diff options
Diffstat (limited to 'intern/cycles/kernel/kernel_light.h')
| -rw-r--r-- | intern/cycles/kernel/kernel_light.h | 25 |
1 files changed, 9 insertions, 16 deletions
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h index 32cb924d25f..262d7df1364 100644 --- a/intern/cycles/kernel/kernel_light.h +++ b/intern/cycles/kernel/kernel_light.h @@ -72,24 +72,17 @@ ccl_device_inline float rect_light_sample(float3 P, float y0 = dot(dir, y); float x1 = x0 + axisu_len; float y1 = y0 + axisv_len; - /* 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 = safe_acosf(-dot(n0, n1)); - float g1 = safe_acosf(-dot(n1, n2)); - float g2 = safe_acosf(-dot(n2, n3)); - float g3 = safe_acosf(-dot(n3, n0)); + float4 diff = make_float4(x0, y1, x1, y0) - make_float4(x1, y0, x0, y1); + float4 nz = make_float4(y0, x1, y1, x0) * diff; + nz = nz / sqrt(z0 * z0 * diff * diff + nz * nz); + float g0 = safe_acosf(-nz.x * nz.y); + float g1 = safe_acosf(-nz.y * nz.z); + float g2 = safe_acosf(-nz.z * nz.w); + float g3 = safe_acosf(-nz.w * nz.x); /* Compute predefined constants. */ - float b0 = n0.z; - float b1 = n2.z; + float b0 = nz.x; + float b1 = nz.z; float b0sq = b0 * b0; float k = M_2PI_F - g2 - g3; /* Compute solid angle from internal angles. */ |