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    • By tj8146
      I am using immediate mode for OpenGL and I am creating a 2D top down car game. I am trying to configure my game loop in order to get my car-like physics working on a square shape. I have working code but it is not doing as I want it to. I am not sure as to whether it is my game loop that is incorrect or my code for the square is incorrect, or maybe both! Could someone help because I have been trying to work this out for over a day now
      I have attached my .cpp file if you wish to run it for yourself.. 
      WinMain code:
      /******************* WIN32 FUNCTIONS ***************************/ int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure bool done=false; // Bool Variable To Exit Loop Car car; car.x = 220; car.y = 140; car.dx = 0; car.dy = 0; car.ang = 0; AllocConsole(); FILE *stream; freopen_s(&stream, "CONOUT$", "w", stdout); // Create Our OpenGL Window if (!CreateGLWindow("OpenGL Win32 Example",screenWidth,screenHeight)) { return 0; // Quit If Window Was Not Created } while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=true; // If So done=TRUE break; } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { if(keys[VK_ESCAPE]) done = true; void processKeys(Car& car); //process keyboard while (game_is_running) { loops = 0; while (GetTickCount() > next_game_tick && loops < MAX_FRAMESKIP) { update(car); // update variables next_game_tick += SKIP_TICKS; loops++; } display(car); // Draw The Scene SwapBuffers(hDC); // Swap Buffers (Double Buffering) } } } // Shutdown KillGLWindow(); // Kill The Window return (int)(msg.wParam); // Exit The Program } //WIN32 Processes function - useful for responding to user inputs or other events. LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back } break; case WM_SIZE: // Resize The OpenGL Window { reshape(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } break; case WM_LBUTTONDOWN: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); LeftPressed = true; } break; case WM_LBUTTONUP: { LeftPressed = false; } break; case WM_MOUSEMOVE: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); } break; case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = true; // If So, Mark It As TRUE return 0; // Jump Back } break; case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = false; // If So, Mark It As FALSE return 0; // Jump Back } break; } // Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); }  
      C++ and OpenGL code:
      int mouse_x=0, mouse_y=0; bool LeftPressed = false; int screenWidth=1080, screenHeight=960; bool keys[256]; float radiansFromDegrees(float deg) { return deg * (M_PI / 180.0f); } float degreesFromRadians(float rad) { return rad / (M_PI / 180.0f); } bool game_is_running = true; const int TICKS_PER_SECOND = 50; const int SKIP_TICKS = 1000 / TICKS_PER_SECOND; const int MAX_FRAMESKIP = 10; DWORD next_game_tick = GetTickCount(); int loops; typedef struct { float x, y; float dx, dy; float ang; }Car; //OPENGL FUNCTION PROTOTYPES void display(const Car& car); //called in winmain to draw everything to the screen void reshape(int width, int height); //called when the window is resized void init(); //called in winmain when the program starts. void processKeys(Car& car); //called in winmain to process keyboard input void update(Car& car); //called in winmain to update variables /************* START OF OPENGL FUNCTIONS ****************/ void display(const Car& car) { const float w = 50.0f; const float h = 50.0f; glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glTranslatef(100, 100, 0); glBegin(GL_POLYGON); glVertex2f(car.x, car.y); glVertex2f(car.x + w, car.y); glVertex2f(car.x + w, car.y + h); glVertex2f(car.x, car.y + h); glEnd(); glFlush(); } void reshape(int width, int height) // Resize the OpenGL window { screenWidth = width; screenHeight = height; // to ensure the mouse coordinates match // we will use these values to set the coordinate system glViewport(0, 0, width, height); // Reset the current viewport glMatrixMode(GL_PROJECTION); // select the projection matrix stack glLoadIdentity(); // reset the top of the projection matrix to an identity matrix gluOrtho2D(0, screenWidth, 0, screenHeight); // set the coordinate system for the window glMatrixMode(GL_MODELVIEW); // Select the modelview matrix stack glLoadIdentity(); // Reset the top of the modelview matrix to an identity matrix } void init() { glClearColor(1.0, 1.0, 0.0, 0.0); //sets the clear colour to yellow //glClear(GL_COLOR_BUFFER_BIT) in the display function //will clear the buffer to this colour. } void processKeys(Car& car) { if (keys[VK_UP]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += cdx; car.dy += cdy; } if (keys[VK_DOWN]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += -cdx; car.dy += -cdy; } if (keys[VK_LEFT]) { car.ang -= 2; } if (keys[VK_RIGHT]) { car.ang += 2; } } void update(Car& car) { car.x += car.dx*next_game_tick; }  
      game.cpp
    • By tj8146
      I am using immediate mode for OpenGL and I am creating a 2D top down car game. I am trying to configure my game loop in order to get my car-like physics working on a square shape. I have working code but it is not doing as I want it to. I am not sure as to whether it is my game loop that is incorrect or my code for the square is incorrect, or maybe both! Could someone help because I have been trying to work this out for over a day now
      I have attached my .cpp file if you wish to run it for yourself.. 
       
