273 lines
9.9 KiB
C++
273 lines
9.9 KiB
C++
#include "PolyVoxCore/BlockVolume.h"
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#include "PolyVoxCore/IndexedSurfacePatch.h"
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#include "PolyVoxCore/SurfaceExtractors.h"
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#include "PolyVoxCore/Utility.h"
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#include <windows.h> // Standard Header For Most Programs
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#ifdef WIN32
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#include "glew/glew.h"
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#else
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#include <gl/gl.h> // The GL Header File
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#endif
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#include <gl/glut.h> // The GL Utility Toolkit (Glut) Header
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#include <iostream>
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//Some namespaces we need
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using namespace std;
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using namespace PolyVox;
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using namespace std;
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//Global variables are easier for demonstration purposes, especially
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//as I'm not sure how/if I can pass variables to the GLUT functions.
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//Global variables are denoted by the 'g_' prefix
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const uint16 g_uVolumeSideLength = 128;
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const uint16 g_uRegionSideLength = 16;
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const uint16 g_uVolumeSideLengthInRegions = g_uVolumeSideLength / g_uRegionSideLength;
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//Creates a volume 128x128x128
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BlockVolume<uint8> g_volData(logBase2(g_uVolumeSideLength));
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//Rather than storing one big mesh, the volume is broken into regions and a mesh is stored for each region
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IndexedSurfacePatch* g_ispRegionSurfaces[g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions];
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GLuint indexBuffers[g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions];
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GLuint vertexBuffers[g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions][g_uVolumeSideLengthInRegions];
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void createSphereInVolume(float fRadius, uint8 uValue)
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{
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//This vector hold the position of the center of the volume
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Vector3DFloat v3dVolCenter(g_volData.getSideLength() / 2, g_volData.getSideLength() / 2, g_volData.getSideLength() / 2);
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//This three-level for loop iterates over every voxel in the volume
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for (int z = 0; z < g_volData.getSideLength(); z++)
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{
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for (int y = 0; y < g_volData.getSideLength(); y++)
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{
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for (int x = 0; x < g_volData.getSideLength(); x++)
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{
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//Store our current position as a vector...
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Vector3DFloat v3dCurrentPos(x,y,z);
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//And compute how far the current position is from the center of the volume
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float fDistToCenter = (v3dCurrentPos - v3dVolCenter).length();
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//If the current voxel is less than 'radius' units from the center
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//then we make it solid, otherwise we make it empty space.
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if(fDistToCenter <= fRadius)
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{
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g_volData.setVoxelAt(x,y,z, uValue);
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}
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else
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{
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g_volData.setVoxelAt(x,y,z, 0);
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}
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}
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}
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}
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}
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void init ( GLvoid ) // Create Some Everyday Functions
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{
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glShadeModel(GL_SMOOTH); // Enable Smooth Shading
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glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background
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glClearDepth(1.0f); // Depth Buffer Setup
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glEnable(GL_DEPTH_TEST); // Enables Depth Testing
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glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do
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glEnable ( GL_COLOR_MATERIAL );
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glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
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}
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void display ( void ) // Create The Display Function
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer
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glLoadIdentity(); // Reset The Current Modelview Matrix
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glTranslatef(-g_uVolumeSideLength/2,-g_uVolumeSideLength/2,-200.0f);
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for(uint16 uRegionZ = 0; uRegionZ < g_uVolumeSideLengthInRegions; ++uRegionZ)
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{
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for(uint16 uRegionY = 0; uRegionY < g_uVolumeSideLengthInRegions; ++uRegionY)
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{
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for(uint16 uRegionX = 0; uRegionX < g_uVolumeSideLengthInRegions; ++uRegionX)
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{
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const vector<uint32>& vecIndices = g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ]->getIndices();
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glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[uRegionX][uRegionY][uRegionZ]);
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glVertexPointer(3, GL_FLOAT, 0, 0);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffers[uRegionX][uRegionY][uRegionZ]);
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glEnableClientState(GL_VERTEX_ARRAY);
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int s = vecIndices.size();
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glDrawElements(GL_TRIANGLE_STRIP, s, GL_UNSIGNED_INT, 0);
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glDisableClientState(GL_VERTEX_ARRAY);
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}
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}
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}
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GLenum errCode;
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const GLubyte *errString;
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if ((errCode = glGetError()) != GL_NO_ERROR)
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{
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errString = gluErrorString(errCode);
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cout << "OpenGL Error: " << errString << endl;
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}
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glutSwapBuffers ( );
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// Swap The Buffers To Not Be Left With A Clear Screen
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}
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void reshape ( int w, int h ) // Create The Reshape Function (the viewport)
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{
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glViewport ( 0, 0, w, h );
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glMatrixMode ( GL_PROJECTION ); // Select The Projection Matrix
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glLoadIdentity ( ); // Reset The Projection Matrix
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if ( h==0 ) // Calculate The Aspect Ratio Of The Window
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gluPerspective ( 80, ( float ) w, 1.0, 5000.0 );
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else
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gluPerspective ( 80, ( float ) w / ( float ) h, 1.0, 5000.0 );
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glMatrixMode ( GL_MODELVIEW ); // Select The Model View Matrix
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glLoadIdentity ( ); // Reset The Model View Matrix
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}
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void keyboard ( unsigned char key, int x, int y ) // Create Keyboard Function
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{
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switch ( key ) {
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case 27: // When Escape Is Pressed...
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exit ( 0 ); // Exit The Program
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break; // Ready For Next Case
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default: // Now Wrap It Up
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break;
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}
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}
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void arrow_keys ( int a_keys, int x, int y ) // Create Special Function (required for arrow keys)
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{
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switch ( a_keys ) {
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case GLUT_KEY_UP: // When Up Arrow Is Pressed...
