44 lines
1.0 KiB
C
44 lines
1.0 KiB
C
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#ifndef SPACEWAR_GRAPHICS_H
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#define SPACEWAR_GRAPHICS_H
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#include <SDL2/SDL.h>
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static inline 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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#endif
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