Add LIGHT_VERTEX to fragment shader

Adds a new variable to the fragment shader to specify
the vertex position used when calculating lighting.

drivers/gles3/shaders/scene.glsl

@@ -1511,10 +1511,24 @@ void main() {
 	float alpha_antialiasing_edge = 0.0;
 	vec2 alpha_texture_coordinate = vec2(0.0, 0.0);
 #endif // ALPHA_ANTIALIASING_EDGE_USED
+
+#ifdef LIGHT_VERTEX_USED
+	vec3 light_vertex = vertex;
+#endif //LIGHT_VERTEX_USED
+
 	{
 #CODE : FRAGMENT
 	}
 
+#ifdef LIGHT_VERTEX_USED
+	vertex = light_vertex;
+#ifdef USE_MULTIVIEW
+	view = -normalize(vertex - eye_offset);
+#else
+	view = -normalize(vertex);
+#endif //USE_MULTIVIEW
+#endif //LIGHT_VERTEX_USED
+
 #ifndef USE_SHADOW_TO_OPACITY
 
 #if defined(ALPHA_SCISSOR_USED)

drivers/gles3/storage/material_storage.cpp

@@ -1274,6 +1274,7 @@ MaterialStorage::MaterialStorage() {
 		actions.renames["CUSTOM2"] = "custom2_attrib";
 		actions.renames["CUSTOM3"] = "custom3_attrib";
 		actions.renames["OUTPUT_IS_SRGB"] = "SHADER_IS_SRGB";
+		actions.renames["LIGHT_VERTEX"] = "light_vertex";
 
 		actions.renames["NODE_POSITION_WORLD"] = "model_matrix[3].xyz";
 		actions.renames["CAMERA_POSITION_WORLD"] = "scene_data.inv_view_matrix[3].xyz";
@@ -1320,6 +1321,7 @@ MaterialStorage::MaterialStorage() {
 		actions.usage_defines["COLOR"] = "#define COLOR_USED\n";
 		actions.usage_defines["INSTANCE_CUSTOM"] = "#define ENABLE_INSTANCE_CUSTOM\n";
 		actions.usage_defines["POSITION"] = "#define OVERRIDE_POSITION\n";
+		actions.usage_defines["LIGHT_VERTEX"] = "#define LIGHT_VERTEX_USED\n";
 
 		actions.usage_defines["ALPHA_SCISSOR_THRESHOLD"] = "#define ALPHA_SCISSOR_USED\n";
 		actions.usage_defines["ALPHA_HASH_SCALE"] = "#define ALPHA_HASH_USED\n";

servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp

@@ -624,6 +624,7 @@ void SceneShaderForwardClustered::init(const String p_defines) {
 		actions.renames["CUSTOM2"] = "custom2_attrib";
 		actions.renames["CUSTOM3"] = "custom3_attrib";
 		actions.renames["OUTPUT_IS_SRGB"] = "SHADER_IS_SRGB";
+		actions.renames["LIGHT_VERTEX"] = "light_vertex";
 
 		actions.renames["NODE_POSITION_WORLD"] = "read_model_matrix[3].xyz";
 		actions.renames["CAMERA_POSITION_WORLD"] = "scene_data.inv_view_matrix[3].xyz";
@@ -670,6 +671,7 @@ void SceneShaderForwardClustered::init(const String p_defines) {
 		actions.usage_defines["COLOR"] = "#define COLOR_USED\n";
 		actions.usage_defines["INSTANCE_CUSTOM"] = "#define ENABLE_INSTANCE_CUSTOM\n";
 		actions.usage_defines["POSITION"] = "#define OVERRIDE_POSITION\n";
+		actions.usage_defines["LIGHT_VERTEX"] = "#define LIGHT_VERTEX_USED\n";
 
 		actions.usage_defines["ALPHA_SCISSOR_THRESHOLD"] = "#define ALPHA_SCISSOR_USED\n";
 		actions.usage_defines["ALPHA_HASH_SCALE"] = "#define ALPHA_HASH_USED\n";

servers/rendering/renderer_rd/forward_mobile/scene_shader_forward_mobile.cpp

@@ -528,6 +528,7 @@ void SceneShaderForwardMobile::init(const String p_defines) {
 		actions.renames["CUSTOM2"] = "custom2_attrib";
 		actions.renames["CUSTOM3"] = "custom3_attrib";
 		actions.renames["OUTPUT_IS_SRGB"] = "SHADER_IS_SRGB";
+		actions.renames["LIGHT_VERTEX"] = "light_vertex";
 
