From: Matthew Owens <matthew@owens.tech>
Date: Fri, 20 Nov 2020 12:25:01 +0000 (+0000)
Subject: added m4_transform_vec
X-Git-Url: https://git.owens.tech///git?a=commitdiff_plain;h=refs%2Fheads%2Ffeature%2Fpicking;p=forks%2Fsingle-header-file-c-libs.git

added m4_transform_vec
---

diff --git a/math_3d.h b/math_3d.h
index 05f71af..2a049fc 100644
--- a/math_3d.h
+++ b/math_3d.h
@@ -210,7 +210,7 @@ static inline mat4_t m4_mul          (mat4_t a, mat4_t b);
 			  mat4_t m4_invert(mat4_t matrix);
               vec3_t m4_mul_pos      (mat4_t matrix, vec3_t position);
               vec3_t m4_mul_dir      (mat4_t matrix, vec3_t direction);
-			  //TODO: implement m4_transform_vec(mat4_t matrix, vec4_t vec);
+			  vec4_t m4_transform_vec(mat4_t matrix, vec4_t vec);
 			  //TODO: ref: https://github.com/LWJGL/lwjgl/blob/2df01dd762e20ca0871edb75daf670ccacc89b60/src/java/org/lwjgl/util/vector/Matrix4f.java
 
               void   m4_print        (mat4_t matrix);
@@ -751,4 +751,21 @@ mat4_t m4_invert(mat4_t m)
 	return inv;
 }
 
+vec4_t m4_transform_vec(mat4_t m, vec4_t v)
+{
+	vec4_t ret = {0};
+
+	float x = m.m00 * v.x + m.m10 * v.y + m.m20 * v.z + m.m30 * v.w;
+	float y = m.m01 * v.x + m.m11 * v.y + m.m21 * v.z + m.m31 * v.w;
+	float z = m.m02 * v.x + m.m12 * v.y + m.m22 * v.z + m.m32 * v.w;
+	float w = m.m03 * v.x + m.m13 * v.y + m.m23 * v.z + m.m33 * v.w;
+
+	ret.x = x;
+	ret.y = y;
+	ret.z = z;
+	ret.w = w;
+
+	return ret;
+}
+
 #endif // MATH_3D_IMPLEMENTATION