From 52d7270ba0a532a759a87ee29043c136811b8736 Mon Sep 17 00:00:00 2001
From: Jonathan Bradley <jcb@pikum.xyz>
Date: Tue, 24 Oct 2023 10:48:22 -0400
Subject: add MathHelpers for glm and bullet translations

---
 src/math-helpers.cpp | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/math-helpers.hpp | 15 +++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 src/math-helpers.cpp
 create mode 100644 src/math-helpers.hpp

(limited to 'src')

diff --git a/src/math-helpers.cpp b/src/math-helpers.cpp
new file mode 100644
index 0000000..ebcd719
--- /dev/null
+++ b/src/math-helpers.cpp
@@ -0,0 +1,49 @@
+#include "math-helpers.hpp"
+
+// https://pybullet.org/Bullet/phpBB3/viewtopic.php?t=11462
+
+void GlmToBullet(const glm::vec3 &vec, btVector3 &btVec) {
+	btVec.setX(vec.x);
+	btVec.setY(vec.y);
+	btVec.setZ(vec.z);
+}
+
+void GlmToBullet(const glm::quat &quat, btQuaternion &btQuat) {
+	btQuat.setX(quat.x);
+	btQuat.setY(quat.y);
+	btQuat.setZ(quat.z);
+	btQuat.setW(quat.w);
+}
+
+void BulletToGlm(const btVector3 &vec, glm::vec3 &glmVec) {
+	glmVec.x = vec.getX();
+	glmVec.y = vec.getY();
+	glmVec.z = vec.getZ();
+}
+
+void BulletToGlm(const btQuaternion &quat, glm::quat &glmQuat) {
+	glmQuat.x = quat.getX();
+	glmQuat.y = quat.getY();
+	glmQuat.z = quat.getZ();
+	glmQuat.w = quat.getW();
+}
+
+void BulletToGlm(const btTransform &trans, glm::mat4 &glmMat4) {
+	const btMatrix3x3& basis = trans.getBasis();
+	// rotation
+	for (int r = 0; r < 3; r++) {
+		for (int c = 0; c < 3; c++) {
+			glmMat4[c][r] = basis[r][c];
+		}
+	} // translation
+	btVector3 origin = trans.getOrigin();
+	glmMat4[3][0] = origin.getX();
+	glmMat4[3][1] = origin.getY();
+	glmMat4[3][2] = origin.getZ();
+	// unit scale
+	glmMat4[0][3] = 0.0f;
+	glmMat4[1][3] = 0.0f;
+	glmMat4[2][3] = 0.0f;
+	glmMat4[3][3] = 1.0f;
+}
+
diff --git a/src/math-helpers.hpp b/src/math-helpers.hpp
new file mode 100644
index 0000000..9276df8
--- /dev/null
+++ b/src/math-helpers.hpp
@@ -0,0 +1,15 @@
+#ifndef PKE_MATH_HELPERS_HPP
+#define PKE_MATH_HELPERS_HPP
+
+#include "vendor/glm_include.hpp"
+#include <LinearMath/btQuaternion.h>
+#include <LinearMath/btVector3.h>
+#include <LinearMath/btTransform.h>
+
+void GlmToBullet(const glm::vec3 &vec, btVector3 &btVec);
+void GlmToBullet(const glm::quat &quat, btQuaternion &btQuat);
+void BulletToGlm(const btVector3 &vec, glm::vec3 &glmVec);
+void BulletToGlm(const btQuaternion &quat, glm::quat &glmQuat);
+void BulletToGlm(const btTransform &trans, glm::mat4 &glmMat4);
+
+#endif /* PKE_MATH_HELPERS_HPP */
-- 
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