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.

(cherry picked from commit 313527b3faf7f121077590acde995e7445edc0cc)

drivers/gles3/shaders/tonemap.glsl

@@ -160,10 +160,6 @@ 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 clamp((white * color + color) / (color * white + white), vec3(0.0f), vec3(1.0f));
 }
 
@@ -347,8 +343,9 @@ void main() {
 #endif
 
 	// Early Tonemap & SRGB Conversion; note that Linear tonemapping does not clamp to [0, 1]; some operations below expect a [0, 1] range and will clamp
-
-	color = apply_tonemapping(color, white);
+	// Ensure color values 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), white);
 
 #ifdef KEEP_3D_LINEAR
 	// leave color as is (-> don't convert to SRGB)