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Don't allocate when drawing by reusing glyp rend buffer

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This commit is contained in:
bloeys
2022-07-04 01:10:37 +04:00
parent edd8d5b71b
commit 3d7d09744d
4 changed files with 76 additions and 22 deletions
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55
glyphs/glyphs.go
View File

@ -13,6 +13,9 @@ import (
"github.com/golang/freetype/truetype"
)
const floatsPerGlyph = 11
const maxGlyphsPerBatch = 16384
type GlyphRend struct {
Atlas *FontAtlas
AtlasTex *assets.Texture
@ -22,7 +25,13 @@ type GlyphRend struct {
GlyphMat *materials.Material
GlyphCount int32
GlyphVBO []float32
//NOTE: Because of the sad realities (bugs?) of CGO, passing an array in a struct
//to C explodes (Go pointer to Go pointer error) even though passing the same array
//allocated inside the function is fine (Go potentially can't detect what's happening properly).
//
//Luckily slices still work, so for now we will use our slice as an array (no appending)
GlyphVBO []float32
// GlyphVBO [floatsPerGlyph * maxGlyphsPerBatch]float32
ScreenWidth int32
ScreenHeight int32
@ -43,13 +52,11 @@ func (gr *GlyphRend) DrawTextOpenGLAbs(text string, screenPos *gglm.Vec3, color
//Prepass to pre-allocate the buffer
rs := []rune(text)
const floatsPerGlyph = 18
// startPos := screenPos.Clone()
pos := screenPos.Clone()
advanceF32 := float32(gr.Atlas.Advance)
lineHeightF32 := float32(gr.Atlas.LineHeight)
instancedData := make([]float32, 0, len(rs)*floatsPerGlyph) //This a larger approximation than needed because we don't count spaces etc
for i := 0; i < len(rs); i++ {
r := rs[i]
@ -62,7 +69,6 @@ func (gr *GlyphRend) DrawTextOpenGLAbs(text string, screenPos *gglm.Vec3, color
pos.SetX(pos.X() + advanceF32)
continue
}
gr.GlyphCount++
scale := gglm.NewVec2(advanceF32, lineHeightF32)
@ -73,17 +79,36 @@ func (gr *GlyphRend) DrawTextOpenGLAbs(text string, screenPos *gglm.Vec3, color
drawPos.SetX(drawPos.X())
drawPos.SetY(drawPos.Y() - g.Descent)
instancedData = append(instancedData, []float32{
g.U, g.V,
color.R(), color.G(), color.B(), color.A(), //Color
roundF32(drawPos.X()), roundF32(drawPos.Y()), drawPos.Z(), //Model pos
scale.X(), scale.Y(), //Model scale
}...)
//Add the glyph information to the vbo
startIndex := gr.GlyphCount * floatsPerGlyph
//UV
gr.GlyphVBO[startIndex+0] = g.U
gr.GlyphVBO[startIndex+1] = g.V
//Color
gr.GlyphVBO[startIndex+2] = color.R()
gr.GlyphVBO[startIndex+3] = color.G()
gr.GlyphVBO[startIndex+4] = color.B()
gr.GlyphVBO[startIndex+5] = color.A()
//Model Pos
gr.GlyphVBO[startIndex+6] = roundF32(drawPos.X())
gr.GlyphVBO[startIndex+7] = roundF32(drawPos.Y())
gr.GlyphVBO[startIndex+8] = drawPos.Z()
//Model Scale
gr.GlyphVBO[startIndex+9] = scale.X()
gr.GlyphVBO[startIndex+10] = scale.Y()
gr.GlyphCount++
pos.SetX(pos.X() + advanceF32)
}
gr.GlyphVBO = append(gr.GlyphVBO, instancedData...)
//If we fill the buffer we issue a draw call
if gr.GlyphCount == maxGlyphsPerBatch {
gr.Draw()
}
}
}
func (gr *GlyphRend) Draw() {
@ -92,14 +117,12 @@ func (gr *GlyphRend) Draw() {
return
}
gr.InstancedBuf.SetData(gr.GlyphVBO)
gr.InstancedBuf.SetData(gr.GlyphVBO[:gr.GlyphCount*floatsPerGlyph])
gr.InstancedBuf.Bind()
gr.GlyphMat.Bind()
gl.DrawElementsInstanced(gl.TRIANGLES, gr.GlyphMesh.Buf.IndexBufCount, gl.UNSIGNED_INT, gl.PtrOffset(0), gr.GlyphCount)
gr.GlyphCount = 0
gr.GlyphVBO = []float32{}
}
//SetFace updates the underlying font atlas used by the glyph renderer.
@ -178,7 +201,7 @@ func NewGlyphRend(fontFile string, fontOptions *truetype.Options, screenWidth, s
gr := &GlyphRend{
GlyphCount: 0,
GlyphVBO: make([]float32, 0),
GlyphVBO: make([]float32, floatsPerGlyph*maxGlyphsPerBatch),
}
//Create glyph mesh

