vtgl

Commit: 216c2baee2b37bcc99db63176fbbb5f71cda4c63
Parent: 106916dc7f689fcdf4961d3da1f57a52582ac88d
Author: Randy Palamar
Date:   Mon,  2 Dec 2024 05:38:11 -0700

don't clobber pending renders when the input and render threads overlap

Diffstat:
M
util.h
 | 
3
++-
M
vtgl.c
 | 
50
++++++++++++++++++++++++--------------------------

2 files changed, 26 insertions(+), 27 deletions(-)
diff --git a/util.h b/util.h
@@ -166,7 +166,6 @@ typedef struct {
 enum gl_flags {
 	NEEDS_RESIZE         = 1 << 0,
 	NEEDS_REFILL         = 1 << 1,
-	UPDATE_RENDER_BUFFER = 1 << 2,
 
 	DRAW_DEBUG_OVERLAY   = 1 << 30,
 };
@@ -219,6 +218,8 @@ typedef struct {
 	u32 glyph_bitmap_tex;
 
 	u32 flags;
+
+	u32 queued_render;
 } GLCtx;
 
 typedef struct {
diff --git a/vtgl.c b/vtgl.c
@@ -237,12 +237,11 @@ get_terminal_top_left(Term *t)
 static void
 resize_terminal(Term *t, PlatformAPI *platform, iv2 window_size)
 {
-	iv2 old_size = t->size;
-
 	v2 ws  = v2_from_iv2(window_size);
 	ws.w  -= 2 * g_term_margin.w;
 	ws.h  -= 2 * g_term_margin.h;
 
+	iv2 old_size = t->size;
 	v2 cs        = get_cell_size(&t->fa);
 	t->size.w    = (i32)(ws.w / cs.w);
 	t->size.h    = (i32)(ws.h / cs.h);
@@ -288,12 +287,16 @@ resize(Term *t, PlatformAPI *platform, iv2 window_size)
 	glBufferData(GL_SHADER_STORAGE_BUFFER, buffer_size, 0, GL_DYNAMIC_DRAW);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, gl->render_shader_ssbo);
 	LABEL_GL_OBJECT(GL_BUFFER, gl->render_shader_ssbo, s8("RenderCells"));
-	gl->flags |= UPDATE_RENDER_BUFFER;
+	gl->queued_render = 1;
 
 	v2 cs = get_cell_size(&t->fa);
 
 	ShaderParameters *sp = &gl->shader_parameters;
 	sp->cell_size        = (iv2){.w = cs.w, .h = cs.h};
+	sp->strike_min       = (t->fa.info.baseline + 0.40 * t->fa.info.h);
+	sp->strike_max       = (t->fa.info.baseline + 0.48 * t->fa.info.h);
+	sp->underline_min    = (0.89 * t->fa.info.h);
+	sp->underline_max    = (0.96 * t->fa.info.h);
 	sp->top_left_margin  = g_term_margin;
 	sp->margin_colour    = g_colours.data[g_colours.bgidx].rgba;
 	//sp->margin_colour    = 0x7f003f00;
@@ -511,24 +514,23 @@ render_framebuffer(Term *t, RenderCell *render_buf, TerminalInput *input, Arena 
 	/* NOTE: draw whole framebuffer */
 	for (u32 row = 0; row < t->size.h; row++) {
 		for (u32 col = 0; col < t->size.w; col++) {
-			Cell *c        = &tv->fb.rows[row][col];
+			Cell c         = tv->fb.rows[row][col];
 			RenderCell *rc = render_buf + (row * t->size.w + col);
 
 			CachedGlyph *cg;
-			rc->gpu_glyph = get_gpu_glyph_index(arena, &t->gl, &t->fa, c->cp, 0,
-			                                    c->bg & FS_MASK, &cg);
-			rc->fg = c->fg;
-			rc->bg = c->bg;
+			rc->gpu_glyph = get_gpu_glyph_index(arena, &t->gl, &t->fa, c.cp, 0,
+			                                    c.bg & FS_MASK, &cg);
+			rc->fg = c.fg;
+			rc->bg = c.bg;
 
