Pad font atlas to avoid bleeding+togglable grid

glyphs/font_atlas.go

@@ -70,13 +70,15 @@ func NewFontAtlasFromFont(f *truetype.Font, face font.Face, pointSize uint) (*Fo
 	atlasSizeX := 512
 	atlasSizeY := 512
 
-	charWidthFixed, _ := face.GlyphAdvance('L')
+	const charPaddingX = 4
-	charWidth := charWidthFixed.Ceil()
+	const charPaddingY = 4
+	charAdvFixed, _ := face.GlyphAdvance('L')
+	charAdv := charAdvFixed.Ceil() + charPaddingX
 
 	lineHeight := face.Metrics().Height.Ceil()
 
 	maxLinesInAtlas := atlasSizeY/lineHeight - 1
-	charsPerLine := atlasSizeX / charWidth
+	charsPerLine := atlasSizeX / charAdv
 	linesNeeded := int(math.Ceil(float64(len(glyphs)) / float64(charsPerLine)))
 
 	for linesNeeded > maxLinesInAtlas {
@@ -86,7 +88,7 @@ func NewFontAtlasFromFont(f *truetype.Font, face font.Face, pointSize uint) (*Fo
 
 		maxLinesInAtlas = atlasSizeY/lineHeight - 1
 
-		charsPerLine = atlasSizeX / charWidth
+		charsPerLine = atlasSizeX / charAdv
 		linesNeeded = int(math.Ceil(float64(len(glyphs)) / float64(charsPerLine)))
 	}
 
@@ -114,6 +116,8 @@ func NewFontAtlasFromFont(f *truetype.Font, face font.Face, pointSize uint) (*Fo
 	//Put glyphs on atlas
 	atlasSizeXF32 := float32(atlasSizeX)
 	atlasSizeYF32 := float32(atlasSizeY)
+	charPaddingXFixed := fixed.I(charPaddingX)
+	charPaddingYFixed := fixed.I(charPaddingY)
 
 	charsOnLine := 0
 	lineHeightFixed := fixed.I(lineHeight)
@@ -127,7 +131,7 @@ func NewFontAtlasFromFont(f *truetype.Font, face font.Face, pointSize uint) (*Fo
 		descent := absFixedI26_6(gBounds.Max.Y)
 		bearingX := absFixedI26_6(gBounds.Min.X)
 
-		glyphWidth := float32((absFixedI26_6(gBounds.Max.X - gBounds.Min.X)).Ceil())
+		glyphWidth := float32((absFixedI26_6(gBounds.Max.X) - absFixedI26_6(gBounds.Min.X)).Ceil())
 		heightRounded := (ascent + descent).Ceil()
 
 		atlas.Glyphs[g] = FontAtlasGlyph{
@@ -144,14 +148,16 @@ func NewFontAtlasFromFont(f *truetype.Font, face font.Face, pointSize uint) (*Fo
 			BearingX: float32(bearingX.Ceil()),
 			Width:    glyphWidth,
 		}
+
 		drawer.DrawString(string(g))
+		drawer.Dot.X += charPaddingXFixed
 
 		charsOnLine++
 		if charsOnLine == charsPerLine {
 
 			charsOnLine = 0
 			drawer.Dot.X = 0
-			drawer.Dot.Y += lineHeightFixed
+			drawer.Dot.Y += lineHeightFixed + charPaddingYFixed
 		}
 	}
 

main.go

@@ -27,6 +27,11 @@ type program struct {
 	FontSize  uint32
 	Dpi       float64
 	GlyphRend *glyphs.GlyphRend
+
+	gridMesh *meshes.Mesh
+	gridMat  *materials.Material
+
+	shouldDrawGrid bool
 }
 
 //nMage TODO:
@@ -61,7 +66,7 @@ func main() {
 		rend:      rend,
 		imguiInfo: nmageimgui.NewImGUI(),
 
-		FontSize: 80,
+		FontSize: 14,
 	}
 
 	p.win.EventCallbacks = append(p.win.EventCallbacks, func(e sdl.Event) {
@@ -97,19 +102,16 @@ func (p *program) Init() {
 	glyphs.SaveImgToPNG(p.GlyphRend.Atlas.Img, "./debug-atlas.png")
 }
 
