[Bf-blender-cvs] [4bd79ac] texture_nodes_refactor: Revert "Cycles: Implement an area preserving parameterization sampling for area lamps"
Sergey Sharybin
noreply at git.blender.org
Sat Oct 11 15:05:19 CEST 2014
Commit: 4bd79aca120eafc9992b4e11aa72aacfd5dbf164
Author: Sergey Sharybin
Date: Sat Oct 11 19:05:09 2014 +0600
Branches: texture_nodes_refactor
https://developer.blender.org/rB4bd79aca120eafc9992b4e11aa72aacfd5dbf164
Revert "Cycles: Implement an area preserving parameterization sampling for area lamps"
This reverts commit c4235ce820b0a9c3d019e31e7d4360162a0282a5.
===================================================================
M intern/cycles/kernel/kernel_light.h
===================================================================
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h
index 2b64b0a..e7f62f2 100644
--- a/intern/cycles/kernel/kernel_light.h
+++ b/intern/cycles/kernel/kernel_light.h
@@ -167,92 +167,12 @@ ccl_device float3 sphere_light_sample(float3 P, float3 center, float radius, flo
return disk_light_sample(normalize(P - center), randu, randv)*radius;
}
-/* Uses the following paper:
- *
- * Carlos Urena et al.
- * An Area-Preserving Parametrization for Spherical Rectangles.
- *
- * https://www.solidangle.com/research/egsr2013_spherical_rectangle.pdf
- */
-ccl_device float3 area_light_sample(float3 P,
- float3 light_p,
- float3 axisu, float3 axisv,
- float randu, float randv,
- float *pdf)
+ccl_device float3 area_light_sample(float3 axisu, float3 axisv, float randu, float randv)
{
- /* In our name system we're using P for the center,
- * which is o in the paper.
- */
-
- float3 corner = light_p - axisu * 0.5f - axisv * 0.5f;
- float axisu_len, axisv_len;
- /* Compute local reference system R. */
- float3 x = normalize_len(axisu, &axisu_len);
- float3 y = normalize_len(axisv, &axisv_len);
- float3 z = cross(x, y);
- /* Compute rectangle coords in local reference system. */
- float3 dir = corner - P;
- float z0 = dot(dir, z);
- /* Flip 'z' to make it point against Q. */
- if(z0 > 0.0f) {
- z *= -1.0f;
- z0 *= -1.0f;
- }
- float z0sq = z0 * z0;
- float x0 = dot(dir, x);
- float y0 = dot(dir, y);
- float x1 = x0 + axisu_len;
- float y1 = y0 + axisv_len;
- float y0sq = y0 * y0;
- float y1sq = y1 * y1;
- /* Create vectors to four vertices. */
- float3 v00 = make_float3(x0, y0, z0);
- float3 v01 = make_float3(x0, y1, z0);
- float3 v10 = make_float3(x1, y0, z0);
- float3 v11 = make_float3(x1, y1, z0);
- /* Compute normals to edges. */
- float3 n0 = normalize(cross(v00, v10));
- float3 n1 = normalize(cross(v10, v11));
- float3 n2 = normalize(cross(v11, v01));
- float3 n3 = normalize(cross(v01, v00));
- /* Compute internal angles (gamma_i). */
- float g0 = acosf(-dot(n0, n1));
- float g1 = acosf(-dot(n1, n2));
- float g2 = acosf(-dot(n2, n3));
- float g3 = acosf(-dot(n3, n0));
- /* Compute predefined constants. */
- float b0 = n0.z;
- float b1 = n2.z;
- float b0sq = b0 * b0;
- float k = 2 * M_PI_F - g2 - g3;
- /* Compute solid angle from internal angles. */
- float S = g0 + g1 - k;
-
- /* Compute cu. */
- float au = randu * S + k;
- float fu = (cosf(au) * b0 - b1) / sinf(au);
- float cu = 1.0f / sqrtf(fu * fu + b0sq) * (fu > 0.0f ? 1.0f : -1.0f);
- cu = clamp(cu, -1.0f, 1.0f);
- /* Compute xu. */
- float xu = -(cu * z0) / sqrtf(1.0f - cu * cu);
- xu = clamp(xu, x0, x1);
- /* Compute yv. */
- float d = sqrt(xu * xu + z0sq);
- float h0 = y0 / sqrtf(d * d + y0sq);
- float h1 = y1 / sqrtf(d * d + y1sq);
- float hv = h0 + randv * (h1 - h0), hv2 = hv * hv;
- float yv = (hv2 < 1.0f - 1e-6f) ? (hv * d) / sqrtf(1.0f - hv2) : y1;
-
- /* Transform (xu, yv, z0) to world coords. */
- float3 p = P + xu * x + yv * y + z0 * z;
-
- /* Calculate pdf as per section 5.2 of the paper. */
- float wi_len;
- float3 wi = normalize_len(P - p, &wi_len);
- float3 np = normalize(cross(axisv, axisu));
- *pdf = 1.0f / S * dot(np, wi) / (wi_len * wi_len);
-
- return p;
+ randu = randu - 0.5f;
+ randv = randv - 0.5f;
+
+ return axisu*randu + axisv*randv;
}
ccl_device float spot_light_attenuation(float4 data1, float4 data2, LightSample *ls)
@@ -366,16 +286,14 @@ ccl_device void lamp_light_sample(KernelGlobals *kg, int lamp,
float3 axisv = make_float3(data2.y, data2.z, data2.w);
float3 D = make_float3(data3.y, data3.z, data3.w);
- ls->P = area_light_sample(P, ls->P,
- axisu, axisv,
- randu, randv,
- &ls->pdf);
-
+ ls->P += area_light_sample(axisu, axisv, randu, randv);
ls->Ng = D;
ls->D = normalize_len(ls->P - P, &ls->t);
float invarea = data2.x;
+
ls->eval_fac = 0.25f*invarea;
+ ls->pdf = invarea;
}
ls->eval_fac *= kernel_data.integrator.inv_pdf_lights;
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