 		actions.renames["NODE_POSITION_WORLD"] = "read_model_matrix[3].xyz";
 		actions.renames["CAMERA_POSITION_WORLD"] = "scene_data.inv_view_matrix[3].xyz";
@@ -574,6 +575,7 @@ void SceneShaderForwardMobile::init(const String p_defines) {
 		actions.usage_defines["COLOR"] = "#define COLOR_USED\n";
 		actions.usage_defines["INSTANCE_CUSTOM"] = "#define ENABLE_INSTANCE_CUSTOM\n";
 		actions.usage_defines["POSITION"] = "#define OVERRIDE_POSITION\n";
+		actions.usage_defines["LIGHT_VERTEX"] = "#define LIGHT_VERTEX\n";
 
 		actions.usage_defines["ALPHA_SCISSOR_THRESHOLD"] = "#define ALPHA_SCISSOR_USED\n";
 		actions.usage_defines["ALPHA_HASH_SCALE"] = "#define ALPHA_HASH_USED\n";

servers/rendering/renderer_rd/shaders/forward_clustered/scene_forward_clustered.glsl

@@ -1022,6 +1022,11 @@ void fragment_shader(in SceneData scene_data) {
 	inv_view_matrix[1][3] = 0.0;
 	inv_view_matrix[2][3] = 0.0;
 #endif
+
+#ifdef LIGHT_VERTEX_USED
+	vec3 light_vertex = vertex;
+#endif //LIGHT_VERTEX_USED
+
 	mat4 read_view_matrix = scene_data.view_matrix;
 	vec2 read_viewport_size = scene_data.viewport_size;
 	{
@@ -1032,6 +1037,15 @@ void fragment_shader(in SceneData scene_data) {
 	transmittance_color.a *= sss_strength;
 #endif
 
+#ifdef LIGHT_VERTEX_USED
+	vertex = light_vertex;
+#ifdef USE_MULTIVIEW
+	view = -normalize(vertex - eye_offset);
+#else
+	view = -normalize(vertex);
+#endif //USE_MULTIVIEW
+#endif //LIGHT_VERTEX_USED
+
 #ifndef USE_SHADOW_TO_OPACITY
 
 #ifdef ALPHA_SCISSOR_USED

servers/rendering/renderer_rd/shaders/forward_mobile/scene_forward_mobile.glsl

@@ -830,6 +830,10 @@ void main() {
 	inv_view_matrix[2][3] = 0.0;
 #endif
 
+#ifdef LIGHT_VERTEX_USED
+	vec3 light_vertex = vertex;
+#endif //LIGHT_VERTEX_USED
+
 	mat4 read_view_matrix = scene_data.view_matrix;
 	vec2 read_viewport_size = scene_data.viewport_size;
 
@@ -837,6 +841,15 @@ void main() {
 #CODE : FRAGMENT
 	}
 
+#ifdef LIGHT_VERTEX_USED
+	vertex = light_vertex;
+#ifdef USE_MULTIVIEW
+	view = -normalize(vertex - eye_offset);
+#else
+	view = -normalize(vertex);
+#endif //USE_MULTIVIEW
+#endif //LIGHT_VERTEX_USED
+
 #ifdef LIGHT_TRANSMITTANCE_USED
 #ifdef SSS_MODE_SKIN
 	transmittance_color.a = sss_strength;

servers/rendering/shader_types.cpp

@@ -111,6 +111,7 @@ ShaderTypes::ShaderTypes() {
 	shader_modes[RS::SHADER_SPATIAL].functions["vertex"].built_ins["EYE_OFFSET"] = constt(ShaderLanguage::TYPE_VEC3);
 
 	shader_modes[RS::SHADER_SPATIAL].functions["fragment"].built_ins["VERTEX"] = constt(ShaderLanguage::TYPE_VEC3);
+	shader_modes[RS::SHADER_SPATIAL].functions["fragment"].built_ins["LIGHT_VERTEX"] = ShaderLanguage::TYPE_VEC3;
 	shader_modes[RS::SHADER_SPATIAL].functions["fragment"].built_ins["FRAGCOORD"] = constt(ShaderLanguage::TYPE_VEC4);
 	shader_modes[RS::SHADER_SPATIAL].functions["fragment"].built_ins["FRONT_FACING"] = constt(ShaderLanguage::TYPE_BOOL);
 	shader_modes[RS::SHADER_SPATIAL].functions["fragment"].built_ins["NORMAL"] = ShaderLanguage::TYPE_VEC3;