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light: avoid NaN's due to rounding error when calculating angles for weighting normals

This commit is contained in:
Eric Wasylishen 2016-02-15 20:28:05 -07:00
parent 1fd1637de1
commit 465cb2a555
1 changed files with 34 additions and 19 deletions
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53
light/light.c
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@ -282,33 +282,48 @@ FindModelInfo(const bsp2_t *bsp, const char *lmscaleoverride)
tracelist = shadowmodels;
}
/* given a triangle, just adds the contribution from the triangle to the given vertexes normals, based upon angles at the verts */
static void
AddTriangleNormals(vec_t *norm, dvertex_t *verts, int v1, int v2, int v3)
static float
AngleBetweenVectors(const vec3_t d1, const vec3_t d2)
{
float cosangle = DotProduct(d1, d2)/(VectorLength(d1)*VectorLength(d2));
if (cosangle < -1) cosangle = -1;
if (cosangle > 1) cosangle = 1;
float angle = acos(cosangle);
return angle;
}
/* returns the angle between vectors p2->p1 and p2->p3 */
static float
AngleBetweenPoints(const vec3_t p1, const vec3_t p2, const vec3_t p3)
{
vec_t *p1 = verts[v1].point;
vec_t *p2 = verts[v2].point;
vec_t *p3 = verts[v3].point;
vec3_t d1, d2;
float weight;
VectorSubtract(p2, p1, d1);
VectorSubtract(p3, p1, d2);
weight = acos(DotProduct(d1, d2)/(VectorLength(d1)*VectorLength(d2)));
VectorMA(vertex_normals[v1], weight, norm, vertex_normals[v1]);
VectorSubtract(p1, p2, d1);
VectorSubtract(p3, p2, d2);
weight = acos(DotProduct(d1, d2)/(VectorLength(d1)*VectorLength(d2)));
float result = AngleBetweenVectors(d1, d2);
return result;
}
/* given a triangle, just adds the contribution from the triangle to the given vertexes normals, based upon angles at the verts */
static void
AddTriangleNormals(const vec_t *norm, const dvertex_t *verts, int v1, int v2, int v3)
{
const vec_t *p1 = verts[v1].point;
const vec_t *p2 = verts[v2].point;
const vec_t *p3 = verts[v3].point;
float weight;
weight = AngleBetweenPoints(p2, p1, p3);
VectorMA(vertex_normals[v1], weight, norm, vertex_normals[v1]);
weight = AngleBetweenPoints(p1, p2, p3);
VectorMA(vertex_normals[v2], weight, norm, vertex_normals[v2]);
VectorSubtract(p1, p3, d1);
VectorSubtract(p2, p3, d2);
weight = acos(DotProduct(d1, d2)/(VectorLength(d1)*VectorLength(d2)));
weight = AngleBetweenPoints(p1, p3, p2);
VectorMA(vertex_normals[v3], weight, norm, vertex_normals[v3]);
}
/* small helper that just retrieves the correct vertex from face->surfedge->edge lookups */
static int GetSurfaceVertex(bsp2_t *const bsp, bsp2_dface_t *f, int v)
static int GetSurfaceVertex(const bsp2_t *bsp, const bsp2_dface_t *f, int v)
{
int edge = f->firstedge + v;
edge = bsp->dsurfedges[edge];
@ -318,7 +333,7 @@ static int GetSurfaceVertex(bsp2_t *const bsp, bsp2_dface_t *f, int v)
}
static void
CalcualateVertexNormals(bsp2_t *const bsp)
CalcualateVertexNormals(const bsp2_t *bsp)
{
int i, j, v1, v2, v3;
bsp2_dface_t *f;