[glfw] Added IK following example

spine-glfw/CMakeLists.txt

@@ -78,6 +78,14 @@ target_link_libraries(spine-glfw-physics LINK_PUBLIC spine-glfw)
 target_link_libraries(spine-glfw-physics PRIVATE glbinding::glbinding)
 set_property(TARGET spine-glfw-physics PROPERTY VS_DEBUGGER_WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/spine-glfw")
 
+# IK Following example
+add_executable(spine-glfw-ik-following example/ik-following.cpp)
+target_link_libraries(spine-glfw-ik-following PRIVATE glfw)
+target_link_libraries(spine-glfw-ik-following PRIVATE OpenGL::GL)
+target_link_libraries(spine-glfw-ik-following LINK_PUBLIC spine-glfw)
+target_link_libraries(spine-glfw-ik-following PRIVATE glbinding::glbinding)
+set_property(TARGET spine-glfw-ik-following PROPERTY VS_DEBUGGER_WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/spine-glfw")
+
 # copy data to build directory
 add_custom_command(TARGET spine-glfw-example PRE_BUILD
         COMMAND ${CMAKE_COMMAND} -E copy_directory
@@ -86,3 +94,7 @@ add_custom_command(TARGET spine-glfw-example PRE_BUILD
 add_custom_command(TARGET spine-glfw-physics PRE_BUILD
         COMMAND ${CMAKE_COMMAND} -E copy_directory
         ${CMAKE_CURRENT_LIST_DIR}/data $<TARGET_FILE_DIR:spine-glfw-physics>/data)
+
+add_custom_command(TARGET spine-glfw-ik-following PRE_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_directory
+        ${CMAKE_CURRENT_LIST_DIR}/data $<TARGET_FILE_DIR:spine-glfw-ik-following>/data)

spine-glfw/example/ik-following.cpp

@@ -0,0 +1,170 @@
+/******************************************************************************
+ * Spine Runtimes License Agreement
+ * Last updated April 5, 2025. Replaces all prior versions.
+ *
+ * Copyright (c) 2013-2025, Esoteric Software LLC
+ *
+ * Integration of the Spine Runtimes into software or otherwise creating
+ * derivative works of the Spine Runtimes is permitted under the terms and
+ * conditions of Section 2 of the Spine Editor License Agreement:
+ * http://esotericsoftware.com/spine-editor-license
+ *
+ * Otherwise, it is permitted to integrate the Spine Runtimes into software
+ * or otherwise create derivative works of the Spine Runtimes (collectively,
+ * "Products"), provided that each user of the Products must obtain their own
+ * Spine Editor license and redistribution of the Products in any form must
+ * include this license and copyright notice.
+ *
+ * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
+ * BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *****************************************************************************/
+
+#include <glbinding/glbinding.h>
+#include <glbinding/gl/gl.h>
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+#include <iostream>
+#include <spine-glfw.h>
+
+using namespace spine;
+
+int width = 800, height = 600;
+
+// Mouse position for IK targeting
+double mouseX = 400, mouseY = 300;
+Skeleton* ikSkeleton = nullptr;
+
+void cursor_position_callback(GLFWwindow* window, double xpos, double ypos) {
+	mouseX = xpos;
+	mouseY = ypos;
+}
+
+GLFWwindow *init_glfw() {
+	if (!glfwInit()) {
+		std::cerr << "Failed to initialize GLFW" << std::endl;
+		return nullptr;
+	}
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+	GLFWwindow *window = glfwCreateWindow(width, height, "spine-glfw IK Following - Move mouse to aim", NULL, NULL);
+	if (!window) {
+		std::cerr << "Failed to create GLFW window" << std::endl;
+		glfwTerminate();
+		return nullptr;
+	}
+	glfwMakeContextCurrent(window);
+	glbinding::initialize(glfwGetProcAddress);
+
+	// Set mouse callback
+	glfwSetCursorPosCallback(window, cursor_position_callback);
+
+	return window;
+}
+
+int main() {
+	// Initialize GLFW and glbinding
+	GLFWwindow *window = init_glfw();
+	if (!window) return -1;
+
+	// We use a y-down coordinate system, see renderer_set_viewport_size()
+	Bone::setYDown(true);
+
+	// Load the atlas and the skeleton data
+	GlTextureLoader textureLoader;
+	Atlas *atlas = new Atlas("data/spineboy-pma.atlas", &textureLoader);
+	SkeletonBinary binary(*atlas);
+	SkeletonData *skeletonData = binary.readSkeletonDataFile("data/spineboy-pro.skel");
+
+	// Create a skeleton from the data
+	Skeleton skeleton(*skeletonData);
+	skeleton.setScaleX(0.5);
+	skeleton.setScaleY(0.5);
+	skeleton.setupPose();
+
+	// Position the skeleton on the left side like in the Flutter example
+	skeleton.setPosition(200, height / 2 + 150);
+
+	// Set the global skeleton pointer for IK
+	ikSkeleton = &skeleton;
+
+	// Create an AnimationState to drive animations on the skeleton
+	AnimationStateData animationStateData(*skeletonData);
+	AnimationState animationState(animationStateData);
+
+	// Set the walk animation on track 0 and aim animation on track 1
+	animationState.setAnimation(0, "walk", true);
+	animationState.setAnimation(1, "aim", true);
+
+	// Create the renderer and set the viewport size to match the window size
+	renderer_t *renderer = renderer_create();
+	renderer_set_viewport_size(renderer, width, height);
+
+	// Rendering loop
+	double lastTime = glfwGetTime();
+	while (!glfwWindowShouldClose(window)) {
+		// Calculate the delta time in seconds
+		double currTime = glfwGetTime();
+		float delta = currTime - lastTime;
+		lastTime = currTime;
+
+		// Update and apply the animation state to the skeleton
+		animationState.update(delta);
+		animationState.apply(skeleton);
+
+		// Update the skeleton time (used for physics)
+		skeleton.update(delta);
+
+		// Update the crosshair bone position based on mouse position
+		Bone* crosshairBone = skeleton.findBone("crosshair");
+		if (crosshairBone != nullptr) {
+			Bone* parent = crosshairBone->getParent();
+			if (parent != nullptr) {
+				// Convert mouse position to world coordinates
+				float worldX = mouseX;
+				float worldY = mouseY;
+
+				// Convert world position to parent's local space
+				float localX, localY;
+				parent->getAppliedPose().worldToLocal(worldX, worldY, localX, localY);
+
+				// Set the crosshair bone position in its applied pose
+				crosshairBone->getAppliedPose().setX(localX);
+				crosshairBone->getAppliedPose().setY(localY);
+			}
+		}
+
+		// Calculate the new pose
+		skeleton.updateWorldTransform(spine::Physics_Update);
+
+		// Clear the screen
+		gl::glClear(gl::GL_COLOR_BUFFER_BIT);
+
+		// Render the skeleton in its current pose
+		renderer_draw(renderer, &skeleton, true);
+
+		// Present the rendering results and poll for events
+		glfwSwapBuffers(window);
+		glfwPollEvents();
+	}
+
+	// Clear the IK skeleton pointer
+	ikSkeleton = nullptr;
+
+	// Dispose everything
+	renderer_dispose(renderer);
+	delete skeletonData;
+	delete atlas;
+
+	// Kill the window and GLFW
+	glfwTerminate();
+	return 0;
+}