 			/* TODO: there is probably a better way to do this */
 			u32 tiles = cg->tile_count;
 			if (tiles > 1) {
-				for (u32 i = 1; i < tiles; i++) {
-					rc[i].gpu_glyph = rc->gpu_glyph + i;
-					rc[i].fg        = rc->fg;
-					rc[i].bg        = rc->bg;
-				}
-				col += tiles - 1;
+				ASSERT(tiles == 2);
+				rc[1].gpu_glyph = rc->gpu_glyph + 1;
+				rc[1].fg        = rc->fg;
+				rc[1].bg        = rc->bg;
+				col++;
 			}
 		}
 	}
@@ -645,7 +647,7 @@ begin_selection(Term *t, u32 click_count, v2 mouse)
 	case SS_NONE:  break;
 	}
 
-	t->gl.flags |= UPDATE_RENDER_BUFFER;
+	t->gl.queued_render = 1;
 }
 
 static void
@@ -684,7 +686,7 @@ update_selection(Term *t, TerminalInput *input)
 	sel->range = normalize_range(sel->range);
 
 	if (!equal_range(old_range, sel->range))
-		t->gl.flags |= UPDATE_RENDER_BUFFER;
+		t->gl.queued_render = 1;
 }
 
 KEYBIND_FN(copy)
@@ -1231,6 +1233,8 @@ DEBUG_EXPORT VTGL_RENDER_FRAME_FN(vtgl_render_frame)
 
 	dt_for_frame = input->dt;
 
+	b32 update_render_buffer = __atomic_exchange_n(&t->gl.queued_render, 0, __ATOMIC_SEQ_CST);
+
 	TempArena temp_arena = begin_temp_arena(&arena);
 
 	if (t->gl.flags & NEEDS_RESIZE || !equal_iv2(input->window_size, t->gl.window_size))
@@ -1259,23 +1263,17 @@ DEBUG_EXPORT VTGL_RENDER_FRAME_FN(vtgl_render_frame)
 	glBindFramebuffer(GL_FRAMEBUFFER, t->gl.fb);
 	clear_colour();
 
-	if (t->gl.flags & UPDATE_RENDER_BUFFER) {
+	if (update_render_buffer) {
 		u32 cell_count = t->size.h * t->size.w;
 		RenderCell *render_buf = alloc(&arena, RenderCell, cell_count);
 		render_framebuffer(t, render_buf, input, arena);
 		glBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, cell_count * sizeof(*render_buf), render_buf);
-		t->gl.flags &= ~UPDATE_RENDER_BUFFER;
 	}
 	render_cursor(t, input->window_focused, arena);
 
 	ShaderParameters *sp = &t->gl.shader_parameters;
 	sp->blink_parameter += 2 * PI * g_blink_speed * dt_for_frame;
 	if (sp->blink_parameter > 2 * PI) sp->blink_parameter -= 2 * PI;
-	sp->strike_min    = (t->fa.info.baseline + 0.40 * t->fa.info.h);
-	sp->strike_max    = (t->fa.info.baseline + 0.48 * t->fa.info.h);
-	sp->underline_min = (0.89 * t->fa.info.h);
-	sp->underline_max = (0.96 * t->fa.info.h);
-
 	sp->reverse_video_mask = REVERSE_VIDEO_MASK * !!(t->mode.win & WM_REVERSE);
 
 	glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(*sp), sp);
@@ -1340,7 +1338,7 @@ DEBUG_EXPORT VTGL_FRAME_STEP_FN(vtgl_frame_step)
 
 	if (t->gl.flags & NEEDS_REFILL) {
 		blit_lines(t, t->arena_for_frame);
-		t->gl.flags |= UPDATE_RENDER_BUFFER;
+		t->gl.queued_render = 1;
 	}
 
 	BEGIN_NAMED_BLOCK(input_from_child);
@@ -1358,7 +1356,7 @@ DEBUG_EXPORT VTGL_FRAME_STEP_FN(vtgl_frame_step)
 			.data = rb->buf + (rb->widx - t->unprocessed_bytes)
 		};
 		handle_input(t, t->arena_for_frame, raw);
-		t->gl.flags |= UPDATE_RENDER_BUFFER;
+		t->gl.queued_render = 1;
 	}
 	END_NAMED_BLOCK(input_from_child);
 
@@ -1370,7 +1368,7 @@ DEBUG_EXPORT VTGL_FRAME_STEP_FN(vtgl_frame_step)
 
 	END_TIMED_BLOCK();
 
-	return (t->gl.flags & UPDATE_RENDER_BUFFER) || input->window_refreshed;
+	return t->gl.queued_render || input->window_refreshed;
 }
 
 #ifdef _DEBUG