OpenGL学习（七） 矩阵学习

// ModelviewProjection.cpp// OpenGL SuperBible// Demonstrates OpenGL the ModelviewProjection matrix// Program by Richard S. Wright Jr.#include <GLTools.h>// OpenGL toolkit#include <GLMatrixStack.h>#include <GLFrame.h>#include <GLFrustum.h>#include <GLGeometryTransform.h>#include <GLBatch.h>#include <StopWatch.h>#include <math.h>#ifdef __APPLE__#include <glut/glut.h>#else#define FREEGLUT_STATIC#include <GL/glut.h>#endif// Global view frustum classGLFrustum           viewFrustum;// The shader managerGLShaderManager     shaderManager;// The torusGLTriangleBatch     torusBatch;// Set up the viewport and the projection matrixvoid 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, 1000.0f);    }// Called to draw scenevoid RenderScene(void){    // Set up time based animation    static CStopWatch rotTimer;    float yRot = rotTimer.GetElapsedSeconds() * 60.0f;    // Clear the window and the depth bufferglClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);    // Matrix Variables    M3DMatrix44f mTranslate, mRotate, mModelview, mModelViewProjection;        // Create a translation matrix to move the torus back and into sight    m3dTranslationMatrix44(mTranslate, 0.0f, 0.0f, -2.5f);        // Create a rotation matrix based on the current value of yRot    m3dRotationMatrix44(mRotate, m3dDegToRad(yRot), 0.0f, 1.0f, 0.0f);        // Add the rotation to the translation, store the result in mModelView    m3dMatrixMultiply44(mModelview, mTranslate, mRotate);        // Add the modelview matrix to the projection matrix,     // the final matrix is the ModelViewProjection matrix.    m3dMatrixMultiply44(mModelViewProjection, viewFrustum.GetProjectionMatrix(),mModelview);    // Pass this completed matrix to the shader, and render the torus    GLfloat vBlack[] = { 0.0f, 0.0f, 0.0f, 1.0f };    shaderManager.UseStockShader(GLT_SHADER_FLAT, mModelViewProjection, vBlack);      torusBatch.Draw();    // Swap buffers, and immediately refresh    glutSwapBuffers();    glutPostRedisplay();}// This function does any needed initialization on the rendering// context. void SetupRC(){// Black backgroundglClearColor(0.8f, 0.8f, 0.8f, 1.0f );    glEnable(GL_DEPTH_TEST);    shaderManager.InitializeStockShaders();      // This makes a torus    gltMakeTorus(torusBatch, 0.4f, 0.15f, 30, 30);    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);}///////////////////////////////////////////////////////////////////////////////// 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("ModelViewProjection Example");    glutReshapeFunc(ChangeSize);    glutDisplayFunc(RenderScene);            GLenum err = glewInit();if (GLEW_OK != err) {fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));return 1;        }SetupRC();    glutMainLoop();return 0;    }