step

examples/core/2d_paint/main.go

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+package main
+
+import (
+	"os"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+const colorCount = 23
+
+func main() {
+	const screenWidth, screenHeight int32 = 800, 450
+
+	rl.InitWindow(screenWidth, screenHeight, "raypaint")
+
+	// Colors to choose from
+	var colors = [colorCount]rl.Color{
+		rl.RayWhite, rl.Yellow, rl.Gold, rl.Orange, rl.Pink, rl.Red, rl.Maroon, rl.Green, rl.Lime, rl.DarkGreen,
+		rl.SkyBlue, rl.Blue, rl.DarkBlue, rl.Purple, rl.Violet, rl.DarkPurple, rl.Beige, rl.Brown, rl.DarkBrown,
+		rl.LightGray, rl.Gray, rl.DarkGray, rl.Black,
+	}
+
+	// Define colorsRecs data (for every rectangle)
+	var colorRecs = [colorCount]rl.Rectangle{}
+
+	for i := 0; i < colorCount; i++ {
+		colorRecs[i].X = float32(10 + 30*i + 2*i)
+		colorRecs[i].Y = 10
+		colorRecs[i].Width = 30
+		colorRecs[i].Height = 30
+	}
+
+	colorSelected := 0
+	colorSelectedPrev := colorSelected
+	colorMouseHover := 0
+	brushSize := 20
+
+	var btnSaveRec = rl.Rectangle{750, 10, 40, 30}
+	btnSaveMouseHover := false
+	showSaveMessage := false
+	saveMessageCounter := 0
+
+	checkSaveHover := func() rl.Color {
+		if btnSaveMouseHover {
+			return rl.Red
+		}
+		return rl.Black
+	}
+
+	// Create a RenderTexture2D to use as a canvas
+	var target rl.RenderTexture2D = rl.LoadRenderTexture(screenWidth, screenHeight)
+
+	// Clear render texture before entering the game loop
+	rl.BeginTextureMode(target)
+	rl.ClearBackground(colors[0])
+	rl.EndTextureMode()
+
+	rl.SetTargetFPS(120)
+
+	// Main game loop
+	for !rl.WindowShouldClose() {
+		mousePos := rl.GetMousePosition()
+
+		// Move between colors with keys
+		if rl.IsKeyPressed(rl.KeyRight) {
+			colorSelected++
+		} else if rl.IsKeyPressed(rl.KeyLeft) {
+			colorSelected--
+		}
+
+		if colorSelected >= colorCount {
+			colorSelected = colorCount - 1
+		} else if colorSelected < 0 {
+			colorSelected = 0
+		}
+
+		// Choose color with mouse
+		for i := 0; i < colorCount; i++ {
+			if rl.CheckCollisionPointRec(mousePos, colorRecs[i]) {
+				colorMouseHover = i
+				break
+			} else {
+				colorMouseHover = -1
+			}
+		}
+
+		if colorMouseHover >= 0 && rl.IsMouseButtonPressed(rl.MouseLeftButton) {
+			colorSelected = colorMouseHover
+			colorSelectedPrev = colorSelected
+		}
+
+		// Change brush size
+		brushSize += int(rl.GetMouseWheelMove() * 5)
+		if brushSize < 2 {
+			brushSize = 2
+		}
+
+		if brushSize > 50 {
+			brushSize = 50
+		}
+
+		if rl.IsKeyPressed(rl.KeyC) {
+			// Clear render texture to clear color
+			rl.BeginTextureMode(target)
+			rl.ClearBackground(colors[0])
+			rl.EndTextureMode()
+		}
+
+		if rl.IsMouseButtonDown(rl.MouseLeftButton) || rl.GetGestureDetected() == rl.GestureDrag {
+			// Clear render texture to clear color
+			rl.BeginTextureMode(target)
+
+			if mousePos.Y > 50 {
+				rl.DrawCircle(int32(mousePos.X), int32(mousePos.Y), float32(brushSize), colors[colorSelected])
+			}
+
+			rl.EndTextureMode()
+		}
+
+		if rl.IsMouseButtonDown(rl.MouseRightButton) {
+			colorSelected = 0
+
+			// Erase circle from render texture
+			rl.BeginTextureMode(target)
+
+			if mousePos.Y > 50 {
+				rl.DrawCircle(int32(mousePos.X), int32(mousePos.Y), float32(brushSize), colors[0])
+			}
+
+			rl.EndTextureMode()
+		} else {
+			colorSelected = colorSelectedPrev
+		}
+
+		if rl.CheckCollisionPointRec(mousePos, btnSaveRec) {
+			btnSaveMouseHover = true
+		} else {
+			btnSaveMouseHover = false
+		}
+
+		if btnSaveMouseHover && rl.IsMouseButtonReleased(rl.MouseLeftButton) || rl.IsKeyPressed(rl.KeyS) {
+			image := rl.LoadImageFromTexture(target.Texture)
+			rl.ImageFlipVertical(*&image)
+			rl.ExportImage(*image, "export.png")
+			rl.UnloadImage(image)
+			showSaveMessage = true
+		}
+
+		if showSaveMessage {
+			// On saving, show a full screen message for 2 seconds
+			saveMessageCounter++
+			if saveMessageCounter > 240 {
+				showSaveMessage = false
+				saveMessageCounter = 0
+			}
+		}
+
+		// Draw
+		//----------------------------------------------------------------------------------
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.RayWhite)
+
+		// NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
+		rl.DrawTextureRec(target.Texture, rl.Rectangle{0, 0, float32(target.Texture.Width), float32(-target.Texture.Height)}, rl.Vector2{0, 0}, rl.White)
+
+		if mousePos.Y > 50 {
+			if rl.IsMouseButtonDown(rl.MouseRightButton) {
+				rl.DrawCircleLines(int32(mousePos.X), int32(mousePos.Y), float32(brushSize), rl.Gray)
+			} else {
+				rl.DrawCircle(rl.GetMouseX(), rl.GetMouseY(), float32(brushSize), colors[colorSelected])
+			}
+		}
+
+		// Draw top panel
+		rl.DrawRectangle(0, 0, int32(rl.GetScreenWidth()), 50, rl.RayWhite)
+		rl.DrawLine(0, 50, int32(rl.GetScreenWidth()), 50, rl.LightGray)
+
+		// Draw color selection rectangles
+		for i := 0; i < colorCount; i++ {
+			rl.DrawRectangleRec(colorRecs[i], colors[i])
+		}
+
+		rl.DrawRectangleLines(10, 10, 30, 30, rl.LightGray)
+
+		if colorMouseHover >= 0 {
+			rl.DrawRectangleRec(colorRecs[colorMouseHover], rl.Fade(rl.White, 0.0))
+		}
+
+		rl.DrawRectangleLinesEx(rl.Rectangle{
+			colorRecs[colorSelected].X - 2, colorRecs[colorSelected].Y - 2, colorRecs[colorSelected].Width + 4, colorRecs[colorSelected].Height + 4,
+		}, 2, rl.Black)
+
+		// Draw save image button
+		rl.DrawRectangleLinesEx(btnSaveRec, 2, checkSaveHover())
+		rl.DrawText("SAVE!", 755, 20, 10, checkSaveHover())
+
+		if showSaveMessage {
+			rl.DrawRectangle(0, 0, int32(rl.GetScreenWidth()), int32(rl.GetScreenHeight()), rl.Fade(rl.RayWhite, 0.8))
+			rl.DrawRectangle(0, 150, int32(rl.GetScreenWidth()), 80, rl.Black)
+			rl.DrawText("IMAGE SAVED:  export.png", 150, 180, 20, rl.RayWhite)
+		}
+
+		rl.EndDrawing()
+
+	}
+
+	// De-Initialization
+	//--------------------------------------------------------------------------------------
+	rl.UnloadRenderTexture(target)
+
+	rl.CloseWindow()
+
+	os.Exit(0)
+
+}