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Rope: Improve graphics when pointed angles (<90 deg) occur

rope
Armin Burgmeier 2012-04-28 19:16:39 +02:00
parent acff7e76be
commit 4b7b924961
2 changed files with 24 additions and 12 deletions
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34
src/game/object/C4Rope.cpp
View File

@ -43,9 +43,8 @@ namespace
// Helper function for Draw: determines vertex positions for one segment
void VertexPos(Vertex& out1, Vertex& out2, Vertex& out3, Vertex& out4,
const Vertex& v1, const Vertex& v2)
const Vertex& v1, const Vertex& v2, float w)
{
static const float w = 5.0f; // segment width
const float l = sqrt( (v1.x - v2.x)*(v1.x - v2.x) + (v1.y - v2.y)*(v1.y - v2.y));
out1.x = v1.x + w/2.0f * (v1.y - v2.y) / l;
@ -172,7 +171,7 @@ void C4RopeEnd::Execute(C4Real dt)
}
C4Rope::C4Rope(C4Object* first_obj, C4Object* second_obj, int32_t n_segments):
n_segments(n_segments), l(ObjectDistance(first_obj, second_obj) / (n_segments + 1)),
w(5.0f), n_segments(n_segments), l(ObjectDistance(first_obj, second_obj) / (n_segments + 1)),
k(Fix1*3), eta(Fix1*3), /* TODO: proper default values for k and eta */ n_iterations(20)
{
if(!PathFree(first_obj->GetX(), first_obj->GetY(), second_obj->GetX(), second_obj->GetY()))
@ -269,21 +268,32 @@ void C4Rope::Draw(C4Facet& cgo)
VertexPos(Vertices[0], Vertices[1], Tmp[0], Tmp[1],
Vertex(fixtof(front->GetX()), fixtof(front->GetY())),
Vertex(fixtof(front->segment->GetX()), fixtof(front->segment->GetY())));
Vertex(fixtof(front->segment->GetX()), fixtof(front->segment->GetY())), w);
unsigned int i = 2;
bool parity = true;
for(C4RopeSegment* cur = front->segment; cur != NULL; cur = cur->next, i += 2)
{
Vertex v1(fixtof(cur->GetX()),
fixtof(cur->GetY()));
Vertex v2(fixtof(cur->next ? cur->next->GetX() : back->GetX()),
fixtof(cur->next ? cur->next->GetY() : back->GetY()));
Vertex v3(fixtof(cur->prev ? cur->prev->GetX() : front->GetX()),
fixtof(cur->prev ? cur->prev->GetY() : front->GetY()));
// Parity -- parity swaps for each pointed angle (<90 deg)
float cx = v1.x - v3.x;
float cy = v1.y - v3.y;
float ex = v1.x - v2.x;
float ey = v1.y - v2.y;
if(cx*ex+cy*ey > 0)
parity = !parity;
// Obtain vertex positions
// TODO: If angle > 90 degrees (dot product negative), then swap indices below
// Might need to adapt texture coordinates for this segment as well to avoid graphical glitch
// when going from 89 to 91 degrees.
VertexPos(Tmp[2], Tmp[3], Vertices[i+2], Vertices[i+3], v1, v2);
if(parity)
VertexPos(Tmp[2], Tmp[3], Vertices[i+2], Vertices[i+3], v1, v2, w);
else
VertexPos(Tmp[3], Tmp[2], Vertices[i+3], Vertices[i+2], v1, v2, w);
Tmp[2].x = (Tmp[0].x + Tmp[2].x)/2.0f;
Tmp[2].y = (Tmp[0].y + Tmp[2].y)/2.0f;
Tmp[3].x = (Tmp[1].x + Tmp[3].x)/2.0f;
@ -295,10 +305,10 @@ void C4Rope::Draw(C4Facet& cgo)
float dx2 = Vertices[i-1].x - Vertices[i-2].x;
float dy2 = Vertices[i-1].y - Vertices[i-2].y;
const float d = (dx2*dx2+dy2*dy2)/(dx*dx2+dy*dy2);
Vertices[i ].x = ( (Tmp[2].x + Tmp[3].x)/2.0f) - (Tmp[3].x - Tmp[2].x)*d/2.0f;
Vertices[i ].y = ( (Tmp[2].y + Tmp[3].y)/2.0f) - (Tmp[3].y - Tmp[2].y)*d/2.0f;
Vertices[i+1].x = ( (Tmp[2].x + Tmp[3].x)/2.0f) + (Tmp[3].x - Tmp[2].x)*d/2.0f;
Vertices[i+1].y = ( (Tmp[2].y + Tmp[3].y)/2.0f) + (Tmp[3].y - Tmp[2].y)*d/2.0f;
Vertices[i ].x = ( (Tmp[2].x + Tmp[3].x)/2.0f) - BoundBy((Tmp[3].x - Tmp[2].x)*d, -w, w)/2.0f;
Vertices[i ].y = ( (Tmp[2].y + Tmp[3].y)/2.0f) - BoundBy((Tmp[3].y - Tmp[2].y)*d, -w, w)/2.0f;
Vertices[i+1].x = ( (Tmp[2].x + Tmp[3].x)/2.0f) + BoundBy((Tmp[3].x - Tmp[2].x)*d, -w, w)/2.0f;
Vertices[i+1].y = ( (Tmp[2].y + Tmp[3].y)/2.0f) + BoundBy((Tmp[3].y - Tmp[2].y)*d, -w, w)/2.0f;
Tmp[0] = Vertices[i+2];
Tmp[1] = Vertices[i+3];

2
src/game/object/C4Rope.h
View File

@ -102,6 +102,8 @@ private:
template<typename TRopeType1, typename TRopeType2>
void Solve(TRopeType1* prev, TRopeType2* next);
const float w; // Width of rope
int32_t n_segments;
// TODO: Add a "dynlength" feature which adapts the spring length to the