Clamp negative colors regardless of the tonemapper to avoid artifacts

Color artifacts could be visible when using negative lights with the
Filmic and ACES tonemapping operators, as these did not clamp negative
colors.

1 files changed, 4 insertions, 6 deletions

diff --git a/servers/rendering/renderer_rd/shaders/tonemap.glsl b/servers/rendering/renderer_rd/shaders/tonemap.glsl
index f028195a74..3c685c25b9 100644
--- a/servers/rendering/renderer_rd/shaders/tonemap.glsl
+++ b/servers/rendering/renderer_rd/shaders/tonemap.glsl
@@ -184,10 +184,6 @@ vec3 tonemap_aces(vec3 color, float white) {
 }
 
 vec3 tonemap_reinhard(vec3 color, float white) {
-	// Ensure color values are positive.
-	// They can be negative in the case of negative lights, which leads to undesired behavior.
-	color = max(vec3(0.0), color);
-
 	return (white * color + color) / (color * white + white);
 }
 
@@ -211,7 +207,7 @@ vec3 apply_tonemapping(vec3 color, float white) { // inputs are LINEAR, always o
 		return tonemap_reinhard(color, white);
 	} else if (params.tonemapper == TONEMAPPER_FILMIC) {
 		return tonemap_filmic(color, white);
-	} else { //aces
+	} else { // TONEMAPPER_ACES
 		return tonemap_aces(color, white);
 	}
 }
@@ -405,7 +401,9 @@ void main() {
 		color += screen_space_dither(gl_FragCoord.xy);
 	}
 
-	color = apply_tonemapping(color, params.white);
+	// Ensure color values passed to tonemappers are positive.
+	// They can be negative in the case of negative lights, which leads to undesired behavior.
+	color = apply_tonemapping(max(vec3(0.0), color), params.white);
 
 	color = linear_to_srgb(color); // regular linear -> SRGB conversion