• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
johnmarinelli

OpenGL
Moving a single object around in 2D

3 posts in this topic

Hi everyone,

I know this question has been asked a few times before, but I still can't get my program to work.

 

I'm working on an Asteroids clone in OpenGL, and I'm starting off by simply getting my spaceship to move around.  I also have 4 quads set up in each respective corner so I know if the movement is working or not.

 

However, it seems like I'm moving the quads around, and not my spaceship.  Here's the code:

void renderScene()
{
	glClear(GL_COLOR_BUFFER_BIT);
	
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	glPushMatrix();

	gSpaceship.render();

	glPopMatrix();

	glPushMatrix();
	//move to bottom right corner
	glTranslatef(SPACE_WIDTH / 2.f, SPACE_HEIGHT / 2.f, 0.f);

	glBegin(GL_QUADS);
		glColor3f(0.f, 1.f, 0.f);
		glVertex2f(0.f, 0.f);
		glVertex2f(50.f, 0.f);
		glVertex2f(50.f, 50.f);
		glVertex2f(0.f, 50.f);
	glEnd();

	//move to bottom left corner
	glTranslatef(-SPACE_WIDTH, 0.f, 0.f);

	glBegin(GL_QUADS);
		glColor3f(0.f, 0.f, 1.f);
		glVertex2f(0.f, 0.f);
		glVertex2f(50.f, 0.f);
		glVertex2f(50.f, 50.f);
		glVertex2f(0.f, 50.f);
	glEnd();

	//move to top left corner
	glTranslatef(0.f, -SPACE_HEIGHT, 0.f);

	glBegin(GL_QUADS);
		glColor3f(1.f, 1.f, 1.f);
		glVertex2f(0.f, 0.f);
		glVertex2f(50.f, 0.f);
		glVertex2f(50.f, 50.f);
		glVertex2f(0.f, 50.f);
	glEnd();

	//move to top right corner
	glTranslatef(SPACE_WIDTH, 0.f, 0.f);

	glBegin(GL_QUADS);
		glColor3f(1.f, 0.f, 1.f);
		glVertex2f(0.f, 0.f);
		glVertex2f(50.f, 0.f);
		glVertex2f(50.f, 50.f);
		glVertex2f(0.f, 50.f);
	glEnd();
	glPopMatrix();

	glFlush();
	
	glutSwapBuffers();
}

and heres' gSpaceship.render(), and consequently, JTexture.render():

void Spaceship::render()
{
       //mGraphics is a JTexture
       //m_xPos and m_yPos start out in the center of the 4 quads
	mGraphics.render(m_xPos, m_yPos);
}

void JTexture::render(GLfloat x, GLfloat y)
{
	if (mTextureID != 0)
	{
		glTranslatef(x, y, 0.f);

		glBindTexture(GL_TEXTURE_2D, mTextureID);

		glBegin(GL_QUADS);
			glTexCoord2f(0.f, 0.f); glVertex2f(0.f, 0.f );
            glTexCoord2f(1.f, 0.f); glVertex2f(mTextureWidth, 0.f );
            glTexCoord2f(1.f, 1.f); glVertex2f(mTextureWidth, mTextureHeight);
            glTexCoord2f(0.f, 1.f); glVertex2f(0.f, mTextureHeight);
        glEnd();
	}
}

also, I'd like to eventually be able to rotate the texture and move in the direction its facing; I know how to rotate a texture, but I know I will be very lost when it comes to moving in a direction thats not axis-aligned.  How does one go about this?

 

Thanks a lot!

Edited by johnmarinelli
0

Share this post


Link to post
Share on other sites

An easy way to deal with position and rotation and everything else related to transforms is to use a matrix to represent an object's transformations.

 

So you can have a class with your object's data (in the case, a single Quad + Texture) in it's original state, and when you're about to draw it, you use glLoadMatrix(matrix) and all it's transformations will be done.

 

Also, a suggestion, do some research about VBOs, what you're doing is called "Immediate Mode" and is pretty outdated and usually bad on performance.

1

Share this post


Link to post
Share on other sites

Here is a basic bare bones multiple triangle animation using modern OpenGL 3.x with inline vertex and fragment shaders.

compile it using :     g++ -o 005_tri_mo_mu_f8_ver3_simple 005_tri_mo_mu_f8_ver3_simple.cpp  -lGL -lGLEW -lglut -lGLU
 

//		g++ -o opengl_tri_multi_move opengl_tri_multi_move.cpp -lGL -lGLU -lGLEW -lglut
//		optirun ./opengl_tri_multi_move


#include <GL/glew.h>
#include <GL/freeglut.h>
#include <vector>
#include <iostream>

#include <string.h>		//	strlen
#include <cstdio>	// printf, sprintf  in cpp c++

// ---------


#include <iomanip>	// std::setprecision
//#include <locale>	// to insert commas into large numbers


#include <sstream>



#define WINDOW_TITLE_PREFIX "move multiple triangles"
int CurrentWidth = 1100, CurrentHeight = 1000, WindowHandle = 0;
unsigned FrameCount = 0;

#define YES 1
#define NO  0

//#define DEBUG YES
#define DEBUG NO

int did_load_program = NO;
int x1_reached_edge = NO;
int y1_reached_edge = NO;

GLfloat x_max = 0.9, y_max = 0.9;
GLfloat x_min = -0.9, y_min = -0.9;
GLfloat min_incr = -0.3, max_incr = 0.3;
// GLfloat size_triangle_side = 0.007;
GLfloat size_triangle_side = 0.2;


struct struct_program {

    static GLuint Load( const char * vert, const char * geom, const char * frag ) {

        GLuint prog = glCreateProgram();
        if( vert ) AttachShader( prog, GL_VERTEX_SHADER, vert );
        if( geom ) AttachShader( prog, GL_GEOMETRY_SHADER, geom );
        if( frag ) AttachShader( prog, GL_FRAGMENT_SHADER, frag );
        glLinkProgram( prog );
        CheckStatus( prog );
        return prog;
    }

private:

    static void CheckStatus( GLuint obj ) {

        GLint status = GL_FALSE, len = 10;
        if( glIsShader(obj) )   glGetShaderiv ( obj, GL_COMPILE_STATUS, & status );
        if( glIsProgram(obj) )  glGetProgramiv( obj, GL_LINK_STATUS, & status );
        if( status == GL_TRUE ) return;
        if( glIsShader(obj) )   glGetShaderiv ( obj, GL_INFO_LOG_LENGTH, & len );
        if( glIsProgram(obj) )  glGetProgramiv( obj, GL_INFO_LOG_LENGTH, & len );
        std::vector< char > log( len, 'X' );
        if( glIsShader(obj) )   glGetShaderInfoLog ( obj, len, NULL, &log[0] );
        if( glIsProgram(obj) )  glGetProgramInfoLog( obj, len, NULL, &log[0] );
        std::cerr << & log[0] << std::endl;
        exit( -1 );
    }

    static void AttachShader( GLuint program, GLenum type, const char * src ) {

        GLuint shader = glCreateShader( type );
        glShaderSource( shader, 1, & src, NULL );
        glCompileShader( shader );
        CheckStatus( shader );
        glAttachShader( program, shader );
        glDeleteShader( shader );
    }
};

#define GLSL(version, shader) "#version " #version "\n" #shader

const char* vert = GLSL (
    400 core,
    layout( location = 0 ) in vec4 vPosition;
    void main()
    {
        gl_Position = vPosition;
    }
);

const char* frag = GLSL (
    400 core,
    out vec4 fColor;
    void main()
    {
        fColor = vec4( 0.0, 0.0, 1.0, 1.0 );
    }
);

//#define total_num_triangles  1500
//#define total_num_triangles  3
//#define total_num_triangles  10000000
// #define total_num_triangles  100000
#define total_num_triangles  10