2
go.mod
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@ -4,7 +4,7 @@ go 1.18
require (
github.com/bloeys/gglm v0.41.10
github.com/bloeys/nmage v0.12.12
github.com/bloeys/nmage v0.12.13
github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784
github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0
github.com/veandco/go-sdl2 v0.4.10

2
go.sum
View File

@ -4,6 +4,8 @@ github.com/bloeys/gglm v0.41.10 h1:R9FMiI+VQVXAI+vDwCB7z9xqzy5VAR1657u8TQTDNKA=
github.com/bloeys/gglm v0.41.10/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
github.com/bloeys/nmage v0.12.12 h1:LeMR6NI+yMqxAZecdz7lOT1re4CWAVd1wDeJFK77+pI=
github.com/bloeys/nmage v0.12.12/go.mod h1:chDDenktiDvAG4BoFYNq1n8nACpbQ6/RFuCgCGmDxh4=
github.com/bloeys/nmage v0.12.13 h1:xvoaMAdHNnVif7LCaQkYR7jewXDZa9B1iV7IdG39dgc=
github.com/bloeys/nmage v0.12.13/go.mod h1:chDDenktiDvAG4BoFYNq1n8nACpbQ6/RFuCgCGmDxh4=
github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784 h1:1Zi56D0LNfvkzM+BdoxKryvUEdyWO7LP8oRT+oSYJW0=

39
main.go
View File

@ -2,6 +2,7 @@ package main
import (
"fmt"
"math/rand"
"github.com/bloeys/gglm/gglm"
"github.com/bloeys/nmage/engine"
@ -9,6 +10,7 @@ import (
"github.com/bloeys/nmage/materials"
"github.com/bloeys/nmage/meshes"
"github.com/bloeys/nmage/renderer/rend3dgl"
"github.com/bloeys/nmage/timing"
nmageimgui "github.com/bloeys/nmage/ui/imgui"
"github.com/bloeys/nterm/glyphs"
"github.com/go-gl/gl/v4.1-core/gl"
@ -154,20 +156,47 @@ func (p *program) Update() {
if input.KeyClicked(sdl.K_SPACE) {
p.shouldDrawGrid = !p.shouldDrawGrid
}
fmt.Println("FPS:", int(timing.GetAvgFPS()), "; Draws per frame:", charsPerFrame/16384)
}
const charsPerFrame = 100_000
var xOff float32 = 0
var yOff float32 = 0
var r = rand.Float32()
var g = rand.Float32()
var b = rand.Float32()
func (p *program) Render() {
const colorSpd = 0.005
defer p.GlyphRend.Draw()
textColor := gglm.NewVec4(1, 1, 1, 1)
// p.GlyphRend.DrawTextOpenGL("y", gglm.NewVec3(0+xOff, 0+yOff, 0), textColor)
// p.GlyphRend.DrawTextOpenGL("A\np-+_; This is", gglm.NewVec3(0.3+xOff, 0.5+yOff, 0), textColor)
// p.GlyphRend.DrawTextOpenGLAbs("Hello there, friend.\nABCDEFGHIJKLMNOPQRSTUVWXYZ", gglm.NewVec3(0, 0, 0), textColor)
p.GlyphRend.DrawTextOpenGLAbs(" ijojo\n\n Hello there, friend|. pq?\n ABCDEFGHIJKLMNOPQRSTUVWXYZ", gglm.NewVec3(xOff, float32(p.GlyphRend.Atlas.LineHeight)*5+yOff, 0), textColor)
r += colorSpd
if r > 1 {
r = 0
}
g += colorSpd
if g > 1 {
g = 0
}
b += colorSpd
if b > 1 {
b = 0
}
textColor := gglm.NewVec4(r, g, b, 1)
str := " ijojo\n\n Hello there, friend|. pq?\n ABCDEFGHIJKLMNOPQRSTUVWXYZ"
strLen := len(str)
for i := 0; i < charsPerFrame/strLen; i++ {
p.GlyphRend.DrawTextOpenGLAbs(str, gglm.NewVec3(xOff, float32(p.GlyphRend.Atlas.LineHeight)*5+yOff, 0), textColor)
}
if p.shouldDrawGrid {
p.drawGrid()