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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 drago28
      I'm using construct 2 physics I have a working bike with everything setup and I'm able to do frontflip and backflip by adding angular velocity to the bike
      I want to increase score/ add points and display the "backflip / frontflip" text when the bike does it.
      so please help me I want to know the logic and how it's done.
      p.s. example about construct 2 is not necessary, just explain me how other games do it or anything else you have to share
      Thanks,
      Drago
    • By otgs17
      You have 12 hours to search for supplies, transportation or you can continue your journey.
      But as soon as night falls, you must find shelter, turn it into a fortress to stand against the hordes of monsters.
      Equip soldiers, use bonuses and do not forget to follow the energy level of your fighters. 
      In battle be useful to your transport, it would be nice to find a tank.
      Every day the number of monsters to get more, they mutate into stronger and more dangerous forms.
      https://play.google.com/store/apps/details?id=com.otgs.FortTD&hl=en
      https://itunes.apple.com/us/app/fortress-td/id1367094965?mt=8
      https://www.youtube.com/watch?v=QIkXPikiRqc





    • By Masson
      Name: Dodging Dots
      Category: Arcade/Casual
      Description:
      Come up with your own strategy. Collect myriads of dots and maneuver from the coming blocks. Beware! There gonna be lots of them!
      The minimalistic world will captivate you for a long time. Try out!
      Features:
      Use upgrades to improve your game experience 🎮 Increase the velocity 🏄 of the dots to avoid the avalanche of blocks. Or you can increase the number of falling boosters to break 💥 through it, the choice is yours! Nice color shades that change throughout the game Ongoing game. Original soundtrack 🎧 Integration with Google Play Games Compete with other players 🏆 18 achievements to warm up your interest 🔥 Simple control, play with one finger Google Play: https://play.google.com/store/apps/details?id=com.groovin.blocks.delicate.survive.gameplay
       
      Feel free to leave comments. We really interested in improving this product and appreciate your support.
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2D Triangle rasterization algorithm

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Hello,

I’m writing research paper on software rasterization algorithms and at one point I gave example of triangle rasterization algorithm.

The algorithm is really basic. If the triangle is flat top or flat bottom it’s possible to determine the minimum and the maximum x values for each scan line using the equation of line for the edges. Then for each scan line fill the pixels between minimum x and maximum x values.
If the triangle is of other kind it’s possible to split it to flat top and flat bottom triangles (finding the fourth vertex) and draw it using the previous algorithm.

I need to cite a reference for this algorithm. I saw it in some book in the ‘90s and I can’t just write it without a reference. The problem is that I can’t remember where I saw it.
I already tried to look at “Computer Graphics: Principles and Practice” but the only similar algorithm there is the polygon rasterization algorithm, which is over engineered for this kind of problem, same with "Computer Graphics: C Version".
I also tried to look at “Black Art of 3D Game Programming”, which have similar algorithm but the algorithm that I saw was in another book and slightly different.

Anyone know a book with this kind of algorithm?
Any help is appreciated.

Thanks.

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Michael Abrash's Graphics Programming Black Book might be another reference, but polygons too IIRC.

Note that rendering polygons is much more efficient than triangles due to less edges to setup - if there is enough planar stuff around.

 

Later there was a SIMD approach which does a bounding rect per triangle and then evaluating 3 side of edge tests in parallel per pixel. I remember a guy named Nicolas Capens who wrote an article about this, might be another good reference.

 

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