Fix T40078: GLSL Lamp with OnlyShadow makes weird colors in object.

To prevent only shadow lamps from producing negative colors, shr->diff
and shr->spec should've been clamped to positive values after lamp loop.

1 files changed, 9 insertions, 7 deletions

diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 5594c085974..5ed47cda8f5 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -765,20 +765,18 @@ static void shade_one_light(GPUShadeInput *shi, GPUShadeResult *shr, GPULamp *la
 			}
 			
 			if (lamp->mode & LA_ONLYSHADOW) {
-				GPUNodeLink *rgb;
+				GPUNodeLink *shadrgb;
 				GPU_link(mat, "shade_only_shadow", i, shadfac,
-					GPU_dynamic_uniform(&lamp->dynenergy, GPU_DYNAMIC_LAMP_DYNENERGY, lamp->ob), &shadfac);
-
-				GPU_link(mat, "shade_mul", shi->rgb, GPU_uniform(lamp->shadow_color), &rgb);
-				GPU_link(mat, "mtex_rgb_invert", rgb, &rgb);
+					GPU_dynamic_uniform(&lamp->dynenergy, GPU_DYNAMIC_LAMP_DYNENERGY, lamp->ob),
+					GPU_uniform(lamp->shadow_color), &shadrgb);
 				
 				if (!(lamp->mode & LA_NO_DIFF)) {
-					GPU_link(mat, "shade_only_shadow_diffuse", shadfac, rgb,
+					GPU_link(mat, "shade_only_shadow_diffuse", shadrgb, shi->rgb,
 						shr->diff, &shr->diff);
 				}
 
 				if (!(lamp->mode & LA_NO_SPEC))
-					GPU_link(mat, "shade_only_shadow_specular", shadfac, shi->specrgb,
+					GPU_link(mat, "shade_only_shadow_specular", shadrgb, shi->specrgb,
 						shr->spec, &shr->spec);
 				
 				add_user_list(&mat->lamps, lamp);
@@ -890,6 +888,10 @@ static void material_lights(GPUShadeInput *shi, GPUShadeResult *shr)
 			free_object_duplilist(lb);
 		}
 	}
+
+	/* prevent only shadow lamps from producing negative colors.*/
+	GPU_link(shi->gpumat, "shade_clamp_positive", shr->spec, &shr->spec);
+	GPU_link(shi->gpumat, "shade_clamp_positive", shr->diff, &shr->diff);
 }
 
 static void texture_rgb_blend(GPUMaterial *mat, GPUNodeLink *tex, GPUNodeLink *out, GPUNodeLink *fact, GPUNodeLink *facg, int blendtype, GPUNodeLink **in)