BLF/OpenGL: more text drawing optimization

Make color values compact. Set color once per primitive. Use new immSkipAttrib to avoid useless color copies.

All of this should make text drawing less CPU hungry.

3 files changed, 38 insertions, 33 deletions

diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c
index f42057a8475..45d03681c43 100644
--- a/source/blender/blenfont/intern/blf.c
+++ b/source/blender/blenfont/intern/blf.c
@@ -517,13 +517,15 @@ static void blf_draw_gl__start(FontBLF *font)
 	if (font->flags & BLF_ROTATION)  /* radians -> degrees */
 		gpuRotateAxis(font->angle * (float)(180.0 / M_PI), 'Z');
 
-	glGetFloatv(GL_CURRENT_COLOR, font->orig_col); /* TODO(merwin): new BLF_color function? */
+	float temp_color[4];
+	glGetFloatv(GL_CURRENT_COLOR, temp_color); /* TODO(merwin): new BLF_color function? */
+	rgba_float_to_uchar(font->color, temp_color);
 
 #ifndef BLF_STANDALONE
 	VertexFormat *format = immVertexFormat();
 	unsigned pos = add_attrib(format, "pos", GL_FLOAT, 2, KEEP_FLOAT);
 	unsigned texCoord = add_attrib(format, "texCoord", GL_FLOAT, 2, KEEP_FLOAT);
-	unsigned color = add_attrib(format, "color", GL_FLOAT, 4, KEEP_FLOAT);
+	unsigned color = add_attrib(format, "color", GL_UNSIGNED_BYTE, 4, NORMALIZE_INT_TO_FLOAT);
 
 	BLI_assert(pos == BLF_POS_ID);
 	BLI_assert(texCoord == BLF_COORD_ID);
@@ -862,7 +864,7 @@ void BLF_shadow(int fontid, int level, const float rgba[4])
 
 	if (font) {
 		font->shadow = level;
-		copy_v4_v4(font->shadow_col, rgba);
+		rgba_float_to_uchar(font->shadow_color, rgba);
 	}
 }
 
diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index 746aa722c4a..b1bab13f3ae 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -315,22 +315,26 @@ void blf_glyph_free(GlyphBLF *g)
 	MEM_freeN(g);
 }
 
-static void blf_texture_draw(float uv[2][2], float dx, float y1, float dx1, float y2)
+static void blf_texture_draw(const unsigned char color[4], float uv[2][2], float dx, float y1, float dx1, float y2)
 {
 	immAttrib2f(BLF_COORD_ID, uv[0][0], uv[0][1]);
+	immSkipAttrib(BLF_COLOR_ID); /* skip color of most vertices */
 	immVertex2f(BLF_POS_ID, dx, y1);
 
 	immAttrib2f(BLF_COORD_ID, uv[0][0], uv[1][1]);
+	immSkipAttrib(BLF_COLOR_ID);
 	immVertex2f(BLF_POS_ID, dx, y2);
 
 	immAttrib2f(BLF_COORD_ID, uv[1][0], uv[1][1]);
+	immSkipAttrib(BLF_COLOR_ID);
 	immVertex2f(BLF_POS_ID, dx1, y2);
 
 	immAttrib2f(BLF_COORD_ID, uv[1][0], uv[0][1]);
+	immAttrib4ubv(BLF_COLOR_ID, color); /* set color of provoking vertex */
 	immVertex2f(BLF_POS_ID, dx1, y1);
 }
 
-static void blf_texture5_draw(const float shadow_col[4], float uv[2][2], float x1, float y1, float x2, float y2)
+static void blf_texture5_draw(const unsigned char color_in[4], float uv[2][2], float x1, float y1, float x2, float y2)
 {
 	const float soft[25] = {1 / 60.0f, 1 / 60.0f, 2 / 60.0f, 1 / 60.0f, 1 / 60.0f,
 	                        1 / 60.0f, 3 / 60.0f, 5 / 60.0f, 3 / 60.0f, 1 / 60.0f,
@@ -339,41 +343,43 @@ static void blf_texture5_draw(const float shadow_col[4], float uv[2][2], float x
 	                        1 / 60.0f, 1 / 60.0f, 2 / 60.0f, 1 / 60.0f, 1 / 60.0f};
 
 	const float *fp = soft;
-	float color[4];
+	unsigned char color[4];
 	float dx, dy;
 
