X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fbuilders%2Fsphere.cpp;fp=source%2Fbuilders%2Fsphere.cpp;h=dd27fad40e28cc1608ad9699b121d1c4af0f0ffb;hb=7aaec9a70b8d7733429bec043f8e33e02956f266;hp=0000000000000000000000000000000000000000;hpb=bec07999d95b76f4b47cffcc564d0cd0afc0435e;p=libs%2Fgl.git

diff --git a/source/builders/sphere.cpp b/source/builders/sphere.cpp
new file mode 100644
index 00000000..dd27fad4
--- /dev/null
+++ b/source/builders/sphere.cpp
@@ -0,0 +1,261 @@
+#define _USE_MATH_DEFINES
+#include <cmath>
+#include <vector>
+#include "primitivebuilder.h"
+#include "sphere.h"
+
+using namespace std;
+
+namespace Msp {
+namespace GL {
+
+UvSphereBuilder::UvSphereBuilder(float r, unsigned s, unsigned n):
+	radius(r),
+	segments(s),
+	rings(n)
+{
+	if(segments<3)
+		segments = 3;
+
+	if(rings==0)
+		rings = (segments+1)/2;
+	else if(rings<2)
+		rings = 2;
+}
+
+void UvSphereBuilder::build(PrimitiveBuilder &builder) const
+{
+	float u_scale = 1.0f/segments;
+	float v_scale = 1.0f/rings;
+	adjust_texture_scale(u_scale, v_scale, radius*M_PI*2, radius*M_PI);
+
+	for(unsigned i=0; i<=rings; ++i)
+	{
+		float av = i*M_PI/rings-M_PI/2;
+		float cv = cos(av);
+		float sv = sin(av);
+
+		for(unsigned j=0; j<=segments; ++j)
+		{
+			float au = j*M_PI*2/segments;
+			float cu = cos(au);
+			float su = sin(au);
+
+			builder.normal(cv*cu, cv*su, sv);
+			builder.texcoord(j*u_scale, i*v_scale);
+			if(generate_tbn)
+			{
+				builder.tangent(-su, cu, 0);
+				builder.binormal(-sv*cu, -sv*su, cv);
+			}
+			builder.vertex(cv*cu*radius, cv*su*radius, sv*radius);
+		}
+	}
+
+	builder.begin(TRIANGLES);
+	for(unsigned j=0; j<segments; ++j)
+	{
+		builder.element(j);
+		builder.element(segments+2+j);
+		builder.element(segments+1+j);
+	}
+	unsigned top = (rings+1)*(segments+1)-1;
+	for(unsigned j=0; j<segments; ++j)
+	{
+		builder.element(top-j);
+		builder.element(top-(segments+2+j));
+		builder.element(top-(segments+1+j));
+	}
+	builder.end();
+
+	for(unsigned i=1; i<rings; ++i)
+	{
+		builder.begin(TRIANGLE_STRIP);
+		unsigned base = i*(segments+1);
+		for(unsigned j=0; j<=segments; ++j)
+		{
+			builder.element(base+segments+1+j);
+			builder.element(base+j);
+		}
+		builder.end();
+	}
+}
+
+
+// https://en.wikipedia.org/wiki/Regular_icosahedron#Cartesian_coordinates
+float IcoSphereBuilder::base_vertices[12*3] =
+{
+	 0.0f,       -0.5257311f, -0.8506508f,
+	 0.0f,        0.5257311f, -0.8506508f,
+	 0.0f,       -0.5257311f,  0.8506508f,
+	 0.0f,        0.5257311f,  0.8506508f,
+	-0.8506508f,  0.0f,       -0.5257311f,
+	-0.8506508f,  0.0f,        0.5257311f,
+	 0.8506508f,  0.0f,       -0.5257311f,
+	 0.8506508f,  0.0f,        0.5257311f,
+	-0.5257311f, -0.8506508f,  0.0f,
+	 0.5257311f, -0.8506508f,  0.0f,
+	-0.5257311f,  0.8506508f,  0.0f,
+	 0.5257311f,  0.8506508f,  0.0f
+};
+
+unsigned IcoSphereBuilder::base_triangles[20*3] =
+{
+	0, 1, 6,
+	1, 0, 4,
+	2, 3, 5,
+	3, 2, 7,
+	4, 5, 10,
+	5, 4, 8,
+	6, 7, 9,
+	7, 6, 11,
+	8, 9, 2,
+	9, 8, 0,
+	10, 11, 1,
+	11, 10, 3,
+	0, 8, 4,
+	0, 6, 9,
+	1, 4, 10,
+	1, 11, 6,
+	2, 5, 8,
+	2, 9, 7,
+	3, 10, 5,
+	3, 7, 11
+};
+
+unsigned IcoSphereBuilder::base_edges[30*2] = { 0, 0 };
+unsigned IcoSphereBuilder::base_tri_edges[20*3] = { 0, 0, 0 };
+
+IcoSphereBuilder::IcoSphereBuilder(float r, unsigned s):
