Cycles: mist pass added, with start/depth/falloff control. If the pass is

enabled in a render layer a Mist Pass panel will be shown in the world
properties.

1 files changed, 27 insertions, 0 deletions

diff --git a/intern/cycles/kernel/kernel_passes.h b/intern/cycles/kernel/kernel_passes.h
index 57dbdc2ffc1..c7d216e4638 100644
--- a/intern/cycles/kernel/kernel_passes.h
+++ b/intern/cycles/kernel/kernel_passes.h
@@ -86,6 +86,31 @@ __device_inline void kernel_write_data_passes(KernelGlobals *kg, __global float
 		L->color_glossy += shader_bsdf_glossy(kg, sd)*throughput;
 	if(flag & (PASS_TRANSMISSION_INDIRECT|PASS_TRANSMISSION_COLOR|PASS_TRANSMISSION_DIRECT))
 		L->color_transmission += shader_bsdf_transmission(kg, sd)*throughput;
+
+	if(flag & PASS_MIST) {
+		/* bring depth into 0..1 range */
+		float mist_start = kernel_data.film.mist_start;
+		float mist_inv_depth = kernel_data.film.mist_inv_depth;
+
+		float depth = camera_distance(kg, sd->P);
+		float mist = clamp((depth - mist_start)*mist_inv_depth, 0.0f, 1.0f);
+
+		/* falloff */
+		float mist_falloff = kernel_data.film.mist_falloff;
+
+		if(mist_falloff == 1.0f)
+			;
+		else if(mist_falloff == 2.0f)
+			mist = mist*mist;
+		else if(mist_falloff == 0.5f)
+			mist = sqrtf(mist);
+		else
+			mist = powf(mist, mist_falloff);
+
+		/* modulate by transparency */
+		float3 alpha = throughput*(make_float3(1.0f, 1.0f, 1.0f) - shader_bsdf_transparency(kg, sd));
+		L->mist += (1.0f - mist)*average(alpha);
+	}
 #endif
 }
 
@@ -128,6 +153,8 @@ __device_inline void kernel_write_light_passes(KernelGlobals *kg, __global float
 		shadow.w = kernel_data.film.pass_shadow_scale;
 		kernel_write_pass_float4(buffer + kernel_data.film.pass_shadow, sample, shadow);
 	}
+	if(flag & PASS_MIST)
+		kernel_write_pass_float(buffer + kernel_data.film.pass_mist, sample, L->mist);
 #endif
 }