Setting up profiling etc

tinyrender1/image.go

@@ -31,6 +31,11 @@ func NewFramebuffer(width uint, height uint) Framebuffer {
 	}
 }
 
+// Sure hope this gets inlined...
+func (fb *Framebuffer) Set(x uint, y uint, color uint) {
+	fb.Data[x+y*fb.Width] = color
+}
+
 // Given some image data, return a string that is the ppm of it
 func (fb *Framebuffer) ExportPPM() string {
 	var result strings.Builder

tinyrender1/main.go

@@ -1,8 +1,11 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"log"
+	"os"
+	"runtime/pprof" // For performance whatever
 )
 
 const (
@@ -10,9 +13,41 @@ const (
 	Height = 512
 )
 
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+// However flag works... idk
+var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+
 func main() {
 	log.Printf("Program start")
+
+	// Little section for doing cpu profiling. I guess that's all you have to do?
+	flag.Parse()
+	if *cpuprofile != "" {
+		log.Printf("CPU profiling requested, write to %s", *cpuprofile)
+		f, err := os.Create(*cpuprofile)
+		must(err)
+		defer f.Close()
+		err = pprof.StartCPUProfile(f)
+		must(err)
+		defer pprof.StopCPUProfile()
+	}
+
 	fb := NewFramebuffer(Width, Height)
+
+	log.Printf("Running render")
+
+	// Just draw a simple line
+	LineDumb(&fb, 0xFFFFFF, 100, 100, 350, 200)
+	LineDumb2(&fb, 0xFF0000, 120, 100, 200, 350)
+	LineDumb2(&fb, 0xFF0000, 350, 200, 100, 100) // backward first line
+
+	log.Printf("Exporting ppm to stdout")
 	fmt.Print(fb.ExportPPM())
+
 	log.Printf("Program end")
 }

tinyrender1/render.go

@@ -0,0 +1,21 @@
+package main
+
+// Draw a line using dumb
+func LineDumb(fb *Framebuffer, color uint, x0 uint, y0 uint, x1 uint, y1 uint) {
+	var t float32
+	for t = 0; t < 1; t += 0.01 {
+		// Very simple interpolation between x and y
+		x := x0 + uint(float32(x1-x0)*t)
+		y := y0 + uint(float32(y1-y0)*t)
+		fb.Set(x, y, color)
+	}
+}
+
+func LineDumb2(fb *Framebuffer, color uint, x0 uint, y0 uint, x1 uint, y1 uint) {
+	for x := x0; x < x1; x++ {
+		// For each pixel across, compute how far across we are and interpolate y
+		t := float32(x-x0) / float32(x1-x0)
+		y := uint(float32(y0)*(1-t) + float32(y1)*t)
+		fb.Set(x, y, color)
+	}
+}

tinyrender1/run.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+go build && ./tinyrender1 >image.ppm