[vulkan] Use linear sampling for glyphs

This requires having padding around the glyphs to avoid texel leak, but
as the atlas is created at runtime, it's possible to get the padding in.

libs/video/renderer/r_font.c

@@ -102,7 +102,8 @@ R_FontLoad (QFile *font_file, int size)
 		FT_Load_Glyph (font->face, gind, FT_LOAD_DEFAULT);
 
 		__auto_type g = font->face->glyph;
-		pixels += g->bitmap.width * g->bitmap.rows;
+		// include padding around the glyph to avoid texel leaks
+		pixels += (g->bitmap.width + 1) * (g->bitmap.rows + 1);
 	}
 	pixels = sqrt (5 * pixels / 4);
 	pixels = BITOP_RUP (pixels);
@@ -118,10 +119,15 @@ R_FontLoad (QFile *font_file, int size)
 		FT_Load_Glyph (font->face, gind, FT_LOAD_DEFAULT);
 		__auto_type slot = font->face->glyph;
 		FT_Render_Glyph (slot, FT_RENDER_MODE_NORMAL);
-		int     width = slot->bitmap.width;
-		int     height = slot->bitmap.rows;
+		// add padding to create a buffer around the glyph to prevent texel
+		// leaks
+		int     width = slot->bitmap.width + 1;
+		int     height = slot->bitmap.rows + 1;
 		*rect = *R_ScrapAlloc (&font->scrap, width, height);
 		*bearing = (vec2i_t) { slot->bitmap_left, slot->bitmap_top };
+		// shrink the rect so as to NOT include the padding
+		rect->width -= 1;
+		rect->height -= 1;
 
 		copy_glyph (rect, slot, font);
 	}

libs/video/renderer/r_progs.c

@@ -474,6 +474,12 @@ bi_Draw_PrintBuffer (progs_t *pr, void *_res)
 	Draw_PrintBuffer (cbuff->buffer, str);
 }
 
+static void
+bi_Draw_SetScale (progs_t *pr, void *_res)
+{
+	Draw_SetScale (P_INT (pr, 0));
+}
+
 static const char *
 bi_draw_get_key (const void *p, void *unused)
 {
@@ -540,6 +546,9 @@ static builtin_t builtins[] = {
 	bi(Draw_ScrollBuffer,   2, p(ptr), p(int)),
 	bi(Draw_CharBuffer,     3, p(int), p(int), p(ptr)),
 	bi(Draw_PrintBuffer,    2, p(ptr), p(string)),
+
+	bi(Draw_SetScale,   1, p(int)),
+
 	{0}
 };
 

libs/video/renderer/vulkan/qfpipeline.plist

@@ -23,6 +23,23 @@
 			borderColor = float_transparent_black;
 			unnormalizedCoordinates = false;
 		};
+		glyph = {
+			magFilter = linear;
+			minFilter = linear;
+			mipmapMode = linear;
+			addressModeU = clamp_to_edge;
+			addressModeV = clamp_to_edge;
+			addressModeW = clamp_to_edge;
+			mipLodBias = 0;
+			anisotropyEnable = false;
+			maxAnisotropy = 0;
+			compareEnable = false;
+			compareOp = always;
+			minLod = 0;
+			maxLod = 0;
+			borderColor = float_transparent_black;
+			unnormalizedCoordinates = false;
+		};
 		palette_sampler = {
 			magFilter = nearest;
 			minFilter = nearest;

libs/video/renderer/vulkan/vulkan_draw.c

@@ -168,7 +168,8 @@ typedef struct drawfontset_s
 	DARRAY_TYPE (drawfont_t) drawfontset_t;
 
 typedef struct drawctx_s {
-	VkSampler   sampler;
+	VkSampler   pic_sampler;
+	VkSampler   glyph_sampler;
 	scrap_t    *scrap;
 	qfv_stagebuf_t *stage;
 	qpic_t     *crosshair;
@@ -576,7 +577,8 @@ Vulkan_Draw_Init (vulkan_ctx_t *ctx)
 										   ctx->cmdpool);
 	dctx->scrap = QFV_CreateScrap (device, "draw_atlas", 2048, tex_rgba,
 								   dctx->stage);
-	dctx->sampler = Vulkan_CreateSampler (ctx, "quakepic");
+	dctx->pic_sampler = Vulkan_CreateSampler (ctx, "quakepic");
+	dctx->glyph_sampler = Vulkan_CreateSampler (ctx, "glyph");
 
 	draw_chars = W_GetLumpName ("conchars");
 	if (draw_chars) {
@@ -623,7 +625,7 @@ Vulkan_Draw_Init (vulkan_ctx_t *ctx)
 	__auto_type pool = Vulkan_CreateDescriptorPool (ctx, "twod_pool");
 
 	VkDescriptorImageInfo imageInfo = {
-		dctx->sampler,
+		dctx->pic_sampler,
 		QFV_ScrapImageView (dctx->scrap),
 		VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
 	};
@@ -1369,20 +1371,20 @@ Vulkan_Draw_AddFont (rfont_t *rfont, vulkan_ctx_t *ctx)
 		float       s = 1.0 / rfont->scrap.width;
 		float       t = 1.0 / rfont->scrap.height;
 		verts[i * 4 + 0] = (glyphvert_t) {
-			.offset = { x + 0,       y + 0 },
-			.uv     = {(u + 0.25) * s, (v + 0.25) * t },
+			.offset = { x,     y },
+			.uv     = { u * s, v * t },
 		};
 		verts[i * 4 + 1] = (glyphvert_t) {
-			.offset = { x + 0,       y + h },
-			.uv     = {(u + 0.25) * s, (v + h - 0.25) * t },
+			.offset = { x,      y + h },
+			.uv     = { u * s, (v + h) * t },
 		};
 		verts[i * 4 + 2] = (glyphvert_t) {
-			.offset = { x + w,       y + 0 },
-			.uv     = {(u + w - 0.25) * s, (v + 0.25) * t },
+			.offset = { x + w,      y },
+			.uv     = {(u + w) * s, v * t },
 		};
 		verts[i * 4 + 3] = (glyphvert_t) {
 			.offset = { x + w,       y + h },
-			.uv     = {(u + w - 0.25) * s, (v + h - 0.25) * t },
+			.uv     = {(u + w) * s, (v + h) * t },
 		};
 	}
 	QFV_PacketCopyBuffer (packet, glyph_data->buffer.buffer,
@@ -1403,7 +1405,7 @@ Vulkan_Draw_AddFont (rfont_t *rfont, vulkan_ctx_t *ctx)
 	__auto_type glyph_sets = QFV_AllocateDescriptorSet (device, pool, layouts);
 	font->set = glyph_sets->a[0];
 	VkDescriptorImageInfo imageInfo = {
-		dctx->sampler,
+		dctx->glyph_sampler,
 		glyph_iview->image_view.view,
 		VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
 	};