OpenGL 入門——座標變換

#include <iostream>
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "Shader.h"
/*圖像載入數據 翻轉*/
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
using namespace std;


//齊次座標系 【-1，1】Normalized Device Coordinates(NDC)
//Vertex input
//GLfloat vertices[] = {
//	//     ---- 位置 ----       ---- 顏色 ----     - 紋理座標 -
//		 0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f,   // 右上
//		 0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f,   // 右下
//		-0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f,   // 左下
//		-0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f    // 左上
//};

float 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
};

unsigned int indices[] = {  // note that we start from 0! 
	0, 1, 2,   // first triangle
	 2,3, 0    // second triangle
};

glm::vec3 cubePositions[] = {
  glm::vec3(0.0f,  0.0f,  0.0f),
  glm::vec3(2.0f,  5.0f, -15.0f),
  glm::vec3(-1.5f, -2.2f, -2.5f),
  glm::vec3(-3.8f, -2.0f, -12.3f),
  glm::vec3(2.4f, -0.4f, -3.5f),
  glm::vec3(-1.7f,  3.0f, -7.5f),
  glm::vec3(1.3f, -2.0f, -2.5f),
  glm::vec3(1.5f,  2.0f, -2.5f),
  glm::vec3(1.5f,  0.2f, -1.5f),
  glm::vec3(-1.3f,  1.0f, -1.5f)
};

void processInput(GLFWwindow* window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		glfwSetWindowShouldClose(window, true);
}

int main(int argc, char* argv[])
{

	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);

	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

	GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", nullptr, nullptr);
	if (window == nullptr)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return EXIT_FAILURE;
	}
	glfwMakeContextCurrent(window);

	//////==========================
	glewExperimental = GL_TRUE;
	if (glewInit() != GLEW_OK)
	{
		std::cout << "Failed to initialize GLEW" << std::endl;
		return EXIT_FAILURE;
	}

	int width, height;
	glfwGetFramebufferSize(window, &width, &height);
	glViewport(0, 0, width, height);
	//線框模式(Wireframe Mode)
	//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); 
	////三角形默認逆時針繪製--背面剔除
	//glEnable(GL_CULL_FACE);
	//glCullFace(GL_BACK);
	glEnable(GL_DEPTH_TEST);

	Shader* myShader = new Shader("vertexSource.txt", "fragmentSource.txt");


	//VAO Vertex Array Object
	 // 1. bind Vertex Array Object 綁定頂點數組對象
	unsigned int VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);

	// vertex buffer objects (VBO)   can store a large number of vertices in the GPU's memory.
	// 2. copy our vertices array in a buffer for OpenGL to use
	unsigned int VBO;
	glGenBuffers(1, &VBO);  //產生一個bufferID 
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	//3.copy our index array in a element buffer for OpenGL to use
	unsigned int EBO;
	glGenBuffers(1, &EBO);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

	// 4. then set our vertex attributes pointers
	// 位置屬性
	glVertexAttribPointer(6, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)0);
	glEnableVertexAttribArray(6);
	//// 顏色屬性
	//glVertexAttribPointer(7, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
	//glEnableVertexAttribArray(7);
	// 紋理屬性
	glVertexAttribPointer(8, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
	glEnableVertexAttribArray(8);

	unsigned int TexBufferA;
	glGenTextures(1, &TexBufferA);
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, TexBufferA);
	// set the texture wrapping/filtering options (on the currently bound texture object)
	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_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	// load and generate the texture
	int widthT, heightT, nrChannelsT;
	unsigned char* data = stbi_load("container.jpg", &widthT, &heightT, &nrChannelsT, 0);
	if (data)
	{
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, widthT, heightT, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);  //多級漸遠紋理
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}
	stbi_image_free(data);


	unsigned int TexBufferB;
	glGenTextures(1, &TexBufferB);
	glActiveTexture(GL_TEXTURE3);
	glBindTexture(GL_TEXTURE_2D, TexBufferB);
	stbi_set_flip_vertically_on_load(true);
	unsigned char* data2 = stbi_load("awesomeface.png", &widthT, &heightT, &nrChannelsT, 0);
	if (data2)
	{
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, widthT, heightT, 0, GL_RGBA, GL_UNSIGNED_BYTE, data2);
		glGenerateMipmap(GL_TEXTURE_2D);  //多級漸遠紋理
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}
	stbi_image_free(data2);

