5 files changed, 79 insertions, 16 deletions
diff --git a/source/blender/blenfont/BLF_api.h b/source/blender/blenfont/BLF_api.h
index fd0c0362300..f9841c83163 100644
--- a/source/blender/blenfont/BLF_api.h
+++ b/source/blender/blenfont/BLF_api.h
@@ -95,6 +95,11 @@ void BLF_color3fv_alpha(int fontid, const float rgb[3], float alpha);
  */
 void BLF_matrix(int fontid, const float m[16]);
 
+/* Batch drawcalls together as long as
+ * the modelview matrix and the font remain unchanged. */
+void BLF_batching_start(void);
+void BLF_batching_end(void);
+
 /* Draw the string using the default font, size and dpi. */
 void BLF_draw_default(float x, float y, float z, const char *str, size_t len) ATTR_NONNULL();
 void BLF_draw_default_ascii(float x, float y, float z, const char *str, size_t len) ATTR_NONNULL();
diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c
index 5b51ecbc047..2407abdaf28 100644
--- a/source/blender/blenfont/intern/blf.c
+++ b/source/blender/blenfont/intern/blf.c
@@ -540,6 +540,19 @@ void BLF_color3f(int fontid, float r, float g, float b)
 	BLF_color4fv(fontid, rgba);
 }
 
+void BLF_batching_start(void)
+{
+	BLI_assert(g_batch.enabled == false);
+	g_batch.enabled = true;
+}
+
+void BLF_batching_end(void)
+{
+	BLI_assert(g_batch.enabled == true);
+	blf_batching_draw(); /* Draw remaining glyphs */
+	g_batch.enabled = false;
+}
+
 void BLF_draw_default(float x, float y, float z, const char *str, size_t len)
 {
 	ASSERT_DEFAULT_SET;
diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c
index 868d8eb775e..1df1dc5706c 100644
--- a/source/blender/blenfont/intern/blf_font.c
+++ b/source/blender/blenfont/intern/blf_font.c
@@ -97,6 +97,11 @@ static void blf_batching_init(void)
 	g_batch.verts = GWN_vertbuf_create_with_format_ex(&format, GWN_USAGE_STREAM);
 	GWN_vertbuf_data_alloc(g_batch.verts, BLF_BATCHING_SIZE);
 
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.pos_loc, &g_batch.pos_step);
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.tex_loc, &g_batch.tex_step);
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.col_loc, &g_batch.col_step);
+	g_batch.glyph_ct = 0;
+
 	g_batch.batch = GWN_batch_create_ex(GWN_PRIM_POINTS, g_batch.verts, NULL, GWN_BATCH_OWNS_VBO);
 }
 
@@ -118,17 +123,53 @@ void blf_batching_start(FontBLF *font)
 		blf_batching_init();
 	}
 
-	zero_v2(g_batch.ofs);
-	if ((font->flags & (BLF_ROTATION | BLF_MATRIX | BLF_ASPECT)) == 0) {
+	const bool font_changed = (g_batch.font != font);
+	g_batch.font = font;
+
+	const bool manual_ofs_active = ((font->flags & (BLF_ROTATION | BLF_MATRIX | BLF_ASPECT)) == 0);
+	g_batch.active = g_batch.enabled && manual_ofs_active;
+
+	if (manual_ofs_active) {
+		/* Offset is applied to each glyph. */
 		copy_v2_v2(g_batch.ofs, font->pos);
 	}
+	else {
+		/* Offset is baked in modelview mat. */
+		zero_v2(g_batch.ofs);
+	}
 
-	/* restart to 1st vertex data pointers */
-	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.pos_loc, &g_batch.pos_step);
-	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.tex_loc, &g_batch.tex_step);
-	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.col_loc, &g_batch.col_step);
-	g_batch.glyph_ct = 0;
-	g_batch.font = font;
+	if (g_batch.active) {
+		float gpumat[4][4];
+		gpuGetModelViewMatrix(gpumat);
+
+		bool mat_changed = (memcmp(gpumat, g_batch.mat, sizeof(g_batch.mat)) != 0);
+		/* Save for next memcmp. */
+		memcpy(g_batch.mat, gpumat, sizeof(g_batch.mat));
+
+		if (mat_changed) {
+			/* Modelviewmat is no longer the same.
+			 * Flush cache but with the previous mat. */
+			gpuPushMatrix();
+			gpuLoadMatrix(g_batch.mat);
+		}
+
+		/* flush cache if config is not the same. */
+		if (mat_changed || font_changed) {
+			blf_batching_draw();
+		}
+		else {
+			/* Nothing changed continue batching. */
+			return;
+		}
+
+		if (mat_changed) {
+			gpuPopMatrix();
+		}
+	}
+	else {
+		/* flush cache */
+		blf_batching_draw();
+	}
 }
 
 void blf_batching_draw(void)
@@ -152,12 +193,16 @@ void blf_batching_draw(void)
 
 	glDisable(GL_BLEND);
 
+	/* restart to 1st vertex data pointers */
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.pos_loc, &g_batch.pos_step);
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.tex_loc, &g_batch.tex_step);
+	GWN_vertbuf_attr_get_raw_data(g_batch.verts, g_batch.col_loc, &g_batch.col_step);
 	g_batch.glyph_ct = 0;
 }
 
 static void blf_batching_end(void)
 {
-	if (!g_batch.enabled) {
+	if (!g_batch.active) {
 		blf_batching_draw();
 	}
 }
diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index b91eceac817..b05cabcd830 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -319,17 +319,17 @@ void blf_glyph_free(GlyphBLF *g)
 
 static void blf_texture_draw(const unsigned char color[4], float uv[2][2], float x1, float y1, float x2, float y2)
 {
-	if (g_batch.glyph_ct == BLF_BATCHING_SIZE) {
-		blf_batching_draw();
-		blf_batching_start(g_batch.font);
-	}
-	g_batch.glyph_ct++;
 	/* Only one vertex per glyph, geometry shader expand it into a quad. */
 	/* TODO Get rid of Geom Shader because it's not optimal AT ALL for the GPU */
 	copy_v4_fl4(GWN_vertbuf_raw_step(&g_batch.pos_step), x1 + g_batch.ofs[0], y1 + g_batch.ofs[1],
 	                                                     x2 + g_batch.ofs[0], y2 + g_batch.ofs[1]);
 	copy_v4_v4(GWN_vertbuf_raw_step(&g_batch.tex_step), (float *)uv);
 	copy_v4_v4_uchar(GWN_vertbuf_raw_step(&g_batch.col_step), color);
+	g_batch.glyph_ct++;
+	/* Flush cache if it's full. */
+	if (g_batch.glyph_ct == BLF_BATCHING_SIZE) {
+		blf_batching_draw();
+	}
 }
 
 static void blf_texture5_draw(const unsigned char color_in[4], float uv[2][2], float x1, float y1, float x2, float y2)
diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h
index 360aae47dd0..91d7917b0b5 100644
--- a/source/blender/blenfont/intern/blf_internal_types.h
+++ b/source/blender/blenfont/intern/blf_internal_types.h
@@ -43,8 +43,8 @@ typedef struct BatchBLF{
 	unsigned int pos_loc, tex_loc, col_loc;
 	unsigned int glyph_ct;
 	float ofs[2];    /* copy of font->pos */
-	float mat[4][4]; /* to catch bad usage */
-	bool enabled;
+	float mat[4][4]; /* previous call modelmatrix. */
+	bool enabled, active;
 } BatchBLF;
 
 extern BatchBLF g_batch;