openGL tutorial 2

draw point

#include <iostream>

// GLEW

#define GLEW_STATIC

#include <GL/glew.h>

// GLFW

#include <GLFW/glfw3.h>

// Window dimensions

const GLuint WIDTH = 800, HEIGHT = 600;

void processInput(GLFWwindow* window);

using namespace std;

void RenderScene();

int main()

{

glfwInit();

glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);

glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);

glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_ANY_PROFILE);

glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

//glfwWindowHint(GLFW_MAXIMIZED, true);

//glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_TRUE);

GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "zi xi", nullptr, nullptr);

//GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "My Title", glfwGetPrimaryMonitor(), NULL);

glfwSetWindowOpacity(window, 0.8f);

glfwMakeContextCurrent(window);

while (!glfwWindowShouldClose(window))

{

// Clear the colorbuffer

glClearColor(1.0f, 0.7f, 1.0f, 1.0f);

glClear(GL_COLOR_BUFFER_BIT);

processInput(window);

RenderScene();

// Swap the screen buffers

glfwSwapBuffers(window);

// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions

glfwPollEvents();

}

// Terminate GLFW, clearing any resources allocated by GLFW.

glfwTerminate();

return EXIT_SUCCESS;

}

void processInput(GLFWwindow* window)

{

if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)

glfwSetWindowShouldClose(window, true);

if (glfwGetKey(window, GLFW_KEY_1) == GLFW_PRESS)

cout << "1" << endl;

}

void RenderScene() {

glPointSize(5);

glColor3f(1, 0, 0);

glBegin(GL_POINTS);

glVertex2f(.25, 0.25);

glVertex2f(.75, .75);

glEnd();

}

draw line

void RenderScene() {

glLineWidth(2);

glColor3f(1, 1, 0);

glBegin(GL_LINES);

glVertex2f(.25, 0.25);

glVertex2f(.75, .75);

glEnd();

}

Draw line strip

void RenderScene() {

glLineWidth(2);

glColor3f(1, 1, 0);

glBegin(GL_LINE_STRIP);

glVertex2f(.25, 0.25);

glVertex2f(.75, .75);

//glVertex2f(.75, .75);

glVertex2f(0.9, 0.5);

//glVertex2f(0.9, 0.5);

glVertex2f(0.8, 0.3);

glEnd();

}

Draw GL_LINE_LOOP

void RenderScene() {

glLineWidth(2);

glColor3f(1, 1, 0);

glBegin(GL_LINE_LOOP);

glVertex2f(.25, 0.25);

glVertex2f(.75, .75);

//glVertex2f(.75, .75);

glVertex2f(0.9, 0.5);

//glVertex2f(0.9, 0.5);

glVertex2f(0.8, 0.3);

glEnd();

}

Draw Triangles

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_TRIANGLES);

glVertex2f(.25, 0.25);

glVertex2f(.75, .75);

glVertex2f(0.9, 0.5);

glColor3f(1, 1, 0);

glVertex2f(-0.3f, -0.3f);

glVertex2f(0.0f, 0.0f);

glVertex2f(0.3f, -0.3f);

glEnd();

}

Draw triangle strip

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_TRIANGLE_STRIP);

glVertex2f(0, 0);

glVertex2f(0.2, 0);

glColor3f(1, 1, 0);

glVertex2f(0.1, 0.1);

glVertex2f(0.3f, 0.1f);

glColor3f(1, 0, 0);

glVertex2f(0.2f, 0.2f);

glVertex2f(0.4f, 0.2f);

glEnd();

}

draw triangle fan

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_TRIANGLE_FAN);

glVertex2f(0, 0);

glVertex2f(0.1, -0.1);

glVertex2f(0.2, 0);

glVertex2f(0.1f, 0.1f);

glVertex2f(-0.1f, 0.1f);

glVertex2f(-0.2f, 0.0f);

glVertex2f(-0.1f, -0.1f);

glEnd();

}

draw Quad

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_QUADS);

glVertex2f(0, 0);

glVertex2f(0.2, 0.0f);

glVertex2f(0.2, 0.2);

glVertex2f(0.0f, 0.2f);

glEnd();

}

slanted quad

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_QUADS);

glVertex2f(0, 0);

glVertex2f(0.2, 0.0f);

glVertex2f(0.3, 0.2);

glVertex2f(0.1f, 0.2f);

glEnd();

}

draw polygon

void RenderScene() {

glColor3f(1, 0, 0);

glBegin(GL_POLYGON);

glVertex2f(0, 0);

glVertex2f(0.1, 0.0f);

glVertex2f(0.2, 0.1);

glVertex2f(0.1f, 0.2f);

glVertex2f(0, 0.2);

glVertex2f(-0.1f, 0.1f);

glEnd();

}