	//變換矩陣  先進行縮放操作，然後是旋轉，最後纔是位移  
	//矩陣相乘是右邊乘，從右往左讀
	glm::mat4 trans = glm::mat4(1.0f);
    //trans = glm::translate(trans, glm::vec3(-0.001f, 0, 0));
	//trans = glm::rotate(trans, glm::radians(90.0f), glm::vec3(0.0, 0.0, 1.0));
    //trans = glm::scale(trans, glm::vec3(0.5, 0.5, 0.5));

	//coordinaite  openGL 右手座標系(z軸向上)
	glm::mat4 modelMat = glm::mat4(1.0f);
	modelMat = glm::rotate(modelMat, glm::radians(-55.0f), glm::vec3(1, 0, 0));
	glm::mat4 viewMat = glm::mat4(1.0f);
	viewMat = glm::translate(viewMat, glm::vec3(0, 0, -3));
	glm::mat4 projMat;
	projMat = glm::perspective(glm::radians(45.0f),800.0f/600.0f , 0.1f, 100.0f);

	while (!glfwWindowShouldClose(window))
	{
		processInput(window);
		glClearColor(0.2, 0.3, 0.3f, 1.0);
		glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

		// 4. draw the object
		myShader->use();

		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, TexBufferA);
		glActiveTexture(GL_TEXTURE3);
		glBindTexture(GL_TEXTURE_2D, TexBufferB);
		glBindVertexArray(VAO);

		/* //設置uniform
		 GLint vertexColorLocation = glGetUniformLocation(myShader->ID, "ourColor");
		 glUseProgram(shaderProgram);
		 glUniform4f(vertexColorLocation, 0.0f, greenValue, 0.0f, 1.0f);*/

		for (int i = 0; i < 10; i++)
		{
			glm::mat4 modelMat = glm::mat4(1.0f);
			modelMat = glm::translate(modelMat, cubePositions[i]);

			glUniform1i(glGetUniformLocation(myShader->ID, "ourTexture"), 0);
			glUniform1i(glGetUniformLocation(myShader->ID, "ourFace"), 3);
			//glUniformMatrix4fv(glGetUniformLocation(myShader->ID, "transform"), 1, GL_FALSE, glm::value_ptr(trans));
			glUniformMatrix4fv(glGetUniformLocation(myShader->ID, "modelMat"), 1, GL_FALSE, glm::value_ptr(modelMat));
			glUniformMatrix4fv(glGetUniformLocation(myShader->ID, "viewMat"), 1, GL_FALSE, glm::value_ptr(viewMat));
			glUniformMatrix4fv(glGetUniformLocation(myShader->ID, "projMat"), 1, GL_FALSE, glm::value_ptr(projMat));

			glDrawArrays(GL_TRIANGLES, 0, 36);
				 
		}

		
		
		//glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

		glfwPollEvents();
		glfwSwapBuffers(window);
	}

	glfwTerminate();
	//std::cin.get();

	return 0;
}




#version 330 core
layout (location = 6) in vec3 aPos;
layout (location = 7) in vec3 aColor;
layout (location = 8) in vec2 aTexCoord;

out vec4 vertexColor; 
out vec2 TexCoord;

//uniform mat4 transform;
uniform mat4 modelMat;
uniform mat4 viewMat;
uniform mat4 projMat;


void main()
{
   //gl_Position =transform * vec4(aPos.x, aPos.y, aPos.z, 1.0);
   gl_Position =projMat *viewMat *modelMat * vec4(aPos.x, aPos.y, aPos.z, 1.0);
   vertexColor=vec4(aColor.x+0.5, aColor.y, aColor.z, 1.0);
   TexCoord = aTexCoord;
}



#version 330 core
in vec4 vertexColor; 
in vec2 TexCoord;
//uniform  vec4 ourColor; 

out vec4 FragColor;  
uniform sampler2D ourTexture;
uniform sampler2D ourFace;

void main()
{
   //FragColor = vertexColor;
   //FragColor = texture(ourTexture, TexCoord) * vertexColor;
   FragColor = mix(texture(ourTexture, TexCoord) , texture(ourFace, TexCoord),0.2);

}