      This is my C++ and OpenGL code:
      int mouse_x=0, mouse_y=0; bool LeftPressed = false; int screenWidth=1080, screenHeight=960; bool keys[256]; float radiansFromDegrees(float deg) { return deg * (M_PI / 180.0f); } float degreesFromRadians(float rad) { return rad / (M_PI / 180.0f); } bool game_is_running = true; const int TICKS_PER_SECOND = 50; const int SKIP_TICKS = 1000 / TICKS_PER_SECOND; const int MAX_FRAMESKIP = 10; DWORD next_game_tick = GetTickCount(); int loops; typedef struct { float x, y; float dx, dy; float ang; }Car; //OPENGL FUNCTION PROTOTYPES void display(const Car& car); //called in winmain to draw everything to the screen void reshape(int width, int height); //called when the window is resized void init(); //called in winmain when the program starts. void processKeys(Car& car); //called in winmain to process keyboard input void update(Car& car); //called in winmain to update variables /************* START OF OPENGL FUNCTIONS ****************/ void display(const Car& car) { const float w = 50.0f; const float h = 50.0f; glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glTranslatef(100, 100, 0); glBegin(GL_POLYGON); glVertex2f(car.x, car.y); glVertex2f(car.x + w, car.y); glVertex2f(car.x + w, car.y + h); glVertex2f(car.x, car.y + h); glEnd(); glFlush(); } void reshape(int width, int height) // Resize the OpenGL window { screenWidth = width; screenHeight = height; // to ensure the mouse coordinates match // we will use these values to set the coordinate system glViewport(0, 0, width, height); // Reset the current viewport glMatrixMode(GL_PROJECTION); // select the projection matrix stack glLoadIdentity(); // reset the top of the projection matrix to an identity matrix gluOrtho2D(0, screenWidth, 0, screenHeight); // set the coordinate system for the window glMatrixMode(GL_MODELVIEW); // Select the modelview matrix stack glLoadIdentity(); // Reset the top of the modelview matrix to an identity matrix } void init() { glClearColor(1.0, 1.0, 0.0, 0.0); //sets the clear colour to yellow //glClear(GL_COLOR_BUFFER_BIT) in the display function //will clear the buffer to this colour. } void processKeys(Car& car) { if (keys[VK_UP]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += cdx; car.dy += cdy; } if (keys[VK_DOWN]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += -cdx; car.dy += -cdy; } if (keys[VK_LEFT]) { car.ang -= 2; } if (keys[VK_RIGHT]) { car.ang += 2; } } void update(Car& car) { car.x += car.dx*next_game_tick; } My WinMain code:
      /******************* WIN32 FUNCTIONS ***************************/ int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure bool done=false; // Bool Variable To Exit Loop Car car; car.x = 220; car.y = 140; car.dx = 0; car.dy = 0; car.ang = 0; AllocConsole(); FILE *stream; freopen_s(&stream, "CONOUT$", "w", stdout); // Create Our OpenGL Window if (!CreateGLWindow("OpenGL Win32 Example",screenWidth,screenHeight)) { return 0; // Quit If Window Was Not Created } while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=true; // If So done=TRUE break; } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { if(keys[VK_ESCAPE]) done = true; void processKeys(Car& car); //process keyboard while (game_is_running) { loops = 0; while (GetTickCount() > next_game_tick && loops < MAX_FRAMESKIP) { update(car); // update variables next_game_tick += SKIP_TICKS; loops++; } display(car); // Draw The Scene SwapBuffers(hDC); // Swap Buffers (Double Buffering) } } } // Shutdown KillGLWindow(); // Kill The Window return (int)(msg.wParam); // Exit The Program } //WIN32 Processes function - useful for responding to user inputs or other events. LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back } break; case WM_SIZE: // Resize The OpenGL Window { reshape(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } break; case WM_LBUTTONDOWN: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); LeftPressed = true; } break; case WM_LBUTTONUP: { LeftPressed = false; } break; case WM_MOUSEMOVE: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); } break; case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = true; // If So, Mark It As TRUE return 0; // Jump Back } break; case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = false; // If So, Mark It As FALSE return 0; // Jump Back } break; } // Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); }  
      game.cpp
    • By lxjk
      Hi guys,
      There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
      Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
      On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
      This method can be naturally extended to clustered light culling as well.
      The following image shows the general ideas