#define index_ArrayBuffer 0
#define NumBuffers 1

//num_vertex_arrays

GLuint vPosition = 0;

//GLuint VAOs[total_num_triangles];
GLuint vertex_array_object;

GLuint Buffers[NumBuffers];

const GLuint  NumVertices = 3;

#define X 0
#define Y 1
//GLfloat tri_location[total_num_triangles][2];
GLfloat vertex_locations[ 3 * total_num_triangles][2];	//	3 vertex per triangle, X&Y per vertex
//GLfloat incr[total_num_triangles][2];

GLfloat triangle_incr[total_num_triangles][2];

// ------------------------

bool get_direction(GLfloat curr_location, GLfloat min_location, GLfloat max_location) {

	bool answer = false;
	if (curr_location < min_location || curr_location > max_location) {

		answer = true;
	}
	return answer;
}

void setup_opengl() {

    glGenVertexArrays(NumBuffers, & vertex_array_object);



    glBindVertexArray(vertex_array_object);

    glGenBuffers(NumBuffers, Buffers);
    glBindBuffer(GL_ARRAY_BUFFER, Buffers[index_ArrayBuffer]);

    // ----------


    glVertexAttribPointer(vPosition, 2, GL_FLOAT, GL_FALSE, 0, (void*)(0) );
    glEnableVertexAttribArray(vPosition);
    glBindVertexArray(vertex_array_object);
}

void display(void) {

	++FrameCount;

    glClear(GL_COLOR_BUFFER_BIT);

//    glGenVertexArrays(total_num_triangles, & vertex_array_object);
//    glGenVertexArrays(NumBuffers, & vertex_array_object);

//	std::cout << "----- top of display ------ " << std::endl;

    // ----------------

    int curr_vertex = 0;
    int curr_triangle = 0;
    for (; curr_triangle < total_num_triangles; curr_triangle++) {

    	if (get_direction(vertex_locations[curr_vertex    ][X], x_min, x_max) ||
    		get_direction(vertex_locations[curr_vertex + 1][X], x_min, x_max) ||
    		get_direction(vertex_locations[curr_vertex + 2][X], x_min, x_max)) {

    		triangle_incr[curr_triangle][X] *= -1.0;
    	}

    	if (get_direction(vertex_locations[curr_vertex    ][Y], y_min, y_max) ||
    		get_direction(vertex_locations[curr_vertex + 1][Y], y_min, y_max) ||
    		get_direction(vertex_locations[curr_vertex + 2][Y], y_min, y_max)) {

    		triangle_incr[curr_triangle][Y] *= -1.0;
    	}

    	// triangle vertex 1
    	vertex_locations[curr_vertex][X] += triangle_incr[curr_triangle][X];
    	vertex_locations[curr_vertex][Y] += triangle_incr[curr_triangle][Y];

    	if (YES == DEBUG) {
        	std::cout << "tri " << curr_triangle;
			std::cout << " X " << vertex_locations[curr_vertex][X]
					  << " Y " << vertex_locations[curr_vertex][Y];
    	}

    	curr_vertex++;

    	// triangle vertex 2
    	vertex_locations[curr_vertex][X] += triangle_incr[curr_triangle][X];
    	vertex_locations[curr_vertex][Y] += triangle_incr[curr_triangle][Y];

    	if (YES == DEBUG) {
			std::cout << "        X " << vertex_locations[curr_vertex][X]
					  <<        " Y " << vertex_locations[curr_vertex][Y];
    	}

    	curr_vertex++;

    	// triangle vertex 3
    	vertex_locations[curr_vertex][X] += triangle_incr[curr_triangle][X];
    	vertex_locations[curr_vertex][Y] += triangle_incr[curr_triangle][Y];

    	if (YES == DEBUG) {
			std::cout << "        X " << vertex_locations[curr_vertex][X]
					  <<        " Y " << vertex_locations[curr_vertex][Y] << std::endl;
    	}

    	curr_vertex++;
    }

    // ----------

    glBindVertexArray(vertex_array_object);

