
 }
 
-
-
-
-
diff --git a/interface/src/VoxelSystem.h b/interface/src/VoxelSystem.h
index 8dc3e97c8c..43b5ff18e0 100644
--- a/interface/src/VoxelSystem.h
+++ b/interface/src/VoxelSystem.h
@@ -26,13 +26,17 @@ class VoxelSystem {
 public:
     void simulate(float deltaTime);
     int render(Voxel * voxel, float scale, glm::vec3 * distance);
+    void render();
     void init();
+    void init(int numberOfRandomVoxels);
     int initVoxels(Voxel * root, float scale, glm::vec3 * position);
     void setVoxelsRendered(int v) {voxelsRendered = v;};
     int getVoxelsRendered() {return voxelsRendered;};
     Voxel * root;
 private:
     int voxelsRendered;
+    GLfloat *verticesArray;
+    GLuint *indicesArray;
 };
 
 #endif
diff --git a/interface/src/main.cpp b/interface/src/main.cpp
index e189b5c715..1a3f560089 100644
--- a/interface/src/main.cpp
+++ b/interface/src/main.cpp
@@ -319,10 +319,7 @@ void initDisplay(void)
 
 void init(void)
 {
-    voxels.init();
-    glm::vec3 position(0,0,0);
-    int voxelsMade = voxels.initVoxels(NULL, 10.0, &position);
-    std::cout << voxelsMade << " voxels made. \n";
+    voxels.init(50000);
     
     myHead.setRenderYaw(start_yaw);
 
@@ -575,15 +572,7 @@ void display(void)
         if (!display_head) cloud.render();
     
         //  Draw voxels
-        glPushMatrix();
-        glTranslatef(WORLD_SIZE/2.0, WORLD_SIZE/2.0, WORLD_SIZE/2.0);
-        glm::vec3 distance(5.0 + location[0], 5.0 + location[1], 5.0 + location[2]);
-        //std::cout << "length: " << glm::length(distance) << "\n";
-        int voxelsRendered = voxels.render(NULL, 10.0, &distance);
-        voxels.setVoxelsRendered(voxelsRendered);
-        //glColor4f(0,0,1,0.5);
-        //glutSolidCube(10.0);
-        glPopMatrix();
+        voxels.render();
     
         //  Draw field vectors
         if (display_field) field.render();