libpng的PNG圖片讀取

libpng的PNG圖片讀取，該程序只支持RGBA方案的PNG圖片不支持PNG其他方案特性
#include <stdio.h>
#include <stdlib.h>
#include <GL\glew.h>
#include <GL\glut.h>
#include "png.h"

#pragma comment(lib, "glew32.lib")

int window_width=600;
int window_height=600;

int pic_width;
int pic_height;
int size;

GLuint texName;
unsigned char *content;

void init()
{
    glewInit();

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glGenTextures(1, &texName);
    glBindTexture(GL_TEXTURE_2D, texName);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, pic_width, pic_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, content);
}

void display_func()
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0, 1.0f, 0.0, 1.0f);

    glViewport(0, 0, window_width, window_height);
    glClearColor(1.0f, 1.0f, 1.0f, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    glEnable(GL_TEXTURE_2D);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    glBindTexture(GL_TEXTURE_2D, texName);

    glBegin(GL_QUADS);
        glTexCoord2f(0.0f, 1.0f); glVertex2f(0.0f, 0.0f);
        glTexCoord2f(1.0f, 1.0f); glVertex2f(1.0f, 0.0f);
        glTexCoord2f(1.0f, 0.0f); glVertex2f(1.0f, 1.0f);
        glTexCoord2f(0.0f, 0.0f); glVertex2f(0.0f, 1.0f);
    glEnd();
    glutSwapBuffers();
}

void reshape_func(int width, int height)
{
    window_width=width;
    window_height=height;
    glutReshapeWindow(window_width, window_height);
}

int main(int argc, char **argv)
{
    FILE* file = fopen("wiki.png", "rb");
    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
    png_infop info_ptr = png_create_info_struct(png_ptr);
    setjmp(png_jmpbuf(png_ptr));
    png_init_io(png_ptr, file);
    png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_EXPAND, 0);

    pic_width = png_get_image_width(png_ptr, info_ptr);
    pic_height = png_get_image_height(png_ptr, info_ptr);
    int color_type = png_get_color_type(png_ptr, info_ptr);

    size = pic_height * pic_width * 4;
    int pos = 0;
    content=(unsigned char *)malloc(sizeof(unsigned char)*size);

    png_bytep* row_pointers = png_get_rows(png_ptr, info_ptr);

    for(int i=0; i
    {
        for(int j=0; j
        {
            content[i*pic_width*4+j*4+0]=row_pointers[i][j*4+0];
            content[i*pic_width*4+j*4+1]=row_pointers[i][j*4+1];
            content[i*pic_width*4+j*4+2]=row_pointers[i][j*4+2];
            content[i*pic_width*4+j*4+3]=row_pointers[i][j*4+3];
        }
    }

    png_destroy_read_struct(&png_ptr, &info_ptr, 0);
    fclose(file);

    window_width=pic_width;
    window_height=pic_height;

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
    glutInitWindowSize(window_width, window_height);
    glutCreateWindow("Picture");

    init();

    glutDisplayFunc(display_func);
    glutReshapeFunc(reshape_func);

    glutMainLoop();

    free(content);

    return 0;
}

顯示結果

libpng 的詳細介紹：請點這裡
libpng 的下載地址：請點這裡