528 lines
15 KiB
C
528 lines
15 KiB
C
// SDL Experiment 18, Barra Ó Catháin.
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// ===================================
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#include <SDL2/SDL.h>
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#include <SDL2/SDL_image.h>
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#include <SDL2/SDL_timer.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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// A 2D vector:
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typedef struct xyVector
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{
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double xComponent;
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double yComponent;
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} xyVector;
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// A struct storing the needed data to draw a ship:
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typedef struct ship
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{
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int number;
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xyVector engine;
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xyVector gravity;
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xyVector position;
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xyVector velocity;
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SDL_Rect rectangle;
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} ship;
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typedef struct playerController
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{
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int number;
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int clockwiseTurn, anticlockwiseTurn, acceleratingAmount;
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bool turningClockwise, turningAnticlockwise, accelerating;
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} playerController;
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// Calculate the vector from point A to point B:
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static inline void xyVectorBetweenPoints(long ax, long ay, long bx, long by, xyVector * vector)
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{
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vector->xComponent = bx - ax;
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vector->yComponent = by - ay;
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}
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// Normalize a vector, returning the magnitude:
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static inline double normalizeXYVector(xyVector * vector)
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{
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double magnitude = sqrt(pow(vector->xComponent, 2) + pow(vector->yComponent, 2));
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if(magnitude != 0)
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{
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vector->xComponent /= magnitude;
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vector->yComponent /= magnitude;
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}
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return magnitude;
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}
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// Get the angle between vectors:
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static inline double angleBetweenVectors(xyVector * vectorA, xyVector * vectorB)
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{
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double dotProduct = (vectorA->xComponent * vectorB->xComponent) + (vectorA->yComponent * vectorB->yComponent);
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double determinant = (vectorA->xComponent * vectorB->yComponent) - (vectorA->yComponent * vectorB->xComponent);
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return atan2(dotProduct, determinant) / 0.01745329;
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}
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// Rotate XY vector by a given number of degrees:
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static inline void rotateXYVector(xyVector * vector, double degrees)
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{
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double xComponent = vector->xComponent, yComponent = vector->yComponent;
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vector->xComponent = (cos(degrees * 0.01745329) * xComponent) - (sin(degrees * 0.01745329) * yComponent);
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vector->yComponent = (sin(degrees * 0.01745329) * xComponent) + (cos(degrees * 0.01745329) * yComponent);
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}
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// Add vector B to vector A:
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static inline void addXYVector(xyVector * vectorA, xyVector * vectorB)
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{
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vectorA->xComponent += vectorB->xComponent;
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vectorA->yComponent += vectorB->yComponent;
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}
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// Add vector B to vector A, scaled for units per frame:
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static inline void addXYVectorDeltaScaled(xyVector * vectorA, xyVector * vectorB, double deltaTime)
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{
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vectorA->xComponent += vectorB->xComponent * (0.001 * deltaTime) * 60;
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vectorA->yComponent += vectorB->yComponent * (0.001 * deltaTime) * 60;
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}
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// Multiply a vector by a scalar constant:
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static inline void multiplyXYVector(xyVector * vector, double scalar)
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{
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vector->xComponent *= scalar;
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vector->yComponent *= scalar;
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}
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void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32_t radius)
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{
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const int32_t diameter = (radius * 2);
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int32_t x = (radius - 1);
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int32_t y = 0;
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int32_t tx = 1;
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int32_t ty = 1;
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int32_t error = (tx - diameter);
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while (x >= y)
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{
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// Each of the following renders an octant of the circle
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SDL_RenderDrawPoint(renderer, centreX + x, centreY - y);
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SDL_RenderDrawPoint(renderer, centreX + x, centreY + y);
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SDL_RenderDrawPoint(renderer, centreX - x, centreY - y);
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SDL_RenderDrawPoint(renderer, centreX - x, centreY + y);
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SDL_RenderDrawPoint(renderer, centreX + y, centreY - x);
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SDL_RenderDrawPoint(renderer, centreX + y, centreY + x);
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SDL_RenderDrawPoint(renderer, centreX - y, centreY - x);
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SDL_RenderDrawPoint(renderer, centreX - y, centreY + x);
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if (error <= 0)
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{
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++y;
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error += ty;
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ty += 2;
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}
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if (error > 0)
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{
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--x;
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tx += 2;
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error += (tx - diameter);
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}
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}
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}
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void calculateGravity(xyVector * starPosition, ship * shipUnderGravity)
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{
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// Calculate the vector between the star and ship:
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xyVectorBetweenPoints(shipUnderGravity->position.xComponent, shipUnderGravity->position.yComponent,
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starPosition->xComponent, starPosition->yComponent, &shipUnderGravity->gravity);
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// Make it into a unit vector:
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double gravityMagnitude = normalizeXYVector(&shipUnderGravity->gravity);
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double gravityAcceleration = 0;
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// Calculate the gravity between the star and ship:
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if(gravityMagnitude != 0)
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{
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if(gravityMagnitude >= 116)
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{
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gravityAcceleration = pow(2, (3000 / (pow(gravityMagnitude, 2)))) / 8;
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}
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else
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{
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gravityAcceleration = 1;
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}
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}
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else
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{
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gravityAcceleration = 1;
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}
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if(gravityAcceleration < 0.01)
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{
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gravityAcceleration = 0.01;
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}
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// Scale the vector:
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multiplyXYVector(&shipUnderGravity->gravity, gravityAcceleration);
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}
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// Create a ship with the given parameters:
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ship createShip(int width, int height, double positionX, double positionY, double velocityX, double velocityY, int number)
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{
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ship newShip;
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// Player number:
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newShip.number = number;
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// Rectangle to show the ship in:
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newShip.rectangle.w = width;
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newShip.rectangle.h = height;
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// Position:
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newShip.position.xComponent = positionX;
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newShip.position.yComponent = positionY;
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// Velocity:
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newShip.velocity.xComponent = velocityX;
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newShip.velocity.yComponent = velocityY;
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// Gravity:
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newShip.gravity.xComponent = 0;
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newShip.gravity.yComponent = 0;
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// Engine:
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newShip.engine.yComponent = 0;
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newShip.engine.xComponent = 0.1;
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return newShip;
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}
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playerController createShipPlayerController(ship * ship)
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{
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playerController newController;
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newController.number = ship->number;
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return newController;
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}
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static inline void takeNetworkInput(playerController * controller, int descriptor)
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{
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recvfrom(descriptor, controller, sizeof(playerController), 0, NULL, NULL);
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}
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void doShipInput(playerController * controller, ship * ship, xyVector starPosition, double deltaTime)
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{
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if(controller->number == ship->number)
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{
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// Calculate the gravity for the ships:
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calculateGravity(&starPosition, ship);
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// Rotate the engine vector if needed:
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if (controller->turningClockwise)
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{
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rotateXYVector(&ship->engine, 0.25 * deltaTime);
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}
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if (controller->turningAnticlockwise)
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{
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rotateXYVector(&ship->engine, -0.25 * deltaTime);
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}
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// Calculate the new current velocity:
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addXYVectorDeltaScaled(&ship->velocity, &ship->gravity, deltaTime);
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if (controller->accelerating)
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{
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addXYVectorDeltaScaled(&ship->velocity, &ship->engine, deltaTime);
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}
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// Calculate the new position:
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addXYVectorDeltaScaled(&ship->position, &ship->velocity, deltaTime);
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}
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}
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int main(int argc, char ** argv)
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{
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SDL_Event event;
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int width = 0, height = 0;
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uint32_t rendererFlags = SDL_RENDERER_ACCELERATED;
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uint64_t thisFrameTime = SDL_GetPerformanceCounter(), lastFrameTime = 0;
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long starPositionX = 0, starPositionY = 0;
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double deltaTime = 0, frameAccumulator = 0;
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bool quit = false, rotatingClockwise = false, rotatingAnticlockwise = false, accelerating = false;
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xyVector engineVector = {0.85, 0}, upVector = {0, 0.1}, starPosition = {0, 0};
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// Create the socket:
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int sendSocket = socket(AF_INET, SOCK_DGRAM, 0);
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if (sendSocket < 0)
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{
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fprintf(stderr, "\tSocket Creation is:\t\033[33;40mRED.\033[0m Aborting launch.\n");
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exit(0);
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}
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printf("\tSocket Creation is:\t\033[32;40mGREEN.\033[0m\n");
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// Create and fill the information needed to bind to the socket:
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struct sockaddr_in sendAddress;
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sendAddress.sin_family = AF_INET; // IPv4
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sendAddress.sin_addr.s_addr = inet_addr("127.0.0.1");
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sendAddress.sin_port = htons(12000);
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int receiveSocket = socket(AF_INET, SOCK_DGRAM, 0);
