diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-01.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-01.c index 8314884..be343ca 100644 --- a/SDL2-Bits-And-Pieces/SDL2-Experiment-01.c +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-01.c @@ -64,11 +64,6 @@ int main(int argc, char ** argv) printf("SDL Initialization Error: %s\n", SDL_GetError()); } - if (SDL_Init(SDL_INIT_EVERYTHING) != 0) - { - printf("SDL Initialization Error: %s\n", SDL_GetError()); - } - IMG_Init(IMG_INIT_PNG); // Create an SDL window and rendering context in that window: diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-02.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-02.c index cca1cef..b3bdd72 100644 --- a/SDL2-Bits-And-Pieces/SDL2-Experiment-02.c +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-02.c @@ -64,11 +64,6 @@ int main(int argc, char ** argv) printf("SDL Initialization Error: %s\n", SDL_GetError()); } - if (SDL_Init(SDL_INIT_EVERYTHING) != 0) - { - printf("SDL Initialization Error: %s\n", SDL_GetError()); - } - IMG_Init(IMG_INIT_PNG); // Create an SDL window and rendering context in that window: diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-03.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-03.c index f648dfb..51ce1ef 100644 --- a/SDL2-Bits-And-Pieces/SDL2-Experiment-03.c +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-03.c @@ -64,11 +64,6 @@ int main(int argc, char ** argv) { printf("SDL Initialization Error: %s\n", SDL_GetError()); } - - if (SDL_Init(SDL_INIT_EVERYTHING) != 0) - { - printf("SDL Initialization Error: %s\n", SDL_GetError()); - } // Create an SDL window and rendering context in that window: SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 640, 0); diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-04.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-04.c index 712c9de..23e165c 100644 --- a/SDL2-Bits-And-Pieces/SDL2-Experiment-04.c +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-04.c @@ -64,11 +64,6 @@ int main(int argc, char ** argv) { printf("SDL Initialization Error: %s\n", SDL_GetError()); } - - if (SDL_Init(SDL_INIT_EVERYTHING) != 0) - { - printf("SDL Initialization Error: %s\n", SDL_GetError()); - } // Create an SDL window and rendering context in that window: SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 640, 0); diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-05.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-05.c index 67a9646..01904b1 100644 --- a/SDL2-Bits-And-Pieces/SDL2-Experiment-05.c +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-05.c @@ -60,11 +60,6 @@ int main(int argc, char ** argv) printf("SDL Initialization Error: %s\n", SDL_GetError()); } - if (SDL_Init(SDL_INIT_EVERYTHING) != 0) - { - printf("SDL Initialization Error: %s\n", SDL_GetError()); - } - // Create an SDL window and rendering context in that window: SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 640, 0); SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags); @@ -105,7 +100,7 @@ int main(int argc, char ** argv) gravityY /= gravityMagnitude; // Calculate the gravity between them and scale the vector: - if(gravityMagnitude > 15) + if(gravityMagnitude > 15) { gravityAcceleration = 2 * (2500 / pow(gravityMagnitude, 2)); gravityX *= gravityAcceleration; diff --git a/SDL2-Bits-And-Pieces/SDL2-Experiment-06.c b/SDL2-Bits-And-Pieces/SDL2-Experiment-06.c new file mode 100644 index 0000000..a150135 --- /dev/null +++ b/SDL2-Bits-And-Pieces/SDL2-Experiment-06.c @@ -0,0 +1,183 @@ +// SDL Experiment 06, Barra Ó Catháin. +// =================================== +#include +#include +#include +#include +#include + +void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32_t radius) +{ + 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); + + 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) + { + --x; + tx += 2; + error += (tx - diameter); + } + } +} + +int main(int argc, char ** argv) +{ + SDL_Event event; + bool quit = false; + int width = 0, height = 0; + uint64_t thisFrameTime = SDL_GetPerformanceCounter(), lastFrameTime = 0; + uint32_t rendererFlags = SDL_RENDERER_ACCELERATED; + double posX = 0, posY = 0, deltaTime = 0; + long positionX = 0, positionY = 0; + double velocityX = 20, velocityY = 0, gravityX = 0, gravityY = 0, gravityMagnitude = 0, gravityAcceleration = 0; + + // Initialize the SDL library, video, sound, and input: + if (SDL_Init(SDL_INIT_EVERYTHING) != 0) + { + printf("SDL Initialization Error: %s\n", SDL_GetError()); + } + + // Create an SDL window and rendering context in that window: + SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 640, 0); + SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags); + + // Enable resizing the window: + SDL_SetWindowResizable(window, SDL_TRUE); + + while (!quit) + { + lastFrameTime = thisFrameTime; + thisFrameTime = SDL_GetPerformanceCounter(); + deltaTime = (double)(((thisFrameTime - lastFrameTime) * 1000) / (double)SDL_GetPerformanceFrequency()); + + // Check if the user wants to quit: + while (SDL_PollEvent(&event)) + { + switch (event.type) + { + case SDL_QUIT: + { + quit = true; + break; + } + default: + { + break; + } + } + } + + // Store the window's current width and height: + SDL_GetWindowSize(window, &width, &height); + + // Calculate the gravity vector: + // Calculate the vector between the star and ship: + gravityX = (width/2 - posX); + gravityY = (height/2 - posY); + + // Make it into a unit vector: + gravityMagnitude = sqrt(pow(gravityX, 2) + pow(gravityY, 2)); + gravityX /= gravityMagnitude; + gravityY /= gravityMagnitude; + + // Calculate the gravity between them and scale the vector: + if(gravityMagnitude > 15) + { + gravityAcceleration = 2 * (2500 / pow(gravityMagnitude, 2)); + gravityX *= gravityAcceleration; + gravityY *= gravityAcceleration; + } + else + { + gravityAcceleration = 0.02 * (2500 / pow(gravityMagnitude, 2)); + gravityX *= gravityAcceleration; + gravityY *= gravityAcceleration; + } + + // Wrap the position if the ship goes off-screen: + if(posX > width + 15) + { + posX = 0; + velocityX *= 0.6; + } + if(posY > height + 15) + { + posY = 0; + velocityY *= 0.6; + } + if(posX < -15) + { + posX = width; + velocityX *= 0.6; + } + if(posY < -15) + { + posY = height; + velocityY *= 0.6; + } + + // Calculate the new current velocity: + velocityX += gravityX * (deltaTime * 0.001) * 60; + velocityY += gravityY * (deltaTime * 0.001) * 60; + + // Calculate the new position: + posX += velocityX * (deltaTime * 0.001) * 60; + posY += velocityY * (deltaTime * 0.001) * 60; + + positionX = (long)posX; + positionY = (long)posY; + + // Set the colour to black: + SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); + + // Clear the screen, filling it with black: + SDL_RenderClear(renderer); + + // Set the colour to green: + SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255); + + // Draw a circle "ship" around the current position: + DrawCircle(renderer, positionX, positionY, 15); + + // Set the colour to yellow: + SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255); + + // Draw a circle in the center as the star: + DrawCircle(renderer, width/2, height/2, 30); + + // Draw a line representing the velocity: + SDL_RenderDrawLine(renderer, positionX, positionY, (long)(posX + velocityX * 3), (long)(posY + velocityY * 3)); + + // Present the rendered graphics: + SDL_RenderPresent(renderer); + } + return 0; +} +// =========================================================================================== +// Local Variables: +// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-06.c -lm" +// End: