Example #1
0
void Shadertoy::loop() {
    GLuint points_vbo;
	glGenBuffers (1, &points_vbo);
	glBindBuffer (GL_ARRAY_BUFFER, points_vbo);
	glBufferData (GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
    
	GLuint vao;
	glGenVertexArrays (1, &vao);
	glBindVertexArray (vao);
	glBindBuffer (GL_ARRAY_BUFFER, points_vbo);
	glVertexAttribPointer (0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
    
    if (!loadFromFile()) {
        compileShaders(vertexSource, fragmentSource);
    }
    
    auto pos = glGetAttribLocation(program, "position");
    glEnableVertexAttribArray (pos);
    
    auto time = glGetUniformLocation(program, "global_time");
    auto resolution = glGetUniformLocation(program, "resolution");
    
    glUseProgram(program);
    
    while (!glfwWindowShouldClose(win)) {
        glfwGetWindowSize(win, &g_width, &g_heigth);
        updateFpsCounter();
        
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glViewport(0, 0, g_width, g_heigth);
        
        auto current_time = glfwGetTime();
        glUniform1f(time, current_time);
        glUniform2f(resolution, g_width, g_heigth);
        
        if(recompile) {
            loadFromFile();
            glUseProgram(program);
            recompile = false;
        }
            
        glBindVertexArray (vao);
        glDrawArrays(GL_TRIANGLE_STRIP, 0, 6);
        
        glfwPollEvents();
        glfwSwapBuffers(win);

    }
}
int main(int argc, char *argv[])
{
	//start context
	if (!glfwInit())
	{
		fprintf(stderr, "Error, could not start GLFW3\n");
		return 1;
	}
	else
	{
		fprintf(stderr, "GLFW initialized properly.");
	}

	//Forward compatibility from version 3.2.
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_SAMPLES, 4); //Anti aliasing (4 passes)
	
	//start logs
	Logger::restartLog(GL_LOG_FILE);
	glfwSetErrorCallback(glfwErrorCallback);

	GLFWmonitor* monitor = glfwGetPrimaryMonitor();
	const GLFWvidmode* mode = glfwGetVideoMode(monitor);

	//init window with primary monitor resolution
	//Set these modes for a fullscreen window and don't for classic fullscreen:
	/*glfwWindowHint(GLFW_RED_BITS, mode->redBits);
	glfwWindowHint(GLFW_GREEN_BITS, mode->greenBits);
	glfwWindowHint(GLFW_BLUE_BITS, mode->blueBits);
	glfwWindowHint(GLFW_REFRESH_RATE, mode->refreshRate);*/
	//------------------------------------------------

	//GLFWwindow * window = glfwCreateWindow(mode->width, mode->height, "Tutorial 1: Draw a triangle", monitor, NULL); //Fullscreen
	GLFWwindow * window = glfwCreateWindow(800, 600, "Tutorial 1: Draw a triangle", NULL, NULL); //Not Fullscreen

	//if window initialisation failed
	if (!window)
	{
		fprintf(stderr, "Could not open window with GLFW3\n");
		glfwTerminate();
		return 1;
	}

	glfwMakeContextCurrent(window);
	glfwSetWindowSizeCallback(window, glfwWindowSizeCallback);

	//start glew extension handler;
	glewExperimental = GL_TRUE;
	glewInit();

	//get version info
	const GLubyte * renderer = glGetString(GL_RENDERER);
	const GLubyte * version = glGetString(GL_VERSION);

	//Log informations
	Logger::printToLog(GL_LOG_FILE, "Starting GLFW: %s \n", glfwGetVersionString());
	logGlParams();

	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LESS);

	//draw triangle
	initTriangles();

	Shader vertex = Shader("vertex.vert", GL_VERTEX_SHADER);
	Shader frag_1 = Shader("frag1.frag", GL_FRAGMENT_SHADER);
	Shader frag_2 = Shader("frag2.frag", GL_FRAGMENT_SHADER);

	Shader shaders_1[2] = { vertex, frag_1 };
	Shader shaders_2[2] = { vertex, frag_2 };

	ShaderProgram shader_programme_1 = ShaderProgram(shaders_1, VERT_FRAG);
	ShaderProgram shader_programme_2 = ShaderProgram(shaders_2, VERT_FRAG);

	while (!glfwWindowShouldClose(window)) {
		updateFpsCounter(window);

		// wipe the drawing surface clear 
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glViewport(0, 0, g_gl_width, g_gl_height);

		glClearColor(0.1f, 0.1f, 0.1f, 0.0f);

		glUseProgram(shader_programme_1.get_program());
		glBindVertexArray(vao_1);

		// draw points 0-5 from the currently bound VAO with current in-use shader 
		glDrawArrays(GL_TRIANGLES, 0, 6);

		glUseProgram(shader_programme_2.get_program());
		glBindVertexArray(vao_2);

		// draw points 0-5 from the currently bound VAO with current in-use shader 
		glDrawArrays(GL_TRIANGLES, 0, 3);

		// update other events like input handling 
		glfwPollEvents();
		// put the stuff we've been drawing onto the display 
		glfwSwapBuffers(window);

		if (GLFW_PRESS == glfwGetKey(window, GLFW_KEY_ESCAPE)) 
		{
			glfwSetWindowShouldClose(window, 1);
		}
	}

	//close gl context and other glfw resources
	glfwTerminate();

	return 0;
}