       
      Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test
       

       
      I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!
       
      Eric
    • By Fadey Duh
      Good evening everyone!

      I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
      Basically I'm trying to find more compatible version of it.

      Thank you!
    • By Jens Eckervogt
      Hello guys, 
       
      Please tell me! 
      How do I know? Why does wavefront not show for me?
      I already checked I have non errors yet.
      using OpenTK; using System.Collections.Generic; using System.IO; using System.Text; namespace Tutorial_08.net.sourceskyboxer { public class WaveFrontLoader { private static List<Vector3> inPositions; private static List<Vector2> inTexcoords; private static List<Vector3> inNormals; private static List<float> positions; private static List<float> texcoords; private static List<int> indices; public static RawModel LoadObjModel(string filename, Loader loader) { inPositions = new List<Vector3>(); inTexcoords = new List<Vector2>(); inNormals = new List<Vector3>(); positions = new List<float>(); texcoords = new List<float>(); indices = new List<int>(); int nextIdx = 0; using (var reader = new StreamReader(File.Open("Contents/" + filename + ".obj", FileMode.Open), Encoding.UTF8)) { string line = reader.ReadLine(); int i = reader.Read(); while (true) { string[] currentLine = line.Split(); if (currentLine[0] == "v") { Vector3 pos = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inPositions.Add(pos); if (currentLine[1] == "t") { Vector2 tex = new Vector2(float.Parse(currentLine[1]), float.Parse(currentLine[2])); inTexcoords.Add(tex); } if (currentLine[1] == "n") { Vector3 nom = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inNormals.Add(nom); } } if (currentLine[0] == "f") { Vector3 pos = inPositions[0]; positions.Add(pos.X); positions.Add(pos.Y); positions.Add(pos.Z); Vector2 tc = inTexcoords[0]; texcoords.Add(tc.X); texcoords.Add(tc.Y); indices.Add(nextIdx); ++nextIdx; } reader.Close(); return loader.loadToVAO(positions.ToArray(), texcoords.ToArray(), indices.ToArray()); } } } } } And It have tried other method but it can't show for me.  I am mad now. Because any OpenTK developers won't help me.
      Please help me how do I fix.

      And my download (mega.nz) should it is original but I tried no success...
      - Add blend source and png file here I have tried tried,.....  
       
      PS: Why is our community not active? I wait very longer. Stop to lie me!
      Thanks !
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OpenGL About text in OpenGl

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Hi i'm using OpenGL2 and i'm tryin to write calculated distance on the screen

this is my code:

in void display:

  drawNumber(distance_1,-0.95,0.9); //distance_1 is a string with one digit number in each box

 

in drawNumber:

void drawNumber(const char *message, float x, float y)
{
int i=0;
glRasterPos2f(x+0.013, y);
//write using bitmap and stroke chars
for (i = 0; i < 3; i++)
{
               glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, message);
}
}
 
it does not work, and if i send drawNumber("456",-0.95,0.9); it does work.
tnx for helping

 

 

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Can you be a bit more specific than 'does not work'? Do you see any text at all? Do you see anything at all? Are you able to draw other text correctly?

