107 lines
2.2 KiB
C
107 lines
2.2 KiB
C
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#include "SDL.h"
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#include <math.h>
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#include <stdbool.h>
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#include <assert.h>
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#include "draw.h"
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#include "config.h"
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void drawPixel(int x, int y, int color) {
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assert(x < SCREEN_WIDTH && x >= 0);
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assert(y < SCREEN_HEIGHT && y >= 0);
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unsigned int *p = (unsigned int*)screen->pixels;
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int lineOffset = y * (screen->pitch/4);
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p[lineOffset+x] = color;
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}
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int _sign(float a) {
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return a > 0 ? 1 : (a < 0 ? -1 : 0);
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}
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float _random(float from, float to) {
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assert(from < to);
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return ((to-from)*((float)rand()/RAND_MAX))+from;
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}
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void drawLine(int x1, int y1, int x2, int y2, int color) {
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float u, s, v, d1x, d1y, d2x, d2y, m, n;
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int x = x1, y = y1;
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u = x2-x1;
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v = y2-y1;
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d1x = d2x = _sign(u);
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d1y = _sign(v);
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d2y = 0;
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m = abs(u);
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n = abs(v);
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if (m <= n) {
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d2x = 0;
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d2y = _sign(v);
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m = abs(v);
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n = abs(u);
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}
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s = (int)(m/2);
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for (int i=0; i<round(m); i++) {
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drawPixel(x, y, color);
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s += n;
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if (s >= m) {
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s -= m;
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x += d1x;
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y += d1y;
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} else {
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x += d2x;
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y += d2y;
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}
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}
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}
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void drawRect(int x1, int y1, int x2, int y2, int color, bool filled) {
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int tmp;
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if (x1 > x2) { tmp = x1; x2 = x1; x1 = tmp; }
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if (y1 > y2) { tmp = y1; y2 = y1; y1 = tmp; }
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if (filled) {
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for (int i=y1; i<=y2; i++) drawLine(x1, i, x2, i, color);
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} else {
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drawLine(x1, y1, x2, y1, color);
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drawLine(x1, y1, x1, y2, color);
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drawLine(x2, y1, x2, y2, color);
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drawLine(x1, y2, x2, y2, color);
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}
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}
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void drawCircle(int x, int y, int radius, int color, bool filled) {
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// TODO: Write some code in here!
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}
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int* generateTerrain(float peakheight, float flatness) {
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float offset = (float)SCREEN_HEIGHT/2;
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float r1 = _random(1.0, 5.0);
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float r2 = _random(1.0, 5.0);
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float r3 = _random(1.0, 5.0);
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int *yvals = (int*)malloc(SCREEN_WIDTH*sizeof(int));
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if (DEBUG) printf("Generate new terrain with randoms: r1=%f, r2=%f, r3=%f\n", r1, r2, r3);
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for (int x=0; x<SCREEN_WIDTH; x++) {
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float y;
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y = peakheight/r1*sin((x/flatness*r1)+r1);
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y += peakheight/r2*sin((x/flatness*r2)+r2);
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y += peakheight/r3*sin((x/flatness*r3)+r3);
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y += offset;
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yvals[x] = (int)y;
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}
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return &(yvals[0]);
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}
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