这节简单实现对三角形的彩色着色，顺便通过vertex shader实现图形的移动，然后是简单的贴图
从上一节可以看到，Shader是流程线中必不可少的部分，单独分离出来方便后面使用
别的也没什么，彩色写在了顶点数据中(可以相像为点着色)
实现移动主要利用uniform变量(可以看作是cpu与gpu之间共享的全局变量)
贴图主要在fragment shader中对纹理按坐标采样就好
https://github.com/WendyAndAndy/OpenGL
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "shader.h"
#include <filesystem.h>
using namespace std;
const unsigned int WIDTH = 800;
const unsigned int HEIGHT = 600;
void framebuffer_size_callback(GLFWwindow*, int, int);
void processInput(GLFWwindow*);
const float vertices[] = {
.5f, -.5f, 0.0f, 1.0f, 0.0f, 0.0f, //bottom right, red
-.5f,-.5f, 0.0f, 0.0f, 1.0f, 0.0f, //bottom left, green
0.0f, .5f, 0.0f, 0.0f, 0.0f, 1.0f //top middle, blue
};
Shader shader;
float xPos = 0.0f; //for vertex-shader move the triangle
float yPos = 0.0f; //for vertex-shader move the triangle
int main()
{
/*cout << "003 hello shader" << endl;
getchar();*/
glfwInit();
glfwWindowHint(GLFW_SAMPLES, 8);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, u8"你好, Shader(WSAD move..)", NULL, NULL);
if (window == NULL)
{
cout << "Failed to create GLFW window\n";
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
cout << "Failed to initialize GLAD\n";
}
shader = Shader(FileSystem::getPath("shaders/002_shader.vs").c_str(), FileSystem::getPath("shaders/002_shader.fs").c_str());
unsigned int VAO, VBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
//position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
//color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
while (!glfwWindowShouldClose(window))
{
processInput(window);
//glClearColor(.2, .3, .3, 1);
glClear(GL_COLOR_BUFFER_BIT);
shader.use();
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
void framebuffer_size_callback(GLFWwindow* window, int w, int h)
{
glViewport(0, 0, w, h);
}
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
{
glfwSetWindowShouldClose(window, true);
}
if (glfwGetKey(window, GLFW_KEY_F3) == GLFW_PRESS)
{
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
cout << "F3 -> wireframe mode" << endl;
}
if (glfwGetKey(window, GLFW_KEY_F4) == GLFW_PRESS)
{
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
cout << "F4 -> polygon mode" << endl;
}
const float SPEED = 0.001f;
//Move Left
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
{
xPos -= SPEED;
shader.setFloat("xPos", xPos);
cout << "pressed A key, xPos = " << xPos << endl;
}
//Move Right
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
{
xPos += SPEED;
shader.setFloat("xPos", xPos);
cout << "pressed D key, xPos = " << xPos << endl;
}
//Move Up
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
{
yPos += SPEED;
shader.setFloat("yPos", yPos);
cout << "pressed W key, yPos = " << yPos << endl;
}
//Move Down
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
{
yPos -= SPEED;
shader.setFloat("yPos", yPos);
cout << "pressed S key, yPos = " << yPos << endl;
}
}