line thicknesses

This commit is contained in:
John Alanbrook 2023-02-16 07:56:22 +00:00
parent e3100e0221
commit 7c0f7ef46f

View file

@ -91,13 +91,62 @@ cpVect inflateline(cpVect a, cpVect b, float d)
return c; return c;
} }
cpVect inflatepoint(cpVect a, cpVect b, cpVect c, float d)
{
cpVect ba = cpvnormalize(cpvsub(a,b));
cpVect bc = cpvnormalize(cpvsub(c,b));
cpVect avg = cpvadd(ba, bc);
avg = cpvmult(avg, 0.5);
float dot = cpvdot(ba, bc);
dot /= cpvlength(ba);
dot /= cpvlength(bc);
float mid = acos(dot)/2;
avg = cpvnormalize(avg);
return cpvadd(b, cpvmult(avg, d/sin(mid)));
}
void inflatepoints(cpVect *r, cpVect *p, float d, int n)
{ if (d == 0) {
for (int i = 0; i < n; i++)
r[i] = p[i];
return;
}
if (cpveql(p[0], p[n-1])) {
r[0] = inflatepoint(p[n-2],p[0],p[1],d);
r[n-1] = r[0];
} else {
cpVect outdir = cpvmult(cpvnormalize(cpvsub(p[0],p[1])),fabs(d));
cpVect perp;
if (d > 0)
perp = cpvperp(outdir);
else
perp = cpvrperp(outdir);
r[0] = cpvadd(p[0],cpvadd(outdir,perp));
outdir = cpvmult(cpvnormalize(cpvsub(p[n-1],p[n-2])),fabs(d));
if (d > 0)
perp = cpvrperp(outdir);
else
perp = cpvperp(outdir);
r[n-1] = cpvadd(p[n-1],cpvadd(outdir,perp));
}
for (int i = 0; i < n-2; i++)
r[i+1] = inflatepoint(p[i],p[i+1],p[i+2], d);
}
void draw_edge(cpVect *points, int n, float *color, int thickness) void draw_edge(cpVect *points, int n, float *color, int thickness)
{ {
static_assert(sizeof(cpVect) == 2*sizeof(float)); static_assert(sizeof(cpVect) == 2*sizeof(float));
shader_use(rectShader); shader_use(rectShader);
shader_setvec3(rectShader, "linecolor", color); shader_setvec3(rectShader, "linecolor", color);
if (thickness <= 1) { if (thickness <= 1) {
shader_setfloat(rectShader, "alpha", 1.f);
glBindBuffer(GL_ARRAY_BUFFER, rectVBO); glBindBuffer(GL_ARRAY_BUFFER, rectVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(float) * n * 2, points, GL_DYNAMIC_DRAW); glBufferData(GL_ARRAY_BUFFER, sizeof(float) * n * 2, points, GL_DYNAMIC_DRAW);
glBindVertexArray(rectVAO); glBindVertexArray(rectVAO);
@ -107,6 +156,34 @@ void draw_edge(cpVect *points, int n, float *color, int thickness)
shader_setfloat(rectShader, "alpha", 1.f); shader_setfloat(rectShader, "alpha", 1.f);
glDrawArrays(GL_LINE_STRIP, 0, n); glDrawArrays(GL_LINE_STRIP, 0, n);
} else { } else {
shader_setfloat(rectShader, "alpha", 0.1f);
thickness /= 2;
glBindBuffer(GL_ARRAY_BUFFER, rectVBO);
glBindVertexArray(rectVAO);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, NULL);
cpVect inflate_out[n];
cpVect inflate_in[n];
inflatepoints(inflate_out, points, thickness, n);
inflatepoints(inflate_in, points, -thickness, n);
cpVect interleaved[n*2];
for (int i = 0; i < n; i++) {
interleaved[i*2] = inflate_in[i];
interleaved[i*2+1] = inflate_out[i];
}
glBufferData(GL_ARRAY_BUFFER, sizeof(interleaved), interleaved, GL_DYNAMIC_DRAW);
glDrawArrays(GL_TRIANGLE_STRIP, 0, n*2);
shader_setfloat(rectShader, "alpha", 1.f);
cpVect inlined[n*2];
for (int i = 0; i < n; i++)
inlined[i] = inflate_out[n-1-i];
memcpy(inlined+n,inflate_in,sizeof(inflate_in));
glBufferData(GL_ARRAY_BUFFER,sizeof(inlined),inlined,GL_DYNAMIC_DRAW);
glDrawArrays(GL_LINE_LOOP,0,n*2);
} }
} }