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if (receiveSocket < 0)
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{
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fprintf(stderr, "\tSocket Creation is:\t\033[33;40mRED.\033[0m Aborting launch.\n");
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exit(0);
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}
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printf("\tSocket Creation is:\t\033[32;40mGREEN.\033[0m\n");
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// Make the socket timeout:
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struct timeval readTimeout;
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readTimeout.tv_sec = 0;
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readTimeout.tv_usec = 800;
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setsockopt(receiveSocket, SOL_SOCKET, SO_RCVTIMEO, &readTimeout, sizeof(readTimeout));
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// Create and fill the information needed to bind to the socket:
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struct sockaddr_in receiveAddress;
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memset(&receiveAddress, 0, sizeof(receiveAddress));
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receiveAddress.sin_family = AF_INET; // IPv4
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receiveAddress.sin_addr.s_addr = INADDR_ANY;
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receiveAddress.sin_port = htons(12001);
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// Bind to the socket:
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if (bind(receiveSocket, (const struct sockaddr *)&receiveAddress, sizeof(receiveAddress)) < 0)
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{
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perror("bind failed");
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exit(EXIT_FAILURE);
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}
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ship shipA = createShip(32, 32, 512, 512, 1, 0, 0);
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ship shipB = createShip(32, 32, -512, -512, 0, 1, 1);
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// Initialize the SDL library, video, sound, and input:
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if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
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{
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printf("SDL Initialization Error: %s\n", SDL_GetError());
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}
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// Check for joysticks:
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SDL_Joystick * controller = NULL;
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SDL_Haptic * haptic = NULL;
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if (SDL_NumJoysticks() < 1 )
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{
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printf( "Warning: No joysticks connected!\n" );
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}
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else
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{
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// Load joystick
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controller = SDL_JoystickOpen(0);
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if (controller == NULL )
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{
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printf( "Warning: Unable to open game controller! SDL Error: %s\n", SDL_GetError() );
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}
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haptic = SDL_HapticOpenFromJoystick(controller);
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SDL_HapticRumbleInit(haptic);
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}
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// Initialize image loading:
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IMG_Init(IMG_INIT_PNG);
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SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2");
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SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");
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// Create an SDL window and rendering context in that window:
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SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 700, 700, 0);
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SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags);
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SDL_SetWindowTitle(window, "Spacewar!");
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// Load in all of our textures:
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SDL_Texture * idleTexture, * acceleratingTexture, * clockwiseTexture, * anticlockwiseTexture, * currentTexture,
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* acceleratingTexture2;
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idleTexture = IMG_LoadTexture(renderer, "./Images/Ship-Idle.png");
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clockwiseTexture = IMG_LoadTexture(renderer, "./Images/Ship-Clockwise.png");
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acceleratingTexture = IMG_LoadTexture(renderer, "./Images/Ship-Accelerating.png");
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anticlockwiseTexture = IMG_LoadTexture(renderer, "./Images/Ship-Anticlockwise.png");
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acceleratingTexture2 = IMG_LoadTexture(renderer, "./Images/Ship-Accelerating-Frame-2.png");
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currentTexture = acceleratingTexture;
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// Enable resizing the window:
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SDL_SetWindowResizable(window, SDL_TRUE);
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playerController playerOne = createShipPlayerController(&shipA);
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playerController playerTwo = createShipPlayerController(&shipB);
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while (!quit)
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{
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lastFrameTime = thisFrameTime;
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thisFrameTime = SDL_GetPerformanceCounter();
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deltaTime = (double)(((thisFrameTime - lastFrameTime) * 1000) / (double)SDL_GetPerformanceFrequency());
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sendto(sendSocket, &shipA, sizeof(ship), 0, (const struct sockaddr *)&sendAddress, sizeof(sendAddress));
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sendto(sendSocket, &shipB, sizeof(ship), 0, (const struct sockaddr *)&sendAddress, sizeof(sendAddress));
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// Store the window's current width and height:
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SDL_GetWindowSize(window, &width, &height);
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// Check input:
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while (SDL_PollEvent(&event))
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{
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switch (event.type)
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{
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case SDL_QUIT:
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{
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quit = true;
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break;
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}
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case SDL_KEYDOWN:
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{
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switch (event.key.keysym.sym)
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{
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case SDLK_LEFT:
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{
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playerOne.turningAnticlockwise = true;
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break;
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}
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case SDLK_RIGHT:
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{
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playerOne.turningClockwise = true;
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break;
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}
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case SDLK_UP:
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{
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playerOne.accelerating = true;
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break;
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}
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default:
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{
