OpenGL学习（五） 几何图形

// GeoTest.cpp// OpenGL SuperBible// Demonstrates OpenGL Backface culling, depth testing, and polygon mode// Program by Richard S. Wright Jr.#include <GLTools.h>// OpenGL toolkit#include <GLMatrixStack.h>#include <GLFrame.h>#include <GLFrustum.h>#include <GLGeometryTransform.h>#include <math.h>#ifdef __APPLE__#include <glut/glut.h>#else#define FREEGLUT_STATIC#include <GL/glut.h>#endifGLFrame             viewFrame;GLFrustum           viewFrustum;GLTriangleBatch     torusBatch;GLMatrixStack       modelViewMatix;GLMatrixStack       projectionMatrix;GLGeometryTransform transformPipeline;GLShaderManager     shaderManager;// Flags for effectsint iCull = 0;int iDepth = 0;///////////////////////////////////////////////////////////////////////////////// Reset flags as appropriate in response to menu selectionsvoid ProcessMenu(int value){switch(value){case 1:iDepth = !iDepth;break;case 2:iCull = !iCull;break;        case 3:            glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);            break;        case 4:            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);            break;                        case 5:            glPolygonMode(GL_FRONT_AND_BACK, GL_POINT);            break;}glutPostRedisplay();}// Called to draw scenevoid RenderScene(void){// Clear the window and the depth bufferglClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);// Turn culling on if flag is setif(iCull)glEnable(GL_CULL_FACE);elseglDisable(GL_CULL_FACE);// Enable depth testing if flag is setif(iDepth)glEnable(GL_DEPTH_TEST);elseglDisable(GL_DEPTH_TEST);    modelViewMatix.PushMatrix(viewFrame);                GLfloat vRed[] = { 1.0f, 0.0f, 0.0f, 1.0f };    //shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vRed);    shaderManager.UseStockShader(GLT_SHADER_DEFAULT_LIGHT, transformPipeline.GetModelViewMatrix(), transformPipeline.GetProjectionMatrix(), vRed);        torusBatch.Draw();    modelViewMatix.PopMatrix();    glutSwapBuffers();}// This function does any needed initialization on the rendering// context. void SetupRC(){// Black backgroundglClearColor(0.3f, 0.3f, 0.3f, 1.0f );    shaderManager.InitializeStockShaders();    viewFrame.MoveForward(7.0f);    // Make the torus    gltMakeTorus(torusBatch, 1.0f, 0.3f, 52, 26);    glPointSize(4.0f);}void SpecialKeys(int key, int x, int y){if(key == GLUT_KEY_UP)viewFrame.RotateWorld(m3dDegToRad(-5.0), 1.0f, 0.0f, 0.0f);if(key == GLUT_KEY_DOWN)viewFrame.RotateWorld(m3dDegToRad(5.0), 1.0f, 0.0f, 0.0f);        if(key == GLUT_KEY_LEFT)viewFrame.RotateWorld(m3dDegToRad(-5.0), 0.0f, 1.0f, 0.0f);        if(key == GLUT_KEY_RIGHT)viewFrame.RotateWorld(m3dDegToRad(5.0), 0.0f, 1.0f, 0.0f);// Refresh the WindowglutPostRedisplay();}void ChangeSize(int w, int h){// Prevent a divide by zeroif(h == 0)h = 1;// Set Viewport to window dimensions    glViewport(0, 0, w, h);    viewFrustum.SetPerspective(35.0f, float(w)/float(h), 1.0f, 100.0f);        projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());    transformPipeline.SetMatrixStacks(modelViewMatix, projectionMatrix);}///////////////////////////////////////////////////////////////////////////////// Main entry point for GLUT based programsint main(int argc, char* argv[])    {gltSetWorkingDirectory(argv[0]);glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);glutInitWindowSize(800, 600);glutCreateWindow("Geometry Test Program");    glutReshapeFunc(ChangeSize);    glutSpecialFunc(SpecialKeys);    glutDisplayFunc(RenderScene);    // Create the Menu    glutCreateMenu(ProcessMenu);    glutAddMenuEntry("Toggle depth test",1);    glutAddMenuEntry("Toggle cull backface",2);    glutAddMenuEntry("Set Fill Mode", 3);    glutAddMenuEntry("Set Line Mode", 4);    glutAddMenuEntry("Set Point Mode", 5);        glutAttachMenu(GLUT_RIGHT_BUTTON);            GLenum err = glewInit();if (GLEW_OK != err) {fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));return 1;    }SetupRC();    glutMainLoop();return 0;    }