From c192ce6717d7c1da741d80671ffcc7ea02e664c8 Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Mon, 5 Nov 2018 10:44:30 +1100
Subject: Gizmo: use fonts for drawing 3D axis characters

---
 .../space_view3d/view3d_gizmo_navigate_type.c      | 63 +++++++++++++++++++++-
 1 file changed, 61 insertions(+), 2 deletions(-)

(limited to 'source/blender/editors/space_view3d/view3d_gizmo_navigate_type.c')

diff --git a/source/blender/editors/space_view3d/view3d_gizmo_navigate_type.c b/source/blender/editors/space_view3d/view3d_gizmo_navigate_type.c
index 169a7387302..5c251fe4136 100644
--- a/source/blender/editors/space_view3d/view3d_gizmo_navigate_type.c
+++ b/source/blender/editors/space_view3d/view3d_gizmo_navigate_type.c
@@ -60,6 +60,11 @@
 
 #include "view3d_intern.h"
 
+#define USE_AXIS_FONT
+#ifdef USE_AXIS_FONT
+#  include "BLF_api.h"
+#endif
+
 #define DIAL_RESOLUTION 32
 
 /* Sizes of axis spheres containing XYZ characters. */
@@ -69,6 +74,7 @@
 /* How far axis handles are away from the center. */
 #define AXIS_HANDLE_OFFSET (1.0f - AXIS_HANDLE_SIZE_FG)
 
+#ifndef USE_AXIS_FONT
 /**
  * \param viewmat_local_unit is typically the 'rv3d->viewmatob'
  * copied into a 3x3 matrix and normalized.
@@ -172,8 +178,12 @@ static void draw_xyz_wire(
 	}
 	immEnd();
 }
+#endif  /* !USE_AXIS_FONT */
 
-static void axis_geom_draw(const wmGizmo *gz, const float color[4], const bool UNUSED(select))
+static void axis_geom_draw(
+        const wmGizmo *gz, const float color[4], const bool UNUSED(select),
+        /* Needed for screen-aligned font drawing. */
+        const float matrix_final[4][4])
 {
 	GPU_line_width(gz->line_width);
 
@@ -199,6 +209,33 @@ static void axis_geom_draw(const wmGizmo *gz, const float color[4], const bool U
 	static const float axis_highlight[4] = {1, 1, 1, 1};
 	static const float axis_black[4] = {0, 0, 0, 1};
 	static float axis_color[3][4];
+
+
+#ifdef USE_AXIS_FONT
+	struct {
+		float matrix[4][4];
+	} font;
+
+	{
+		BLF_disable(blf_mono_font, BLF_ROTATION | BLF_SHADOW | BLF_MATRIX | BLF_ASPECT | BLF_WORD_WRAP);
+		BLF_color4fv(blf_mono_font, axis_black);
+		BLF_size(blf_mono_font, 11 * U.dpi_fac, 72);
+
+		/* Calculate the inverse of the (matrix_final * matrix_offset).
+		 * This allows us to use the final location, while reversing the rotation so fonts
+		 * show without any rotation. */
+		float m3[3][3];
+		float m3_offset[3][3];
+		copy_m3_m4(m3, matrix_final);
+		copy_m3_m4(m3_offset, gz->matrix_offset);
+		mul_m3_m3m3(m3, m3, m3_offset);
+		invert_m3(m3);
+		copy_m4_m3(font.matrix, m3);
+	}
+#else
+	UNUSED_VARS(matrix_final);
+#endif
+
 	GPU_matrix_push();
 	GPU_matrix_mul(gz->matrix_offset);
 
@@ -292,15 +329,37 @@ static void axis_geom_draw(const wmGizmo *gz, const float color[4], const bool U
 
 			/* Axis XYZ Character. */
 			if (show_axis_char) {
+#ifdef USE_AXIS_FONT
+				immUnbindProgram();
+
+				GPU_matrix_push();
+				GPU_matrix_translate_3fv(v_final);
+				GPU_matrix_mul(font.matrix);
+
+				const char axis_str[2] = {'X' + axis, 0};
+				float offset[2] = {0};
+				BLF_width_and_height(blf_mono_font, axis_str, 2, &offset[0], &offset[1]);
+				BLF_position(blf_mono_font, roundf(offset[0] * -0.5f), roundf(offset[1] * -0.5f), 0);
+				BLF_draw_ascii(blf_mono_font, axis_str, 2);
+				GPU_blend(true);  /* XXX, blf disables */
+				GPU_matrix_pop();
+
+				immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);
+#else
 				GPU_line_width(1.0f);
 				float m3[3][3];
 				copy_m3_m4(m3, gz->matrix_offset);
 				immUniformColor4fv(axis_black);
 				draw_xyz_wire(pos_id, m3, v_final, 1.0, axis);
+#endif
 			}
 		}
 	}
 
+#ifdef USE_AXIS_FONT
+	BLF_disable(blf_mono_font, BLF_MATRIX);
+#endif
+
 	GPU_matrix_pop();
 	immUnbindProgram();
 }
@@ -325,7 +384,7 @@ static void axis3d_draw_intern(
 	GPU_matrix_mul(matrix_final);
 
 	GPU_blend(true);
-	axis_geom_draw(gz, color, select);
+	axis_geom_draw(gz, color, select, matrix_final);
 	GPU_blend(false);
 	GPU_matrix_pop();
 }
-- 
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