Move debanding into internal sky shader code so that it is applied after everything else.

This ensures that the debanding does not scale with exposure or any other effect.

2 files changed, 14 insertions, 0 deletions

diff --git a/drivers/gles3/shaders/sky.glsl b/drivers/gles3/shaders/sky.glsl
index 21f01d2a8f..4c0fe47f6b 100644
--- a/drivers/gles3/shaders/sky.glsl
+++ b/drivers/gles3/shaders/sky.glsl
@@ -104,6 +104,15 @@ uniform uint directional_light_count;
 
 layout(location = 0) out vec4 frag_color;
 
+#ifdef USE_DEBANDING
+// https://www.iryoku.com/next-generation-post-processing-in-call-of-duty-advanced-warfare
+vec3 interleaved_gradient_noise(vec2 pos) {
+	const vec3 magic = vec3(0.06711056f, 0.00583715f, 52.9829189f);
+	float res = fract(magic.z * fract(dot(pos, magic.xy))) * 2.0 - 1.0;
+	return vec3(res, -res, res) / 255.0;
+}
+#endif
+
 void main() {
 	vec3 cube_normal;
 	cube_normal.z = -1.0;
@@ -168,4 +177,8 @@ void main() {
 
 	frag_color.rgb = color;
 	frag_color.a = alpha;
+
+#ifdef USE_DEBANDING
+	frag_color.rgb += interleaved_gradient_noise(gl_FragCoord.xy);
+#endif
 }
diff --git a/drivers/gles3/storage/material_storage.cpp b/drivers/gles3/storage/material_storage.cpp
index 3dbc75392c..523c9dd8e6 100644
--- a/drivers/gles3/storage/material_storage.cpp
+++ b/drivers/gles3/storage/material_storage.cpp
@@ -1715,6 +1715,7 @@ ShaderCompiler::DefaultIdentifierActions actions;
 		actions.usage_defines["HALF_RES_COLOR"] = "\n#define USES_HALF_RES_COLOR\n";
 		actions.usage_defines["QUARTER_RES_COLOR"] = "\n#define USES_QUARTER_RES_COLOR\n";
 		actions.render_mode_defines["disable_fog"] = "#define DISABLE_FOG\n";
+		actions.render_mode_defines["use_debanding"] = "#define USE_DEBANDING\n";
 
 		actions.default_filter = ShaderLanguage::FILTER_LINEAR_MIPMAP;
 		actions.default_repeat = ShaderLanguage::REPEAT_ENABLE;