Edit Mesh: Rework new implementation and use geometry shader to draw lines

This make it (theoriticaly) compatible with all supported hardware with
consistent results.

Also we now draw the lines with analytic anti-aliasing instead of relying
on MSAA (which offers less benefits in our case).

The remaining aliasing comes from edges cut in half by the mesh which is
not rendered with MSAA. Hopefully this is not too much distracting and only
happen if the face is almost parallel to the view.

1 files changed, 44 insertions, 64 deletions

diff --git a/source/blender/draw/modes/edit_mesh_mode.c b/source/blender/draw/modes/edit_mesh_mode.c
index 0af90ad6f4b..d0b7e6484e3 100644
--- a/source/blender/draw/modes/edit_mesh_mode.c
+++ b/source/blender/draw/modes/edit_mesh_mode.c
@@ -104,7 +104,6 @@ typedef struct EDIT_MESH_Shaders {
 	GPUShader *overlay_vert;
 	GPUShader *overlay_edge;
 	GPUShader *overlay_edge_flat;
-	GPUShader *overlay_edge_deco;
 	GPUShader *overlay_face;
 	GPUShader *overlay_facedot;
 
@@ -137,7 +136,6 @@ typedef struct EDIT_MESH_PrivateData {
 
 	DRWShadingGroup *vert_shgrp;
 	DRWShadingGroup *edge_shgrp;
-	DRWShadingGroup *edge_deco_shgrp;
 	DRWShadingGroup *face_shgrp;
 	DRWShadingGroup *face_cage_shgrp;
 	DRWShadingGroup *facedot_shgrp;
@@ -150,7 +148,6 @@ typedef struct EDIT_MESH_PrivateData {
 	bool do_zbufclip;
 	bool do_faces;
 	bool do_edges;
-	float edge_width_scale;
 } EDIT_MESH_PrivateData; /* Transient data */
 
 /* *********** FUNCTIONS *********** */
@@ -192,7 +189,12 @@ static void EDIT_MESH_engine_init(void *vedata)
 		});
 
 		char *lib = BLI_string_joinN(world_clip_lib_or_empty, datatoc_common_globals_lib_glsl, datatoc_edit_mesh_overlay_common_lib_glsl);
-		const bool use_geom_shader = GPU_max_line_width() <= 2.0f;
+		/* Use geometry shader to draw edge wireframe. This ensure us
+		 * the same result accross platforms and more flexibility. But
+		 * we pay the cost of running a geometry shader.
+		 * In the future we might consider using only the vertex shader
+		 * and loading data manually with buffer textures. */
+		const bool use_geom_shader = true;
 		const char *geom_sh_code[] = {lib, datatoc_edit_mesh_overlay_geom_glsl, NULL};
 		if (!use_geom_shader) {
 			geom_sh_code[0] = NULL;
@@ -211,16 +213,10 @@ static void EDIT_MESH_engine_init(void *vedata)
 		});
 		sh_data->overlay_edge_flat = GPU_shader_create_from_arrays({
 		        .vert = (const char *[]){lib, datatoc_edit_mesh_overlay_vert_glsl, NULL},
-		        .frag = (const char *[]){datatoc_gpu_shader_flat_color_frag_glsl, NULL},
+		        .frag = (const char *[]){lib, datatoc_edit_mesh_overlay_frag_glsl, NULL},
 		        .defs = (const char *[]){world_clip_def_or_empty, use_geom_def, "#define EDGE\n", "#define FLAT\n", NULL},
 		        .geom = (use_geom_shader) ? geom_sh_code : NULL,
 		});
-		sh_data->overlay_edge_deco = GPU_shader_create_from_arrays({
-		        .vert = (const char *[]){lib, datatoc_edit_mesh_overlay_vert_glsl, NULL},
-		        .frag = (const char *[]){datatoc_gpu_shader_flat_color_frag_glsl, NULL},
-		        .defs = (const char *[]){world_clip_def_or_empty, use_geom_def, "#define EDGE_DECORATION\n", "#define FLAT\n", NULL},
-		        .geom = (use_geom_shader) ? geom_sh_code : NULL,
-		});
 		sh_data->overlay_vert = GPU_shader_create_from_arrays({
 		        .vert = (const char *[]){lib, datatoc_edit_mesh_overlay_vert_glsl, NULL},
 		        .frag = (const char *[]){datatoc_gpu_shader_point_varying_color_frag_glsl, NULL},
@@ -268,10 +264,10 @@ static void EDIT_MESH_engine_init(void *vedata)
 }
 
 static DRWPass *edit_mesh_create_overlay_pass(
-        float *face_alpha, float *edge_width_scale, int *data_mask, bool do_edges, bool UNUSED(xray),
+        float *face_alpha, int *data_mask, bool do_edges, bool UNUSED(xray),
         DRWState statemod,
         DRWShadingGroup **r_face_shgrp, DRWShadingGroup **r_face_cage_shgrp, DRWShadingGroup **r_facedot_shgrp,
-        DRWShadingGroup **r_edge_shgrp, DRWShadingGroup **r_edge_deco_shgrp, DRWShadingGroup **r_vert_shgrp)
+        DRWShadingGroup **r_edge_shgrp, DRWShadingGroup **r_vert_shgrp)
 {
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 	RegionView3D *rv3d = draw_ctx->rv3d;
@@ -280,6 +276,7 @@ static DRWPass *edit_mesh_create_overlay_pass(
 	EDIT_MESH_Shaders *sh_data = &e_data.sh_data[draw_ctx->shader_cfg];
 	const bool select_vert = (tsettings->selectmode & SCE_SELECT_VERTEX) != 0;
 	const bool select_face = (tsettings->selectmode & SCE_SELECT_FACE) != 0;
+	const bool select_edge = (tsettings->selectmode & SCE_SELECT_EDGE) != 0;
 	float winmat[4][4];
 	float viewdist = rv3d->dist;
 	DRW_viewport_matrix_get(winmat, DRW_MAT_WIN);
@@ -295,17 +292,15 @@ static DRWPass *edit_mesh_create_overlay_pass(
 
 	DRWShadingGroup *grp;
 
-	/* TEST */
 	GPUShader *vert_sh = sh_data->overlay_vert;
 	GPUShader *edge_sh = (select_vert) ? sh_data->overlay_edge : sh_data->overlay_edge_flat;
 	GPUShader *face_sh = sh_data->overlay_face;
 	GPUShader *facedot_sh = sh_data->overlay_facedot;
-	GPUShader *edge_deco_sh = sh_data->overlay_edge_deco;
+
 	/* Faces */
 	if (select_face) {
 		grp = *r_facedot_shgrp = DRW_shgroup_create(facedot_sh, pass);
 		DRW_shgroup_uniform_block(grp, "globalsBlock", G_draw.block_ubo);
-		DRW_shgroup_uniform_float(grp, "edgeScale", edge_width_scale, 1);
 		DRW_shgroup_state_enable(grp, DRW_STATE_WRITE_DEPTH);
 		if (rv3d->rflag & RV3D_CLIPPING) {
 			DRW_shgroup_world_clip_planes_from_rv3d(grp, rv3d);
@@ -315,7 +310,6 @@ static DRWPass *edit_mesh_create_overlay_pass(
 	grp = *r_face_shgrp = DRW_shgroup_create(face_sh, pass);
 	DRW_shgroup_uniform_block(grp, "globalsBlock", G_draw.block_ubo);
 	DRW_shgroup_uniform_float(grp, "faceAlphaMod", face_alpha, 1);
-	DRW_shgroup_uniform_float(grp, "edgeScale", edge_width_scale, 1);
 	DRW_shgroup_uniform_ivec4(grp, "dataMask", data_mask, 1);
 	DRW_shgroup_uniform_bool_copy(grp, "doEdges", do_edges);
 	DRW_shgroup_uniform_float_copy(grp, "ofs", 0.0f);
@@ -332,7 +326,6 @@ static DRWPass *edit_mesh_create_overlay_pass(
 		grp = *r_vert_shgrp = DRW_shgroup_create(vert_sh, pass);
 		DRW_shgroup_uniform_block(grp, "globalsBlock", G_draw.block_ubo);
 		DRW_shgroup_uniform_vec2(grp, "viewportSize", DRW_viewport_size_get(), 1);
-		DRW_shgroup_uniform_float(grp, "edgeScale", edge_width_scale, 1);
 		DRW_shgroup_uniform_float_copy(grp, "ofs", depth_ofs * 1.5f);
 		DRW_shgroup_state_enable(grp, DRW_STATE_OFFSET_NEGATIVE | DRW_STATE_WRITE_DEPTH);
 		DRW_shgroup_state_disable(grp, DRW_STATE_BLEND);
@@ -342,32 +335,19 @@ static DRWPass *edit_mesh_create_overlay_pass(
 	}
 