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glutFullScreen ( ); // Go Into Full Screen Mode
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break;
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case GLUT_KEY_DOWN: // When Down Arrow Is Pressed...
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glutReshapeWindow ( 500, 500 ); // Go Into A 500 By 500 Window
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break;
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default:
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break;
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}
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}
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void main ( int argc, char** argv ) // Create Main Function For Bringing It All Together
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{
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glutInit ( &argc, argv ); // Erm Just Write It =)
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init ();
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glutInitDisplayMode ( GLUT_RGB | GLUT_DOUBLE ); // Display Mode
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glutInitWindowSize ( 500, 500 ); // If glutFullScreen wasn't called this is the window size
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glutCreateWindow ( "PolyVox OpenGL Example" ); // Window Title (argv[0] for current directory as title)
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//glutFullScreen ( ); // Put Into Full Screen
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glutDisplayFunc ( display ); // Matching Earlier Functions To Their Counterparts
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glutReshapeFunc ( reshape );
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glutKeyboardFunc ( keyboard );
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glutSpecialFunc ( arrow_keys );
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#ifdef WIN32
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//If we are on Windows we will need GLEW to access recent OpenGL functionality
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GLenum err = glewInit();
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if (GLEW_OK != err)
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{
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/* Problem: glewInit failed, something is seriously wrong. */
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cout << "Error: " << glewGetErrorString(err) << endl;
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}
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#endif
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//Make our volume contain a sphere in the center.
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createSphereInVolume(50.0f, 1);
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//Our volume is broken down into cuboid regions, and we create one mesh for each region.
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//This three-level for loop iterates over each region.
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for(uint16 uRegionZ = 0; uRegionZ < g_uVolumeSideLengthInRegions; ++uRegionZ)
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{
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for(uint16 uRegionY = 0; uRegionY < g_uVolumeSideLengthInRegions; ++uRegionY)
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{
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for(uint16 uRegionX = 0; uRegionX < g_uVolumeSideLengthInRegions; ++uRegionX)
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{
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//Create a new surface patch (which is basiaclly the PolyVox term for a mesh).
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g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ] = new IndexedSurfacePatch();
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IndexedSurfacePatch* ispCurrent = g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ];
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//Compute the extents of the current region
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//FIXME - This is a little complex? PolyVox could
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//provide more functions for dealing with regions?
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uint16 regionStartX = uRegionX * g_uRegionSideLength;
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uint16 regionStartY = uRegionY * g_uRegionSideLength;
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uint16 regionStartZ = uRegionZ * g_uRegionSideLength;
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uint16 regionEndX = regionStartX + g_uRegionSideLength;
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uint16 regionEndY = regionStartY + g_uRegionSideLength;
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uint16 regionEndZ = regionStartZ + g_uRegionSideLength;
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Vector3DInt32 regLowerCorner(regionStartX, regionStartY, regionStartZ);
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Vector3DInt32 regUpperCorner(regionEndX, regionEndY, regionEndZ);
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//Extract the surface for this region
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extractReferenceSurface(&g_volData, Region(regLowerCorner, regUpperCorner), ispCurrent);
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const vector<SurfaceVertex>& vecVertices = g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ]->getVertices();
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const vector<uint32>& vecIndices = g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ]->getIndices();
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glGenBuffers(1, &(indexBuffers[uRegionX][uRegionY][uRegionZ]));
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffers[uRegionX][uRegionY][uRegionZ]);
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int s = vecIndices.size() * sizeof(GLint);
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if(s != 0)
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{
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GLvoid* blah = (GLvoid*)(&(vecIndices[0]));
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, s, blah, GL_STATIC_DRAW);
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}
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glGenBuffers(1, &(vertexBuffers[uRegionX][uRegionY][uRegionZ]));
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glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[uRegionX][uRegionY][uRegionZ]);
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glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(GLfloat) * 3, 0, GL_STATIC_DRAW);
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GLfloat* ptr = (GLfloat*)glMapBuffer(GL_ARRAY_BUFFER, GL_READ_WRITE);
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for(vector<SurfaceVertex>::const_iterator iterVertex = vecVertices.begin(); iterVertex != vecVertices.end(); ++iterVertex)
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{
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const SurfaceVertex& vertex = *iterVertex;
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const Vector3DFloat& v3dVertexPos = vertex.getPosition();
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const Vector3DFloat v3dRegionOffset(uRegionX * g_uRegionSideLength, uRegionY * g_uRegionSideLength, uRegionZ * g_uRegionSideLength);
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const Vector3DFloat v3dFinalVertexPos = v3dVertexPos + v3dRegionOffset;
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*ptr = v3dFinalVertexPos.getX();
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ptr++;
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*ptr = v3dFinalVertexPos.getY();
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ptr++;
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*ptr = v3dFinalVertexPos.getZ();
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ptr++;
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}
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glUnmapBuffer(GL_ARRAY_BUFFER);
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}
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}
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}
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glutMainLoop ( ); // Initialize The Main Loop
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//Delete all the surface patches we created.
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for(uint16 uRegionZ = 0; uRegionZ < g_uVolumeSideLengthInRegions; ++uRegionZ)
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{
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for(uint16 uRegionY = 0; uRegionY < g_uVolumeSideLengthInRegions; ++uRegionY)
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{
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for(uint16 uRegionX = 0; uRegionX < g_uVolumeSideLengthInRegions; ++uRegionX)
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{
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delete g_ispRegionSurfaces[uRegionX][uRegionY][uRegionZ];
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}
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}
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}
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}
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