3D View: Support edit-mesh clipping (only verts)

We'll need to replace built-in shaders to add support for clipping.

2 files changed, 68 insertions, 18 deletions

diff --git a/source/blender/draw/modes/edit_lattice_mode.c b/source/blender/draw/modes/edit_lattice_mode.c
index 4bfdf24ad61..794dc91d374 100644
--- a/source/blender/draw/modes/edit_lattice_mode.c
+++ b/source/blender/draw/modes/edit_lattice_mode.c
@@ -35,14 +35,12 @@
 
 #include "draw_mode_engines.h"
 
+extern char datatoc_common_world_clip_lib_glsl[];
 extern char datatoc_common_globals_lib_glsl[];
+
 extern char datatoc_edit_lattice_overlay_loosevert_vert_glsl[];
 extern char datatoc_edit_lattice_overlay_frag_glsl[];
 
-extern char datatoc_gpu_shader_3D_vert_glsl[];
-extern char datatoc_gpu_shader_uniform_color_frag_glsl[];
-extern char datatoc_gpu_shader_point_uniform_color_frag_glsl[];
-
 /* *********** LISTS *********** */
 /* All lists are per viewport specific datas.
  * They are all free when viewport changes engines
@@ -91,6 +89,11 @@ typedef struct EDIT_LATTICE_Data {
 	EDIT_LATTICE_StorageList *stl;
 } EDIT_LATTICE_Data;
 
+typedef struct EDIT_LATTICE_Shaders {
+	GPUShader *wire;
+	GPUShader *overlay_vert;
+} EDIT_LATTICE_Shaders;
+
 /* *********** STATIC *********** */
 
 static struct {
@@ -98,9 +101,9 @@ static struct {
 	 * Add sources to source/blender/draw/modes/shaders
 	 * init in EDIT_LATTICE_engine_init();
 	 * free in EDIT_LATTICE_engine_free(); */
-	GPUShader *wire_sh;
 
-	GPUShader *overlay_vert_sh;
+	/* 0: normal, 1: clipped. */
+	EDIT_LATTICE_Shaders sh_data[2];
 
 } e_data = {NULL}; /* Engine data */
 
@@ -113,6 +116,14 @@ typedef struct EDIT_LATTICE_PrivateData {
 
 /* *********** FUNCTIONS *********** */
 
+static int EDIT_LATTICE_sh_data_index_from_rv3d(const RegionView3D *rv3d)
+{
+	if (rv3d->rflag & RV3D_CLIPPING) {
+		return 1;
+	}
+	return 0;
+}
+
 /* Init Textures, Framebuffers, Storage and Shaders.
  * It is called for every frames.
  * (Optional) */
@@ -139,15 +150,32 @@ static void EDIT_LATTICE_engine_init(void *vedata)
 	 *                     tex, 2);
 	 */
 
-	if (!e_data.wire_sh) {
-		e_data.wire_sh = GPU_shader_get_builtin_shader(GPU_SHADER_3D_SMOOTH_COLOR);
+	const DRWContextState *draw_ctx = DRW_context_state_get();
+	EDIT_LATTICE_Shaders *sh_data = &e_data.sh_data[EDIT_LATTICE_sh_data_index_from_rv3d(draw_ctx->rv3d)];
+	const bool is_clip = (draw_ctx->rv3d->rflag & RV3D_CLIPPING) != 0;
+	if (is_clip) {
+		DRW_state_clip_planes_set_from_rv3d(draw_ctx->rv3d);
+	}
+	const char *world_clip_lib_or_empty = is_clip ? datatoc_common_world_clip_lib_glsl : "";
+	const char *world_clip_def_or_empty = is_clip ? "#define USE_WORLD_CLIP_PLANES\n" : "";
+
+	if (!sh_data->wire) {
+		sh_data->wire = GPU_shader_get_builtin_shader(GPU_SHADER_3D_SMOOTH_COLOR);
 	}
 
-	if (!e_data.overlay_vert_sh) {
-		e_data.overlay_vert_sh = DRW_shader_create_with_lib(
-		        datatoc_edit_lattice_overlay_loosevert_vert_glsl, NULL,
-		        datatoc_edit_lattice_overlay_frag_glsl,
-		        datatoc_common_globals_lib_glsl, NULL);
+	if (!sh_data->overlay_vert) {
+		sh_data->overlay_vert = DRW_shader_create_from_arrays({
+		        .vert = (const char *[]){
+		            world_clip_lib_or_empty,
+		            datatoc_common_globals_lib_glsl,
+		            datatoc_edit_lattice_overlay_loosevert_vert_glsl,
+		            NULL},
+		        .frag = (const char *[]){
+		            datatoc_common_globals_lib_glsl,
+		            datatoc_edit_lattice_overlay_frag_glsl,
+		            NULL},
+		        .defs = (const char *[]){world_clip_def_or_empty, NULL}});
+
 	}
 }
 
