From e8e2a99e5b3b553e08e60b98201453ced403b3c4 Mon Sep 17 00:00:00 2001
From: bjorn <tie.372@gmail.com>
Date: Wed, 18 Jan 2017 00:51:09 -0800
Subject: [PATCH] Finish internal math library;

---
 src/graphics/graphics.c |  20 ++-
 src/graphics/graphics.h |   2 +-
 src/graphics/model.c    |  21 ++-
 src/graphics/model.h    |   3 +-
 src/graphics/shader.c   |   4 +-
 src/graphics/shader.h   |   2 +-
 src/graphics/texture.c  |   4 +-
 src/headset/vive.c      |  10 +-
 src/loaders/model.c     |   2 +-
 src/math/mat4.c         | 257 +++++++++++++++++++++++++++++++++++++
 src/math/mat4.h         |  16 +++
 src/math/math.h         |   9 ++
 src/math/quat.c         | 144 +++++++++++++++++++++
 src/math/quat.h         |  12 ++
 src/math/vec3.c         |  40 +++++-
 src/math/vec3.h         |  12 +-
 src/matrix.c            | 276 ----------------------------------------
 src/matrix.h            |  26 ----
 18 files changed, 520 insertions(+), 340 deletions(-)
 create mode 100644 src/math/mat4.c
 create mode 100644 src/math/mat4.h
 create mode 100644 src/math/math.h
 create mode 100644 src/math/quat.c
 create mode 100644 src/math/quat.h
 delete mode 100644 src/matrix.c
 delete mode 100644 src/matrix.h

diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 7f005a03..b583ae94 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -1,5 +1,6 @@
 #include "graphics/graphics.h"
 #include "loaders/texture.h"
+#include "math/quat.h"
 #include "util.h"
 #include "glfw.h"
 #define _USE_MATH_DEFINES
@@ -39,7 +40,7 @@ void lovrGraphicsDestroy() {
   lovrGraphicsSetShader(NULL);
   glUseProgram(0);
   for (int i = 0; i < MAX_TRANSFORMS; i++) {
-    mat4_deinit(state.transforms[i]);
+    free(state.transforms[i]);
   }
   for (int i = 0; i < MAX_CANVASES; i++) {
     free(state.canvases[i]);
@@ -203,7 +204,7 @@ mat4 lovrGraphicsGetProjection() {
 void lovrGraphicsSetProjection(float near, float far, float fov) {
   int width, height;
   glfwGetWindowSize(window, &width, &height);
-  mat4_setPerspective(state.canvases[state.canvas]->projection, near, far, fov, (float) width / height);
+  mat4_perspective(state.canvases[state.canvas]->projection, near, far, fov, (float) width / height);
 }
 
 void lovrGraphicsSetProjectionRaw(mat4 projection) {
@@ -333,7 +334,7 @@ int lovrGraphicsPop() {
 }
 
 void lovrGraphicsOrigin() {
-  mat4_setIdentity(state.transforms[state.transform]);
+  mat4_identity(state.transforms[state.transform]);
 }
 
 void lovrGraphicsTranslate(float x, float y, float z) {
@@ -341,7 +342,10 @@ void lovrGraphicsTranslate(float x, float y, float z) {
 }
 
 void lovrGraphicsRotate(float angle, float ax, float ay, float az) {
-  mat4_rotate(state.transforms[state.transform], angle, ax, ay, az);
+  float rotation[4];
+  float axis[3] = { ax, ay, az };
+  quat_fromAngleAxis(rotation, angle, axis);
+  mat4_rotate(state.transforms[state.transform], rotation);
 }
 
 void lovrGraphicsScale(float x, float y, float z) {
@@ -349,12 +353,16 @@ void lovrGraphicsScale(float x, float y, float z) {
 }
 
 void lovrGraphicsTransform(float tx, float ty, float tz, float sx, float sy, float sz, float angle, float ax, float ay, float az) {
+  float rotation[4];
+  float axis[3] = { ax, ay, az };
+  quat_fromAngleAxis(rotation, angle, axis);
 
   // M *= T * S * R
   float transform[16];
-  mat4_setTranslation(transform, tx, ty, tz);
+  mat4_identity(transform);
+  mat4_translate(transform, tx, ty, tz);
   mat4_scale(transform, sx, sy, sz);
-  mat4_rotate(transform, angle, ax, ay, az);
+  mat4_rotate(transform, rotation);
   lovrGraphicsMatrixTransform(transform);
 }
 
diff --git a/src/graphics/graphics.h b/src/graphics/graphics.h
index 2af33d15..22f77a85 100644
--- a/src/graphics/graphics.h
+++ b/src/graphics/graphics.h
@@ -3,7 +3,7 @@
 #include "graphics/shader.h"
 #include "graphics/skybox.h"
 #include "graphics/texture.h"
-#include "matrix.h"
+#include "math/mat4.h"
 
 #ifndef LOVR_GRAPHICS_TYPES
 #define LOVR_GRAPHICS_TYPES
diff --git a/src/graphics/model.c b/src/graphics/model.c
index 91a8532e..d4362051 100644
--- a/src/graphics/model.c
+++ b/src/graphics/model.c
@@ -3,12 +3,10 @@
 #include <stdlib.h>
 
 static void visitNode(ModelData* modelData, ModelNode* node, mat4 transform, vec_float_t* vertices, vec_uint_t* indices) {
-  mat4 newTransform;
+  mat4 newTransform = mat4_init();
 
-  if (!transform) {
-    newTransform = mat4_init();
-  } else {
-    newTransform = mat4_copy(transform);
+  if (transform) {
+    mat4_set(newTransform, transform);
   }
 
   mat4_multiply(newTransform, node->transform);
@@ -23,15 +21,14 @@ static void visitNode(ModelData* modelData, ModelNode* node, mat4 transform, vec
     for (int v = 0; v < mesh->vertices.length; v++) {
       ModelVertex vertex = mesh->vertices.data[v];
 
-      float transformedVertex[4] = {
+      float vec[3] = {
         vertex.x,
         vertex.y,
-        vertex.z,
-        1.f
+        vertex.z
       };
 
-      mat4_multiplyVector(newTransform, transformedVertex);
-      vec_pusharr(vertices, transformedVertex, 3);
+      vec3_transform(vec, newTransform);
+      vec_pusharr(vertices, vec, 3);
 
       if (modelData->hasNormals) {
         ModelVertex normal = mesh->normals.data[v];
@@ -60,7 +57,7 @@ static void visitNode(ModelData* modelData, ModelNode* node, mat4 transform, vec
     visitNode(modelData, node->children.data[c], newTransform, vertices, indices);
   }
 
-  mat4_deinit(newTransform);
+  free(newTransform);
 }
 
 Model* lovrModelCreate(ModelData* modelData) {
@@ -136,7 +133,7 @@ void lovrModelDataDestroy(ModelData* modelData) {
   while (nodes.length > 0) {
     ModelNode* node = vec_first(&nodes);
     vec_extend(&nodes, &node->children);
-    mat4_deinit(node->transform);
+    free(node->transform);
     vec_deinit(&node->meshes);
     vec_deinit(&node->children);
     vec_splice(&nodes, 0, 1);
diff --git a/src/graphics/model.h b/src/graphics/model.h
index a8894827..835fda52 100644
--- a/src/graphics/model.h
+++ b/src/graphics/model.h
@@ -1,6 +1,7 @@
 #include "graphics/buffer.h"
 #include "graphics/texture.h"
-#include "matrix.h"
+#include "math/mat4.h"
+#include "math/vec3.h"
 #include "glfw.h"
 #include "util.h"
 #include "vendor/vec/vec.h"
diff --git a/src/graphics/shader.c b/src/graphics/shader.c
index 37d0f84f..f3883b41 100644
--- a/src/graphics/shader.c
+++ b/src/graphics/shader.c
@@ -175,8 +175,8 @@ Shader* lovrShaderCreate(const char* vertexSource, const char* fragmentSource) {
 void lovrShaderDestroy(const Ref* ref) {
   Shader* shader = containerof(ref, Shader);
   glDeleteProgram(shader->id);
-  mat4_deinit(shader->transform);
-  mat4_deinit(shader->projection);
+  free(shader->transform);
+  free(shader->projection);
   map_deinit(&shader->uniforms);
   free(shader);
 }
diff --git a/src/graphics/shader.h b/src/graphics/shader.h
index 30dd02ab..751062f1 100644
--- a/src/graphics/shader.h
+++ b/src/graphics/shader.h
@@ -1,5 +1,5 @@
 #include "glfw.h"
-#include "matrix.h"
+#include "math/mat4.h"
 #include "vendor/map/map.h"
 #include "util.h"
 
diff --git a/src/graphics/texture.c b/src/graphics/texture.c
index 4e93e5f0..dc1fbe41 100644
--- a/src/graphics/texture.c
+++ b/src/graphics/texture.c
@@ -109,7 +109,7 @@ void lovrTextureBindFramebuffer(Texture* texture) {
 
   if (texture->projection == PROJECTION_ORTHOGRAPHIC) {
     float projection[16];
-    mat4_setOrthographic(projection, 0, w, 0, h, -1, 1);
+    mat4_orthographic(projection, 0, w, 0, h, -1, 1);
     lovrGraphicsSetProjectionRaw(projection);
   } else if (texture->projection == PROJECTION_PERSPECTIVE) {
     mat4 projection = lovrGraphicsGetProjection();
@@ -122,7 +122,7 @@ void lovrTextureBindFramebuffer(Texture* texture) {
     float far = k * near;
     float fov = 2.f * atan(1.f / b);
     float newProjection[16];
-    mat4_setPerspective(newProjection, near, far, fov, aspect);
+    mat4_perspective(newProjection, near, far, fov, aspect);
     lovrGraphicsSetProjectionRaw(newProjection);
   }
 }
diff --git a/src/headset/vive.c b/src/headset/vive.c
index 322deb10..2b4b2ab8 100644
--- a/src/headset/vive.c
+++ b/src/headset/vive.c
@@ -2,6 +2,8 @@
 #include "event/event.h"
 #include "graphics/graphics.h"
 #include "loaders/texture.h"
+#include "math/mat4.h"
+#include "math/quat.h"
 #include "util.h"
 #include <stdlib.h>
 #include <stdint.h>
@@ -265,7 +267,9 @@ void viveGetOrientation(void* headset, float* w, float* x, float* y, float *z) {
   }
 
   float matrix[16];
-  mat4_getRotation(mat4_fromMat44(matrix, pose.mDeviceToAbsoluteTracking.m), w, x, y, z);
+  float rotation[4];
+  mat4_toQuat(mat4_fromMat44(matrix, pose.mDeviceToAbsoluteTracking.m), rotation);
+  quat_toAngleAxis(rotation, w, x, y, z);
 }
 
 void viveGetVelocity(void* headset, float* x, float* y, float* z) {
@@ -349,7 +353,9 @@ void viveControllerGetOrientation(void* headset, Controller* controller, float*
   }
 
   float matrix[16];
-  mat4_getRotation(mat4_fromMat44(matrix, pose.mDeviceToAbsoluteTracking.m), w, x, y, z);
+  float rotation[4];
+  mat4_toQuat(mat4_fromMat44(matrix, pose.mDeviceToAbsoluteTracking.m), rotation);
+  quat_toAngleAxis(rotation, w, x, y, z);
 }
 
 float viveControllerGetAxis(void* headset, Controller* controller, ControllerAxis axis) {
diff --git a/src/loaders/model.c b/src/loaders/model.c
index a0e3751f..b06a9a7f 100644
--- a/src/loaders/model.c
+++ b/src/loaders/model.c
@@ -9,7 +9,7 @@ static void assimpNodeTraversal(ModelNode* node, struct aiNode* assimpNode) {
   // Transform
   struct aiMatrix4x4 m = assimpNode->mTransformation;
   aiTransposeMatrix4(&m);
-  node->transform = mat4_copy((float*) &m);
+  node->transform = mat4_set(mat4_init(), (float*) &m);
 
   // Meshes
   vec_init(&node->meshes);
diff --git a/src/math/mat4.c b/src/math/mat4.c
new file mode 100644
index 00000000..0be059ae
--- /dev/null
+++ b/src/math/mat4.c
@@ -0,0 +1,257 @@
+#include "math/mat4.h"
+#include "util.h"
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+// m0 m4 m8  m12
+// m1 m5 m9  m13
+// m2 m6 m10 m14
+// m3 m7 m11 m15
+
+mat4 mat4_init() {
+  mat4 m = malloc(16 * sizeof(float));
+  return mat4_identity(m);
+}
+
+mat4 mat4_fromMat34(mat4 m, float (*n)[4]) {
+  m[0] = n[0][0];
+  m[1] = n[1][0];
+  m[2] = n[2][0];
+  m[3] = 0.f;
+  m[4] = n[0][1];
+  m[5] = n[1][1];
+  m[6] = n[2][1];
+  m[7] = 0.f;
+  m[8] = n[0][2];
+  m[9] = n[1][2];
+  m[10] = n[2][2];
+  m[11] = 0.f;
+  m[12] = n[0][3];
+  m[13] = n[1][3];
+  m[14] = n[2][3];
+  m[15] = 1.f;
+  return m;
+}
+
+mat4 mat4_fromMat44(mat4 m, float (*n)[4]) {
+  m[0] = n[0][0];
+  m[1] = n[1][0];
+  m[2] = n[2][0];
+  m[3] = n[3][0];
+  m[4] = n[0][1];
+  m[5] = n[1][1];
+  m[6] = n[2][1];
+  m[7] = n[3][1];
+  m[8] = n[0][2];
+  m[9] = n[1][2];
+  m[10] = n[2][2];
+  m[11] = n[3][2];
+  m[12] = n[0][3];
+  m[13] = n[1][3];
+  m[14] = n[2][3];
+  m[15] = n[3][3];
+  return m;
+}
+
+mat4 mat4_set(mat4 m, mat4 n) {
+  return memcpy(m, n, 16 * sizeof(float));
+}
+
+mat4 mat4_identity(mat4 m) {
+  memset(m, 0, 16 * sizeof(float));
+  m[0] = m[5] = m[10] = m[15] = 1.f;
+  return m;
+}
+
+mat4 mat4_transpose(mat4 m) {
+  float m1 = m[1];
+  float m2 = m[2];
+  float m3 = m[3];
+  float m6 = m[6];
+  float m7 = m[7];
+  float m11 = m[11];
+  m[1] = m[4];
+  m[2] = m[8];
+  m[3] = m[12];
+  m[4] = m1;
+  m[6] = m[9];
+  m[7] = m[13];
+  m[8] = m2;
+  m[9] = m6;
+  m[11] = m[14];
+  m[12] = m3;
+  m[13] = m7;
+  m[14] = m11;
+  return m;
+}
+
+// Modified from gl-matrix.c
+mat4 mat4_invert(mat4 m) {
+  float a00 = m[0], a01 = m[1], a02 = m[2], a03 = m[3],
+        a10 = m[4], a11 = m[5], a12 = m[6], a13 = m[7],
+        a20 = m[8], a21 = m[9], a22 = m[10], a23 = m[11],
+        a30 = m[12], a31 = m[13], a32 = m[14], a33 = m[15],
+
+        b00 = a00 * a11 - a01 * a10,
+        b01 = a00 * a12 - a02 * a10,
+        b02 = a00 * a13 - a03 * a10,
+        b03 = a01 * a12 - a02 * a11,
+        b04 = a01 * a13 - a03 * a11,
+        b05 = a02 * a13 - a03 * a12,
+        b06 = a20 * a31 - a21 * a30,
+        b07 = a20 * a32 - a22 * a30,
+        b08 = a20 * a33 - a23 * a30,
+        b09 = a21 * a32 - a22 * a31,
+        b10 = a21 * a33 - a23 * a31,
+        b11 = a22 * a33 - a23 * a32,
+
+        d = (b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06),
+        invDet;
+
+  if (!d) { return NULL; }
+  invDet = 1 / d;
+
+  m[0] = (a11 * b11 - a12 * b10 + a13 * b09) * invDet;
+  m[1] = (-a01 * b11 + a02 * b10 - a03 * b09) * invDet;
+  m[2] = (a31 * b05 - a32 * b04 + a33 * b03) * invDet;
+  m[3] = (-a21 * b05 + a22 * b04 - a23 * b03) * invDet;
+  m[4] = (-a10 * b11 + a12 * b08 - a13 * b07) * invDet;
+  m[5] = (a00 * b11 - a02 * b08 + a03 * b07) * invDet;
+  m[6] = (-a30 * b05 + a32 * b02 - a33 * b01) * invDet;
+  m[7] = (a20 * b05 - a22 * b02 + a23 * b01) * invDet;
+  m[8] = (a10 * b10 - a11 * b08 + a13 * b06) * invDet;
+  m[9] = (-a00 * b10 + a01 * b08 - a03 * b06) * invDet;
+  m[10] = (a30 * b04 - a31 * b02 + a33 * b00) * invDet;
+  m[11] = (-a20 * b04 + a21 * b02 - a23 * b00) * invDet;
+  m[12] = (-a10 * b09 + a11 * b07 - a12 * b06) * invDet;
+  m[13] = (a00 * b09 - a01 * b07 + a02 * b06) * invDet;
+  m[14] = (-a30 * b03 + a31 * b01 - a32 * b00) * invDet;
+  m[15] = (a20 * b03 - a21 * b01 + a22 * b00) * invDet;
+
+  return m;
+}
+
+// Modified from gl-matrix.c
+mat4 mat4_multiply(mat4 m, mat4 n) {
+  float m00 = m[0], m01 = m[1], m02 = m[2], m03 = m[3],
+        m10 = m[4], m11 = m[5], m12 = m[6], m13 = m[7],
+        m20 = m[8], m21 = m[9], m22 = m[10], m23 = m[11],
+        m30 = m[12], m31 = m[13], m32 = m[14], m33 = m[15],
+
+        n00 = n[0], n01 = n[1], n02 = n[2], n03 = n[3],
+        n10 = n[4], n11 = n[5], n12 = n[6], n13 = n[7],
+        n20 = n[8], n21 = n[9], n22 = n[10], n23 = n[11],
+        n30 = n[12], n31 = n[13], n32 = n[14], n33 = n[15];
+
+  m[0] = n00 * m00 + n01 * m10 + n02 * m20 + n03 * m30;
+  m[1] = n00 * m01 + n01 * m11 + n02 * m21 + n03 * m31;
+  m[2] = n00 * m02 + n01 * m12 + n02 * m22 + n03 * m32;
+  m[3] = n00 * m03 + n01 * m13 + n02 * m23 + n03 * m33;
+  m[4] = n10 * m00 + n11 * m10 + n12 * m20 + n13 * m30;
+  m[5] = n10 * m01 + n11 * m11 + n12 * m21 + n13 * m31;
+  m[6] = n10 * m02 + n11 * m12 + n12 * m22 + n13 * m32;
+  m[7] = n10 * m03 + n11 * m13 + n12 * m23 + n13 * m33;
+  m[8] = n20 * m00 + n21 * m10 + n22 * m20 + n23 * m30;
+  m[9] = n20 * m01 + n21 * m11 + n22 * m21 + n23 * m31;
+  m[10] = n20 * m02 + n21 * m12 + n22 * m22 + n23 * m32;
+  m[11] = n20 * m03 + n21 * m13 + n22 * m23 + n23 * m33;
+  m[12] = n30 * m00 + n31 * m10 + n32 * m20 + n33 * m30;
+  m[13] = n30 * m01 + n31 * m11 + n32 * m21 + n33 * m31;
+  m[14] = n30 * m02 + n31 * m12 + n32 * m22 + n33 * m32;
+  m[15] = n30 * m03 + n31 * m13 + n32 * m23 + n33 * m33;
+
+  return m;
+}
+
+mat4 mat4_translate(mat4 m, float x, float y, float z) {
+  m[12] = m[0] * x + m[4] * y + m[8] * z + m[12];
+  m[13] = m[1] * x + m[5] * y + m[9] * z + m[13];
+  m[14] = m[2] * x + m[6] * y + m[10] * z + m[14];
+  m[15] = m[3] * x + m[7] * y + m[11] * z + m[15];
+  return m;
+}
+
+mat4 mat4_scale(mat4 m, float x, float y, float z) {
+  m[0] *= x;
+  m[1] *= x;
+  m[2] *= x;
+  m[3] *= x;
+  m[4] *= y;
+  m[5] *= y;
+  m[6] *= y;
+  m[7] *= y;
+  m[8] *= z;
+  m[9] *= z;
+  m[10] *= z;
+  m[11] *= z;
+  return m;
+}
+
+mat4 mat4_rotate(mat4 m, quat q) {
+  float x = q[0];
+  float y = q[1];
+  float z = q[2];
+  float w = q[3];
+  float rotation[16];
+  mat4_identity(rotation);
+  rotation[0] = 1 - 2 * y * y - 2 * z * z;
+  rotation[1] = 2 * x * y + 2 * w * z;
+  rotation[2] = 2 * x * z - 2 * w * y;
+  rotation[4] = 2 * x * y - 2 * w * z;
+  rotation[5] = 1 - 2 * x * x - 2 * z * z;
+  rotation[6] = 2 * y * z + 2 * w * x;
+  rotation[8] = 2 * x * z + 2 * w * y;
+  rotation[9] = 2 * y * z - 2 * w * x;
+  rotation[10] = 1 - 2 * x * x - 2 * y * y;
+  return mat4_multiply(m, rotation);
+}
+
+mat4 mat4_orthographic(mat4 m, float left, float right, float top, float bottom, float near, float far) {
+  float rl = right - left;
+  float tb = top - bottom;
+  float fn = far - near;
+  mat4_identity(m);
+  m[0] = 2 / rl;
+  m[5] = 2 / tb;
+  m[10] = -2 / fn;
+  m[12] = -(left + right) / rl;
+  m[13] = -(top + bottom) / tb;
+  m[14] = -(far + near) / fn;
+  m[15] = 1;
+  return m;
+}
+
+mat4 mat4_perspective(mat4 m, float near, float far, float fovy, float aspect) {
+  float range = tan(fovy * .5f) * near;
+  float sx = (2.0f * near) / (range * aspect + range * aspect);
+  float sy = near / range;
+  float sz = -(far + near) / (far - near);
+  float pz = (-2.0f * far * near) / (far - near);
+  mat4_identity(m);
+  m[0] = sx;
+  m[5] = sy;
+  m[10] = sz;
+  m[11] = -1.0f;
+  m[14] = pz;
+  m[15] = 0.0f;
+  return m;
+}
+
+quat mat4_toQuat(mat4 m, quat q) {
+  float x = sqrt(MAX(0, 1 + m[0] - m[5] - m[10])) / 2;
+  float y = sqrt(MAX(0, 1 - m[0] + m[5] - m[10])) / 2;
+  float z = sqrt(MAX(0, 1 - m[0] - m[5] + m[10])) / 2;
+  float w = sqrt(MAX(0, 1 + m[0] + m[5] + m[10])) / 2;
+
+  x = (m[9] - m[6]) > 0 ? -x : x;
+  y = (m[2] - m[8]) > 0 ? -y : y;
+  z = (m[4] - m[1]) > 0 ? -z : z;
+
+  q[0] = x;
+  q[1] = y;
+  q[2] = z;
+  q[3] = w;
+
+  return q;
+}
diff --git a/src/math/mat4.h b/src/math/mat4.h
new file mode 100644
index 00000000..b92eeab1
--- /dev/null
+++ b/src/math/mat4.h
@@ -0,0 +1,16 @@
+#include "math/math.h"
+
+mat4 mat4_init();
+mat4 mat4_fromMat34(mat4 m, float (*n)[4]);
+mat4 mat4_fromMat44(mat4 m, float (*n)[4]);
+mat4 mat4_set(mat4 m, mat4 n);
+mat4 mat4_identity(mat4 m);
+mat4 mat4_transpose(mat4 m);
+mat4 mat4_invert(mat4 m);
+mat4 mat4_multiply(mat4 m, mat4 n);
+mat4 mat4_translate(mat4 m, float x, float y, float z);
+mat4 mat4_scale(mat4 m, float x, float y, float z);
+mat4 mat4_rotate(mat4 m, quat q);
+mat4 mat4_orthographic(mat4 m, float left, float right, float top, float bottom, float near, float far);
+mat4 mat4_perspective(mat4 m, float near, float far, float fov, float aspect);
+quat mat4_toQuat(mat4 m, quat q);
diff --git a/src/math/math.h b/src/math/math.h
new file mode 100644
index 00000000..f530080e
--- /dev/null
+++ b/src/math/math.h
@@ -0,0 +1,9 @@
+#include "vendor/vec/vec.h"
+
+#ifndef LOVR_MATH_TYPES
+#define LOVR_MATH_TYPES
+typedef float* vec3;
+typedef float* quat;
+typedef float* mat4;
+typedef vec_t(mat4) vec_mat4_t;
+#endif
diff --git a/src/math/quat.c b/src/math/quat.c
new file mode 100644
index 00000000..b5913b63
--- /dev/null
+++ b/src/math/quat.c
@@ -0,0 +1,144 @@
+#include "math/quat.h"
+#include "math/vec3.h"
+#include <math.h>
+#include <stdlib.h>
+
+quat quat_init(float x, float y, float z, float w) {
+  quat q = malloc(4 * sizeof(float));
+  q[0] = x;
+  q[1] = y;
+  q[2] = z;
+  q[3] = w;
+  return q;
+}
+
+quat quat_fromAngleAxis(quat q, float angle, vec3 axis) {
+  vec3_normalize(axis);
+  float s = sin(angle * .5f);
+  float c = cos(angle * .5f);
+  q[0] = s * axis[0];
+  q[1] = s * axis[1];
+  q[2] = s * axis[2];
+  q[3] = c;
+  return q;
+}
+
+quat quat_fromDirection(quat q, vec3 forward, vec3 up) {
+  vec3 qq = (vec3) q;
+  vec3_set(qq, forward);
+  vec3_normalize(qq);
+  vec3_normalize(up);
+  q[3] = 1 + vec3_dot(qq, up);
+  vec3_cross(qq, up);
+  return q;
+}
+
+quat quat_set(quat q, quat r) {
+  q[0] = r[0];
+  q[1] = r[1];
+  q[2] = r[2];
+  q[3] = r[3];
+  return q;
+}
+
+quat quat_multiply(quat q, quat r) {
+  float qx = q[0];
+  float qy = q[1];
+  float qz = q[2];
+  float qw = q[3];
+  float rx = r[0];
+  float ry = r[1];
+  float rz = r[2];
+  float rw = r[3];
+  q[0] = qx * rw + qw * rx - qy * rz - qz * ry;
+  q[1] = qy * rw + qw * ry - qz * rx - qx * rz;
+  q[2] = qz * rw + qw * rz - qx * ry - qy * rx;
+  q[3] = qw * rw - qx * rx - qy * ry - qz * rz;
+  return q;
+}
+
+quat quat_normalize(quat q) {
+  float len = quat_length(q);
+  if (len == 0) {
+    return q;
+  }
+
+  len = 1 / len;
+  q[0] *= len;
+  q[1] *= len;
+  q[2] *= len;
+  q[3] *= len;
+  return q;
+}
+
+float quat_length(quat q) {
+  return sqrt(q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3]);
+}
+
+// From gl-matrix
+quat quat_slerp(quat q, quat r, float t) {
+  float dot = q[0] * r[0] + q[1] * r[1] + q[2] * r[2] + q[3] * r[3];
+  if (fabs(dot) >= 1.f) {
+    return q;
+  }
+
+  float halfTheta = acos(dot);
+  float sinHalfTheta = sqrt(1.f - dot * dot);
+
+  if (fabs(sinHalfTheta) < .001) {
+    q[0] = q[0] * .5 + r[0] * .5;
+    q[1] = q[1] * .5 + r[1] * .5;
+    q[2] = q[2] * .5 + r[2] * .5;
+    q[3] = q[3] * .5 + r[3] * .5;
+    return q;
+  }
+
+  float a = sin((1 - t) * halfTheta) / sinHalfTheta;
+  float b = sin(t * halfTheta) / sinHalfTheta;
+
+  q[0] = q[0] * a + r[0] * b;
+  q[1] = q[1] * a + r[1] * b;
+  q[2] = q[2] * a + r[2] * b;
+  q[3] = q[3] * a + r[3] * b;
+
+  return q;
+}
+
+quat quat_between(quat q, vec3 u, vec3 v) {
+  float dot = vec3_dot(u, v);
+  if (dot > .99999) {
+    q[0] = q[1] = q[2] = 0.f;
+    q[3] = 1.f;
+    return q;
+  } else if (dot < -.99999) {
+    float axis[3] = { 1, 0, 0 };
+    vec3_cross(axis, u);
+    if (vec3_length(axis) < .00001) {
+      axis[0] = 0;
+      axis[1] = 1;
+      axis[2] = 0;
+      vec3_cross(axis, u);
+    }
+    vec3_normalize(axis);
+    quat_fromAngleAxis(q, M_PI, axis);
+    return q;
+  }
+
+  vec3_cross(vec3_set(q, u), v);
+  q[3] = 1 + dot;
+  return quat_normalize(q);
+}
+
+void quat_toAngleAxis(quat q, float* angle, float* x, float* y, float* z) {
+  if (q[3] > 1 || q[3] < -1) {
+    quat_normalize(q);
+  }
+
+  float qw = q[3];
+  float s = sqrt(1 - qw * qw);
+  s = s < .0001 ? 1 : 1 / s;
+  *angle = 2 * acos(qw);
+  *x = q[0] * s;
+  *y = q[1] * s;
+  *z = q[2] * s;
+}
diff --git a/src/math/quat.h b/src/math/quat.h
new file mode 100644
index 00000000..cfbc67bd
--- /dev/null
+++ b/src/math/quat.h
@@ -0,0 +1,12 @@
+#include "math/math.h"
+
+quat quat_init(float x, float y, float z, float w);
+quat quat_fromAngleAxis(quat q, float angle, vec3 axis);
+quat quat_fromDirection(quat q, vec3 forward, vec3 up);
+quat quat_set(quat q, quat r);
+quat quat_multiply(quat q, quat r);
+quat quat_normalize(quat q);
+float quat_length(quat q);
+quat quat_slerp(quat q, quat r, float t);
+quat quat_between(quat q, vec3 u, vec3 v);
+void quat_toAngleAxis(quat q, float* angle, float* x, float* y, float* z);
diff --git a/src/math/vec3.c b/src/math/vec3.c
index 40f8e91e..9e7db735 100644
--- a/src/math/vec3.c
+++ b/src/math/vec3.c
@@ -1,4 +1,5 @@
 #include "math/vec3.h"
+#include "math/quat.h"
 #include <math.h>
 #include <stdlib.h>
 
@@ -45,8 +46,15 @@ vec3 vec3_div(vec3 v, vec3 u) {
   return v;
 }
 
+vec3 vec3_scale(vec3 v, float s) {
+  v[0] *= s;
+  v[1] *= s;
+  v[2] *= s;
+  return v;
+}
+
 vec3 vec3_normalize(vec3 v) {
-  float len = vec3_len(v);
+  float len = vec3_length(v);
   if (len == 0) {
     return v;
   }
@@ -58,11 +66,11 @@ vec3 vec3_normalize(vec3 v) {
   return v;
 }
 
-float vec3_len(vec3 v) {
+float vec3_length(vec3 v) {
   return sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
 }
 
-float vec3_dist(vec3 v, vec3 u) {
+float vec3_distance(vec3 v, vec3 u) {
   float dx = v[0] - u[0];
   float dy = v[1] - u[1];
   float dz = v[2] - u[2];
@@ -70,7 +78,7 @@ float vec3_dist(vec3 v, vec3 u) {
 }
 
 float vec3_angle(vec3 v, vec3 u) {
-  return acos(vec3_dot(v, u) / (vec3_len(v) * vec3_len(u)));
+  return acos(vec3_dot(v, u) / (vec3_length(v) * vec3_length(u)));
 }
 
 float vec3_dot(vec3 v, vec3 u) {
@@ -87,6 +95,30 @@ vec3 vec3_cross(vec3 v, vec3 u) {
   return v;
 }
 
+vec3 vec3_rotate(vec3 v, quat q) {
+  float s = q[3];
+  float u[3];
+  float c[3];
+  vec3_set(u, q);
+  vec3_cross(vec3_set(c, u), v);
+  float uu = vec3_dot(u, u);
+  float uv = vec3_dot(u, v);
+  vec3_scale(u, 2 * uv);
+  vec3_scale(v, s * s - uu);
+  vec3_scale(c, 2 * s);
+  return vec3_add(v, vec3_add(u, c));
+}
+
+vec3 vec3_transform(vec3 v, mat4 m) {
+  float v0 = v[0];
+  float v1 = v[1];
+  float v2 = v[2];
+  v[0] = v0 * m[0] + v1 * m[4] + v2 * m[8] + m[12];
+  v[1] = v0 * m[1] + v1 * m[5] + v2 * m[9] + m[13];
+  v[2] = v0 * m[2] + v1 * m[6] + v2 * m[10] + m[14];
+  return v;
+}
+
 vec3 vec3_lerp(vec3 v, vec3 u, float t) {
   v[0] += (u[0] - v[0]) * t;
   v[1] += (u[1] - v[1]) * t;
diff --git a/src/math/vec3.h b/src/math/vec3.h
index 879c1c11..a3fef7de 100644
--- a/src/math/vec3.h
+++ b/src/math/vec3.h
@@ -1,7 +1,4 @@
-#ifndef LOVR_VECTOR_TYPES
-#define LOVR_VECTOR_TYPES
-typedef float* vec3;
-#endif
+#include "math/math.h"
 
 vec3 vec3_init(float x, float y, float z);
 vec3 vec3_set(vec3 v, vec3 u);
@@ -9,10 +6,13 @@ vec3 vec3_add(vec3 v, vec3 u);
 vec3 vec3_sub(vec3 v, vec3 u);
 vec3 vec3_mul(vec3 v, vec3 u);
 vec3 vec3_div(vec3 v, vec3 u);
+vec3 vec3_scale(vec3 v, float s);
 vec3 vec3_normalize(vec3 v);
-float vec3_len(vec3 v);
-float vec3_dist(vec3 v, vec3 u);
+float vec3_length(vec3 v);
+float vec3_distance(vec3 v, vec3 u);
 float vec3_angle(vec3 v, vec3 u);
 float vec3_dot(vec3 v, vec3 u);
 vec3 vec3_cross(vec3 v, vec3 u);
+vec3 vec3_rotate(vec3 v, quat q);
+vec3 vec3_transform(vec3 v, mat4 m);
 vec3 vec3_lerp(vec3 v, vec3 u, float t);
diff --git a/src/matrix.c b/src/matrix.c
deleted file mode 100644
index 5521d33d..00000000
--- a/src/matrix.c
+++ /dev/null
@@ -1,276 +0,0 @@
-#include "matrix.h"
-#include "util.h"
-#include <math.h>
-#include <stdlib.h>
-#include <string.h>
-
-/*
-   m0 m4 m8  m12
-   m1 m5 m9  m13
-   m2 m6 m10 m14
-   m3 m7 m11 m15
-*/
-
-mat4 mat4_init() {
-  mat4 matrix = malloc(16 * sizeof(float));
-  return mat4_setIdentity(matrix);
-}
-
-void mat4_deinit(mat4 matrix) {
-  free(matrix);
-}
-
-mat4 mat4_copy(mat4 source) {
-  mat4 matrix = mat4_init();
-  memcpy(matrix, source, 16 * sizeof(float));
-  return matrix;
-}
-
-mat4 mat4_fromMat34(mat4 matrix, float (*source)[4]) {
-  matrix[0] = source[0][0];
-  matrix[1] = source[1][0];
-  matrix[2] = source[2][0];
-  matrix[3] = 0.f;
-  matrix[4] = source[0][1];
-  matrix[5] = source[1][1];
-  matrix[6] = source[2][1];
-  matrix[7] = 0.f;
-  matrix[8] = source[0][2];
-  matrix[9] = source[1][2];
-  matrix[10] = source[2][2];
-  matrix[11] = 0.f;
-  matrix[12] = source[0][3];
-  matrix[13] = source[1][3];
-  matrix[14] = source[2][3];
-  matrix[15] = 1.f;
-  return matrix;
-}
-
-mat4 mat4_fromMat44(mat4 matrix, float (*source)[4]) {
-  matrix[0] = source[0][0];
-  matrix[1] = source[1][0];
-  matrix[2] = source[2][0];
-  matrix[3] = source[3][0];
-  matrix[4] = source[0][1];
-  matrix[5] = source[1][1];
-  matrix[6] = source[2][1];
-  matrix[7] = source[3][1];
-  matrix[8] = source[0][2];
-  matrix[9] = source[1][2];
-  matrix[10] = source[2][2];
-  matrix[11] = source[3][2];
-  matrix[12] = source[0][3];
-  matrix[13] = source[1][3];
-  matrix[14] = source[2][3];
-  matrix[15] = source[3][3];
-  return matrix;
-}
-
-mat4 mat4_setIdentity(mat4 matrix) {
-  memset(matrix, 0, 16 * sizeof(float));
-  matrix[0] = matrix[5] = matrix[10] = matrix[15] = 1.f;
-  return matrix;
-}
-
-mat4 mat4_setTranslation(mat4 matrix, float x, float y, float z) {
-  mat4_setIdentity(matrix);
-  matrix[12] = x;
-  matrix[13] = y;
-  matrix[14] = z;
-  return matrix;
-}
-
-mat4 mat4_setRotation(mat4 matrix, float angle, float ax, float ay, float az) {
-
-  // Normalize rotation vector
-  float len = sqrtf(ax * ax + ay * ay + az * az);
-  if (len != 1 && len != 0) {
-    len = 1 / len;
-    ax *= len;
-    ay *= len;
-    az *= len;
-  }
-
-  // Convert angle-axis to quaternion
-  float cos2 = cos(angle / 2.f);
-  float sin2 = sin(angle / 2.f);
-  float w = cos2;
-  float x = sin2 * ax;
-  float y = sin2 * ay;
-  float z = sin2 * az;
-
-  mat4_setIdentity(matrix);
-  matrix[0] = 1 - 2 * y * y - 2 * z * z;
-  matrix[1] = 2 * x * y + 2 * w * z;
-  matrix[2] = 2 * x * z - 2 * w * y;
-  matrix[4] = 2 * x * y - 2 * w * z;
-  matrix[5] = 1 - 2 * x * x - 2 * z * z;
-  matrix[6] = 2 * y * z + 2 * w * x;
-  matrix[8] = 2 * x * z + 2 * w * y;
-  matrix[9] = 2 * y * z - 2 * w * x;
-  matrix[10] = 1 - 2 * x * x - 2 * y * y;
-  return matrix;
-}
-
-mat4 mat4_setScale(mat4 matrix, float x, float y, float z) {
-  mat4_setIdentity(matrix);
-  matrix[0] = x;
-  matrix[5] = y;
-  matrix[10] = z;
-  return matrix;
-}
-
-mat4 mat4_setOrthographic(mat4 matrix, float left, float right, float top, float bottom, float near, float far) {
-  float rl = right - left;
-  float tb = top - bottom;
-  float fn = far - near;
-  mat4_setIdentity(matrix);
-  matrix[0] = 2 / rl;
-  matrix[5] = 2 / tb;
-  matrix[10] = -2 / fn;
-  matrix[12] = -(left + right) / rl;
-  matrix[13] = -(top + bottom) / tb;
-  matrix[14] = -(far + near) / fn;
-  matrix[15] = 1;
-  return matrix;
-}
-
-mat4 mat4_setPerspective(mat4 matrix, float near, float far, float fov, float aspect) {
-  float range = tan(fov * .5f) * near;
-  float sx = (2.0f * near) / (range * aspect + range * aspect);
-  float sy = near / range;
-  float sz = -(far + near) / (far - near);
-  float pz = (-2.0f * far * near) / (far - near);
-  mat4_setIdentity(matrix);
-  matrix[0] = sx;
-  matrix[5] = sy;
-  matrix[10] = sz;
-  matrix[11] = -1.0f;
-  matrix[14] = pz;
-  matrix[15] = 0.0f;
-  return matrix;
-}
-
-void mat4_getRotation(mat4 matrix, float* w, float* x, float* y, float* z) {
-  float qw = sqrt(MAX(0, 1 + matrix[0] + matrix[5] + matrix[10])) / 2;
-  float qx = sqrt(MAX(0, 1 + matrix[0] - matrix[5] - matrix[10])) / 2;
-  float qy = sqrt(MAX(0, 1 - matrix[0] + matrix[5] - matrix[10])) / 2;
-  float qz = sqrt(MAX(0, 1 - matrix[0] - matrix[5] + matrix[10])) / 2;
-  qx = (matrix[9] - matrix[6]) > 0 ? -qx : qx;
-  qy = (matrix[2] - matrix[8]) > 0 ? -qy : qy;
-  qz = (matrix[4] - matrix[1]) > 0 ? -qz : qz;
-
-  float s = sqrt(1 - qw * qw);
-  s = s < .001 ? 1 : s;
-  *w = 2 * acos(qw);
-  *x = qx / s;
-  *y = qy / s;
-  *z = qz / s;
-}
-
-mat4 mat4_translate(mat4 matrix, float x, float y, float z) {
-  float translation[16];
-  mat4_setTranslation(translation, x, y, z);
-  return mat4_multiply(matrix, translation);
-}
-
-mat4 mat4_rotate(mat4 matrix, float angle, float ax, float ay, float az) {
-  float rotation[16];
-  mat4_setRotation(rotation, angle, ax, ay, az);
-  return mat4_multiply(matrix, rotation);
-}
-
-mat4 mat4_scale(mat4 matrix, float x, float y, float z) {
-  float scale[16];
-  mat4_setScale(scale, x, y, z);
-  return mat4_multiply(matrix, scale);
-}
-
-// Modified from gl-matrix.c
-mat4 mat4_multiply(mat4 a, mat4 b) {
-  float a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3],
-        a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7],
-        a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11],
-        a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15],
-
-        b00 = b[0], b01 = b[1], b02 = b[2], b03 = b[3],
-        b10 = b[4], b11 = b[5], b12 = b[6], b13 = b[7],
-        b20 = b[8], b21 = b[9], b22 = b[10], b23 = b[11],
-        b30 = b[12], b31 = b[13], b32 = b[14], b33 = b[15];
-
-  a[0] = b00 * a00 + b01 * a10 + b02 * a20 + b03 * a30;
-  a[1] = b00 * a01 + b01 * a11 + b02 * a21 + b03 * a31;
-  a[2] = b00 * a02 + b01 * a12 + b02 * a22 + b03 * a32;
-  a[3] = b00 * a03 + b01 * a13 + b02 * a23 + b03 * a33;
-  a[4] = b10 * a00 + b11 * a10 + b12 * a20 + b13 * a30;
-  a[5] = b10 * a01 + b11 * a11 + b12 * a21 + b13 * a31;
-  a[6] = b10 * a02 + b11 * a12 + b12 * a22 + b13 * a32;
-  a[7] = b10 * a03 + b11 * a13 + b12 * a23 + b13 * a33;
-  a[8] = b20 * a00 + b21 * a10 + b22 * a20 + b23 * a30;
-  a[9] = b20 * a01 + b21 * a11 + b22 * a21 + b23 * a31;
-  a[10] = b20 * a02 + b21 * a12 + b22 * a22 + b23 * a32;
-  a[11] = b20 * a03 + b21 * a13 + b22 * a23 + b23 * a33;
-  a[12] = b30 * a00 + b31 * a10 + b32 * a20 + b33 * a30;
-  a[13] = b30 * a01 + b31 * a11 + b32 * a21 + b33 * a31;
-  a[14] = b30 * a02 + b31 * a12 + b32 * a22 + b33 * a32;
-  a[15] = b30 * a03 + b31 * a13 + b32 * a23 + b33 * a33;
-
-  return a;
-}
-
-void mat4_multiplyVector(mat4 m, float* v) {
-  float v0 = v[0];
-  float v1 = v[1];
-  float v2 = v[2];
-  float v3 = v[3];
-  v[0] = v0 * m[0] + v1 * m[4] + v2 * m[8] + v3 * m[12];
-  v[1] = v0 * m[1] + v1 * m[5] + v2 * m[9] + v3 * m[13];
-  v[2] = v0 * m[2] + v1 * m[6] + v2 * m[10] + v3 * m[14];
-  v[3] = v0 * m[3] + v1 * m[7] + v2 * m[11] + v3 * m[15];
-}
-
-// Modified from gl-matrix.c
-mat4 mat4_invert(mat4 m) {
-  float a00 = m[0], a01 = m[1], a02 = m[2], a03 = m[3],
-        a10 = m[4], a11 = m[5], a12 = m[6], a13 = m[7],
-        a20 = m[8], a21 = m[9], a22 = m[10], a23 = m[11],
-        a30 = m[12], a31 = m[13], a32 = m[14], a33 = m[15],
-
-        b00 = a00 * a11 - a01 * a10,
-        b01 = a00 * a12 - a02 * a10,
-        b02 = a00 * a13 - a03 * a10,
-        b03 = a01 * a12 - a02 * a11,
-        b04 = a01 * a13 - a03 * a11,
-        b05 = a02 * a13 - a03 * a12,
-        b06 = a20 * a31 - a21 * a30,
-        b07 = a20 * a32 - a22 * a30,
-        b08 = a20 * a33 - a23 * a30,
-        b09 = a21 * a32 - a22 * a31,
-        b10 = a21 * a33 - a23 * a31,
-        b11 = a22 * a33 - a23 * a32,
-
-        d = (b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06),
-        invDet;
-
-  if (!d) { return NULL; }
-  invDet = 1 / d;
-
-  m[0] = (a11 * b11 - a12 * b10 + a13 * b09) * invDet;
-  m[1] = (-a01 * b11 + a02 * b10 - a03 * b09) * invDet;
-  m[2] = (a31 * b05 - a32 * b04 + a33 * b03) * invDet;
-  m[3] = (-a21 * b05 + a22 * b04 - a23 * b03) * invDet;
-  m[4] = (-a10 * b11 + a12 * b08 - a13 * b07) * invDet;
-  m[5] = (a00 * b11 - a02 * b08 + a03 * b07) * invDet;
-  m[6] = (-a30 * b05 + a32 * b02 - a33 * b01) * invDet;
-  m[7] = (a20 * b05 - a22 * b02 + a23 * b01) * invDet;
-  m[8] = (a10 * b10 - a11 * b08 + a13 * b06) * invDet;
-  m[9] = (-a00 * b10 + a01 * b08 - a03 * b06) * invDet;
-  m[10] = (a30 * b04 - a31 * b02 + a33 * b00) * invDet;
-  m[11] = (-a20 * b04 + a21 * b02 - a23 * b00) * invDet;
-  m[12] = (-a10 * b09 + a11 * b07 - a12 * b06) * invDet;
-  m[13] = (a00 * b09 - a01 * b07 + a02 * b06) * invDet;
-  m[14] = (-a30 * b03 + a31 * b01 - a32 * b00) * invDet;
-  m[15] = (a20 * b03 - a21 * b01 + a22 * b00) * invDet;
-
-  return m;
-}
diff --git a/src/matrix.h b/src/matrix.h
deleted file mode 100644
index 3bd5c75c..00000000
--- a/src/matrix.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#include "vendor/vec/vec.h"
-
-#ifndef LOVR_MATRIX_TYPES
-#define LOVR_MATRIX_TYPES
-typedef float* mat4;
-typedef vec_t(mat4) vec_mat4_t;
-#endif
-
-mat4 mat4_init();
-void mat4_deinit(mat4 matrix);
-mat4 mat4_copy(mat4 source);
-mat4 mat4_fromMat34(mat4 matrix, float (*source)[4]);
-mat4 mat4_fromMat44(mat4 matrix, float (*source)[4]);
-mat4 mat4_setIdentity(mat4 matrix);
-mat4 mat4_setTranslation(mat4 matrix, float x, float y, float z);
-mat4 mat4_setRotation(mat4 matrix, float angle, float ax, float ay, float az);
-mat4 mat4_setScale(mat4 matrix, float x, float y, float z);
-mat4 mat4_setOrthographic(mat4 matrix, float left, float right, float top, float bottom, float near, float far);
-mat4 mat4_setPerspective(mat4 matrix, float near, float far, float fov, float aspect);
-void mat4_getRotation(mat4 matrix, float* w, float* x, float* y, float* z);
-mat4 mat4_translate(mat4 matrix, float x, float y, float z);
-mat4 mat4_rotate(mat4 matrix, float angle, float ax, float ay, float az);
-mat4 mat4_scale(mat4 matrix, float x, float y, float z);
-mat4 mat4_multiply(mat4 a, mat4 b);
-void mat4_multiplyVector(mat4 m, float* v);
-mat4 mat4_invert(mat4 m);