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Spacewar
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Added basic ship controls.

This commit is contained in:
Barra Ó Catháin 2023-03-15 23:49:26 +00:00
parent 9402a97ab7
commit e828b4b70a
1 changed files with 97 additions and 29 deletions
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116
Spacewar.c
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@ -1,4 +1,4 @@
// SDL Experiment 08, Barra Ó Catháin.
// SDL Experiment 09, Barra Ó Catháin.
// ===================================
#include <SDL2/SDL.h>
#include <SDL2/SDL_timer.h>
@ -28,6 +28,13 @@ static inline double normalizeXYVector(xyVector * vector)
return magnitude;
}
static inline void rotateXYVector(xyVector * vector, double degrees)
{
double xComponent = vector->xComponent, yComponent = vector->yComponent;
vector->xComponent = (cos(degrees * 0.01745329) * xComponent) - (sin(degrees * 0.01745329) * yComponent);
vector->yComponent = (sin(degrees * 0.01745329) * xComponent) + (cos(degrees * 0.01745329) * yComponent);
}
// Add vector B to vector A:
static inline void addXYVector(xyVector * vectorA, xyVector * vectorB)
{
@ -89,13 +96,13 @@ void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32
int main(int argc, char ** argv)
{
SDL_Event event;
bool quit = false;
int width = 0, height = 0;
long positionX = 0, positionY = 0;
int width = 0, height = 0, mouseX = 0, mouseY = 0;
uint32_t rendererFlags = SDL_RENDERER_ACCELERATED;
double deltaTime = 0, gravityMagnitude = 0, gravityAcceleration = 0;
uint64_t thisFrameTime = SDL_GetPerformanceCounter(), lastFrameTime = 0;
xyVector positionVector = {100, 100}, velocityVector = {20, 0}, gravityVector = {0, 0};
bool quit = false, rotatingClockwise = false, rotatingAnticlockwise = false, accelerating = false;
xyVector positionVector = {100, 100}, velocityVector = {0, 0}, gravityVector = {0, 0}, engineVector = {0.1, 0};
// Initialize the SDL library, video, sound, and input:
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
@ -126,6 +133,58 @@ int main(int argc, char ** argv)
quit = true;
break;
}
case SDL_KEYDOWN:
{
switch (event.key.keysym.sym)
{
case SDLK_LEFT:
{
rotatingAnticlockwise = true;
break;
}
case SDLK_RIGHT:
{
rotatingClockwise = true;
break;
}
case SDLK_UP:
{
accelerating = true;
break;
}
default:
{
break;
}
}
break;
}
case SDL_KEYUP:
{
switch (event.key.keysym.sym)
{
case SDLK_LEFT:
{
rotatingAnticlockwise = false;
break;
}
case SDLK_RIGHT:
{
rotatingClockwise = false;
break;
}
case SDLK_UP:
{
accelerating = false;
break;
}
default:
{
break;
}
}
break;
}
default:
{
break;
@ -136,25 +195,16 @@ int main(int argc, char ** argv)
// Store the window's current width and height:
SDL_GetWindowSize(window, &width, &height);
// Store the mouse pointer's current position in the window:
SDL_GetMouseState(&mouseX, &mouseY);
// Calculate the vector between the star and ship:
xyVectorBetweenPoints(positionVector.xComponent, positionVector.yComponent, mouseX, mouseY, &gravityVector);
xyVectorBetweenPoints(positionVector.xComponent, positionVector.yComponent, width/2, height/2, &gravityVector);
// Make it into a unit vector:
gravityMagnitude = normalizeXYVector(&gravityVector);
// Calculate the gravity between the star and ship:
if(gravityMagnitude > 45)
{
gravityAcceleration = 2 * (2500 / pow(gravityMagnitude, 2));
}
else
{
gravityAcceleration = 0;
multiplyXYVector(&velocityVector, -0.98);
}
gravityAcceleration = (gravityMagnitude >= 45) ?
0.5 * (2500 / pow(gravityMagnitude, 2)):
0;
// Scale the vector:
multiplyXYVector(&gravityVector, gravityAcceleration);
@ -180,9 +230,22 @@ int main(int argc, char ** argv)
positionVector.yComponent = height;
velocityVector.yComponent *= 0.6;
}
// Rotate the engine vector if needed:
if(rotatingClockwise)
{
rotateXYVector(&engineVector, 0.1);
}
if(rotatingAnticlockwise)
{
rotateXYVector(&engineVector, -0.1);
}
// Calculate the new current velocity:
addXYVectorDeltaScaled(&velocityVector, &gravityVector, deltaTime);
if(accelerating)
{
addXYVectorDeltaScaled(&velocityVector, &engineVector, deltaTime);
}
// Calculate the new position:
addXYVectorDeltaScaled(&positionVector, &velocityVector, deltaTime);
@ -206,22 +269,27 @@ int main(int argc, char ** argv)
SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
// Draw a circle in the center as the star:
DrawCircle(renderer, mouseX, mouseY, 30);
DrawCircle(renderer, width/2, height/2, 30);
// Draw a line representing the velocity:
SDL_RenderDrawLine(renderer, positionX, positionY,
(long)(positionVector.xComponent + velocityVector.xComponent * 3),
(long)(positionVector.yComponent + velocityVector.yComponent * 3));
(long)(positionVector.xComponent + velocityVector.xComponent * 15),
(long)(positionVector.yComponent + velocityVector.yComponent * 15));
// Set the colour to blue:
SDL_SetRenderDrawColor(renderer, 0, 0, 255, 255);
// Draw a line showing the direction the engine will accelerate:
SDL_RenderDrawLine(renderer, positionX, positionY,
(long)(positionVector.xComponent + engineVector.xComponent * 300),
(long)(positionVector.yComponent + engineVector.yComponent * 300));
// Present the rendered graphics:
SDL_RenderPresent(renderer);
// Delay enough so that we run at 60 frames:
SDL_Delay(1000 / 144);
}
return 0;
}
// ===========================================================================================
// Local Variables:
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-08.c -lm"
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-09.c -lm"
// End: