Reworked version of dashed line shader.

Using geometry shader allows us to get rid of the 'line origin' extra
vertex attribute, which means dashed shader no longer requires fiddling
with those vertex attributes definition, and, most importantly, does not
require anymore special drawing code!

As you can see, this makes code much simpler, and much less verbose,
especially in complex cases.

In addition, changed how dashes are handled, to have two 'modes', a
simple one with single color (using default "color" uniform name), and a
more advanced one allowing more complex and multi-color patterns.

Note that since GLSL 1.2 does not support geometry shaders, a hack was
added for now (which gives solid lines, but at least does not make
Blender crash).

1 files changed, 66 insertions, 102 deletions

diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 62d8f771b8c..08b15957dbb 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -417,7 +417,7 @@ void ED_view3d_calc_camera_border(
 	view3d_camera_border(scene, ar, v3d, rv3d, r_viewborder, no_shift, false);
 }
 
-static void drawviewborder_grid3(uint pos, uint line_origin, float x1, float x2, float y1, float y2, float fac)
+static void drawviewborder_grid3(uint shdr_pos, float x1, float x2, float y1, float y2, float fac)
 {
 	float x3, y3, x4, y4;
 
@@ -428,28 +428,24 @@ static void drawviewborder_grid3(uint pos, uint line_origin, float x1, float x2,
 
 	immBegin(PRIM_LINES, 8);
 
-	immAttrib2f(line_origin, x1, y3);
-	immVertex2f(pos, x1, y3);
-	immVertex2f(pos, x2, y3);
+	immVertex2f(shdr_pos, x1, y3);
+	immVertex2f(shdr_pos, x2, y3);
 
-	immAttrib2f(line_origin, x1, y4);
-	immVertex2f(pos, x1, y4);
-	immVertex2f(pos, x2, y4);
+	immVertex2f(shdr_pos, x1, y4);
+	immVertex2f(shdr_pos, x2, y4);
 
-	immAttrib2f(line_origin, x3, y1);
-	immVertex2f(pos, x3, y1);
-	immVertex2f(pos, x3, y2);
+	immVertex2f(shdr_pos, x3, y1);
+	immVertex2f(shdr_pos, x3, y2);
 
-	immAttrib2f(line_origin, x4, y1);
-	immVertex2f(pos, x4, y1);
-	immVertex2f(pos, x4, y2);
+	immVertex2f(shdr_pos, x4, y1);
+	immVertex2f(shdr_pos, x4, y2);
 
 	immEnd();
 }
 
 /* harmonious triangle */
 static void drawviewborder_triangle(
-        uint pos, uint line_origin, float x1, float x2, float y1, float y2, const char golden, const char dir)
+        uint shdr_pos, float x1, float x2, float y1, float y2, const char golden, const char dir)
 {
 	float ofs;
 	float w = x2 - x1;
@@ -466,17 +462,14 @@ static void drawviewborder_triangle(
 		}
 		if (dir == 'B') SWAP(float, y1, y2);
 
-		immAttrib2f(line_origin, x1, y1);
-		immVertex2f(pos, x1, y1);
-		immVertex2f(pos, x2, y2);
+		immVertex2f(shdr_pos, x1, y1);
+		immVertex2f(shdr_pos, x2, y2);
 
-		immAttrib2f(line_origin, x2, y1);
-		immVertex2f(pos, x2, y1);
-		immVertex2f(pos, x1 + (w - ofs), y2);
+		immVertex2f(shdr_pos, x2, y1);
+		immVertex2f(shdr_pos, x1 + (w - ofs), y2);
 
-		immAttrib2f(line_origin, x1, y2);
-		immVertex2f(pos, x1, y2);
-		immVertex2f(pos, x1 + ofs, y1);
+		immVertex2f(shdr_pos, x1, y2);
+		immVertex2f(shdr_pos, x1 + ofs, y1);
 	}
 	else {
 		if (golden) {
@@ -487,17 +480,14 @@ static void drawviewborder_triangle(
 		}
 		if (dir == 'B') SWAP(float, x1, x2);
 
-		immAttrib2f(line_origin, x1, y1);
-		immVertex2f(pos, x1, y1);
-		immVertex2f(pos, x2, y2);
+		immVertex2f(shdr_pos, x1, y1);
+		immVertex2f(shdr_pos, x2, y2);
 
-		immAttrib2f(line_origin, x2, y1);
-		immVertex2f(pos, x2, y1);
-		immVertex2f(pos, x1, y1 + ofs);
+		immVertex2f(shdr_pos, x2, y1);
+		immVertex2f(shdr_pos, x1, y1 + ofs);
 
-		immAttrib2f(line_origin, x1, y2);
-		immVertex2f(pos, x1, y2);
-		immVertex2f(pos, x2, y1 + (h - ofs));
+		immVertex2f(shdr_pos, x1, y2);
+		immVertex2f(shdr_pos, x2, y1 + (h - ofs));
 	}
 
 	immEnd();
@@ -538,9 +528,10 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 	x2i = (int)(x2 + (1.0f - 0.0001f));
 	y2i = (int)(y2 + (1.0f - 0.0001f));
 
+	uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
+
 	/* First, solid lines. */
 	{
-		unsigned int pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 		immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 
 		/* passepartout, specified in camera edit buttons */
@@ -559,24 +550,24 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 			immUniformColor4f(0.0f, 0.0f, 0.0f, alpha);
 
 			if (x1i > 0.0f)
-				immRectf(pos, 0.0f, winy, x1i, 0.0f);
+				immRectf(shdr_pos, 0.0f, winy, x1i, 0.0f);
 			if (x2i < winx)
-				immRectf(pos, x2i, winy, winx, 0.0f);
+				immRectf(shdr_pos, x2i, winy, winx, 0.0f);
 			if (y2i < winy)
-				immRectf(pos, x1i, winy, x2i, y2i);
+				immRectf(shdr_pos, x1i, winy, x2i, y2i);
 			if (y2i > 0.0f)
-				immRectf(pos, x1i, y1i, x2i, 0.0f);
+				immRectf(shdr_pos, x1i, y1i, x2i, 0.0f);
 
 			glDisable(GL_BLEND);
 		}
 
 		immUniformThemeColor(TH_BACK);
-		imm_draw_line_box(pos, x1i, y1i, x2i, y2i);
+		imm_draw_line_box(shdr_pos, x1i, y1i, x2i, y2i);
 
 #ifdef VIEW3D_CAMERA_BORDER_HACK
 		if (view3d_camera_border_hack_test == true) {
 			immUniformColor3ubv(view3d_camera_border_hack_col);
-			imm_draw_line_box(pos, x1i + 1, y1i + 1, x2i - 1, y2i - 1);
+			imm_draw_line_box(shdr_pos, x1i + 1, y1i + 1, x2i - 1, y2i - 1);
 			view3d_camera_border_hack_test = false;
 		}
 #endif
@@ -586,34 +577,24 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 
 	/* And now, the dashed lines! */
 	{
-		VertexFormat *format = immVertexFormat();
-		unsigned int pos = VertexFormat_add_attrib(format, "pos", COMP_F32, 2, KEEP_FLOAT);
-		unsigned int line_origin = VertexFormat_add_attrib(format, "line_origin", COMP_F32, 2, KEEP_FLOAT);
-		float color1[4] = {1.0f, 1.0f, 1.0f, 1.0f};
-
-		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-		glEnable(GL_BLEND);
-
 		immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
 		float viewport_size[4];
 		glGetFloatv(GL_VIEWPORT, viewport_size);
 		immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-		immUniform4f("color2", 0.0f, 0.0f, 0.0f, 0.0f);
+		immUniform1i("num_colors", 0);  /* "simple" mode */
 		immUniform1f("dash_width", 6.0f);
-		immUniform1f("dash_width_on", 3.0f);
+		immUniform1f("dash_factor", 0.5f);
 
 		/* outer line not to confuse with object selection */
 		if (v3d->flag2 & V3D_LOCK_CAMERA) {
-			UI_GetThemeColor4fv(TH_REDALERT, color1);
-			immUniform4fv("color1", color1);
-			imm_draw_line_box_dashed(pos, line_origin, x1i - 1, y1i - 1, x2i + 1, y2i + 1);
+			immUniformThemeColor(TH_REDALERT);
+			imm_draw_line_box(shdr_pos, x1i - 1, y1i - 1, x2i + 1, y2i + 1);
 		}
 
