OpenGL 繪圖移動

前言

在上一篇OpenGL 環境搭建基礎上修改main.cpp檔案，完成使用OpenGL圖片繪製和移動效果。

程式碼

詳細程式碼已做註釋：

#include "GLShaderManager.h"
#include "GLTools.h"
#include <GLUT/GLUT.h>

//著色管理器
GLShaderManager shaderManager;

//批次容器
GLBatch quadsBatch;

//矩形座標長度
GLfloat blockSize = 0.1f;

//頂點座標
GLfloat vVerts[] = {
    -blockSize,-blockSize,0.0f,
    blockSize,-blockSize,0.0f,
    blockSize,blockSize,0.0f,
    -blockSize,blockSize,0.0f
};

//視窗大小修改回撥
void changeSize(int w, int h) {
    glViewport(0, 0, w, h);
}

//區域渲染
void renderScene(void) {
    //清除一個快取區
    glClear(GL_COLOR_BUFFER_BIT);
    
    GLfloat vBlue[] = {0.0,0.0,1.0,1.0f};
    //使用著色器渲染
    shaderManager.UseStockShader(GLT_SHADER_IDENTITY,vBlue);
    quadsBatch.Draw();
    //後臺緩衝區渲染完畢後交給前臺顯示
    glutSwapBuffers();
    
}

//初始化
void setupRC() {
    glClearColor(0.5f, 0.5f, 0.5f, 0.5f);
    shaderManager.InitializeStockShaders();
    quadsBatch.Begin(GL_QUADS, 4);
    quadsBatch.CopyVertexData3f(vVerts);
    quadsBatch.End();
}

//處理鍵盤控制圖形移動
void specialKeys(int key, int x, int y) {
    
    GLfloat stepSize = 0.01f;
    
    GLfloat blockX = vVerts[0];
    GLfloat blockY = 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;
    }
    
    if (blockX < -1.0f) {
        blockX = -1.0f;
    }
    
    if (blockX > (1.0 - blockSize * 2)) {
        blockX = 1.0f - blockSize * 2;
    }
    
    if (blockY < -1.0f + blockSize * 2 ) {
        
        blockY = -1.0f + blockSize * 2;
    }
    
    if (blockY > 1.0f) {
        
        blockY = 1.0f;
        
    }
    
    //處理頂點
    vVerts[0] = blockX;
    vVerts[1] = blockY - blockSize*2;
    
    vVerts[3] = blockX + blockSize*2;
    vVerts[4] = blockY - blockSize*2;
    
    vVerts[6] = blockX + blockSize*2;
    vVerts[7] = blockY;
    
    vVerts[9] = blockX;
    vVerts[10] = blockY;
    
    quadsBatch.CopyVertexData3f(vVerts);
    glutPostRedisplay();
}


int main(int argc, char *argv[]) {
    //設定工作目錄
    gltSetWorkingDirectory(argv[0]);
    //初始化glut庫
    glutInit(&argc, argv);
    //初始化一個雙緩衝區，離屏區渲染，視窗區顯示
    glutInitDisplayMode(GLUT_DOUBLE);
    glutInitWindowSize(600, 600);
    glutCreateWindow("dowZhange");
    
    //註冊重塑函式
    glutReshapeFunc(changeSize);
    //註冊顯示函式
    glutDisplayFunc(renderScene);
    
    glutSpecialFunc(specialKeys);
    
    //用於檢查OpenGL API對程式可用
    GLenum status = glewInit();
    
    if (GLEW_OK != status) {
        return 1;
    }
    
    setupRC();
    glutMainLoop();
    
    return 0;
}

複製程式碼