Graphics_02.cpp

#include<iostream>

//GLEW
#define GLEW_STATIC
#include<GL/glew.h>

//GLFW
#include<GLFW/glfw3.h>

#include "Shader.h"

//SOIL2
#include "SOIL2/SOIL2.h"
#include "SOIL2/stb_image.h"

const GLint WIDTH = 800, HEIGHT = 600;

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

	GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LEARN OPENGL B19030313", nullptr, nullptr);
	// next two lines are for mac retina display
	int screenWidth, screenHeight;
	glfwGetFramebufferSize(window, &screenWidth, &screenHeight);

	if (nullptr == window) {
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	glewExperimental = GL_TRUE;

	if (GLEW_OK != glewInit()) {
		std::cout << "Failed to initialize GLEW" << std::endl;
		return -1;
	}

	Shader ourShader = Shader("res/shaders/core2.vs", "res/shaders/core2.fs");

	// now the vertex information comes below
	GLfloat vertices[] = {
		// position           //color          // texture coords
		0.5f,0.5f,0.0f,       1.0f,0.0f,0.0f,  1.0f,1.0f,   //top right
		0.5f,-0.5f,0.0f,      1.0f,0.0f,0.0f,  1.0f,0.0f,   //bottom right
		-0.5f,-0.5f,0.0f,     1.0f,0.0f,0.0f,  0.0f,0.0f,   //bottom left
		-0.5f,0.5f,0.0f,      1.0f,0.0f,0.0f,  0.0f,1.0f    //top left
	};

	unsigned int indices[] = {
		0,1,3,
		1,2,3
	};

	// the data should be transfered to the memory on Graphics Card
	GLuint VAO, VBO;
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	// connect the VAO and VBO
	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	// transfer the data
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
	// set the attribute
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
	glEnableVertexAttribArray(2);

	GLuint EBO;
	glGenBuffers(1, &EBO);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindVertexArray(0);

	int width, height;
	GLuint texture0;
	glGenTextures(1, &texture0);
	glBindTexture(GL_TEXTURE_2D, texture0);
	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_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);

	unsigned char* image_01 = SOIL_load_image("res/images/01.jpg", &width, &height, 0, SOIL_LOAD_RGBA);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image_01);
	glGenerateMipmap(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, 0);

	GLuint texture1;
	glGenTextures(1, &texture1);
	glBindTexture(GL_TEXTURE_2D, texture1);
	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_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

	unsigned char* image_02 = SOIL_load_image("res/images/02.jpg", &width, &height, 0, SOIL_LOAD_RGBA);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image_02);
	glGenerateMipmap(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, 0);


	while (!glfwWindowShouldClose(window))
	{
		float time = glfwGetTime();
		float value = sin(time) / 2.0f + 0.5f;
		glViewport(0, 0, screenWidth, screenHeight);
		glfwPollEvents();
		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);
		ourShader.Use();
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, texture0);
		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, texture1);
		glUniform1i(glGetUniformLocation(ourShader.Program, "texture0"), 0);
		glUniform1i(glGetUniformLocation(ourShader.Program, "texture1"), 1);
		glUniform1f(glGetUniformLocation(ourShader.Program, "value"),value);	// ÕÒµ½valueµÄË÷Òý
		glBindVertexArray(VAO);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
		glBindVertexArray(0);
		glBindTexture(GL_TEXTURE_2D, 0);
		glfwSwapBuffers(window);
	}

	glfwTerminate();
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glDeleteBuffers(1, &EBO);
	glDeleteTextures(1, &texture0);
	glDeleteTextures(1, &texture1);
	return 0;
}