Initial commit

render/engine.go

@@ -0,0 +1,47 @@
+package render
+
+import (
+	"github.com/pnx/go-raytracer/graphics"
+	"github.com/pnx/go-raytracer/math"
+	"github.com/pnx/go-raytracer/world"
+)
+
+func DrawColumn(ctx *graphics.Context, x int32, wall_h int32, color math.Color) {
+	if wall_h < ctx.Height() {
+		y1 := (ctx.Height() - wall_h) / 2
+		y2 := (ctx.Height() + wall_h) / 2
+
+		// Top
+		// renderer.SetDrawColor(90, 90, 0, 255)
+		ctx.DrawLine(x, 0, int32(x), y1, math.Color{R: 90, G: 90, B: 0, A: 255})
+
+		// // Middle
+		// renderer.SetDrawColor(color.R, color.G, color.B, color.A)
+		ctx.DrawLine(x, y1, int32(x), y2, color)
+
+		// Bottom
+		if y2 < ctx.Height() {
+			// renderer.SetDrawColor(50, 50, 50, 255)
+			ctx.DrawLine(x, y2, int32(x), ctx.Height(), math.Color{R: 50, G: 50, B: 50, A: 255})
+		}
+		return
+	}
+
+	// ctx.SetDrawColor(color.R, color.G, color.B, color.A)
+	ctx.DrawLine(x, 0, int32(x), ctx.Height(), color)
+}
+
+func DrawScene(ctx *graphics.Context, camera math.Transform, level *world.Level, colorMap []math.Color) {
+	for x := range ctx.Width() {
+		result := CastRay(camera, level, int(x), int(ctx.Width()))
+		lineHeight := int(float64(ctx.Height()) / result.Distance)
+
+		color := colorMap[level.Cell(int(result.Cell.X), int(result.Cell.Y))-1]
+
+		if result.Side > 0 {
+			color = color.Shade(2)
+		}
+
+		DrawColumn(ctx, int32(x), int32(lineHeight), color)
+	}
+}