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break;
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}
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}
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break;
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}
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case SDL_KEYUP:
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{
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switch (event.key.keysym.sym)
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{
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case SDLK_LEFT:
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{
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playerOne.turningAnticlockwise = false;
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break;
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}
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case SDLK_RIGHT:
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{
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playerOne.turningClockwise = false;
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break;
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}
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case SDLK_UP:
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{
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playerOne.accelerating = false;
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frameAccumulator = 0;
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break;
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}
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default:
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{
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break;
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}
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}
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break;
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}
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default:
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{
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break;
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}
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}
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}
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// Wrap the positions if the ship goes interstellar:
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if(shipA.position.xComponent > 4096)
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{
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shipA.position.xComponent = -2000;
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}
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else if(shipA.position.xComponent < -4096)
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{
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shipA.position.xComponent = 2000;
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}
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if(shipA.position.yComponent > 4096)
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{
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shipA.position.yComponent = -2000;
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}
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else if(shipA.position.yComponent < -4096)
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{
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shipA.position.yComponent = 2000;
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}
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if(shipB.position.xComponent > 4096)
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{
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shipB.position.xComponent = -2000;
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shipB.velocity.xComponent *= 0.9;
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}
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else if(shipB.position.xComponent < -4096)
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{
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shipB.position.xComponent = 2000;
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shipB.velocity.xComponent *= 0.9;
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}
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if(shipB.position.yComponent > 4096)
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{
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shipB.position.yComponent = -2000;
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shipB.velocity.yComponent *= 0.9;
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}
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else if(shipB.position.yComponent < -4096)
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{
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shipB.position.yComponent = 2000;
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shipB.velocity.yComponent *= 0.9;
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}
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//
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doShipInput(&playerOne, &shipA, starPosition, deltaTime);
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takeNetworkInput(&playerTwo, receiveSocket);
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doShipInput(&playerTwo, &shipB, starPosition, deltaTime);
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shipA.rectangle.x = (width/2) - 16 - (shipA.velocity.xComponent * 15);
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shipA.rectangle.y = (height/2) - 16 - (shipA.velocity.yComponent * 15);
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shipB.rectangle.x = (long)((((shipB.position.xComponent - shipA.position.xComponent) - 32) + width/2) - (shipA.velocity.xComponent * 15));
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shipB.rectangle.y = (long)((((shipB.position.yComponent - shipA.position.yComponent) - 32) + height/2) - (shipA.velocity.yComponent * 15));
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// Set the colour to black:
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SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
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// Clear the screen, filling it with black:
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SDL_RenderClear(renderer);
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// Draw the ship:
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SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipA.rectangle,
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angleBetweenVectors(&shipA.engine, &upVector) + 90, NULL, 0);
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SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipB.rectangle,
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angleBetweenVectors(&shipB.engine, &upVector) + 90, NULL, 0);
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// Set the colour to yellow:
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SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
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// Draw a circle as the star:
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DrawCircle(renderer, (long)(starPositionX - shipA.position.xComponent) + width/2 - (shipA.velocity.xComponent * 15),
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(long)(starPositionY - shipA.position.yComponent) + height/2 - (shipA.velocity.yComponent * 15), 50);
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// Draw a line representing the velocity:
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SDL_RenderDrawLine(renderer, width/2 - (shipA.velocity.xComponent * 15),
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height/2 - (shipA.velocity.yComponent * 15),
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(long)((width/2) + shipA.velocity.xComponent * 15) - (shipA.velocity.xComponent * 15),
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(long)((height/2) + shipA.velocity.yComponent * 15) - (shipA.velocity.yComponent * 15));
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// Set the colour to blue:
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SDL_SetRenderDrawColor(renderer, 0, 0, 255, 255);
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// Draw a line representing the direction of the star:
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normalizeXYVector(&shipA.gravity);
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multiplyXYVector(&shipA.gravity, 100);
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SDL_RenderDrawLine(renderer,
|
|
width/2 - (shipA.velocity.xComponent * 15),
|
|
height/2 - (shipA.velocity.yComponent * 15),
|
|
(width/2 - (shipA.velocity.xComponent * 15)) + shipA.gravity.xComponent,
|
|
((height/2) - (shipA.velocity.yComponent * 15)) + shipA.gravity.yComponent);
|
|
|
|
// Present the rendered graphics:
|
|
SDL_RenderPresent(renderer);
|
|
}
|
|
return 0;
|
|
}
|
|
// ========================================================================================================
|
|
// Local Variables:
|
|
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-18.c -lSDL2_image -lm -o 'Spacewar!'"
|
|
// End:
|