Added a second ship to the simulation.

This commit is contained in:
Barra Ó Catháin 2023-03-16 00:27:43 +00:00
parent 2605f681f6
commit 89befd110f
6 changed files with 173 additions and 107 deletions

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@ -1,4 +1,4 @@
// SDL Experiment 12, Barra Ó Catháin.
// SDL Experiment 13, Barra Ó Catháin.
// ===================================
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
@ -7,12 +7,22 @@
#include <stdbool.h>
#include <stdint.h>
// A 2D vector:
typedef struct xyVector
{
double xComponent;
double yComponent;
} xyVector;
// A struct storing the needed data to draw a ship:
typedef struct ship
{
SDL_Rect rectangle;
xyVector position;
xyVector velocity;
xyVector gravity;
} ship;
// Calculate the vector from point A to point B:
static inline void xyVectorBetweenPoints(long ax, long ay, long bx, long by, xyVector * vector)
{
@ -24,8 +34,11 @@ static inline void xyVectorBetweenPoints(long ax, long ay, long bx, long by, xyV
static inline double normalizeXYVector(xyVector * vector)
{
double magnitude = sqrt(pow(vector->xComponent, 2) + pow(vector->yComponent, 2));
vector->xComponent /= magnitude;
vector->yComponent /= magnitude;
if(magnitude != 0)
{
vector->xComponent /= magnitude;
vector->yComponent /= magnitude;
}
return magnitude;
}
@ -38,6 +51,7 @@ static inline double angleBetweenVectors(xyVector * vectorA, xyVector * vectorB)
return atan2(dotProduct, determinant) / 0.01745329;
}
// Rotate XY vector by a given number of degrees:
static inline void rotateXYVector(xyVector * vector, double degrees)
{
double xComponent = vector->xComponent, yComponent = vector->yComponent;
@ -65,42 +79,94 @@ static inline void multiplyXYVector(xyVector * vector, double scalar)
vector->xComponent *= scalar;
vector->yComponent *= scalar;
}
void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32_t radius)
{
const int32_t diameter = (radius * 2);
const int32_t diameter = (radius * 2);
int32_t x = (radius - 1);
int32_t y = 0;
int32_t tx = 1;
int32_t ty = 1;
int32_t error = (tx - diameter);
int32_t x = (radius - 1);
int32_t y = 0;
int32_t tx = 1;
int32_t ty = 1;
int32_t error = (tx - diameter);
while (x >= y)
{
// Each of the following renders an octant of the circle
SDL_RenderDrawPoint(renderer, centreX + x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX + x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX + y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX + y, centreY + x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY + x);
while (x >= y)
{
// Each of the following renders an octant of the circle
SDL_RenderDrawPoint(renderer, centreX + x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX + x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX + y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX + y, centreY + x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY + x);
if (error <= 0)
{
++y;
error += ty;
ty += 2;
}
if (error <= 0)
{
++y;
error += ty;
ty += 2;
}
if (error > 0)
{
--x;
tx += 2;
error += (tx - diameter);
}
}
if (error > 0)
{
--x;
tx += 2;
error += (tx - diameter);
}
}
}
void calculateGravity(xyVector * starPosition, ship * shipUnderGravity)
{
// Calculate the vector between the star and ship:
xyVectorBetweenPoints(shipUnderGravity->position.xComponent, shipUnderGravity->position.yComponent,
starPosition->xComponent, starPosition->yComponent, &shipUnderGravity->gravity);
// Make it into a unit vector:
double gravityMagnitude = normalizeXYVector(&shipUnderGravity->gravity);
double gravityAcceleration = 0;
// Calculate the gravity between the star and ship:
if(gravityMagnitude != 0)
{
if(gravityMagnitude >= 116)
{
gravityAcceleration = 0.1 * (35000 / (pow(gravityMagnitude, 2)));
}
else
{
gravityAcceleration = 0;
}
}
else
{
gravityAcceleration = 1;
}
if(gravityAcceleration < 0.01)
{
gravityAcceleration = 0.01;
}
// Scale the vector:
multiplyXYVector(&shipUnderGravity->gravity, gravityAcceleration);
}
// Create a ship with the given parameters:
ship createShip(int width, int height, double positionX, double positionY, double velocityX, double velocityY)
{
ship newShip;
newShip.rectangle.w = width;
newShip.rectangle.h = height;
newShip.position.xComponent = positionX;
newShip.position.yComponent = positionY;
newShip.velocity.xComponent = velocityX;
newShip.velocity.yComponent = velocityY;