 	/* Edges */
-	grp = *r_edge_deco_shgrp = DRW_shgroup_create(edge_deco_sh, pass);
-	DRW_shgroup_uniform_block(grp, "globalsBlock", G_draw.block_ubo);
-	DRW_shgroup_uniform_vec2(grp, "viewportSize", DRW_viewport_size_get(), 1);
-	DRW_shgroup_uniform_vec2(grp, "viewportSizeInv", DRW_viewport_invert_size_get(), 1);
-	DRW_shgroup_uniform_ivec4(grp, "dataMask", data_mask, 1);
-	DRW_shgroup_uniform_bool_copy(grp, "doEdges", do_edges);
-	DRW_shgroup_uniform_float_copy(grp, "ofs", depth_ofs);
-	DRW_shgroup_state_enable(grp, DRW_STATE_OFFSET_NEGATIVE);
-	DRW_shgroup_state_enable(grp, DRW_STATE_BLEND);
-	DRW_shgroup_state_enable(grp, DRW_STATE_WIRE_WIDE);
-	/* To match blender loop structure. */
-	DRW_shgroup_state_enable(grp, DRW_STATE_FIRST_VERTEX_CONVENTION);
-	if (rv3d->rflag & RV3D_CLIPPING) {
-		DRW_shgroup_world_clip_planes_from_rv3d(grp, rv3d);
-	}
-
 	grp = *r_edge_shgrp = DRW_shgroup_create(edge_sh, pass);
 	DRW_shgroup_uniform_block(grp, "globalsBlock", G_draw.block_ubo);
 	DRW_shgroup_uniform_vec2(grp, "viewportSize", DRW_viewport_size_get(), 1);
 	DRW_shgroup_uniform_vec2(grp, "viewportSizeInv", DRW_viewport_invert_size_get(), 1);
-	DRW_shgroup_uniform_float(grp, "edgeScale", edge_width_scale, 1);
 	DRW_shgroup_uniform_ivec4(grp, "dataMask", data_mask, 1);
 	DRW_shgroup_uniform_bool_copy(grp, "doEdges", do_edges);
 	DRW_shgroup_uniform_float_copy(grp, "ofs", depth_ofs);
-	DRW_shgroup_state_enable(grp, DRW_STATE_WRITE_DEPTH);
+	DRW_shgroup_uniform_float_copy(grp, "edgeScale", select_edge ? 1.75f : 1.0f);
 	DRW_shgroup_state_enable(grp, DRW_STATE_OFFSET_NEGATIVE);
+	/* TODO remove this when we draw only one line per edge. */
+	DRW_shgroup_state_enable(grp, DRW_STATE_WRITE_DEPTH);
+	DRW_shgroup_state_disable(grp, DRW_STATE_DEPTH_LESS_EQUAL);
+	DRW_shgroup_state_enable(grp, DRW_STATE_DEPTH_LESS);
 	/* To match blender loop structure. */
 	DRW_shgroup_state_enable(grp, DRW_STATE_FIRST_VERTEX_CONVENTION);
 	if (rv3d->rflag & RV3D_CLIPPING) {
@@ -406,9 +386,6 @@ static void EDIT_MESH_cache_init(void *vedata)
 
 	stl->g_data->do_zbufclip = ((v3d)->shading.flag & XRAY_FLAG(v3d)) != 0;
 
-	/* Applies on top of the theme edge width, so edge-mode can have thick edges. */
-	stl->g_data->edge_width_scale = (tsettings->selectmode & (SCE_SELECT_EDGE)) ? 1.75f : 1.0f;
-
 	stl->g_data->data_mask[0] = 0xFF; /* Face Flag */
 	stl->g_data->data_mask[1] = 0xFF; /* Edge Flag */
 	stl->g_data->data_mask[2] = 0xFF; /* Crease */
@@ -518,25 +495,23 @@ static void EDIT_MESH_cache_init(void *vedata)
 
 	if (!stl->g_data->do_zbufclip) {
 		psl->edit_face_overlay = edit_mesh_create_overlay_pass(
-		        &face_mod, &stl->g_data->edge_width_scale, stl->g_data->data_mask, stl->g_data->do_edges, false,
+		        &face_mod, stl->g_data->data_mask, stl->g_data->do_edges, false,
 		        DRW_STATE_DEPTH_LESS_EQUAL | DRW_STATE_BLEND,
 		        &stl->g_data->face_shgrp,
 		        &stl->g_data->face_cage_shgrp,
 		        &stl->g_data->facedot_shgrp,
 		        &stl->g_data->edge_shgrp,
-		        &stl->g_data->edge_deco_shgrp,
 		        &stl->g_data->vert_shgrp);
 	}
 	else {
 		/* We render all wires with depth and opaque to a new fbo and blend the result based on depth values */
 		psl->edit_face_occluded = edit_mesh_create_overlay_pass(
-		        &zero, &stl->g_data->edge_width_scale, stl->g_data->data_mask, stl->g_data->do_edges, true,
+		        &zero, stl->g_data->data_mask, stl->g_data->do_edges, true,
 		        DRW_STATE_DEPTH_LESS_EQUAL | DRW_STATE_WRITE_DEPTH,
 		        &stl->g_data->face_shgrp,
 		        &stl->g_data->face_cage_shgrp,
 		        &stl->g_data->facedot_shgrp,
 		        &stl->g_data->edge_shgrp,
-		        &stl->g_data->edge_deco_shgrp,
 		        &stl->g_data->vert_shgrp);
 