-		UI_GetThemeColor4fv(TH_VIEW_OVERLAY, color1);
-		immUniform4fv("color1", color1);
-		imm_draw_line_box_dashed(pos, line_origin, x1i, y1i, x2i, y2i);
+		immUniformThemeColor(TH_VIEW_OVERLAY);
+		imm_draw_line_box(shdr_pos, x1i, y1i, x2i, y2i);
 
 		/* border */
 		if (scene->r.mode & R_BORDER) {
@@ -624,15 +605,13 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 			x4 = floorf(x1 + (scene->r.border.xmax * (x2 - x1))) + (U.pixelsize - 1);
 			y4 = floorf(y1 + (scene->r.border.ymax * (y2 - y1))) + (U.pixelsize - 1);
 
-			immUniform4f("color1", 1.0f, 0.25f, 0.25f, 1.0f);
-			imm_draw_line_box_dashed(pos, line_origin, x3, y3, x4, y4);
+			immUniformColor3f(1.0f, 0.25f, 0.25f);
+			imm_draw_line_box(shdr_pos, x3, y3, x4, y4);
 		}
 
 		/* safety border */
 		if (ca) {
-			UI_GetThemeColorBlend3f(TH_VIEW_OVERLAY, TH_BACK, 0.25f, color1);
-			color1[3] = 1.0f;
-			immUniform4fv("color1", color1);
+			immUniformThemeColorBlend(TH_VIEW_OVERLAY, TH_BACK, 0.25f);
 
 			if (ca->dtx & CAM_DTX_CENTER) {
 				float x3, y3;
@@ -642,13 +621,11 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 
 				immBegin(PRIM_LINES, 4);
 
-				immAttrib2f(line_origin, x1, y3);
-				immVertex2f(pos, x1, y3);
-				immVertex2f(pos, x2, y3);
+				immVertex2f(shdr_pos, x1, y3);
+				immVertex2f(shdr_pos, x2, y3);
 
-				immAttrib2f(line_origin, x3, y1);
-				immVertex2f(pos, x3, y1);
-				immVertex2f(pos, x3, y2);
+				immVertex2f(shdr_pos, x3, y1);
+				immVertex2f(shdr_pos, x3, y2);
 
 				immEnd();
 			}
@@ -656,52 +633,46 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 			if (ca->dtx & CAM_DTX_CENTER_DIAG) {
 				immBegin(PRIM_LINES, 4);
 
-				immAttrib2f(line_origin, x1, y1);
-				immVertex2f(pos, x1, y1);
-				immVertex2f(pos, x2, y2);
+				immVertex2f(shdr_pos, x1, y1);
+				immVertex2f(shdr_pos, x2, y2);
 
-				immAttrib2f(line_origin, x1, y2);
-				immVertex2f(pos, x1, y2);
-				immVertex2f(pos, x2, y1);
+				immVertex2f(shdr_pos, x1, y2);
+				immVertex2f(shdr_pos, x2, y1);
 
 				immEnd();
 			}
 
 			if (ca->dtx & CAM_DTX_THIRDS) {
-				drawviewborder_grid3(pos, line_origin, x1, x2, y1, y2, 1.0f / 3.0f);
+				drawviewborder_grid3(shdr_pos, x1, x2, y1, y2, 1.0f / 3.0f);
 			}
 
 			if (ca->dtx & CAM_DTX_GOLDEN) {
-				drawviewborder_grid3(pos, line_origin, x1, x2, y1, y2, 1.0f - (1.0f / 1.61803399f));
+				drawviewborder_grid3(shdr_pos, x1, x2, y1, y2, 1.0f - (1.0f / 1.61803399f));
 			}
 
 			if (ca->dtx & CAM_DTX_GOLDEN_TRI_A) {
-				drawviewborder_triangle(pos, line_origin, x1, x2, y1, y2, 0, 'A');
+				drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 0, 'A');
 			}
 
 			if (ca->dtx & CAM_DTX_GOLDEN_TRI_B) {
-				drawviewborder_triangle(pos, line_origin, x1, x2, y1, y2, 0, 'B');
+				drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 0, 'B');
 			}
 
