记录一下GLFW的2D贴图

//
//  New.c
//  Gmaedemo
//
//

#include 
#include 
#include 
#include "SOIL.h"

#define TITLE "Test"
#define WIDTH 1024
#define HEIGHT 768
GLFWwindow* window;
#define UPDATE_INTERVAL 1       /* 10ms */

GLuint texture[5];
GLuint texture1;



GLuint Loadbmpfile(const char* Image)
{
    GLuint Tex;
    printf("Reading image %s\n", Image);
    FILE* img = NULL;
    img = fopen(Image,"rb");
    
    unsigned long bWidth = 0;
    unsigned long bHeight = 0;
    unsigned int size = 0;
    
    fseek(img,18,SEEK_SET);
    fread(&bWidth,4,1,img);
    fread(&bHeight,4,1,img);
    fseek(img,0,SEEK_END);
    size = ftell(img) - 54;
    
    unsigned char *data = (unsigned char*)malloc(size);
    
    fseek(img,54,SEEK_SET);    // image data
    fread(data,size,1,img);
    fclose(img);
    
    
    glGenTextures(1, &Tex);
    glBindTexture(GL_TEXTURE_2D, Tex);
    gluBuild2DMipmaps(GL_TEXTURE_2D, 3, bWidth, bHeight, GL_BGR_EXT, GL_UNSIGNED_BYTE, data);
    //glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bWidth, bHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    
    if (data)
        free(data);
    return Tex;
}

//取时间
static uint32_t _gettime(void) {
    uint32_t t;
    struct timeval tv;
    gettimeofday(&tv, NULL);
    t = (uint32_t)(tv.tv_sec & 0xffffff) * 100;
    t += tv.tv_usec / 10000;
    return t;
}

//取按键
static void _glfw_key_cb(GLFWwindow* window, int key, int scancode, int action, int mods) {
    if(key == GLFW_KEY_Q && action == GLFW_PRESS) {
        glfwSetWindowShouldClose(window, GL_TRUE);
    }
}

void init(){
    if (glfwInit() != GL_TRUE){
        printf("Unable to initialize GLFW");
    }
    glfwDefaultWindowHints();
    glfwWindowHint(GLFW_VISIBLE, GL_FALSE); // the window will stay hidden after creation
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE); // the window will be resizable
    window = glfwCreateWindow(WIDTH, HEIGHT, TITLE, NULL, NULL);
    if (window == NULL) {
        glfwTerminate();
        printf("Failed to create the GLFW window");
    }
    glfwSetKeyCallback(window,_glfw_key_cb);
    
    glfwMakeContextCurrent(window);
    // Enable v-sync
    glfwSwapInterval(1);
    
    // Make the window visible
    glfwShowWindow(window);

}
//显示图片
void drawTex2D(GLuint textureId, int x, int y, int width, int height) {
    glTranslatef(x, y, 0);
    glBindTexture(GL_TEXTURE_2D, textureId);
    glBegin(GL_QUADS);
    glTexCoord2f(0, 0);
    glVertex2f(0, 0);
    glTexCoord2f(1, 0);
    glVertex2f(width, 0);
    glTexCoord2f(1, 1);
    glVertex2f(width, height);
    glTexCoord2f(0, 1);
    glVertex2f(0, height);
    glEnd();
    glBindTexture(GL_TEXTURE_2D, 0);
    glLoadIdentity();
}


void update(){
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer
    
    for(int si=0;si<=5;si++){
        drawTex2D(texture[si], 470+(si)*48, 0, 48, 160);
    }
   drawTex2D(texture1, 0, 0, 470, 436);
    glFlush();
}


void setupgl(){
    // 操作投影矩阵
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity(); // 复位
    // 将坐标系置为左上角(0,0)，右下角(width,height)
    glOrtho(0, WIDTH, HEIGHT, 0, 1, -1);
    // 操作模型矩阵
    glMatrixMode(GL_MODELVIEW);
    // 开启2D纹理支持
    glEnable(GL_TEXTURE_2D);
    // 开启混合渲染
    glEnable(GL_BLEND);
}


void settex(){
    for(int i=0;i<=5;i++){
        texture[i] = Loadbmpfile("2.bmp");
    }
    texture1 = Loadbmpfile("uvtemplate.bmp");
}



void loop(){
    glViewport(0, 0, WIDTH*2, HEIGHT*2);
    uint32_t timestamp = 0;
    glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
    while (glfwWindowShouldClose(window) == GL_FALSE) {
        uint32_t current = _gettime();
        if(current - timestamp >= UPDATE_INTERVAL) {
            timestamp = current;
            update();
            
            GLenum error = glGetError();
            if(error != GL_NO_ERROR)
                printf("error: %d\n",error);
            
        }
        
        glfwSwapBuffers(window); // swap the color buffers
        
        // Poll for window events. The key callback above will only be
        // invoked during this call.
        glfwPollEvents();
    }
    glfwDestroyWindow(window);
    glfwTerminate();
}
int main(){
    init();
    setupgl();
    settex();
    loop();
    return 0;
}