 		/* however we loose the front faces value (because we need the depth of occluded wires and
@@ -586,14 +561,12 @@ static void edit_mesh_add_ob_to_pass(
 	DRWShadingGroup *face_shgrp = (has_edit_mesh_cage) ? g_data->face_cage_shgrp : g_data->face_shgrp;
 	DRWShadingGroup *vert_shgrp = g_data->vert_shgrp;
 	DRWShadingGroup *edge_shgrp = g_data->edge_shgrp;
-	DRWShadingGroup *edge_deco_shgrp = g_data->edge_deco_shgrp;
 
 	face_shgrp = (facefill_shgrp != NULL) ? facefill_shgrp : face_shgrp;
 
 	geom_tris = DRW_mesh_batch_cache_get_edit_triangles(ob->data);
 	geom_edges = DRW_mesh_batch_cache_get_edit_edges(ob->data);
 	DRW_shgroup_call_add(edge_shgrp, geom_edges, ob->obmat);
-	DRW_shgroup_call_add(edge_deco_shgrp, geom_edges, ob->obmat);
 	DRW_shgroup_call_add(face_shgrp, geom_tris, ob->obmat);
 
 	if ((tsettings->selectmode & SCE_SELECT_VERTEX) != 0) {
@@ -733,27 +706,34 @@ static void EDIT_MESH_draw_scene(void *vedata)
 		const DRWContextState *draw_ctx = DRW_context_state_get();
 		View3D *v3d = draw_ctx->v3d;
 
-		if (v3d->shading.type == OB_SOLID && (v3d->shading.flag & XRAY_FLAG(v3d)) == 0) {
-			if (stl->g_data->ghost_ob == 1 && stl->g_data->edit_ob == 1) {
-				/* In the case of single ghost object edit (common case for retopology):
-				 * we duplicate the depht+stencil buffer and clear all depth to 1.0f where
-				 * the stencil buffer is no 0x00. */
-				const float *viewport_size = DRW_viewport_size_get();
-				const int size[2] = {(int)viewport_size[0], (int)viewport_size[1]};
-				struct GPUTexture *ghost_depth_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_DEPTH24_STENCIL8, &draw_engine_edit_mesh_type);
-				GPU_framebuffer_ensure_config(&fbl->ghost_wire_fb, {
-					GPU_ATTACHMENT_TEXTURE(ghost_depth_tx),
-					GPU_ATTACHMENT_TEXTURE(dtxl->color),
-				});
-
-				GPU_framebuffer_blit(dfbl->depth_only_fb, 0, fbl->ghost_wire_fb, 0, GPU_DEPTH_BIT | GPU_STENCIL_BIT);
-				GPU_framebuffer_bind(fbl->ghost_wire_fb);
-
-				DRW_draw_pass(psl->ghost_clear_depth);
-			}
+		if (v3d->shading.type == OB_SOLID && (v3d->shading.flag & XRAY_FLAG(v3d)) == 0 &&
+		    stl->g_data->ghost_ob == 1 && stl->g_data->edit_ob == 1)
+		{
+			/* In the case of single ghost object edit (common case for retopology):
+			 * we duplicate the depht+stencil buffer and clear all depth to 1.0f where
+			 * the stencil buffer is no 0x00. */
+			const float *viewport_size = DRW_viewport_size_get();
+			const int size[2] = {(int)viewport_size[0], (int)viewport_size[1]};
+			struct GPUTexture *ghost_depth_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_DEPTH24_STENCIL8, &draw_engine_edit_mesh_type);
+			GPU_framebuffer_ensure_config(&fbl->ghost_wire_fb, {
+				GPU_ATTACHMENT_TEXTURE(ghost_depth_tx),
+				GPU_ATTACHMENT_TEXTURE(dtxl->color),
+			});
+
+			GPU_framebuffer_blit(dfbl->depth_only_fb, 0, fbl->ghost_wire_fb, 0, GPU_DEPTH_BIT | GPU_STENCIL_BIT);
+			GPU_framebuffer_bind(fbl->ghost_wire_fb);
+
+			DRW_draw_pass(psl->ghost_clear_depth);
+
+			DRW_draw_pass(psl->edit_face_overlay);
 		}
+		else {
+			// MULTISAMPLE_SYNC_ENABLE(dfbl, dtxl);
+
+			DRW_draw_pass(psl->edit_face_overlay);
 
-		DRW_draw_pass(psl->edit_face_overlay);
+			// MULTISAMPLE_SYNC_DISABLE(dfbl, dtxl)
+		}
 	}
 
 	DRW_state_clip_planes_reset();