//    glGenBuffers(NumBuffers, Buffers);
//    glBindBuffer(GL_ARRAY_BUFFER, Buffers[index_ArrayBuffer]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_locations), vertex_locations, GL_STATIC_DRAW);
//    glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_locations), vertex_locations, GL_DYNAMIC_DRAW);
//
//    glVertexAttribPointer(vPosition, 2, GL_FLOAT, GL_FALSE, 0, (void*)(0) );
//    glEnableVertexAttribArray(vPosition);
//    glBindVertexArray(vertex_array_object);

    glDrawArrays(GL_TRIANGLES, 0, 3 * total_num_triangles);
//    glDrawArrays(GL_TRIANGLES, 0, total_num_triangles);

    // ----------

    glutSwapBuffers();
}

// ---------------

void process_SHIFT_ALT_CTRL(unsigned char key, int x, int y) {

    switch(key) {

    	case 27: {

//    		printf ("just hit ESC key\n");
    		exit(8);
    	}
    }
}

// --------------

const char * insert_commas_into_int(int given_integer) {

	std::ostringstream stm ;
	stm << given_integer;
	std::string str_num(stm.str());

	int size_str = str_num.size() ;

//	std::cout << " num digits in " << given_integer << " is " << size_str << std::endl;
	for( int i = size_str ; i > 0 ; i -= 3 ) {

		if (i != size_str)
			str_num.insert( i, 1, ',' ) ;
	}
//	std::cout << str_num << '\n' ;

	return str_num.c_str();
}

// --------------

void TimerFunction(int Value) {

	if (0 != Value) {
		char* TempString = (char*)
			malloc(512 + strlen(WINDOW_TITLE_PREFIX));

		sprintf(
			TempString,
			"%s: %s triangles doing %d Frames Per Second @ %d x %d",
			WINDOW_TITLE_PREFIX,
			insert_commas_into_int(total_num_triangles),
			FrameCount * 4,
			CurrentWidth,
			CurrentHeight
		);

		glutSetWindowTitle(TempString);
		free(TempString);
	}

	FrameCount = 0;
	glutTimerFunc(250, TimerFunction, 1);
}

GLfloat get_random_in_range(GLfloat minimum, GLfloat maximum) {

	return(minimum + (float)rand()/((float)RAND_MAX/(maximum - minimum)));
}
void IdleFunction(void)
{
	glutPostRedisplay();
}


static void define_callbacks() {

    glutDisplayFunc(display);
    glutKeyboardFunc( process_SHIFT_ALT_CTRL );
	glutIdleFunc(IdleFunction);
	glutTimerFunc(0, TimerFunction, 0);
}

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

	// initialize random seed
	srand ( time(NULL) );

	glutInit(&argc, argv);
	glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE );
 	glutInitWindowSize(CurrentWidth, CurrentHeight);

     glutInitContextVersion(4, 0);
     glutInitContextProfile(GLUT_CORE_PROFILE);
     glutCreateWindow(argv[0]);

     glewExperimental = GL_TRUE;
     if( GLEW_OK != glewInit() )
         exit(EXIT_FAILURE);

     int curr_vertex = 0;
     int curr_triangle = 0;
     for (; curr_triangle < total_num_triangles; curr_triangle++) {

    	 triangle_incr[curr_triangle][X] = get_random_in_range(min_incr, max_incr) / 50.0;
    	 triangle_incr[curr_triangle][Y] = get_random_in_range(min_incr, max_incr) / 50.0;


     	if (YES == DEBUG) {
			 std::cout << " triangle_incr X " << triangle_incr[curr_triangle][X]
					   << " triangle_incr Y " << triangle_incr[curr_triangle][Y] << std::endl;
     	}

