From 17c744aa8c36c564ec3d18df730d456edea5fb0a Mon Sep 17 00:00:00 2001 From: havoc Date: Thu, 16 Sep 2004 20:00:11 +0000 Subject: [PATCH] optimized Mod_BuildBumpVectors slightly git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@4505 d7cf8633-e32d-0410-b094-e92efae38249 --- model_shared.c | 53 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 36 insertions(+), 17 deletions(-) diff --git a/model_shared.c b/model_shared.c index f2a0ccc7..309b40e1 100644 --- a/model_shared.c +++ b/model_shared.c @@ -622,26 +622,45 @@ void Mod_ValidateElements(const int *elements, int numtriangles, int numverts, c void Mod_BuildBumpVectors(const float *v0, const float *v1, const float *v2, const float *tc0, const float *tc1, const float *tc2, float *svector3f, float *tvector3f, float *normal3f) { - float f, tangentcross[3]; - normal3f[0] = (v1[1] - v0[1]) * (v2[2] - v0[2]) - (v1[2] - v0[2]) * (v2[1] - v0[1]); - normal3f[1] = (v1[2] - v0[2]) * (v2[0] - v0[0]) - (v1[0] - v0[0]) * (v2[2] - v0[2]); - normal3f[2] = (v1[0] - v0[0]) * (v2[1] - v0[1]) - (v1[1] - v0[1]) * (v2[0] - v0[0]); + float f, tangentcross[3], v10[3], v20[3], tc10[2], tc20[2]; + // 103 add/sub/negate/multiply (1 cycle), 3 divide (20 cycle), 3 sqrt (22 cycle), 4 compare (3 cycle?), total cycles not counting load/store/exchange roughly 241 cycles + // 12 add, 28 subtract, 57 multiply, 3 divide, 3 sqrt, 4 compare, 50% chance of 6 negates + + // 18 multiply, 19 subtract + VectorSubtract(v1, v0, v10); + VectorSubtract(v2, v0, v20); + normal3f[0] = v10[1] * v20[2] - v10[2] * v20[1]; + normal3f[1] = v10[2] * v20[0] - v10[0] * v20[2]; + normal3f[2] = v10[0] * v20[1] - v10[1] * v20[0]; + tc10[1] = tc1[1] - tc0[1]; + tc20[1] = tc2[1] - tc0[1]; + svector3f[0] = tc10[1] * v20[0] - tc20[1] * v10[0]; + svector3f[1] = tc10[1] * v20[1] - tc20[1] * v10[1]; + svector3f[2] = tc10[1] * v20[2] - tc20[1] * v10[2]; + tc10[0] = tc1[0] - tc0[0]; + tc20[0] = tc2[0] - tc0[0]; + tvector3f[0] = tc10[0] * v20[0] - tc20[0] * v10[0]; + tvector3f[1] = tc10[0] * v20[1] - tc20[0] * v10[1]; + tvector3f[2] = tc10[0] * v20[2] - tc20[0] * v10[2]; + // 1 sqrt, 1 divide, 6 multiply, 2 add, 1 compare VectorNormalize(normal3f); - tvector3f[0] = ((tc1[0] - tc0[0]) * (v2[0] - v0[0]) - (tc2[0] - tc0[0]) * (v1[0] - v0[0])); - tvector3f[1] = ((tc1[0] - tc0[0]) * (v2[1] - v0[1]) - (tc2[0] - tc0[0]) * (v1[1] - v0[1])); - tvector3f[2] = ((tc1[0] - tc0[0]) * (v2[2] - v0[2]) - (tc2[0] - tc0[0]) * (v1[2] - v0[2])); - f = -DotProduct(tvector3f, normal3f); - VectorMA(tvector3f, f, normal3f, tvector3f); - VectorNormalize(tvector3f); - // note: can't be a CrossProduct as that sometimes flips the texture - svector3f[0] = ((tc1[1] - tc0[1]) * (v2[0] - v0[0]) - (tc2[1] - tc0[1]) * (v1[0] - v0[0])); - svector3f[1] = ((tc1[1] - tc0[1]) * (v2[1] - v0[1]) - (tc2[1] - tc0[1]) * (v1[1] - v0[1])); - svector3f[2] = ((tc1[1] - tc0[1]) * (v2[2] - v0[2]) - (tc2[1] - tc0[1]) * (v1[2] - v0[2])); - f = -DotProduct(svector3f, normal3f); - VectorMA(svector3f, f, normal3f, svector3f); + // 12 multiply, 4 add, 6 subtract + f = DotProduct(svector3f, normal3f); + svector3f[0] -= f * normal3f[0]; + svector3f[1] -= f * normal3f[1]; + svector3f[2] -= f * normal3f[2]; + f = DotProduct(tvector3f, normal3f); + tvector3f[0] -= f * normal3f[0]; + tvector3f[1] -= f * normal3f[1]; + tvector3f[2] -= f * normal3f[2]; + // 2 sqrt, 2 divide, 12 multiply, 4 add, 2 compare VectorNormalize(svector3f); + VectorNormalize(tvector3f); + // if texture is mapped the wrong way (counterclockwise), the tangents + // have to be flipped, this is detected by calculating a normal from the + // two tangents, and seeing if it is opposite the surface normal + // 9 multiply, 2 add, 3 subtract, 1 compare, 50% chance of: 6 negates CrossProduct(tvector3f, svector3f, tangentcross); - // if texture is mapped the wrong way (counterclockwise), the tangents have to be flipped, this is detected by calculating a normal from the two tangents, and seeing if it is opposite the surface normal if (DotProduct(tangentcross, normal3f) < 0) { VectorNegate(svector3f, svector3f); -- 2.39.2