73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
//
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// Created by Wouter Groeneveld on 14/12/18.
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//
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#include <libgba-sprite-engine/vectorfx.h>
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std::deque<VECTOR> VectorFx::bresenhamLineTo(VECTOR dest) {
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// https://www.coranac.com/tonc/text/bitmaps.htm - Bresenham's line algorithm with fixed points
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VECTOR src = this->v;
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VECTOR step, delta;
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std::deque<VECTOR> coords;
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if(src.x > dest.x) {
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step.x = -1;
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delta.x = (src.x - dest.x);
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} else {
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step.x = +1;
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delta.x = (dest.x - src.x);
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}
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if(src.y > dest.y) {
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step.y = -1;
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delta.y = (src.y - dest.y);
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} else {
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step.y = +1;
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delta.y = (dest.y - src.y);
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}
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int dd, x = src.x, y = src.y, ii;
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if(delta.y == 0) {
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// horizontal
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for(ii = 0; ii <= delta.x; ii++) {
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coords.push_back({x, y});
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x += step.x;
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}
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} else if(delta.x == 0) {
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// vertical
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for(ii = 0; ii <= delta.y; ii++) {
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coords.push_back({x, y});
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y += step.y;
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}
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} else if(delta.x >= delta.y) {
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// Diagonal, slopeFx <= 1
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dd = 2 * delta.y - delta.x;
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for(ii = 0; ii <= delta.x; ii++) {
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coords.push_back({x, y});
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if(dd >= 0) {
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dd -= 2 * delta.x;
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y += step.y;
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}
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dd += 2 * delta.y;
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x += step.x;
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}
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} else {
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// Diagonal, slopeFx > 1
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dd = 2 * delta.x - delta.y;
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for(ii = 0; ii <= delta.y; ii++) {
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coords.push_back({x, y});
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if(dd >= 0) {
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dd -= 2 * delta.y;
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x += step.x;
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}
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dd += 2 * delta.x;
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y += step.y;
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}
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}
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return coords;
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} |