    	 GLfloat x_curr = get_random_in_range(min_incr, max_incr);
    	 GLfloat y_curr = get_random_in_range(min_incr, max_incr);

    	 // triangle vertex 1
    	 vertex_locations[curr_vertex][X] = x_curr;
    	 vertex_locations[curr_vertex][Y] = y_curr;

     	if (YES == DEBUG) {
			 std::cout << "tri " << curr_triangle << std::endl;
			 std::cout << " vertex 1 X " << vertex_locations[curr_vertex][X]
					   << " Y " << vertex_locations[curr_vertex][Y] << std::endl;
     	}

    	 // triangle vertex 2
    	 vertex_locations[curr_vertex + 1][X] = x_curr;
    	 vertex_locations[curr_vertex + 1][Y] = y_curr - size_triangle_side;

     	if (YES == DEBUG) {
			 std::cout << " vertex 2 X " << vertex_locations[curr_vertex + 1][X]
					 << " Y " << vertex_locations[curr_vertex + 1][Y] << std::endl;
     	}

    	 // triangle vertex 3
    	 vertex_locations[curr_vertex + 2][X] = x_curr - size_triangle_side;
    	 vertex_locations[curr_vertex + 2][Y] = y_curr - size_triangle_side;

     	if (YES == DEBUG) {
			 std::cout << " vertex 3 X " << vertex_locations[curr_vertex + 2][X]
					 << " Y " << vertex_locations[curr_vertex + 2][Y] << std::endl;
     	}

    	 curr_vertex += 3;	// 3 vertex per triangle
     }

     // -----------

     GLuint program = struct_program::Load( vert, NULL, frag );
     glUseProgram(program);

     // -----------

     setup_opengl();

     define_callbacks();

     glutMainLoop();
}


1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0

  • Similar Content

    • By Solid_Spy
      Hello, I have been working on SH Irradiance map rendering, and I have been using a GLSL pixel shader to render SH irradiance to 2D irradiance maps for my static objects. I already have it working with 9 3D textures so far for the first 9 SH functions.
      In my GLSL shader, I have to send in 9 SH Coefficient 3D Texures that use RGBA8 as a pixel format. RGB being used for the coefficients for red, green, and blue, and the A for checking if the voxel is in use (for the 3D texture solidification shader to prevent bleeding).
      My problem is, I want to knock this number of textures down to something like 4 or 5. Getting even lower would be a godsend. This is because I eventually plan on adding more SH Coefficient 3D Textures for other parts of the game map (such as inside rooms, as opposed to the outside), to circumvent irradiance probe bleeding between rooms separated by walls. I don't want to reach the 32 texture limit too soon. Also, I figure that it would be a LOT faster.
      Is there a way I could, say, store 2 sets of SH Coefficients for 2 SH functions inside a texture with RGBA16 pixels? If so, how would I extract them from inside GLSL? Let me know if you have any suggestions ^^.
    • By DaniDesu
      #include "MyEngine.h" int main() { MyEngine myEngine; myEngine.run(); return 0; } MyEngine.h
      #pragma once #include "MyWindow.h" #include "MyShaders.h" #include "MyShapes.h" class MyEngine { private: GLFWwindow * myWindowHandle; MyWindow * myWindow; public: MyEngine(); ~MyEngine(); void run(); }; MyEngine.cpp
      #include "MyEngine.h" MyEngine::MyEngine() { MyWindow myWindow(800, 600, "My Game Engine"); this->myWindow = &myWindow; myWindow.createWindow(); this->myWindowHandle = myWindow.getWindowHandle(); // Load all OpenGL function pointers for use gladLoadGLLoader((GLADloadproc)glfwGetProcAddress); } MyEngine::~MyEngine() { this->myWindow->destroyWindow(); } void MyEngine::run() { MyShaders myShaders("VertexShader.glsl", "FragmentShader.glsl"); MyShapes myShapes; GLuint vertexArrayObjectHandle; float coordinates[] = { 0.5f, 0.5f, 0.0f, 0.5f, -0.5f, 0.0f, -0.5f, 0.5f, 0.0f }; vertexArrayObjectHandle = myShapes.drawTriangle(coordinates); while (!glfwWindowShouldClose(this->myWindowHandle)) { glClearColor(0.5f, 0.5f, 0.5f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Draw something glUseProgram(myShaders.getShaderProgram()); glBindVertexArray(vertexArrayObjectHandle); glDrawArrays(GL_TRIANGLES, 0, 3); glfwSwapBuffers(this->myWindowHandle); glfwPollEvents(); } } MyShaders.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> #include "MyFileHandler.h" class MyShaders { private: const char * vertexShaderFileName; const char * fragmentShaderFileName; const char * vertexShaderCode; const char * fragmentShaderCode; GLuint vertexShaderHandle; GLuint fragmentShaderHandle; GLuint shaderProgram; void compileShaders(); public: MyShaders(const char * vertexShaderFileName, const char * fragmentShaderFileName); ~MyShaders(); GLuint getShaderProgram(); const char * getVertexShaderCode(); const char * getFragmentShaderCode(); }; MyShaders.cpp
      #include "MyShaders.h" MyShaders::MyShaders(const char * vertexShaderFileName, const char * fragmentShaderFileName) { this->vertexShaderFileName = vertexShaderFileName; this->fragmentShaderFileName = fragmentShaderFileName; // Load shaders from files MyFileHandler myVertexShaderFileHandler(this->vertexShaderFileName); this->vertexShaderCode = myVertexShaderFileHandler.readFile(); MyFileHandler myFragmentShaderFileHandler(this->fragmentShaderFileName); this->fragmentShaderCode = myFragmentShaderFileHandler.readFile(); // Compile shaders this->compileShaders(); } MyShaders::~MyShaders() { } void MyShaders::compileShaders() { this->vertexShaderHandle = glCreateShader(GL_VERTEX_SHADER); this->fragmentShaderHandle = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(this->vertexShaderHandle, 1, &(this->vertexShaderCode), NULL); glShaderSource(this->fragmentShaderHandle, 1, &(this->fragmentShaderCode), NULL); glCompileShader(this->vertexShaderHandle); glCompileShader(this->fragmentShaderHandle); this->shaderProgram = glCreateProgram(); glAttachShader(this->shaderProgram, this->vertexShaderHandle); glAttachShader(this->shaderProgram, this->fragmentShaderHandle); glLinkProgram(this->shaderProgram); return; } GLuint MyShaders::getShaderProgram() { return this->shaderProgram; } const char * MyShaders::getVertexShaderCode() { return this->vertexShaderCode; } const char * MyShaders::getFragmentShaderCode() { return this->fragmentShaderCode; } MyWindow.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> class MyWindow { private: GLFWwindow * windowHandle; int windowWidth; int windowHeight; const char * windowTitle; public: MyWindow(int windowWidth, int windowHeight, const char * windowTitle); ~MyWindow(); GLFWwindow * getWindowHandle(); void createWindow(); void MyWindow::destroyWindow(); }; MyWindow.cpp
      #include "MyWindow.h" MyWindow::MyWindow(int windowWidth, int windowHeight, const char * windowTitle) { this->windowHandle = NULL; this->windowWidth = windowWidth; this->windowWidth = windowWidth; this->windowHeight = windowHeight; this->windowTitle = windowTitle; glfwInit(); } MyWindow::~MyWindow() { } GLFWwindow * MyWindow::getWindowHandle() { return this->windowHandle; } void MyWindow::createWindow() { // Use OpenGL 3.3 and GLSL 3.3 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // Limit backwards compatibility glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Prevent resizing window glfwWindowHint(GLFW_RESIZABLE, GL_FALSE); // Create window this->windowHandle = glfwCreateWindow(this->windowWidth, this->windowHeight, this->windowTitle, NULL, NULL); glfwMakeContextCurrent(this->windowHandle); } void MyWindow::destroyWindow() { glfwTerminate(); } MyShapes.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> class MyShapes { public: MyShapes(); ~MyShapes(); GLuint & drawTriangle(float coordinates[]); }; MyShapes.cpp
      #include "MyShapes.h" MyShapes::MyShapes() { } MyShapes::~MyShapes() { } GLuint & MyShapes::drawTriangle(float coordinates[]) { GLuint vertexBufferObject{}; GLuint vertexArrayObject{}; // Create a VAO glGenVertexArrays(1, &vertexArrayObject); glBindVertexArray(vertexArrayObject); // Send vertices to the GPU glGenBuffers(1, &vertexBufferObject); glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject); glBufferData(GL_ARRAY_BUFFER, sizeof(coordinates), coordinates, GL_STATIC_DRAW); // Dertermine the interpretation of the array buffer glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), (void *)0); glEnableVertexAttribArray(0); // Unbind the buffers glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(0); return vertexArrayObject; } MyFileHandler.h
      #pragma once #include <cstdio> #include <cstdlib> class MyFileHandler { private: const char * fileName; unsigned long fileSize; void setFileSize(); public: MyFileHandler(const char * fileName); ~MyFileHandler(); unsigned long getFileSize(); const char * readFile(); }; MyFileHandler.cpp
      #include "MyFileHandler.h" MyFileHandler::MyFileHandler(const char * fileName) { this->fileName = fileName; this->setFileSize(); } MyFileHandler::~MyFileHandler() { } void MyFileHandler::setFileSize() { FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fseek(fileHandle, 0L, SEEK_END); this->fileSize = ftell(fileHandle); rewind(fileHandle); fclose(fileHandle); return; } unsigned long MyFileHandler::getFileSize() { return (this->fileSize); } const char * MyFileHandler::readFile() { char * buffer = (char *)malloc((this->fileSize)+1); FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fread(buffer, this->fileSize, sizeof(char), fileHandle); fclose(fileHandle); buffer[this->fileSize] = '\0'; return buffer; } VertexShader.glsl
      #version 330 core layout (location = 0) vec3 VertexPositions; void main() { gl_Position = vec4(VertexPositions, 1.0f); } FragmentShader.glsl
      #version 330 core out vec4 FragmentColor; void main() { FragmentColor = vec4(1.0f, 0.0f, 0.0f, 1.0f); } I am attempting to create a simple engine/graphics utility using some object-oriented paradigms. My first goal is to get some output from my engine, namely, a simple red triangle.
      For this goal, the MyShapes class will be responsible for defining shapes such as triangles, polygons etc. Currently, there is only a drawTriangle() method implemented, because I first wanted to see whether it works or not before attempting to code other shape drawing methods.
      The constructor of the MyEngine class creates a GLFW window (GLAD is also initialized here to load all OpenGL functionality), and the myEngine.run() method in Main.cpp is responsible for firing up the engine. In this run() method, the shaders get loaded from files via the help of my FileHandler class. The vertices for the triangle are processed by the myShapes.drawTriangle() method where a vertex array object, a vertex buffer object and vertrex attributes are set for this purpose.
      The while loop in the run() method should be outputting me the desired red triangle, but all I get is a grey window area. Why?
      Note: The shaders are compiling and linking without any errors.
      (Note: I am aware that this code is not using any good software engineering practices (e.g. exceptions, error handling). I am planning to implement them later, once I get the hang of OpenGL.)

       
    • By KarimIO
      EDIT: I thought this was restricted to Attribute-Created GL contexts, but it isn't, so I rewrote the post.
      Hey guys, whenever I call SwapBuffers(hDC), I get a crash, and I get a "Too many posts were made to a semaphore." from Windows as I call SwapBuffers. What could be the cause of this?
      Update: No crash occurs if I don't draw, just clear and swap.
      static PIXELFORMATDESCRIPTOR pfd = // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format 32, // Select Our Color Depth 0, 0, 0, 0, 0, 0, // Color Bits Ignored 0, // No Alpha Buffer 0, // Shift Bit Ignored 0, // No Accumulation Buffer 0, 0, 0, 0, // Accumulation Bits Ignored 24, // 24Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC = GetDC(windowHandle))) return false; unsigned int PixelFormat; if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd))) return false; if (!SetPixelFormat(hDC, PixelFormat, &pfd)) return false; hRC = wglCreateContext(hDC); if (!hRC) { std::cout << "wglCreateContext Failed!\n"; return false; } if (wglMakeCurrent(hDC, hRC) == NULL) { std::cout << "Make Context Current Second Failed!\n"; return false; } ... // OGL Buffer Initialization glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); glBindVertexArray(vao); glUseProgram(myprogram); glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, (void *)indexStart); SwapBuffers(GetDC(window_handle));  
    • By Tchom
      Hey devs!
       
      I've been working on a OpenGL ES 2.0 android engine and I have begun implementing some simple (point) lighting. I had something fairly simple working, so I tried to get fancy and added color-tinting light. And it works great... with only one or two lights. Any more than that, the application drops about 15 frames per light added (my ideal is at least 4 or 5). I know implementing lighting is expensive, I just didn't think it was that expensive. I'm fairly new to the world of OpenGL and GLSL, so there is a good chance I've written some crappy shader code. If anyone had any feedback or tips on how I can optimize this code, please let me know.
       
      Vertex Shader
      uniform mat4 u_MVPMatrix; uniform mat4 u_MVMatrix; attribute vec4 a_Position; attribute vec3 a_Normal; attribute vec2 a_TexCoordinate; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { v_Position = vec3(u_MVMatrix * a_Position); v_TexCoordinate = a_TexCoordinate; v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0)); gl_Position = u_MVPMatrix * a_Position; } Fragment Shader
      precision mediump float; uniform vec4 u_LightPos["+numLights+"]; uniform vec4 u_LightColours["+numLights+"]; uniform float u_LightPower["+numLights+"]; uniform sampler2D u_Texture; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { gl_FragColor = (texture2D(u_Texture, v_TexCoordinate)); float diffuse = 0.0; vec4 colourSum = vec4(1.0); for (int i = 0; i < "+numLights+"; i++) { vec3 toPointLight = vec3(u_LightPos[i]); float distance = length(toPointLight - v_Position); vec3 lightVector = normalize(toPointLight - v_Position); float diffuseDiff = 0.0; // The diffuse difference contributed from current light diffuseDiff = max(dot(v_Normal, lightVector), 0.0); diffuseDiff = diffuseDiff * (1.0 / (1.0 + ((1.0-u_LightPower[i])* distance * distance))); //Determine attenuatio diffuse += diffuseDiff; gl_FragColor.rgb *= vec3(1.0) / ((vec3(1.0) + ((vec3(1.0) - vec3(u_LightColours[i]))*diffuseDiff))); //The expensive part } diffuse += 0.1; //Add ambient light gl_FragColor.rgb *= diffuse; } Am I making any rookie mistakes? Or am I just being unrealistic about what I can do? Thanks in advance
    • By yahiko00
      Hi,
      Not sure to post at the right place, if not, please forgive me...
      For a game project I am working on, I would like to implement a 2D starfield as a background.
      I do not want to deal with static tiles, since I plan to slowly animate the starfield. So, I am trying to figure out how to generate a random starfield for the entire map.
      I feel that using a uniform distribution for the stars will not do the trick. Instead I would like something similar to the screenshot below, taken from the game Star Wars: Empire At War (all credits to Lucasfilm, Disney, and so on...).

      Is there someone who could have an idea of a distribution which could result in such a starfield?
      Any insight would be appreciated
  • Popular Now