christoph/cpp-masssprings
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store masses/springs inside vector and manage unordered_maps for a state<->index mapping

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this reduces the time required to iterate over all masses/springs
because data is stored in contiguous memory
This commit is contained in:
Christoph Urlacher
2026-02-24 00:01:04 +01:00
parent 404a76654c
commit bfe8c6d572
4 changed files with 89 additions and 115 deletions
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60
src/renderer.cpp
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@ -70,17 +70,20 @@ auto Renderer::DrawMassSprings(const MassSpringSystem &mass_springs,
ZoneScoped;
// Prepare cube instancing
if (mass_springs.masses.size() < DRAW_VERTICES_LIMIT) {
if (transforms == nullptr) {
AllocateGraphInstancing(mass_springs);
}
ReallocateGraphInstancingIfNecessary(mass_springs);
{
ZoneNamedN(prepare_masses, "PrepareMasses", true);
if (mass_springs.masses.size() < DRAW_VERTICES_LIMIT) {
if (transforms == nullptr) {
AllocateGraphInstancing(mass_springs);
}
ReallocateGraphInstancingIfNecessary(mass_springs);
int i = 0;
for (const auto &[state, mass] : mass_springs.masses) {
transforms[i] =
MatrixTranslate(mass.position.x, mass.position.y, mass.position.z);
++i;
int i = 0;
for (const auto &mass : mass_springs.masses) {
transforms[i] =
MatrixTranslate(mass.position.x, mass.position.y, mass.position.z);
++i;
}
}
}
@ -90,24 +93,31 @@ auto Renderer::DrawMassSprings(const MassSpringSystem &mass_springs,
BeginMode3D(camera.camera);
// Draw springs (batched)
rlBegin(RL_LINES);
for (const auto &[states, spring] : mass_springs.springs) {
rlColor4ub(EDGE_COLOR.r, EDGE_COLOR.g, EDGE_COLOR.b, EDGE_COLOR.a);
rlVertex3f(spring.massA.position.x, spring.massA.position.y,
spring.massA.position.z);
rlVertex3f(spring.massB.position.x, spring.massB.position.y,
spring.massB.position.z);
{
ZoneNamedN(draw_springs, "DrawSprings", true);
rlBegin(RL_LINES);
for (const auto &spring : mass_springs.springs) {
// We have to do a lookup of the actual mass object, which is slow :(
const Mass &a = mass_springs.masses.at(spring.mass_a);
const Mass &b = mass_springs.masses.at(spring.mass_b);
rlColor4ub(EDGE_COLOR.r, EDGE_COLOR.g, EDGE_COLOR.b, EDGE_COLOR.a);
rlVertex3f(a.position.x, a.position.y, a.position.z);
rlVertex3f(b.position.x, b.position.y, b.position.z);
}
rlEnd();
}
rlEnd();
// Draw masses (instanced)
if (mass_springs.masses.size() < DRAW_VERTICES_LIMIT) {
// NOTE: I don't know if drawing all this inside a shader would make it much
// faster...
// The amount of data sent to the GPU would be reduced (just positions
// instead of matrices), but is this noticable for < 100000 cubes?
DrawMeshInstanced(cube_instance, vertex_mat, transforms,
mass_springs.masses.size());
{
ZoneNamedN(draw_masses, "DrawMasses", true);
if (mass_springs.masses.size() < DRAW_VERTICES_LIMIT) {
// NOTE: I don't know if drawing all this inside a shader would make it
// much faster... The amount of data sent to the GPU would be
// reduced (just positions instead of matrices), but is this
// noticable for < 100000 cubes?
DrawMeshInstanced(cube_instance, vertex_mat, transforms,
mass_springs.masses.size());
}
}
// Mark winning states