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, 33 insertions, 104 deletions

diff --git a/source/blender/windowmanager/intern/wm_gesture.c b/source/blender/windowmanager/intern/wm_gesture.c
index 0ee0e415782..92215757d88 100644
--- a/source/blender/windowmanager/intern/wm_gesture.c
+++ b/source/blender/windowmanager/intern/wm_gesture.c
@@ -171,10 +171,8 @@ int wm_gesture_evaluate(wmGesture *gesture)
 static void wm_gesture_draw_line(wmGesture *gt)
 {
 	rcti *rect = (rcti *)gt->customdata;
-	
-	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);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -182,21 +180,16 @@ static void wm_gesture_draw_line(wmGesture *gt)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 0.4f, 0.4f, 0.4f, 1.0f);
-	immUniform4f("color2", 1.0f, 1.0f, 1.0f, 1.0f);
+	immUniform1i("num_colors", 2);  /* "advanced" mode */
+	immUniformArray4fv("colors", (float *)(float[][4]){{0.4f, 0.4f, 0.4f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f}}, 2);
 	immUniform1f("dash_width", 8.0f);
-	immUniform1f("dash_width_on", 4.0f);
 
 	float xmin = (float)rect->xmin;
 	float ymin = (float)rect->ymin;
 
 	immBegin(PRIM_LINES, 2);
-
-	immAttrib2f(line_origin, xmin, ymin);
-	immVertex2f(pos, xmin, ymin);
-	immAttrib2f(line_origin, xmin, ymin);
-	immVertex2f(pos, (float)rect->xmax, (float)rect->ymax);
-
+	immVertex2f(shdr_pos, xmin, ymin);
+	immVertex2f(shdr_pos, (float)rect->xmax, (float)rect->ymax);
 	immEnd();
 
 	immUnbindProgram();
@@ -206,23 +199,20 @@ static void wm_gesture_draw_rect(wmGesture *gt)
 {
 	rcti *rect = (rcti *)gt->customdata;
 
-	VertexFormat *format = immVertexFormat();
-	unsigned int pos = VertexFormat_add_attrib(format, "pos", COMP_I32, 2, CONVERT_INT_TO_FLOAT);
+	uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_I32, 2, CONVERT_INT_TO_FLOAT);
 
 	glEnable(GL_BLEND);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 	immUniformColor4f(1.0f, 1.0f, 1.0f, 0.05f);
 
-	immRecti(pos, rect->xmin, rect->ymin, rect->xmax, rect->ymax);
+	immRecti(shdr_pos, rect->xmin, rect->ymin, rect->xmax, rect->ymax);
 
 	immUnbindProgram();
 
 	glDisable(GL_BLEND);
 
-	format = immVertexFormat();
-	pos = VertexFormat_add_attrib(format, "pos", COMP_F32, 2, KEEP_FLOAT);
-	unsigned line_origin = VertexFormat_add_attrib(format, "line_origin", COMP_F32, 2, KEEP_FLOAT);
+	shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -230,64 +220,33 @@ static void wm_gesture_draw_rect(wmGesture *gt)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 0.4f, 0.4f, 0.4f, 1.0f);
-	immUniform4f("color2", 1.0f, 1.0f, 1.0f, 1.0f);
+	immUniform1i("num_colors", 2);  /* "advanced" mode */
+	immUniformArray4fv("colors", (float *)(float[][4]){{0.4f, 0.4f, 0.4f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f}}, 2);
 	immUniform1f("dash_width", 8.0f);
-	immUniform1f("dash_width_on", 4.0f);
-	
-	imm_draw_line_box_dashed(pos, line_origin,
-		(float)rect->xmin, (float)rect->ymin, (float)rect->xmax, (float)rect->ymax);
+
+	imm_draw_line_box(shdr_pos, (float)rect->xmin, (float)rect->ymin, (float)rect->xmax, (float)rect->ymax);
 
 	immUnbindProgram();
 
 	// wm_gesture_draw_line(gt); // draws a diagonal line in the lined box to test wm_gesture_draw_line
 }
 
-static void imm_draw_lined_dashed_circle(unsigned pos, unsigned line_origin, float x, float y, float rad, int nsegments)
-{
-	float xpos, ypos;
-
-	xpos = x + rad;
-	ypos = y;
-
-	immBegin(PRIM_LINES, nsegments * 2);
-
-	for (int i = 1; i <= nsegments; ++i) {
-		float angle = 2 * M_PI * ((float)i / (float)nsegments);
-
-		immAttrib2f(line_origin, xpos, ypos);
-		immVertex2f(pos, xpos, ypos);
-
-		xpos = x + rad * cosf(angle);
-		ypos = y + rad * sinf(angle);
-
-		immVertex2f(pos, xpos, ypos);
-	}
-
-	immEnd();
-}
-
 static void wm_gesture_draw_circle(wmGesture *gt)
 {
 	rcti *rect = (rcti *)gt->customdata;
 
 	glEnable(GL_BLEND);
 
