A better triangle fill algorithm
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@ -49,3 +49,5 @@ def update():
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@ -1,6 +1,7 @@
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from scene import Scene
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from triangles import draw_line
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from triangles import lineTri
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import math
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white = 63
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fire1 = 6
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fire2 = 5
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@ -132,5 +133,24 @@ class Particles(Scene):
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text("Num Particles: " + str(len(self.fireParts) + len(self.waterParts)), 2, 15, 30)
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text("FPS: " + str(fps()), 3, 29, 59)
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text("FPS: " + str(fps()), 2, 28, 29)
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# triangle(10, 10, 50, 10, mouseX, mouseY, 5)
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# lineTri(10, 10, 50, 10, mouseX, mouseY, 9)
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pixel(mouseX, mouseY, 9)
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cx = width/2
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cy = height/2
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ang = math.atan2(mouseY - cy, mouseX - cx)
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dist = math.sqrt(math.pow(mouseX - cx, 2) + math.pow(mouseY - cy, 2))
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x2 = cx + cos(ang + (math.pi * 2 / 3)) * dist
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y2 = cy + sin(ang + (math.pi * 2 / 3)) * dist
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x3 = cx + cos(ang + (math.pi * 2 / 3 * 2)) * dist
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y3 = cy + sin(ang + (math.pi * 2 / 3 * 2)) * dist
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# triangle(mouseX, mouseY, x2, y2, x3, y3, 9)
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# lineTri(mouseX, mouseY, x2, y2, x3, y3, 8)
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@ -363,97 +363,148 @@ int Graphics::GetPixel(int x, int y) {
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return m_virtualScreenColorBuffer[y * m_screenWidth + x];
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}
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void Graphics::fillBottomFlatTriangle(float x1, float y1, float x2, float y2, float x3, float y3, int paletteIndex)
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// https://github.com/OneLoneCoder/olcPixelGameEngine/blob/master/olcPixelGameEngine.h#L2456
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void Graphics::Triangle(int32_t x1, int32_t y1, int32_t x2, int32_t y2, int32_t x3, int32_t y3, int paletteIndex)
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{
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float invslope1 = (x2 - x1) / (y2 - y1);
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float invslope2 = (x3 - x1) / (y3 - y1);
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auto drawline = [&](int sx, int ex, int ny) { for (int i = sx; i <= ex; i++) Pixel(i, ny, paletteIndex); };
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float curx1 = x1;
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float curx2 = x1;
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int t1x, t2x, y, minx, maxx, t1xp, t2xp;
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bool changed1 = false;
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bool changed2 = false;
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int signx1, signx2, dx1, dy1, dx2, dy2;
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int e1, e2;
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// Sort vertices
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if (y1 > y2) { std::swap(y1, y2); std::swap(x1, x2); }
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if (y1 > y3) { std::swap(y1, y3); std::swap(x1, x3); }
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if (y2 > y3) { std::swap(y2, y3); std::swap(x2, x3); }
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for (int scanlineY = y1; scanlineY <= y2; scanlineY++)
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{
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h_line((int)curx1, scanlineY, (int)curx2, paletteIndex);
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curx1 += invslope1;
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curx2 += invslope2;
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t1x = t2x = x1; y = y1; // Starting points
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dx1 = (int)(x2 - x1);
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if (dx1 < 0) { dx1 = -dx1; signx1 = -1; }
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else signx1 = 1;
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dy1 = (int)(y2 - y1);
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dx2 = (int)(x3 - x1);
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if (dx2 < 0) { dx2 = -dx2; signx2 = -1; }
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else signx2 = 1;
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dy2 = (int)(y3 - y1);
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if (dy1 > dx1) { std::swap(dx1, dy1); changed1 = true; }
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if (dy2 > dx2) { std::swap(dy2, dx2); changed2 = true; }
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e2 = (int)(dx2 >> 1);
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// Flat top, just process the second half
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if (y1 == y2) goto next;
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e1 = (int)(dx1 >> 1);
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for (int i = 0; i < dx1;) {
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t1xp = 0; t2xp = 0;
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if (t1x < t2x) { minx = t1x; maxx = t2x; }
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else { minx = t2x; maxx = t1x; }
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// process first line until y value is about to change
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while (i < dx1) {
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i++;
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e1 += dy1;
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while (e1 >= dx1) {
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e1 -= dx1;
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if (changed1) t1xp = signx1;//t1x += signx1;
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else goto next1;
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}
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if (changed1) break;
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else t1x += signx1;
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}
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void Graphics::fillTopFlatTriangle(float x1, float y1, float x2, float y2, float x3, float y3, int paletteIndex)
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{
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float invslope1 = (x3 - x1) / (y3 - y1);
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float invslope2 = (x3 - x2) / (y3 - y2);
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float curx1 = x3;
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float curx2 = x3;
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for (int scanlineY = y3; scanlineY > y1; scanlineY--)
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{
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h_line((int)curx1, scanlineY, (int)curx2, paletteIndex);
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curx1 -= invslope1;
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curx2 -= invslope2;
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// Move line
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next1:
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// process second line until y value is about to change
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while (1) {
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e2 += dy2;
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while (e2 >= dx2) {
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e2 -= dx2;
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if (changed2) t2xp = signx2;//t2x += signx2;
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else goto next2;
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}
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if (changed2) break;
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else t2x += signx2;
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}
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next2:
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if (minx > t1x) minx = t1x;
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if (minx > t2x) minx = t2x;
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if (maxx < t1x) maxx = t1x;
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if (maxx < t2x) maxx = t2x;
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drawline(minx, maxx, y); // Draw line from min to max points found on the y
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// Now increase y
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if (!changed1) t1x += signx1;
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t1x += t1xp;
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if (!changed2) t2x += signx2;
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t2x += t2xp;
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y += 1;
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if (y == y2) break;
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}
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next:
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// Second half
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dx1 = (int)(x3 - x2); if (dx1 < 0) { dx1 = -dx1; signx1 = -1; }
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else signx1 = 1;
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dy1 = (int)(y3 - y2);
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t1x = x2;
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if (dy1 > dx1) { // swap values
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std::swap(dy1, dx1);
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changed1 = true;
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}
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else changed1 = false;
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e1 = (int)(dx1 >> 1);
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for (int i = 0; i <= dx1; i++) {
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t1xp = 0; t2xp = 0;
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if (t1x < t2x) { minx = t1x; maxx = t2x; }
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else { minx = t2x; maxx = t1x; }
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// process first line until y value is about to change
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while (i < dx1) {
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e1 += dy1;
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while (e1 >= dx1) {
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e1 -= dx1;
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if (changed1) { t1xp = signx1; break; }//t1x += signx1;
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else goto next3;
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}
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if (changed1) break;
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else t1x += signx1;
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if (i < dx1) i++;
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}
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next3:
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// process second line until y value is about to change
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while (t2x != x3) {
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e2 += dy2;
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while (e2 >= dx2) {
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e2 -= dx2;
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if (changed2) t2xp = signx2;
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else goto next4;
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}
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if (changed2) break;
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else t2x += signx2;
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}
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next4:
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if (minx > t1x) minx = t1x;
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if (minx > t2x) minx = t2x;
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if (maxx < t1x) maxx = t1x;
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if (maxx < t2x) maxx = t2x;
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drawline(minx, maxx, y);
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if (!changed1) t1x += signx1;
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t1x += t1xp;
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if (!changed2) t2x += signx2;
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t2x += t2xp;
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y += 1;
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if (y > y3) return;
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}
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void Graphics::Triangle(int x1, int y1, int x2, int y2, int x3, int y3, int paletteIndex)
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{
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int aX = x1;
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int aY = y1;
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int bX = x2;
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int bY = y2;
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int cX = x3;
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int cY = y3;
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if(bY < aY){
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int t = bY;
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bY = aY;
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aY = t;
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t = bX;
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bX = aX;
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aX = t;
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}
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if(cY < aY){
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int t = cY;
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cY = aY;
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aY = t;
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t = cX;
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cX = aX;
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aX = t;
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}
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if(cY < bY){
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int t = cY;
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cY = bY;
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bY = t;
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t = cX;
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cX = bX;
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bX = t;
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}
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//std::cout << aX << " " << aY << " " << bX << " " << bY << " " << cX << " " << cY << "\n";
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/* here we know that v1.y <= v2.y <= v3.y */
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/* check for trivial case of bottom-flat triangle */
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if (bY == cY)
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{
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fillBottomFlatTriangle(aX, aY, bX, bY, cX, cY, paletteIndex);
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}
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/* check for trivial case of top-flat triangle */
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else if (aY == bY)
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{
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fillTopFlatTriangle(aX, aY, bX, bY, cX, cY, paletteIndex);
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}
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else
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{
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/* general case - split the triangle in a topflat and bottom-flat one */
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int dX = aX + ((float)(bY - aY) / (float)(cY - aY)) * (cX - aX);
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int dY = bY;
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fillBottomFlatTriangle(aX, aY, bX, bY, dX, dY, paletteIndex);
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fillTopFlatTriangle(bX, bY, dX, dY, cX, cY, paletteIndex);
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}
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void Graphics::swap(float &a, float &b) {
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float temp = a;
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a = b;
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b = temp;
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}
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@ -26,6 +26,8 @@ private:
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std::vector<uint8_t> m_virtualScreenColorBuffer;
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Image m_virtualScreenImageBuffer;
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static void swap(float &a, float &b);
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private:
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void renderVirtualScreen();
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@ -72,7 +74,7 @@ public:
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void Rect(int x, int y, int width, int height, int paletteIndex);
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void RectBorder(int x, int y, int width, int height, int paletteIndex);
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void Text(std::string s, int x, int y, int paletteIndex);
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void Triangle(int x1, int y1, int x2, int y2, int x3, int y3, int paletteIndex);
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void Triangle(int32_t x1, int32_t y1, int32_t x2, int32_t y2, int32_t x3, int32_t y3, int paletteIndex);
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int GetPixel(int x, int y);
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