Fix #26807: glsl diffuse/specular was not clamping negative values, giving

some inconsistent results with the renderer.

2 files changed, 14 insertions, 4 deletions

diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 962c486c159..1bf70fbd38b 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -557,7 +557,7 @@ static void add_to_diffuse(GPUMaterial *mat, Material *ma, GPUShadeInput *shi, G
 		addcol = shi->rgb;
 
 	/* output to */
-	GPU_link(mat, "shade_madd", *diff, rgb, addcol, diff);
+	GPU_link(mat, "shade_madd_clamped", *diff, rgb, addcol, diff);
 }
 
 static void ramp_spec_result(GPUShadeInput *shi, GPUNodeLink **spec)
@@ -730,7 +730,7 @@ static void shade_one_light(GPUShadeInput *shi, GPUShadeResult *shr, GPULamp *la
 		if(lamp->type == LA_HEMI) {
 			GPU_link(mat, "shade_hemi_spec", vn, lv, view, GPU_uniform(&ma->spec), shi->har, visifac, &t);
 			GPU_link(mat, "shade_add_spec", t, GPU_dynamic_uniform(lamp->dyncol), shi->specrgb, &outcol);
-			GPU_link(mat, "shade_add", shr->spec, outcol, &shr->spec);
+			GPU_link(mat, "shade_add_clamped", shr->spec, outcol, &shr->spec);
 		}
 		else {
 			if(ma->spec_shader==MA_SPEC_PHONG)
@@ -753,11 +753,11 @@ static void shade_one_light(GPUShadeInput *shi, GPUShadeResult *shr, GPULamp *la
 				GPUNodeLink *spec;
 				do_specular_ramp(shi, specfac, t, &spec);
 				GPU_link(mat, "shade_add_spec", t, GPU_dynamic_uniform(lamp->dyncol), spec, &outcol);
-				GPU_link(mat, "shade_add", shr->spec, outcol, &shr->spec);
+				GPU_link(mat, "shade_add_clamped", shr->spec, outcol, &shr->spec);
 			}
 			else {
 				GPU_link(mat, "shade_add_spec", t, GPU_dynamic_uniform(lamp->dyncol), shi->specrgb, &outcol);
-				GPU_link(mat, "shade_add", shr->spec, outcol, &shr->spec);
+				GPU_link(mat, "shade_add_clamped", shr->spec, outcol, &shr->spec);
 			}
 		}
 	}
diff --git a/source/blender/gpu/intern/gpu_shader_material.glsl b/source/blender/gpu/intern/gpu_shader_material.glsl
index 03883fb4f57..feb0a84fa87 100644
--- a/source/blender/gpu/intern/gpu_shader_material.glsl
+++ b/source/blender/gpu/intern/gpu_shader_material.glsl
@@ -1686,6 +1686,16 @@ void shade_madd(vec4 col, vec4 col1, vec4 col2, out vec4 outcol)
 	outcol = col + col1*col2;
 }
 
+void shade_add_clamped(vec4 col1, vec4 col2, out vec4 outcol)
+{
+	outcol = col1 + max(col2, vec4(0.0, 0.0, 0.0, 0.0));
+}
+
+void shade_madd_clamped(vec4 col, vec4 col1, vec4 col2, out vec4 outcol)
+{
+	outcol = col + max(col1*col2, vec4(0.0, 0.0, 0.0, 0.0));
+}
+
 void shade_maddf(vec4 col, float f, vec4 col1, out vec4 outcol)
 {
 	outcol = col + f*col1;