opengl 绘制简单的带纹理贴图的立方体

#include <gl/glew.h>
#include <glfw/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>

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

using namespace std;

int main()
{
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

	GLFWwindow *window = glfwCreateWindow(800, 600, "opengl", nullptr, nullptr);

	if (window == NULL)
	{
		cerr << "Failed to create window" << endl;
		glfwTerminate();
		exit(-1);
	}
	glfwMakeContextCurrent(window);

	glewExperimental = GL_TRUE;
	GLenum err = glewInit();
	if (err != GLEW_OK)
	{
		cerr << "Failed to init glew : " << glewGetErrorString(err) << endl;
		exit(-1);
	}

	GLfloat vertices[] = {
		-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
		0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
		0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
		0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
		-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
		-0.5f, -0.5f, -0.5f, 0.0f, 0.0f,

		-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
		0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
		0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
		0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
		-0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
		-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,

		-0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
		-0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
		-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
		-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
		-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
		-0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

		0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
		0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
		0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
		0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
		0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
		0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

		-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
		0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
		0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
		0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
		-0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
		-0.5f, -0.5f, -0.5f, 0.0f, 1.0f,

		-0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
		0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
		0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
		0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
		-0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
		-0.5f, 0.5f, -0.5f, 0.0f, 1.0f
	};

	GLuint vao, vbo;
	GLuint texture;

	glEnable(GL_DEPTH_TEST);
	ourProgram our("vershader.txt", "fragshader.txt");
	GLuint program = our.getProgram();

	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);

	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	GLuint pos_loc = glGetAttribLocation(program, "vposition");
	glVertexAttribPointer(pos_loc, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void *)0);
	glEnableVertexAttribArray(pos_loc);

	GLuint text_loc = glGetAttribLocation(program, "vtex_coord");
	glVertexAttribPointer(text_loc, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void *)(3 * sizeof(GLfloat)));
	glEnableVertexAttribArray(text_loc);

	glBindVertexArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, 0);

	glGenTextures(1, &texture);
	glBindTexture(GL_TEXTURE_2D, texture);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

	int width, height;
	unsigned char *image = SOIL_load_image("wall.jpg", &width, &height, 0, SOIL_LOAD_RGB);

	if (image == NULL)
	{
		cerr << "Failed to load image" << endl;
		exit(-2);
	}

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
	glGenerateMipmap(GL_TEXTURE_2D);

	SOIL_free_image_data(image);
	glBindTexture(GL_TEXTURE_2D, 0);

	GLuint projection_loc = glGetUniformLocation(program, "projection_matrix");
	GLuint view_loc = glGetUniformLocation(program, "view_matrix");
	GLuint model_loc = glGetUniformLocation(program, "model_matrix");

	glm::mat4 model, view, projection;
	model = glm::rotate(model, glm::radians(45.0f), glm::vec3(0.0f, 1.0f, 0.0f));
	view = glm::lookAt(glm::vec3(0.0f, 0.0f, 2.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
	projection = glm::perspective(glm::radians(45.0f), 800.0f/600.0f, 0.1f, 100.0f);

	glUniformMatrix4fv(projection_loc, 1, GL_FALSE, glm::value_ptr(projection));
	glUniformMatrix4fv(view_loc, 1, GL_FALSE, glm::value_ptr(view));
	glUniformMatrix4fv(model_loc, 1, GL_FALSE, glm::value_ptr(model));

	glViewport(0, 0, 800, 600);

	while (!glfwWindowShouldClose(window))
	{
		glfwPollEvents();
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glBindVertexArray(vao);

		glActiveTexture(GL_TEXTURE0);
		glUniform1i(glGetUniformLocation(program, "texture"), 0);
		glBindTexture(GL_TEXTURE_2D, texture);

		glDrawArrays(GL_TRIANGLES, 0, 36);
		glFlush();
		glfwSwapBuffers(window);
	}

	glfwTerminate();

	return 0;
}