-	VertexFormat *format = immVertexFormat();
-	unsigned int pos = VertexFormat_add_attrib(format, "pos", COMP_F32, 2, KEEP_FLOAT);
+	const uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 
 	immUniformColor4f(1.0f, 1.0f, 1.0f, 0.05f);
-	imm_draw_circle_fill(pos, (float)rect->xmin, (float)rect->ymin, (float)rect->xmax, 40);
+	imm_draw_circle_fill(shdr_pos, (float)rect->xmin, (float)rect->ymin, (float)rect->xmax, 40);
 
 	immUnbindProgram();
 
 	glDisable(GL_BLEND);
-	
-	format = immVertexFormat();
-	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);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -295,13 +254,11 @@ static void wm_gesture_draw_circle(wmGesture *gt)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 0.4f, 0.4f, 0.4f, 1.0f);
-	immUniform4f("color2", 1.0f, 1.0f, 1.0f, 1.0f);
+	immUniform1i("num_colors", 2);  /* "advanced" mode */
+	immUniformArray4fv("colors", (float *)(float[][4]){{0.4f, 0.4f, 0.4f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f}}, 2);
 	immUniform1f("dash_width", 4.0f);
-	immUniform1f("dash_width_on", 2.0f);
-	
-	imm_draw_lined_dashed_circle(pos, line_origin,
-		(float)rect->xmin, (float)rect->ymin, (float)rect->xmax, 40);
+
+	imm_draw_circle_wire(shdr_pos, (float)rect->xmin, (float)rect->ymin, (float)rect->xmax, 40);
 
 	immUnbindProgram();
 }
@@ -383,26 +340,20 @@ static void draw_filled_lasso(wmWindow *win, wmGesture *gt)
 static void wm_gesture_draw_lasso(wmWindow *win, wmGesture *gt, bool filled)
 {
 	const short *lasso = (short *)gt->customdata;
-	int i, numverts;
-	float x, y;
+	int i;
 
 	if (filled) {
 		draw_filled_lasso(win, gt);
 	}
 
-	numverts = gt->points;
-	if (gt->type == WM_GESTURE_LASSO) {
-		numverts++;
-	}
+	const int numverts = gt->points;
 
 	/* Nothing to draw, do early output. */
 	if (numverts < 2) {
 		return;
 	}
 
-	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);
+	const uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -410,29 +361,14 @@ static void wm_gesture_draw_lasso(wmWindow *win, wmGesture *gt, bool filled)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 0.4f, 0.4f, 0.4f, 1.0f);
-	immUniform4f("color2", 1.0f, 1.0f, 1.0f, 1.0f);
+	immUniform1i("num_colors", 2);  /* "advanced" mode */
+	immUniformArray4fv("colors", (float *)(float[][4]){{0.4f, 0.4f, 0.4f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f}}, 2);
 	immUniform1f("dash_width", 2.0f);
-	immUniform1f("dash_width_on", 1.0f);
 
-	immBegin(PRIM_LINE_STRIP, numverts);
+	immBegin((gt->type == WM_GESTURE_LASSO) ? PRIM_LINE_LOOP : PRIM_LINE_STRIP, numverts);
 
 	for (i = 0; i < gt->points; i++, lasso += 2) {
-
-		/* get line_origin coordinates only from the first vertex of each line */
-		if (!(i % 2)) {
-			x = (float)lasso[0];
-			y = (float)lasso[1];
-		}
-
-		immAttrib2f(line_origin, x, y);
-		immVertex2f(pos, (float)lasso[0], (float)lasso[1]);
-	}
-
-	if (gt->type == WM_GESTURE_LASSO) {
-		immAttrib2f(line_origin, x, y);
-		lasso = (short *)gt->customdata;
-		immVertex2f(pos, (float)lasso[0], (float)lasso[1]);
+		immVertex2f(shdr_pos, (float)lasso[0], (float)lasso[1]);
 	}
 
 	immEnd();
@@ -448,9 +384,7 @@ static void wm_gesture_draw_cross(wmWindow *win, wmGesture *gt)
 
 	float x1, x2, y1, y2;
 
-	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);
+	const uint shdr_pos = VertexFormat_add_attrib(immVertexFormat(), "pos", COMP_F32, 2, KEEP_FLOAT);
 
 	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_COLOR);
 
@@ -458,10 +392,9 @@ static void wm_gesture_draw_cross(wmWindow *win, wmGesture *gt)
 	glGetFloatv(GL_VIEWPORT, viewport_size);
 	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
 
-	immUniform4f("color1", 0.4f, 0.4f, 0.4f, 1.0f);
-	immUniform4f("color2", 1.0f, 1.0f, 1.0f, 1.0f);
+	immUniform1i("num_colors", 2);  /* "advanced" mode */
+	immUniformArray4fv("colors", (float *)(float[][4]){{0.4f, 0.4f, 0.4f, 1.0f}, {1.0f, 1.0f, 1.0f, 1.0f}}, 2);
 	immUniform1f("dash_width", 8.0f);
-	immUniform1f("dash_width_on", 4.0f);
 
 	immBegin(PRIM_LINES, 4);
 
@@ -470,20 +403,16 @@ static void wm_gesture_draw_cross(wmWindow *win, wmGesture *gt)
 	x2 = (float)(rect->xmin + winsize_x);
 	y2 = y1;
 
-	immAttrib2f(line_origin, x1, y1);
-	immVertex2f(pos, x1, y1);
-	immAttrib2f(line_origin, x1, y1);
-	immVertex2f(pos, x2, y2);
+	immVertex2f(shdr_pos, x1, y1);
+	immVertex2f(shdr_pos, x2, y2);
 
 	x1 = (float)rect->xmin;
 	y1 = (float)(rect->ymin - winsize_y);
 	x2 = x1;
 	y2 = (float)(rect->ymin + winsize_y);
 
-	immAttrib2f(line_origin, x1, y1);
-	immVertex2f(pos, x1, y1);
-	immAttrib2f(line_origin, x1, y1);
-	immVertex2f(pos, x2, y2);
+	immVertex2f(shdr_pos, x1, y1);
+	immVertex2f(shdr_pos, x2, y2);
 
 	immEnd();