 

Can you show the code where you create distance_1? That will probably be the most useful thing to see since you say the drawNumber("456",-0.95,0.9); does work correctly, that suggests there's a problem with your string.

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to use that you need to setup ortho etc. anyway you use opengl 2.0 and you use fixed function pipeline when you should use shaders.


void glWriteTEXT(int X,int Y, AnsiString text)
{
  glPushAttrib(GL_DEPTH_TEST);  // Save the current Depth test settings (Used for blending )
  glDisable(GL_DEPTH_TEST);     // Turn off depth testing (otherwise we get no FPS)


  glMatrixMode(GL_PROJECTION);  // Switch to the projection matrix
  glPushMatrix();               // Save current projection matrix
  glLoadIdentity();

//  GetWindowRect(GetDesktopWindow(), drawRect);  // Get current window size
  glOrtho(0, WINDOW_WIDTH, 0, WINDOW_HEIGHT, -1, 1);  // Change the projection matrix using an orthgraphic projection
  glMatrixMode(GL_MODELVIEW);  // Return to the modelview matrix
  glPushMatrix();              // Save the current modelview matrix
  glLoadIdentity();
 // glColor3f(1.0, 1.0, 1.0);    // Text color

  glRasterPos2i(X, Y);                                // Position the Text
  glPushAttrib(GL_LIST_BIT);                          // Save's the current base list
  glListBase(base);                              // Set the base list to our character list
  glCallLists(text.Length(), GL_UNSIGNED_BYTE, text.c_str());  // Display the text
  glPopAttrib();                                      // Restore the old base list

  glMatrixMode(GL_PROJECTION);  //Switch to projection matrix
  glPopMatrix();                // Restore the old projection matrix
  glMatrixMode(GL_MODELVIEW);   // Return to modelview matrix
  glPopMatrix();                // Restore old modelview matrix
 // glEnable(GL_TEXTURE_2D);      // Turn on textures, don't want our text textured
 // glEnable(GL_LIGHTING);
  glPopAttrib();                // Restore depth testing


}

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I know this may be hard to understand because he's writing it in a custom game engine made in his tutorials, however, I think you may find this useful as it overall explains text rendering very well:

And the second part for quality:

 

Just make sure to uniform as many text parameters as possible to have more control;)

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WiredCat now that looks easy. No additional libs like glut needed? Thanks for the code, I'll try tomorrow.

 

Beware of unspecified dependencies.

 

AnsiString text
 

What is "AnsiString"?  A custom class?  Something from a library?  Which library?

 

glListBase(base);                              // Set the base list to our character list
glCallLists(text.Length(), GL_UNSIGNED_BYTE, text.c_str());  // Display the text

 

What is base?  Where does it's value come from?  What is used to generate the display lists?  Where are they generated?  Does this generation have any other dependencies?

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Seems to need glut, freetype etc., but I don't want dependencies. I'll try to link statically sdl_ttf now.

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void BuildFont(unsigned int  & Ufont)
{

HFONT font;

  Ufont = glGenLists(256);                  // Generate enough display lists to hold

  font = CreateFont(22,                           // height of font
			 0,                             // average character width
			 0,                             // angle of escapement
			 0,                             // base-line orientation angle
			 FW_BOLD,                       // font weight
			 0,			            // italic
			 0,                             // underline
			 0,			            // strikeout
			 DEFAULT_CHARSET,                  // character set
			 OUT_TT_PRECIS,	            // output precision
			 CLIP_DEFAULT_PRECIS,           // clipping precision
			 ANTIALIASED_QUALITY,           // output quality
			 FF_DONTCARE || DEFAULT_PITCH,  // pitch and family
			 "Courier New");                     // font

  SelectObject((*dc), font);               // Sets the new font as the current font in the device context
  wglUseFontBitmaps((*dc), 0, 256, Ufont);  // Creates a set display lists containing the bitmap fonts


}

AnsiString can be std::string

where BuildFont(base);

 

and where unsigned int base;

 

 

 

 

but my point was that you didnt se proper perspective projection for using glrasterpos

 

 

you should anyway use shaders, and one texture where you have all font characters, and quit using old stuff ;] ;p

Edited by WiredCat

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