newShip.gravity.xComponent = 0;
newShip.gravity.yComponent = 0;
return newShip;
}
int main(int argc, char ** argv)
@ -112,8 +178,13 @@ int main(int argc, char ** argv)
long positionX = 512, positionY = 512, starPositionX = 0, starPositionY = 0;
double deltaTime = 0, gravityMagnitude = 0, gravityAcceleration = 0, frameAccumulator = 0;
bool quit = false, rotatingClockwise = false, rotatingAnticlockwise = false, accelerating = false;
xyVector positionVector = {512, 512}, velocityVector = {1, 0}, gravityVector = {0, 0}, engineVector = {0.16, 0}, upVector = {0, 0.1};
xyVector positionVector = {512, 512}, velocityVector = {1, 0}, gravityVector = {0, 0},
engineVector = {0.04, 0}, upVector = {0, 0.1}, starPosition = {0, 0};
// Get the initial
ship shipA = createShip(32, 32, 512, 512, 1, 0);
ship shipB = createShip(32, 32, -512, -512, 0, 1);
// Initialize the SDL library, video, sound, and input:
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
{
@ -123,12 +194,7 @@ int main(int argc, char ** argv)
// Initialize image loading:
IMG_Init(IMG_INIT_PNG);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2");
// Create a rectangle to put the ship in:
SDL_Rect shipRect;
shipRect.w = 32;
shipRect.h = 32;
// Create an SDL window and rendering context in that window:
SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 700, 700, 0);
SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags);
@ -137,11 +203,11 @@ int main(int argc, char ** argv)
SDL_Texture * idleTexture, * acceleratingTexture, * clockwiseTexture, * anticlockwiseTexture, * currentTexture,
* acceleratingTexture2;
idleTexture = IMG_LoadTexture(renderer, "./Experiment-12-Images/Ship-Idle.png");
clockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-12-Images/Ship-Clockwise.png");
acceleratingTexture = IMG_LoadTexture(renderer, "./Experiment-12-Images/Ship-Accelerating.png");
anticlockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-12-Images/Ship-Anticlockwise.png");
acceleratingTexture2 = IMG_LoadTexture(renderer, "./Experiment-12-Images/Ship-Accelerating-Frame-2.png");
idleTexture = IMG_LoadTexture(renderer, "./Experiment-13-Images/Ship-Idle.png");
clockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-13-Images/Ship-Clockwise.png");
acceleratingTexture = IMG_LoadTexture(renderer, "./Experiment-13-Images/Ship-Accelerating.png");
anticlockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-13-Images/Ship-Anticlockwise.png");
acceleratingTexture2 = IMG_LoadTexture(renderer, "./Experiment-13-Images/Ship-Accelerating-Frame-2.png");
// Enable resizing the window:
SDL_SetWindowResizable(window, SDL_TRUE);
@ -157,7 +223,7 @@ int main(int argc, char ** argv)
{
switch (event.type)
{
case SDL_QUIT:
case SDL_QUIT:
{
quit = true;
break;
@ -222,62 +288,55 @@ int main(int argc, char ** argv)
}
}
// Wrap the position if the ship goes interstellar:
if(positionVector.xComponent > 4096)
// Wrap the positions if the ship goes interstellar:
if(shipA.position.xComponent > 4096)
{
positionVector.xComponent = -2000;
velocityVector.xComponent *= 0.9;
shipA.position.xComponent = -2000;
shipA.velocity.xComponent *= 0.9;
}
else if(positionVector.xComponent < -4096)
else if(shipA.position.xComponent < -4096)
{
positionVector.xComponent = 2000;
velocityVector.xComponent *= 0.9;
shipA.position.xComponent = 2000;
shipA.velocity.xComponent *= 0.9;
}
if(shipA.position.yComponent > 4096)
{
shipA.position.yComponent = -2000;
shipA.velocity.yComponent *= 0.9;
}
else if(shipA.position.yComponent < -4096)
{
shipA.position.yComponent = 2000;
shipA.velocity.yComponent *= 0.9;
}
if(positionVector.yComponent > 4096)
if(shipB.position.xComponent > 4096)
{
positionVector.yComponent = -2000;
velocityVector.yComponent *= 0.9;
shipB.position.xComponent = -2000;
shipB.velocity.xComponent *= 0.9;
}
else if(positionVector.yComponent < -4096)
else if(shipB.position.xComponent < -4096)
{
positionVector.yComponent = 2000;
velocityVector.yComponent *= 0.9;
shipB.position.xComponent = 2000;
shipB.velocity.xComponent *= 0.9;
}
if(shipB.position.yComponent > 4096)
{
shipB.position.yComponent = -2000;
shipB.velocity.yComponent *= 0.9;
}
else if(shipB.position.yComponent < -4096)
{
shipB.position.yComponent = 2000;
shipB.velocity.yComponent *= 0.9;
}
// Store the window's current width and height:
SDL_GetWindowSize(window, &width, &height);
// Calculate the vector between the star and ship:
xyVectorBetweenPoints(positionVector.xComponent, positionVector.yComponent, starPositionX, starPositionY, &gravityVector);
// Make it into a unit vector:
gravityMagnitude = normalizeXYVector(&gravityVector);
// Calculate the gravity between the star and ship:
if(gravityMagnitude != 0)
{
if(gravityMagnitude >= 215)
{
gravityAcceleration = 10 * (9000 / (pow(gravityMagnitude, 2)));
}
else
{
gravityAcceleration = 0.5 * (5000 / (pow(gravityMagnitude, 2)));
}
}
else
{
gravityAcceleration = 1;
}
if(gravityAcceleration < 0.01)
{
gravityAcceleration = 0.01;
}
// Scale the vector:
multiplyXYVector(&gravityVector, gravityAcceleration);
// Calculate the gravity for the ships:
calculateGravity(&starPosition, &shipA);
calculateGravity(&starPosition, &shipB);
// Set the texture to idle:
currentTexture = idleTexture;
@ -295,10 +354,12 @@ int main(int argc, char ** argv)
}
// Calculate the new current velocity:
addXYVectorDeltaScaled(&velocityVector, &gravityVector, deltaTime);
addXYVectorDeltaScaled(&shipA.velocity, &shipA.gravity, deltaTime);
addXYVectorDeltaScaled(&shipB.velocity, &shipB.gravity, deltaTime);
if(accelerating)
{
addXYVectorDeltaScaled(&velocityVector, &engineVector, deltaTime);
addXYVectorDeltaScaled(&shipA.velocity, &engineVector, deltaTime);
frameAccumulator += deltaTime;
currentTexture = acceleratingTexture;
if((long)frameAccumulator % 4)
@ -308,14 +369,15 @@ int main(int argc, char ** argv)
}
// Calculate the new position:
addXYVectorDeltaScaled(&positionVector, &velocityVector, deltaTime);
addXYVectorDeltaScaled(&shipA.position, &shipA.velocity, deltaTime);
addXYVectorDeltaScaled(&shipB.position, &shipB.velocity, deltaTime);
positionX = (long)positionVector.xComponent;
positionY = (long)positionVector.yComponent;
// Calculate the position of the sprites:
shipA.rectangle.x = (width/2) - 16;
shipA.rectangle.y = (height/2) - 16;
// Calculate the position of the sprite:
shipRect.x = (width/2) - 15;
shipRect.y = (height/2) - 15;
shipB.rectangle.x = (long)(((shipB.position.xComponent - shipA.position.xComponent) - 32) + width/2);
shipB.rectangle.y = (long)(((shipB.position.yComponent - shipA.position.yComponent) - 32) + height/2);
// Set the colour to black:
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
@ -324,28 +386,32 @@ int main(int argc, char ** argv)
SDL_RenderClear(renderer);
// Draw the ship:
SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipRect, angleBetweenVectors(&engineVector, &upVector) + 90, NULL, 0);
SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipA.rectangle,
angleBetweenVectors(&engineVector, &upVector) + 90, NULL, 0);
SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipB.rectangle,
angleBetweenVectors(&shipB.velocity, &upVector) + 90, NULL, 0);
// Set the colour to yellow:
SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
// Draw a circle as the star:
DrawCircle(renderer, (long)(starPositionX - positionX) + width/2, (long)(starPositionY - positionY) + height/2 , 200);
DrawCircle(renderer, (long)(starPositionX - shipA.position.xComponent) + width/2,
(long)(starPositionY - shipA.position.yComponent) + height/2, 50);
// Draw a line representing the velocity:
SDL_RenderDrawLine(renderer, width/2, height/2,
(long)((width/2) + velocityVector.xComponent * 15),
(long)((height/2) + velocityVector.yComponent * 15));
(long)((width/2) + shipA.velocity.xComponent * 15),
(long)((height/2) + shipA.velocity.yComponent * 15));
// Set the colour to blue:
SDL_SetRenderDrawColor(renderer, 0, 0, 255, 255);
// Draw a line representing the direction of the star:
normalizeXYVector(&gravityVector);
multiplyXYVector(&gravityVector, 100);
normalizeXYVector(&shipA.gravity);
multiplyXYVector(&shipA.gravity, 100);
SDL_RenderDrawLine(renderer, width/2, height/2,
(long)((width/2) + gravityVector.xComponent),
(long)((height/2) + gravityVector.yComponent));
(long)((width/2) + shipA.gravity.xComponent),
(long)((height/2) + shipA.gravity.yComponent));
// Present the rendered graphics:
SDL_RenderPresent(renderer);
@ -354,5 +420,5 @@ int main(int argc, char ** argv)
}
// ===========================================================================================
// Local Variables:
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-12.c -lSDL2_image -lm"
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-13.c -lSDL2_image -lm"
// End: