Cleanup sweeping algo
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@ -49,6 +49,10 @@ func line(fb *Framebuffer, color uint, v0 Vec2i, v1 Vec2i) {
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}*/
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func Triangle1(fb *Framebuffer, color uint, v0 Vec2i, v1 Vec2i, v2 Vec2i) {
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// The dude gets rid of "degenerate" triangles so... we do too?
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if v2.Y == v1.Y && v1.Y == v0.Y {
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return
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}
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// Very silly manual sorting by Y
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if v2.Y < v0.Y {
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v0, v2 = v2, v0
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@ -59,29 +63,30 @@ func Triangle1(fb *Framebuffer, color uint, v0 Vec2i, v1 Vec2i, v2 Vec2i) {
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if v2.Y < v1.Y {
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v1, v2 = v2, v1
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}
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//log.Print(v0, v1, v2)
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// Don't worry about speed for now...
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var v02step, v01step, v12step, xlong, xshort float32
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xlong = float32(v0.X)
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xshort = xlong
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// The first and last Y CAN'T be equal because sorting!!
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if v1.Y == v0.Y {
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xshort = float32(v1.X)
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}
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// We can check just for greater than because we sorted the vertices
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// Assume 02 is on the right(?) and 01 on the left
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v02step = (float32(v2.X - v0.X)) / (float32(v2.Y-v0.Y) + 0.001) // long side always
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v01step = (float32(v1.X - v0.X)) / (float32(v1.Y-v0.Y) + 0.001) // first short side
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v12step = (float32(v2.X - v1.X)) / (float32(v2.Y-v1.Y) + 0.001) // second short side
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xshort += v01step / 2
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xlong += v02step / 2
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for y := v0.Y; y <= v2.Y; y++ {
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xleft := int(math.Floor(float64(xshort)))
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xright := int(math.Floor(float64(xlong)))
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xleft := int(xshort)
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xright := int(xlong)
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if xleft > xright {
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xleft, xright = xright, xleft
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}
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// Draw a horizontal line from elft to right
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// Draw a horizontal line from left to right
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for x := xleft; x <= xright; x++ {
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fb.SetSafe(uint(x), uint(y), color)
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}
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@ -92,8 +97,4 @@ func Triangle1(fb *Framebuffer, color uint, v0 Vec2i, v1 Vec2i, v2 Vec2i) {
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xshort += v12step
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}
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}
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// line(fb, color, v0, v1)
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// line(fb, color, v1, v2)
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// line(fb, color, v2, v0)
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}
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