(WIP) Getting started in 3d land

1 files changed, 21 insertions, 0 deletions

diff --git a/shared_cpp/mathlib.h b/shared_cpp/mathlib.h
index 3ed61cd..ec0ae87 100644
--- a/shared_cpp/mathlib.h
+++ b/shared_cpp/mathlib.h
@@ -87,6 +87,10 @@ struct Vector3 {
     float x = 0.f;
     float y = 0.f;
     float z = 0.f;
+
+    float length() {
+		return sqrtf(x * x + y * y + z * z);
+	}
 };
 
 struct Vector4 {
@@ -217,6 +221,21 @@ struct Mat4x4 {
         return inv;
     }
 
+	Mat4x4 getPerspectiveProjection(float near, float far, float fieldOfViewRadians, float aspectRatio) {
+		float halfFieldOfView = fieldOfViewRadians * 0.5f;
+		float top = tan(halfFieldOfView) * near;
+		float bottom = -top;
+		float right = top * aspectRatio;
+		float left = -right;
+
+		return {
+			{ (2 * near) / (right - left), 0, 0, 0,
+			  0, (2 * near) / (top - bottom), 0, 0,
+			  (right + left) / (right - left), (top + bottom) / (top - bottom), -(far + near) / (far - near), -1,
+			  0, 0, (-2 * far * near) / (far - near), 0 }
+		};
+	}
+
 	void print() {
 		printf("[ ");
 		for (int idx = 0; idx < 16; idx++) {
@@ -225,3 +244,5 @@ struct Mat4x4 {
 		printf(" ]\n");
 	}
 };
+
+