-	color[0] = shadow_col[0];
-	color[1] = shadow_col[1];
-	color[2] = shadow_col[2];
+	color[0] = color_in[0];
+	color[1] = color_in[1];
+	color[2] = color_in[2];
+
+	const float alpha_in = (1 / 255.0f) * color_in[3];
 
 	for (dx = -2; dx < 3; dx++) {
 		for (dy = -2; dy < 3; dy++, fp++) {
-			color[3] = *(fp) * shadow_col[3];
-			immAttrib4fv(BLF_COLOR_ID, color);
-			blf_texture_draw(uv, x1 + dx, y1 + dy, x2 + dx, y2 + dy);
+			color[3] = FTOCHAR(*fp * alpha_in);
+			blf_texture_draw(color, uv, x1 + dx, y1 + dy, x2 + dx, y2 + dy);
 		}
 	}
 }
 
-static void blf_texture3_draw(const float shadow_col[4], float uv[2][2], float x1, float y1, float x2, float y2)
+static void blf_texture3_draw(const unsigned char color_in[4], float uv[2][2], float x1, float y1, float x2, float y2)
 {
 	const float soft[9] = {1 / 16.0f, 2 / 16.0f, 1 / 16.0f,
 	                       2 / 16.0f, 4 / 16.0f, 2 / 16.0f,
 	                       1 / 16.0f, 2 / 16.0f, 1 / 16.0f};
 
 	const float *fp = soft;
-	float color[4];
+	unsigned char color[4];
 	float dx, dy;
 
-	color[0] = shadow_col[0];
-	color[1] = shadow_col[1];
-	color[2] = shadow_col[2];
+	color[0] = color_in[0];
+	color[1] = color_in[1];
+	color[2] = color_in[2];
+
+	const float alpha_in = (1 / 255.0f) * color_in[3];
 
 	for (dx = -1; dx < 2; dx++) {
 		for (dy = -1; dy < 2; dy++, fp++) {
-			color[3] = *(fp) * shadow_col[3];
-			immAttrib4fv(BLF_COLOR_ID, color);
-			blf_texture_draw(uv, x1 + dx, y1 + dy, x2 + dx, y2 + dy);
+			color[3] = FTOCHAR(*fp * alpha_in);
+			blf_texture_draw(color, uv, x1 + dx, y1 + dy, x2 + dx, y2 + dy);
 		}
 	}
 }
@@ -478,31 +484,28 @@ void blf_glyph_render(FontBLF *font, GlyphBLF *g, float x, float y)
 		                    y + (float)font->shadow_y);
 
 		if (font->shadow == 0) {
-			immAttrib4fv(BLF_COLOR_ID, font->shadow_col);
-			blf_texture_draw(g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
+			blf_texture_draw(font->shadow_color, g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
 		}
 		else if (font->shadow <= 4) {
-			blf_texture3_draw(font->shadow_col, g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
+			blf_texture3_draw(font->shadow_color, g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
 		}
 		else {
-			blf_texture5_draw(font->shadow_col, g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
+			blf_texture5_draw(font->shadow_color, g->uv, rect_ofs.xmin, rect_ofs.ymin, rect_ofs.xmax, rect_ofs.ymax);
 		}
 	}
 
 #if BLF_BLUR_ENABLE
 	switch (font->blur) {
 		case 3:
-			blf_texture3_draw(font->orig_col, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
+			blf_texture3_draw(font->color, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
 			break;
 		case 5:
-			blf_texture5_draw(font->orig_col, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
+			blf_texture5_draw(font->color, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
 			break;
 		default:
-			immAttrib4fv(BLF_COLOR_ID, font->orig_col);
-			blf_texture_draw(g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
+			blf_texture_draw(font->color, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
 	}
 #else
-	immAttrib4fv(BLF_COLOR_ID, font->orig_col);
-	blf_texture_draw(g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
+	blf_texture_draw(font->color, g->uv, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
 #endif
 }
diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h
index 26d7fd3adac..7cddb46d025 100644
--- a/source/blender/blenfont/intern/blf_internal_types.h
+++ b/source/blender/blenfont/intern/blf_internal_types.h
@@ -188,10 +188,10 @@ typedef struct FontBLF {
 	int shadow_y;
 
 	/* shadow color. */
-	float shadow_col[4];
+	unsigned char shadow_color[4];
 
-	/* store color here when drawing shadow or blur. */
-	float orig_col[4];
+	/* main text color. */
+	unsigned char color[4];
 
 	/* Multiplied this matrix with the current one before
 	 * draw the text! see blf_draw__start.