DRW: Split ViewProjectionMatrix in order to increase precision

This also removes the need to compute the persmat and saves some memory
from the `ViewInfos` struct. This is needed to allow multiview support.

Initial testing found no major performance regression during vertex
heavy workload.

Test file: {F13610017}

Results:
| Platform | Master | Split Matrix|
| Linux + Mesa + AMD W6600 | 48 fps | 47 fps |
| Macbook Pro M1 | 50 fps | 51 fps |
| Linux + NVidia 1080Ti | 51 fps | 52 fps |
| Linux + Radeon Vega 64 | 25.6 fps | 26.7 fps |

Increased precision when far from origin:
{F13610024}

{F13610025}

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D16125

8 files changed, 9 insertions, 9 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/overlay_armature_envelope_solid_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_armature_envelope_solid_vert.glsl
index 4d21ffd96b5..17aed643224 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_armature_envelope_solid_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_armature_envelope_solid_vert.glsl
@@ -38,5 +38,5 @@ void main()
   view_clipping_distances(sp);
 
   vec4 pos_4d = vec4(sp, 1.0);
-  gl_Position = drw_view.persmat * pos_4d;
+  gl_Position = drw_view.winmat * (drw_view.viewmat * pos_4d);
 }
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_armature_shape_solid_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_armature_shape_solid_vert.glsl
index 68f7e75673f..2b5605c85d3 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_armature_shape_solid_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_armature_shape_solid_vert.glsl
@@ -25,7 +25,7 @@ void main()
   finalColor.a = 1.0;
 
   vec4 world_pos = model_mat * vec4(pos, 1.0);
-  gl_Position = drw_view.persmat * world_pos;
+  gl_Position = drw_view.winmat * (drw_view.viewmat * world_pos);
 
   view_clipping_distances(world_pos.xyz);
 }
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_skin_root_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_skin_root_vert.glsl
index 76a944c6987..caca123a0c2 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_skin_root_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_skin_root_vert.glsl
@@ -9,7 +9,7 @@ void main()
   vec3 up = normalize(imat * screenVecs[1].xyz);
   vec3 screen_pos = (right * pos.x + up * pos.z) * size;
   vec4 pos_4d = ModelMatrix * vec4(local_pos + screen_pos, 1.0);
-  gl_Position = drw_view.persmat * pos_4d;
+  gl_Position = drw_view.winmat * (drw_view.viewmat * pos_4d);
   /* Manual stipple: one segment out of 2 is transparent. */
   finalColor = ((gl_VertexID & 1) == 0) ? colorSkinRoot : vec4(0.0);
 
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_grid_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_grid_vert.glsl
index b43b1eb4a52..6a027f94f49 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_grid_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_grid_vert.glsl
@@ -39,5 +39,5 @@ void main()
     local_pos.z = clamp(local_pos.z, -1.0, 0.0);
   }
 
-  gl_Position = drw_view.persmat * vec4(real_pos, 1.0);
+  gl_Position = drw_view.winmat * (drw_view.viewmat * vec4(real_pos, 1.0));
 }
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert.glsl
index e6281f75b8f..50c24de0838 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert.glsl
@@ -18,7 +18,7 @@ vec2 proj(vec4 pos)
 
 void main()
 {
-  gl_Position = drw_view.persmat * vec4(pos, 1.0);
+  gl_Position = drw_view.winmat * (drw_view.viewmat * vec4(pos, 1.0));
 
   interp.ss_pos = proj(gl_Position);
 
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert_no_geom.glsl b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert_no_geom.glsl
index 89878a63c4b..c83e7f095a7 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert_no_geom.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_line_vert_no_geom.glsl
@@ -108,8 +108,8 @@ void main()
   vec3 in_pos0 = vertex_fetch_attribute(base_vertex_id, pos, vec3);
   vec3 in_pos1 = vertex_fetch_attribute(base_vertex_id + 1, pos, vec3);
 
-  vec4 out_pos0 = ViewProjectionMatrix * vec4(in_pos0, 1.0);
-  vec4 out_pos1 = ViewProjectionMatrix * vec4(in_pos1, 1.0);
+  vec4 out_pos0 = ProjectionMatrix * (ViewMatrix * vec4(in_pos0, 1.0));
+  vec4 out_pos1 = ProjectionMatrix * (ViewMatrix * vec4(in_pos1, 1.0));
 
   /* Final calculations required for Geometry Shader alternative.
    * We need to calculate values for each vertex position to correctly determine the final output
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_point_vert.glsl b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_point_vert.glsl
index 70892954cd8..7305d00c052 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_motion_path_point_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_motion_path_point_vert.glsl
@@ -9,7 +9,7 @@
 
 void main()
 {
-  gl_Position = drw_view.persmat * vec4(pos, 1.0);
+  gl_Position = drw_view.winmat * (drw_view.viewmat * vec4(pos, 1.0));
   gl_PointSize = float(pointSize + 2);
 
   int frame = gl_VertexID + cacheStart;
diff --git a/source/blender/draw/engines/overlay/shaders/overlay_outline_prepass_gpencil_frag.glsl b/source/blender/draw/engines/overlay/shaders/overlay_outline_prepass_gpencil_frag.glsl
index 92be9ec3bcb..a575d42231e 100644
--- a/source/blender/draw/engines/overlay/shaders/overlay_outline_prepass_gpencil_frag.glsl
+++ b/source/blender/draw/engines/overlay/shaders/overlay_outline_prepass_gpencil_frag.glsl
@@ -25,7 +25,7 @@ void main()
     bool is_persp = drw_view.winmat[3][3] == 0.0;
     vec2 uvs = vec2(gl_FragCoord.xy) * drw_view.viewport_size_inverse;
     vec3 pos_ndc = vec3(uvs, gl_FragCoord.z) * 2.0 - 1.0;
-    vec4 pos_world = drw_view.persinv * vec4(pos_ndc, 1.0);
+    vec4 pos_world = drw_view.viewinv * (drw_view.wininv * vec4(pos_ndc, 1.0));
     vec3 pos = pos_world.xyz / pos_world.w;
 
     vec3 ray_ori = pos;