-var gridMesh *meshes.Mesh
-var gridMat *materials.Material
-
 func (p *program) Start() {
 
 	var err error
-	gridMesh, err = meshes.NewMesh("grid", "./res/models/quad.obj", 0)
+	p.gridMesh, err = meshes.NewMesh("grid", "./res/models/quad.obj", 0)
 	if err != nil {
 		panic(err.Error())
 	}
 
-	gridMat = materials.NewMaterial("grid", "./res/shaders/grid")
+	p.gridMat = materials.NewMaterial("grid", "./res/shaders/grid")
-	gridMat.SetAttribute(gridMesh.Buf)
+	p.gridMat.SetAttribute(p.gridMesh.Buf)
 	p.handleWindowResize()
 }
 
@@ -126,6 +128,7 @@ func (p *program) Update() {
 		p.handleWindowResize()
 	}
 
+	//Font sizing
 	oldFont := p.FontSize
 	fontSizeChanged := false
 	if input.KeyClicked(sdl.K_KP_PLUS) {
@@ -144,10 +147,11 @@ func (p *program) Update() {
 			println("Failed to update font face. Err: " + err.Error())
 		} else {
 			glyphs.SaveImgToPNG(p.GlyphRend.Atlas.Img, "./debug-atlas.png")
-			println("New font size:", p.FontSize)
+			println("New font size:", p.FontSize, "; New texture size:", p.GlyphRend.Atlas.Img.Rect.Max.X, "\n")
 		}
 	}
 
+	//Move text
 	var speed float32 = 1
 	if input.KeyDown(sdl.K_RIGHT) {
 		xOff += speed
@@ -160,6 +164,11 @@ func (p *program) Update() {
 	} else if input.KeyDown(sdl.K_DOWN) {
 		yOff -= speed
 	}
+
+	//Grid
+	if input.KeyClicked(sdl.K_SPACE) {
+		p.shouldDrawGrid = !p.shouldDrawGrid
+	}
 }
 
 var xOff float32 = 0
@@ -175,7 +184,9 @@ func (p *program) Render() {
 	// p.GlyphRend.DrawTextOpenGLAbs("Hello there, friend.\nABCDEFGHIJKLMNOPQRSTUVWXYZ", gglm.NewVec3(0, 0, 0), textColor)
 	p.GlyphRend.DrawTextOpenGLAbs(" Hello there, friend|.\n ABCDEFGHIJKLMNOPQRSTUVWXYZ", gglm.NewVec3(xOff, float32(p.GlyphRend.Atlas.LineHeight)*2+yOff, 0), textColor)
 
-	// p.drawGrid()
+	if p.shouldDrawGrid {
+		p.drawGrid()
+	}
 }
 
 func (p *program) drawGrid() {
@@ -186,12 +197,12 @@ func (p *program) drawGrid() {
 	//columns
 	adv := p.GlyphRend.Atlas.Glyphs['A'].Advance
 	for i := int32(0); i < p.GlyphRend.ScreenWidth; i += int32(adv) {
-		p.rend.Draw(gridMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(float32(i)+0.5, sizeY/2, 0)).Scale(gglm.NewVec3(1, sizeY, 1)), gridMat)
+		p.rend.Draw(p.gridMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(float32(i)+0.5, sizeY/2, 0)).Scale(gglm.NewVec3(1, sizeY, 1)), p.gridMat)
 	}
 
 	//rows
 	for i := int32(0); i < p.GlyphRend.ScreenHeight; i += int32(p.GlyphRend.Atlas.LineHeight) {
-		p.rend.Draw(gridMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(sizeX/2, float32(i), 0)).Scale(gglm.NewVec3(sizeX, 1, 1)), gridMat)
+		p.rend.Draw(p.gridMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(sizeX/2, float32(i), 0)).Scale(gglm.NewVec3(sizeX, 1, 1)), p.gridMat)
 	}
 }
 
@@ -220,5 +231,5 @@ func (p *program) handleWindowResize() {
 
 	projMtx := gglm.Ortho(0, float32(w), float32(h), 0, 0.1, 20)
 	viewMtx := gglm.LookAt(gglm.NewVec3(0, 0, -10), gglm.NewVec3(0, 0, 0), gglm.NewVec3(0, 1, 0))
-	gridMat.SetUnifMat4("projViewMat", &projMtx.Mul(viewMtx).Mat4)
+	p.gridMat.SetUnifMat4("projViewMat", &projMtx.Mul(viewMtx).Mat4)
 }