 			if (ca->dtx & CAM_DTX_HARMONY_TRI_A) {
-				drawviewborder_triangle(pos, line_origin, x1, x2, y1, y2, 1, 'A');
+				drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 1, 'A');
 			}
 
 			if (ca->dtx & CAM_DTX_HARMONY_TRI_B) {
-				drawviewborder_triangle(pos, line_origin, x1, x2, y1, y2, 1, 'B');
+				drawviewborder_triangle(shdr_pos, x1, x2, y1, y2, 1, 'B');
 			}
 
 			if (ca->flag & CAM_SHOW_SAFE_MARGINS) {
-				UI_draw_safe_areas(
-						pos, line_origin, x1, x2, y1, y2,
-						scene->safe_areas.title,
-						scene->safe_areas.action);
+				UI_draw_safe_areas(shdr_pos, x1, x2, y1, y2,
+				                   scene->safe_areas.title, scene->safe_areas.action);
 
 				if (ca->flag & CAM_SHOW_SAFE_CENTER) {
-					UI_draw_safe_areas(
-							pos, line_origin, x1, x2, y1, y2,
-							scene->safe_areas.title_center,
-							scene->safe_areas.action_center);
+					UI_draw_safe_areas(shdr_pos, x1, x2, y1, y2,
+					                   scene->safe_areas.title_center, scene->safe_areas.action_center);
 				}
 			}
 		}
@@ -738,18 +709,15 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 			}
 
 			/* draw */
-			UI_GetThemeColorShade4fv(TH_VIEW_OVERLAY, 100, color1);
-			immUniform4fv("color1", color1);
+			immUniformThemeColorShade(TH_VIEW_OVERLAY, 100);
 
 			/* TODO Was using UI_draw_roundbox_4fv(false, rect.xmin, rect.ymin, rect.xmax, rect.ymax, 2.0f, color).
 			 * We'll probably need a new imm_draw_line_roundbox_dashed dor that - though in practice the
 			 * 2.0f round corner effect was nearly not visible anyway... */
-			imm_draw_line_box_dashed(pos, line_origin, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
+			imm_draw_line_box(shdr_pos, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
 		}
 
 		immUnbindProgram();
-
-		glDisable(GL_BLEND);
 	}
 
 	/* camera name - draw in highlighted text color */
@@ -763,13 +731,9 @@ static void drawviewborder(Scene *scene, ARegion *ar, View3D *v3d)
 static void drawrenderborder(ARegion *ar, View3D *v3d)
 {
 	/* use the same program for everything */
-	VertexFormat *format = immVertexFormat();
-	unsigned int pos = VertexFormat_add_attrib(format, "pos", COMP_F32, 2, KEEP_FLOAT);
-	unsigned int line_origin = VertexFormat_add_attrib(format, "line_origin", COMP_F32, 2, KEEP_FLOAT);
+	uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 
 	glLineWidth(1.0f);
-	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-	glEnable(GL_BLEND);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -777,14 +741,14 @@ static void drawrenderborder(ARegion *ar, View3D *v3d)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 1.0f, 0.25f, 0.25f, 1.0f);
-	immUniform4f("color2", 0.0f, 0.0f, 0.0f, 0.0f);
+	immUniform1i("num_colors", 0);  /* "simple" mode */
+	immUniform4f("color", 1.0f, 0.25f, 0.25f, 1.0f);
 	immUniform1f("dash_width", 6.0f);
-	immUniform1f("dash_width_on", 3.0f);
+	immUniform1f("dash_factor", 0.5f);
 
-	imm_draw_line_box_dashed(pos, line_origin,
-	                         v3d->render_border.xmin * ar->winx, v3d->render_border.ymin * ar->winy,
-	                         v3d->render_border.xmax * ar->winx, v3d->render_border.ymax * ar->winy);
+	imm_draw_line_box(shdr_pos,
+	                  v3d->render_border.xmin * ar->winx, v3d->render_border.ymin * ar->winy,
+	                  v3d->render_border.xmax * ar->winx, v3d->render_border.ymax * ar->winy);
 
 	immUnbindProgram();
 }