From ff6e61f09ab2c86edef651fc38c242f5fefdd569 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Foucault?= <foucault.clem@gmail.com>
Date: Fri, 23 Nov 2018 18:02:34 +0100
Subject: DRW: Support Wireframe for metaball objects

---
 .../blender/draw/intern/draw_cache_impl_metaball.c | 92 +++++++++++++++++++++-
 1 file changed, 89 insertions(+), 3 deletions(-)

(limited to 'source/blender/draw/intern/draw_cache_impl_metaball.c')

diff --git a/source/blender/draw/intern/draw_cache_impl_metaball.c b/source/blender/draw/intern/draw_cache_impl_metaball.c
index 6dab46ccaa0..b41b443039a 100644
--- a/source/blender/draw/intern/draw_cache_impl_metaball.c
+++ b/source/blender/draw/intern/draw_cache_impl_metaball.c
@@ -39,6 +39,8 @@
 
 #include "GPU_batch.h"
 
+#include "DRW_render.h"
+
 #include "draw_cache_impl.h"  /* own include */
 
 
@@ -50,8 +52,19 @@ static void metaball_batch_cache_clear(MetaBall *mb);
 typedef struct MetaBallBatchCache {
 	GPUBatch *batch;
 	GPUBatch **shaded_triangles;
-
 	int mat_len;
+
+	/* Shared */
+	GPUVertBuf *pos_nor_in_order;
+
+	/* Wireframe */
+	struct {
+		GPUVertBuf *elem_vbo;
+		GPUTexture *elem_tx;
+		GPUTexture *verts_tx;
+		int tri_count;
+	} face_wire;
+
 	/* settings to determine if cache is invalid */
 	bool is_dirty;
 } MetaBallBatchCache;
@@ -80,6 +93,11 @@ static void metaball_batch_cache_init(MetaBall *mb)
 	cache->mat_len = 0;
 	cache->shaded_triangles = NULL;
 	cache->is_dirty = false;
+	cache->pos_nor_in_order = NULL;
+	cache->face_wire.elem_vbo = NULL;
+	cache->face_wire.elem_tx = NULL;
+	cache->face_wire.verts_tx = NULL;
+	cache->face_wire.tri_count = 0;
 }
 
 static MetaBallBatchCache *metaball_batch_cache_get(MetaBall *mb)
@@ -113,7 +131,12 @@ static void metaball_batch_cache_clear(MetaBall *mb)
 		return;
 	}
 
+	GPU_VERTBUF_DISCARD_SAFE(cache->face_wire.elem_vbo);
+	DRW_TEXTURE_FREE_SAFE(cache->face_wire.elem_tx);
+	DRW_TEXTURE_FREE_SAFE(cache->face_wire.verts_tx);
+
 	GPU_BATCH_DISCARD_SAFE(cache->batch);
+	GPU_VERTBUF_DISCARD_SAFE(cache->pos_nor_in_order);
 	/* Note: shaded_triangles[0] is already freed by cache->batch */
 	MEM_SAFE_FREE(cache->shaded_triangles);
 	cache->mat_len = 0;
@@ -125,6 +148,45 @@ void DRW_mball_batch_cache_free(MetaBall *mb)
 	MEM_SAFE_FREE(mb->batch_cache);
 }
 
+static GPUVertBuf *mball_batch_cache_get_pos_and_normals(Object *ob, MetaBallBatchCache *cache)
+{
+	if (cache->pos_nor_in_order == NULL) {
+		ListBase *lb = &ob->runtime.curve_cache->disp;
+		cache->pos_nor_in_order = DRW_displist_vertbuf_calc_pos_with_normals(lb);
+	}
+	return cache->pos_nor_in_order;
+}
+
+static GPUTexture *mball_batch_cache_get_edges_overlay_texture_buf(Object *ob, MetaBallBatchCache *cache)
+{
+	if (cache->face_wire.elem_tx != NULL) {
+		return cache->face_wire.elem_tx;
+	}
+
+	ListBase *lb = &ob->runtime.curve_cache->disp;
+
+	/* We need a special index buffer. */
+	GPUVertBuf *vbo = cache->face_wire.elem_vbo = DRW_displist_create_edges_overlay_texture_buf(lb);
+
+	/* Upload data early because we need to create the texture for it. */
+	GPU_vertbuf_use(vbo);
+	cache->face_wire.elem_tx = GPU_texture_create_from_vertbuf(vbo);
+	cache->face_wire.tri_count = vbo->vertex_alloc / 3;
+
+	return cache->face_wire.elem_tx;
+}
+
+static GPUTexture *mball_batch_cache_get_vert_pos_and_nor_in_order_buf(Object *ob, MetaBallBatchCache *cache)
+{
+	if (cache->face_wire.verts_tx == NULL) {
+		GPUVertBuf *vbo = mball_batch_cache_get_pos_and_normals(ob, cache);
+		GPU_vertbuf_use(vbo); /* Upload early for buffer texture creation. */
+		cache->face_wire.verts_tx = GPU_texture_create_buffer(GPU_R32F, vbo->vbo_id);
+	}
+
+	return cache->face_wire.verts_tx;
+}
+
 /* -------------------------------------------------------------------- */
 
 /** \name Public Object/MetaBall API
@@ -143,9 +205,9 @@ GPUBatch *DRW_metaball_batch_cache_get_triangles_with_normals(Object *ob)
 		ListBase *lb = &ob->runtime.curve_cache->disp;
 		cache->batch = GPU_batch_create_ex(
 		        GPU_PRIM_TRIS,
-		        DRW_displist_vertbuf_calc_pos_with_normals(lb),
+		        mball_batch_cache_get_pos_and_normals(ob, cache),
 		        DRW_displist_indexbuf_calc_triangles_in_order(lb),
-		        GPU_BATCH_OWNS_VBO | GPU_BATCH_OWNS_INDEX);
+		        GPU_BATCH_OWNS_INDEX);
 	}
 
 	return cache->batch;
@@ -169,3 +231,27 @@ GPUBatch **DRW_metaball_batch_cache_get_surface_shaded(Object *ob, MetaBall *mb,
 	return cache->shaded_triangles;
 
 }
+
+void DRW_metaball_batch_cache_get_wireframes_face_texbuf(
+        Object *ob, struct GPUTexture **verts_data, struct GPUTexture **face_indices, int *tri_count)
+{
+	if (!BKE_mball_is_basis(ob)) {
+		*verts_data = NULL;
+		*face_indices = NULL;
+		*tri_count = 0;
+		return;
+	}
+
+	MetaBall *mb = ob->data;
+	MetaBallBatchCache *cache = metaball_batch_cache_get(mb);
+
+	if (cache->face_wire.verts_tx == NULL) {
+		*verts_data = mball_batch_cache_get_vert_pos_and_nor_in_order_buf(ob, cache);
+		*face_indices = mball_batch_cache_get_edges_overlay_texture_buf(ob, cache);
+	}
+	else {
+		*verts_data = cache->face_wire.verts_tx;
+		*face_indices = cache->face_wire.elem_tx;
+	}
+	*tri_count = cache->face_wire.tri_count;
+}
\ No newline at end of file
-- 
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