eliminated calls to Matrix4x4_CreateIdentity (now copies from the already existing...

[xonotic/darkplaces.git] / model_shared.c

diff --git a/model_shared.c b/model_shared.c
index 2b9f947615d2f0f834547adfe9ca2037240fefd0..558e0deaba79b3b3a83f45812b01852acfbcfefa 100644 (file)
--- a/model_shared.c
+++ b/model_shared.c
@@ -593,6 +593,8 @@ void Mod_BuildTextureVectorsAndNormals(int firstvertex, int numvertices, int num
 {
        int i, tnum;
        float sdir[3], tdir[3], normal[3], *v;
+       const float *v0, *v1, *v2, *tc0, *tc1, *tc2;
+       float f, tangentcross[3], v10[3], v20[3], tc10[2], tc20[2];
        const int *e;
        // clear the vectors
        if (svector3f)
@@ -604,7 +606,59 @@ void Mod_BuildTextureVectorsAndNormals(int firstvertex, int numvertices, int num
        // process each vertex of each triangle and accumulate the results
        for (tnum = 0, e = elements;tnum < numtriangles;tnum++, e += 3)
        {
-               Mod_BuildBumpVectors(vertex3f + e[0] * 3, vertex3f + e[1] * 3, vertex3f + e[2] * 3, texcoord2f + e[0] * 2, texcoord2f + e[1] * 2, texcoord2f + e[2] * 2, sdir, tdir, normal);
+               v0 = vertex3f + e[0] * 3;
+               v1 = vertex3f + e[1] * 3;
+               v2 = vertex3f + e[2] * 3;
+               tc0 = texcoord2f + e[0] * 2;
+               tc1 = texcoord2f + e[1] * 2;
+               tc2 = texcoord2f + e[2] * 2;
+
+               // 79 add/sub/negate/multiply (1 cycle), 1 compare (3 cycle?), total cycles not counting load/store/exchange roughly 82 cycles
+               // 6 add, 28 subtract, 39 multiply, 1 compare, 50% chance of 6 negates
+
+               // calculate the edge directions and surface normal
+               // 6 multiply, 9 subtract
+               VectorSubtract(v1, v0, v10);
+               VectorSubtract(v2, v0, v20);
+               normal[0] = v20[1] * v10[2] - v20[2] * v10[1];
+               normal[1] = v20[2] * v10[0] - v20[0] * v10[2];
+               normal[2] = v20[0] * v10[1] - v20[1] * v10[0];
+
+               // calculate the tangents
+               // 12 multiply, 10 subtract
+               tc10[1] = tc1[1] - tc0[1];
+               tc20[1] = tc2[1] - tc0[1];
+               sdir[0] = tc10[1] * v20[0] - tc20[1] * v10[0];
+               sdir[1] = tc10[1] * v20[1] - tc20[1] * v10[1];
+               sdir[2] = tc10[1] * v20[2] - tc20[1] * v10[2];
+               tc10[0] = tc1[0] - tc0[0];
+               tc20[0] = tc2[0] - tc0[0];
+               tdir[0] = tc10[0] * v20[0] - tc20[0] * v10[0];
+               tdir[1] = tc10[0] * v20[1] - tc20[0] * v10[1];
+               tdir[2] = tc10[0] * v20[2] - tc20[0] * v10[2];
+
+               // make the tangents completely perpendicular to the surface normal
+               // 12 multiply, 4 add, 6 subtract
+               f = DotProduct(sdir, normal);
+               sdir[0] -= f * normal[0];
+               sdir[1] -= f * normal[1];
+               sdir[2] -= f * normal[2];
+               f = DotProduct(tdir, normal);
+               tdir[0] -= f * normal[0];
+               tdir[1] -= f * normal[1];
+               tdir[2] -= f * normal[2];
+
+               // 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(tdir, sdir, tangentcross);
+               if (DotProduct(tangentcross, normal) < 0)
+               {
+                       VectorNegate(sdir, sdir);
+                       VectorNegate(tdir, tdir);
+               }
+
                if (!areaweighting)
                {
                        VectorNormalize(sdir);