Add multiview/stereoscopic rendering support to the clustered forward renderer

2 files changed, 43 insertions, 1 deletions

diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
index a8648fc96a..f9cee011d2 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
@@ -99,6 +99,18 @@ layout(location = 8) out float dp_clip;
 
 layout(location = 9) out flat uint instance_index_interp;
 
+#ifdef USE_MULTIVIEW
+#ifdef has_VK_KHR_multiview
+#define ViewIndex gl_ViewIndex
+#else // has_VK_KHR_multiview
+// !BAS! This needs to become an input once we implement our fallback!
+#define ViewIndex 0
+#endif // has_VK_KHR_multiview
+#else // USE_MULTIVIEW
+// Set to zero, not supported in non stereo
+#define ViewIndex 0
+#endif //USE_MULTIVIEW
+
 invariant gl_Position;
 
 #GLOBALS
@@ -244,7 +256,13 @@ void main() {
 	vec4 position;
 #endif
 
+#ifdef USE_MULTIVIEW
+	mat4 projection_matrix = scene_data.projection_matrix_view[ViewIndex];
+	mat4 inv_projection_matrix = scene_data.inv_projection_matrix_view[ViewIndex];
+#else
 	mat4 projection_matrix = scene_data.projection_matrix;
+	mat4 inv_projection_matrix = scene_data.inv_projection_matrix;
+#endif //USE_MULTIVIEW
 
 //using world coordinates
 #if !defined(SKIP_TRANSFORM_USED) && defined(VERTEX_WORLD_COORDS_USED)
@@ -421,10 +439,26 @@ layout(location = 8) in float dp_clip;
 
 layout(location = 9) in flat uint instance_index_interp;
 
+#ifdef USE_MULTIVIEW
+#ifdef has_VK_KHR_multiview
+#define ViewIndex gl_ViewIndex
+#else // has_VK_KHR_multiview
+// !BAS! This needs to become an input once we implement our fallback!
+#define ViewIndex 0
+#endif // has_VK_KHR_multiview
+#else // USE_MULTIVIEW
+// Set to zero, not supported in non stereo
+#define ViewIndex 0
+#endif //USE_MULTIVIEW
+
 //defines to keep compatibility with vertex
 
 #define world_matrix instances.data[instance_index].transform
+#ifdef USE_MULTIVIEW
+#define projection_matrix scene_data.projection_matrix_view[ViewIndex]
+#else
 #define projection_matrix scene_data.projection_matrix
+#endif
 
 #if defined(ENABLE_SSS) && defined(ENABLE_TRANSMITTANCE)
 //both required for transmittance to be enabled
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_clustered_inc.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_clustered_inc.glsl
index 3b110aded2..2e31503669 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_clustered_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_clustered_inc.glsl
@@ -2,6 +2,7 @@
 #define ROUGHNESS_MAX_LOD 5
 
 #define MAX_VOXEL_GI_INSTANCES 8
+#define MAX_VIEWS 2
 
 #if defined(has_GL_KHR_shader_subgroup_ballot) && defined(has_GL_KHR_shader_subgroup_arithmetic)
 
@@ -12,6 +13,10 @@
 
 #endif
 
+#if defined(USE_MULTIVIEW) && defined(has_VK_KHR_multiview)
+#extension GL_EXT_multiview : enable
+#endif
+
 #include "cluster_data_inc.glsl"
 #include "decal_data_inc.glsl"
 
@@ -169,10 +174,13 @@ sdfgi;
 layout(set = 1, binding = 0, std140) uniform SceneData {
 	mat4 projection_matrix;
 	mat4 inv_projection_matrix;
-
 	mat4 camera_matrix;
 	mat4 inv_camera_matrix;
 
+	// only used for multiview
+	mat4 projection_matrix_view[MAX_VIEWS];
+	mat4 inv_projection_matrix_view[MAX_VIEWS];
+
 	vec2 viewport_size;
 	vec2 screen_pixel_size;