@@ -158,6 +186,10 @@ static void EDIT_LATTICE_cache_init(void *vedata)
 	EDIT_LATTICE_PassList *psl = ((EDIT_LATTICE_Data *)vedata)->psl;
 	EDIT_LATTICE_StorageList *stl = ((EDIT_LATTICE_Data *)vedata)->stl;
 
+	const DRWContextState *draw_ctx = DRW_context_state_get();
+	RegionView3D *rv3d = draw_ctx->rv3d;
+	EDIT_LATTICE_Shaders *sh_data = &e_data.sh_data[EDIT_LATTICE_sh_data_index_from_rv3d(rv3d)];
+
 	if (!stl->g_data) {
 		/* Alloc transient pointers */
 		stl->g_data = MEM_mallocN(sizeof(*stl->g_data), __func__);
@@ -167,14 +199,18 @@ static void EDIT_LATTICE_cache_init(void *vedata)
 		psl->wire_pass = DRW_pass_create(
 		        "Lattice Wire",
 		        DRW_STATE_WRITE_COLOR | DRW_STATE_WRITE_DEPTH | DRW_STATE_DEPTH_LESS_EQUAL | DRW_STATE_WIRE);
-		stl->g_data->wire_shgrp = DRW_shgroup_create(e_data.wire_sh, psl->wire_pass);
+		stl->g_data->wire_shgrp = DRW_shgroup_create(sh_data->wire, psl->wire_pass);
 
 		psl->vert_pass = DRW_pass_create(
 		        "Lattice Verts",
 		        DRW_STATE_WRITE_COLOR | DRW_STATE_WRITE_DEPTH | DRW_STATE_POINT);
-		stl->g_data->vert_shgrp = DRW_shgroup_create(e_data.overlay_vert_sh, psl->vert_pass);
-
+		stl->g_data->vert_shgrp = DRW_shgroup_create(sh_data->overlay_vert, psl->vert_pass);
 		DRW_shgroup_uniform_block(stl->g_data->vert_shgrp, "globalsBlock", G_draw.block_ubo);
+		if (rv3d->rflag & RV3D_CLIPPING) {
+			DRW_shgroup_world_clip_planes_from_rv3d(stl->g_data->vert_shgrp, rv3d);
+		}
+
+
 	}
 }
 
@@ -249,8 +285,16 @@ static void EDIT_LATTICE_draw_scene(void *vedata)
  * Mostly used for freeing shaders */
 static void EDIT_LATTICE_engine_free(void)
 {
-	// Currently built-in, dont free
-	DRW_SHADER_FREE_SAFE(e_data.overlay_vert_sh);
+	for (int sh_data_index = 0; sh_data_index < ARRAY_SIZE(e_data.sh_data); sh_data_index++) {
+		EDIT_LATTICE_Shaders *sh_data = &e_data.sh_data[sh_data_index];
+		/* Don't free builtins. */
+		sh_data->wire = NULL;
+		GPUShader **sh_data_as_array = (GPUShader **)sh_data;
+		for (int i = 0; i < (sizeof(EDIT_LATTICE_Shaders) / sizeof(GPUShader *)); i++) {
+			DRW_SHADER_FREE_SAFE(sh_data_as_array[i]);
+		}
+	}
+
 }
 
 static const DrawEngineDataSize EDIT_LATTICE_data_size = DRW_VIEWPORT_DATA_SIZE(EDIT_LATTICE_Data);
diff --git a/source/blender/draw/modes/shaders/edit_lattice_overlay_loosevert_vert.glsl b/source/blender/draw/modes/shaders/edit_lattice_overlay_loosevert_vert.glsl
index 0cbc66a2b1f..bf0357632e6 100644
--- a/source/blender/draw/modes/shaders/edit_lattice_overlay_loosevert_vert.glsl
+++ b/source/blender/draw/modes/shaders/edit_lattice_overlay_loosevert_vert.glsl
@@ -2,6 +2,7 @@
 /* Draw Lattice Vertices */
 
 uniform mat4 ModelViewProjectionMatrix;
+uniform mat4 ModelMatrix;
 uniform vec2 viewportSize;
 
 in vec3 pos;
@@ -36,4 +37,9 @@ void main()
 
 	gl_PointSize = sizeVertex;
 	gl_Position = pPos;
+
+#ifdef USE_WORLD_CLIP_PLANES
+	world_clip_planes_calc_clip_distance((ModelMatrix * vec4(pos, 1.0)).xyz);
+#endif
+
 }