OpenGL代码学习（2）

#include "GLShaderManager.h"//着色管理器类
#include "GLTools.h"//包含了大部分GLTool中类似C语言的独立函数
#include <GLUT/GLUT.h>//在Mac系统下使用GLUT，在Window或Linux上使用的是freeglut的静态库

GLShaderManager shaderManager;//定义一个着色管理器
GLBatch triangleBatch;//简单的批次容器，是GLTools的一个简单的容器类

GLfloat blockSize = 0.2f;//边长

GLfloat vVerts[] = {
    -blockSize/2, -blockSize/2, 0.f,
    blockSize/2, -blockSize/2, 0.f,
    blockSize/2, blockSize/2, 0.f,
    -blockSize/2, blockSize/2, 0.f
};//正方形的4个点坐标

void changeSize(int w, int h) {
    glViewport(0, 0, w, h);
    
    printf("w:%d   h:%d\n", w, h);
    
//    glMatrixMode (GL_PROJECTION);
//    glLoadIdentity ( );
//    gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
//    glClear (GL_COLOR_BUFFER_BIT);
};

void RenderScene(void) {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
    GLfloat vRed[] = {1.f, 0.f, 0.f, 1.f};
    shaderManager.UseStockShader(GLT_SHADER_IDENTITY, vRed);
    triangleBatch.Draw();
    glutSwapBuffers();
};

void setupRC(void) {
    glClearColor(0.98f, 0.40f, 0.70f, 1);
    shaderManager.InitializeStockShaders();
    triangleBatch.Begin(GL_TRIANGLE_FAN, 4);
    triangleBatch.CopyVertexData3f(vVerts);
    triangleBatch.End();
}

void SpecialKeys(int key, int x, int y) {
    GLfloat stepSize = 0.025f;
    GLfloat blockX = vVerts[0];
    GLfloat blockY = vVerts[10];
    
    printf("v[0] = %f\n", vVerts[0]);
    printf("v[10] = %f\n", vVerts[10]);
    
    if (key == GLUT_KEY_UP) {
        blockY += stepSize;
    }
    if (key == GLUT_KEY_DOWN) {
        blockY -= stepSize;
    }
    if (key == GLUT_KEY_LEFT) {
        blockX -= stepSize;
    }
    if (key == GLUT_KEY_RIGHT) {
        blockX += stepSize;
    }
    
    // 触碰到边界的处理
    if (blockX < -1.f) {
        blockX = -1.f;
    }
    if (blockX > (1.f - blockSize)) {
        blockX = 1.f - blockSize;
    }
    if (blockY < (-1.f + blockSize)) {
        blockY = -1.f + blockSize;
    }
    if (blockY > 1.f) {
        blockY = 1.f;
    }
    
    vVerts[0] = blockX;
    vVerts[1] = blockY - blockSize;
    
    vVerts[3] = blockX + blockSize;
    vVerts[4] = blockY - blockSize;
    
    vVerts[6] = blockX + blockSize;
    vVerts[7] = blockY;
    
    vVerts[9] = blockX;
    vVerts[10] = blockY;
    
    triangleBatch.CopyVertexData3f(vVerts);
    glutPostRedisplay();
}

int main(int argc, char * argv[]) {
    
    gltSetWorkingDirectory(argv[0]);
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL);
    glutInitWindowSize(800, 700);
    //glutInitWindowSize(800, 720);
    glutCreateWindow("OpenGL测试");
    
    glutReshapeFunc(changeSize);
    glutDisplayFunc(RenderScene);
    glutSpecialFunc(SpecialKeys);
    
    GLenum status = glewInit();
    if (GLEW_OK != status) {
        printf("GLEW Error:%s\n", glewGetErrorString(status));
        return 1;
    }
    
    // 设置渲染环境
    setupRC();
    
    glutMainLoop();
    
    return 0;
}