Adding gif and sprite animation examples.

-Added new UpdateTextureUnsafe method to support it.

examples/textures/textures_gif_player/main.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"fmt"
+	"unsafe"
+
+	rl "github.com/gen2brain/raylib-go/raylib"
+)
+
+func main() {
+
+	const MAX_FRAME_DELAY int32 = 20
+	const MIN_FRAME_DELAY int32 = 1
+
+	// Initialization
+	const screenWidth int32 = 800
+	const screenHeight int32 = 450
+
+	rl.InitWindow(screenWidth, screenHeight, "raylib [textures] example - gif playing")
+
+	var animFrames int32 = 0
+
+	// Load all GIF animation frames into a single Image
+	// NOTE: GIF data is always loaded as RGBA (32bit) by default
+	// NOTE: Frames are just appended one after another in image.data memory
+	var imScarfyAnim *rl.Image = rl.LoadImageAnim("scarfy_run.gif", &animFrames)
+
+	// Load texture from image
+	// NOTE: We will update this texture when required with next frame data
+	// WARNING: It's not recommended to use this technique for sprites animation,
+	// use spritesheets instead, like illustrated in textures_sprite_anim example
+	var texScarfyAnim rl.Texture2D = rl.LoadTextureFromImage(imScarfyAnim)
+
+	var nextFrameDataOffset uint32 = 0 // Current byte offset to next frame in image.data
+
+	var currentAnimFrame int32 = 0 // Current animation frame to load and draw
+	var frameDelay int32 = 8       // Frame delay to switch between animation frames
+	var frameCounter int32 = 0     // General frames counter
+
+	rl.SetTargetFPS(60) // Set our game to run at 60 frames-per-second
+
+	// Main game loop
+	for !rl.WindowShouldClose() { // Detect window close button or ESC key
+		// Update
+		frameCounter++
+		if frameCounter >= frameDelay {
+			// Move to next frame
+			// NOTE: If final frame is reached we return to first frame
+			currentAnimFrame++
+			if currentAnimFrame >= animFrames {
+				currentAnimFrame = 0
+			}
+
+			// Get memory offset position for next frame data in image.data
+			nextFrameDataOffset = uint32(imScarfyAnim.Width * imScarfyAnim.Height * int32(4) * currentAnimFrame)
+
+			// Update GPU texture data with next frame image data
+			// WARNING: Data size (frame size) and pixel format must match already created texture
+			// here we needed to make the Data as public
+			rl.UpdateTextureUnsafe(texScarfyAnim, unsafe.Pointer(uintptr(imScarfyAnim.Data)+uintptr(nextFrameDataOffset)))
+
+			frameCounter = 0
+		}
+
+		// Control frames delay
+		if rl.IsKeyPressed(rl.KeyRight) {
+			frameDelay++
+		} else if rl.IsKeyPressed(rl.KeyLeft) {
+			frameDelay--
+		}
+
+		if frameDelay > MAX_FRAME_DELAY {
+			frameDelay = MAX_FRAME_DELAY
+		} else if frameDelay < MIN_FRAME_DELAY {
+			frameDelay = MIN_FRAME_DELAY
+		}
+
+		// Draw
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.RayWhite)
+
+		rl.DrawText(fmt.Sprintf("TOTAL GIF FRAMES:  %02d", animFrames), 50, 30, 20, rl.LightGray)
+		rl.DrawText(fmt.Sprintf("CURRENT FRAME: %02d", currentAnimFrame), 50, 60, 20, rl.Gray)
+		rl.DrawText(fmt.Sprintf("CURRENT FRAME IMAGE.DATA OFFSET: %02d", nextFrameDataOffset), 50, 90, 20, rl.Gray)
+
+		rl.DrawText("FRAMES DELAY: ", 100, 305, 10, rl.DarkGray)
+		rl.DrawText(fmt.Sprintf("%02d frames", frameDelay), 620, 305, 10, rl.DarkGray)
+		rl.DrawText("PRESS RIGHT/LEFT KEYS to CHANGE SPEED!", 290, 350, 10, rl.DarkGray)
+
+		for i := int32(0); i < MAX_FRAME_DELAY; i++ {
+			if i < frameDelay {
+				rl.DrawRectangle(190+21*i, 300, 20, 20, rl.Red)
+			}
+			rl.DrawRectangleLines(190+21*i, 300, 20, 20, rl.Maroon)
+		}
+
+		rl.DrawTexture(texScarfyAnim, int32(rl.GetScreenWidth()/2)-texScarfyAnim.Width/2, 140, rl.White)
+
+		rl.DrawText("(c) Scarfy sprite by Eiden Marsal", screenWidth-200, screenHeight-20, 10, rl.Gray)
+
+		rl.EndDrawing()
+	}
+
+	// De-Initialization
+	defer rl.UnloadTexture(texScarfyAnim) // Unload texture
+	defer rl.UnloadImage(imScarfyAnim)    // Unload image (contains all frames)
+
+	defer rl.CloseWindow() // Close window and OpenGL context
+
+}