Ensure that all spec constants are given a value in the mobile post process shader so that re-spirv can pick up on them and optimize them out of the final shader

This is needed to workaround a bug on Adreno devices when using input attachments and spec constants in the same shader

Author: clayjohn

servers/rendering/renderer_rd/effects/tone_mapper.cpp

@@ -324,7 +324,7 @@ void ToneMapper::tonemapper_subpass(RD::DrawListID p_subpass_draw_list, RID p_so
 	tonemap_mobile.push_constant.white = p_settings.white;
 	tonemap_mobile.push_constant.luminance_multiplier = p_settings.luminance_multiplier;
 
-	uint32_t spec_constant = 0;
+	uint32_t spec_constant = TONEMAP_MOBILE_ADRENO_BUG;
 	spec_constant |= p_settings.use_bcs ? TONEMAP_MOBILE_FLAG_USE_BCS : 0;
 	//spec_constant |= p_settings.use_glow ? TONEMAP_MOBILE_FLAG_USE_GLOW : 0;
 	//spec_constant |= p_settings.glow_map_strength > 0.01 ? TONEMAP_MOBILE_FLAG_USE_GLOW_MAP : 0;

servers/rendering/renderer_rd/effects/tone_mapper.h

@@ -100,6 +100,7 @@ class ToneMapper {
 		TONEMAP_MOBILE_FLAG_GLOW_MODE_SOFTLIGHT = (1 << 15),
 		TONEMAP_MOBILE_FLAG_GLOW_MODE_REPLACE = (1 << 16),
 		TONEMAP_MOBILE_FLAG_GLOW_MODE_MIX = (1 << 17),
+		TONEMAP_MOBILE_ADRENO_BUG = (1 << 18), // Needs to be last so we force the pipeline cache to specify specializations for all variants.
 	};
 
 	struct TonemapPushConstant {

servers/rendering/renderer_rd/pipeline_cache_rd.cpp

@@ -46,14 +46,12 @@ RID PipelineCacheRD::_generate_version(RD::VertexFormatID p_vertex_format_id, RD
 	uint32_t bool_index = 0;
 	uint32_t bool_specializations = p_bool_specializations;
 	while (bool_specializations) {
-		if (bool_specializations & (1 << bool_index)) {
-			RD::PipelineSpecializationConstant sc;
-			sc.bool_value = true;
-			sc.constant_id = bool_index;
-			sc.type = RD::PIPELINE_SPECIALIZATION_CONSTANT_TYPE_BOOL;
-			specialization_constants.push_back(sc);
-			bool_specializations &= ~(1 << bool_index);
-		}
+		RD::PipelineSpecializationConstant sc;
+		sc.bool_value = bool(bool_specializations & (1 << bool_index));
+		sc.constant_id = bool_index;
+		sc.type = RD::PIPELINE_SPECIALIZATION_CONSTANT_TYPE_BOOL;
+		specialization_constants.push_back(sc);
+		bool_specializations &= ~(1 << bool_index);
 		bool_index++;
 	}