+	radius(r),
+	subdivision(s)
+{
+	if(base_edges[0]==base_edges[1])
+		initialize_edges();
+}
+
+void IcoSphereBuilder::initialize_edges()
+{
+	vector<int> edge_map(12*12, -1);
+	unsigned next_edge = 0;
+	for(unsigned i=0; i<20; ++i)
+		for(unsigned j=0; j<3; ++j)
+		{
+			unsigned v1 = base_triangles[i*3+j];
+			unsigned v2 = base_triangles[i*3+(j+1)%3];
+			int e = edge_map[v1*12+v2];
+			if(e<0)
+			{
+				e = next_edge++;
+				base_edges[e*2] = v1;
+				base_edges[e*2+1] = v2;
+				// The other triangle using this edge will have the vertices swapped
+				edge_map[v2*12+v1] = e|32;
+			}
+			base_tri_edges[i*3+j] = e;
+		}
+}
+
+void IcoSphereBuilder::build(PrimitiveBuilder &bld) const
+{
+	for(unsigned i=0; i<12; ++i)
+	{
+		const float *v = base_vertices+i*3;
+		bld.normal(v[0], v[1], v[2]);
+		bld.vertex(v[0]*radius, v[1]*radius, v[2]*radius);
+	}
+
+	if(subdivision>1)
+	{
+		vector<Vector3> edge_subdiv(30*(subdivision+1));
+		for(unsigned i=0; i<30; ++i)
+		{
+			Vector3 v1(base_vertices+base_edges[i*2]*3);
+			Vector3 v2(base_vertices+base_edges[i*2+1]*3);
+			for(unsigned j=1; j<subdivision; ++j)
+			{
+				float t = static_cast<float>(j)/subdivision;
+				Vector3 v = v1*(1.0f-t)+v2*t;
+				edge_subdiv[i*(subdivision-1)+j-1] = v;
+				v.normalize();
+				bld.normal(v);
+				bld.vertex(v*radius);
+			}
+		}
+
+		for(unsigned i=0; i<20; ++i)
+			for(unsigned j=1; j<subdivision; ++j)
+			{
+				unsigned e = base_tri_edges[i*3];
+				Vector3 v1 = edge_subdiv[edge_vertex(e, subdivision-j)];
+				e = base_tri_edges[i*3+1];
+				Vector3 v2 = edge_subdiv[edge_vertex(e, j)];
+				for(unsigned k=1; k<j; ++k)
+				{
+					float t = static_cast<float>(k)/j;
+					Vector3 v = normalize(v1*(1.0f-t)+v2*t);
+					bld.normal(v);
+					bld.vertex(v*radius);
+				}
+			}
+
+		for(unsigned i=0; i<20; ++i)
+		{
+			unsigned mid = 12+30*(subdivision-1)+i*(subdivision-1)*(subdivision-2)/2;
+			for(unsigned j=1; j<=subdivision; ++j)
+			{
+				bld.begin(TRIANGLE_STRIP);
+				if(j==subdivision)
+					bld.element(base_triangles[i*3]);
+				else
+					bld.element(12+edge_vertex(base_tri_edges[i*3], subdivision-j));
+
+				if(j==1)
+				{
+					bld.element(base_triangles[i*3+1]);
+					bld.element(12+edge_vertex(base_tri_edges[i*3+1], j));
+				}
+				else
+				{
+					bld.element(12+edge_vertex(base_tri_edges[i*3], subdivision-j+1));
+
+					if(j==subdivision)
+						bld.element(12+edge_vertex(base_tri_edges[i*3+2], subdivision-1));
+					else
+						bld.element(mid+(j-1)*(j-2)/2);
+
+					for(unsigned k=2; k<j; ++k)
+					{
+						bld.element(mid+(j-2)*(j-3)/2+k-2);
+						if(j==subdivision)
+							bld.element(12+edge_vertex(base_tri_edges[i*3+2], subdivision-k));
+						else
+							bld.element(mid+(j-1)*(j-2)/2+k-1);
+					}
+
+					bld.element(12+edge_vertex(base_tri_edges[i*3+1], j-1));
+					if(j==subdivision)
+						bld.element(base_triangles[i*3+2]);
+					else
+						bld.element(12+edge_vertex(base_tri_edges[i*3+1], j));
+				}
+				bld.end();
+			}
+		}
+	}
+	else
+	{
+		bld.begin(TRIANGLES);
+		for(unsigned i=0; i<20*3; ++i)
+			bld.element(base_triangles[i]);
+		bld.end();
+	}
+}
+
+unsigned IcoSphereBuilder::edge_vertex(unsigned e, unsigned i) const
+{
+	return (e&31)*(subdivision-1)+((e&32)?subdivision-i:i)-1;
+}
+
+} // namespace GL
+} // namespace Msp