From 435d7a9cf86aae9ab8e7e0404053933a51288392 Mon Sep 17 00:00:00 2001
From: bjorn <tie.372@gmail.com>
Date: Mon, 26 Sep 2016 23:48:09 -0700
Subject: [PATCH] Projection matrices;

---
 src/graphics/graphics.c | 64 ++++++++++++++++++++++-------------------
 src/graphics/graphics.h | 11 ++++++-
 src/headset/headset.c   | 20 +++++++++----
 src/headset/headset.h   |  4 +++
 src/headset/vive.c      | 64 ++++++++++++++++++++++-------------------
 src/headset/vive.h      |  2 ++
 src/lovr/graphics.c     | 13 +++++++--
 src/lovr/graphics.h     |  1 +
 src/lovr/headset.c      | 24 ++++++++++++++--
 src/lovr/headset.h      |  8 ++++--
 src/matrix.c            | 44 ++++++++++++++++++++++++++++
 src/matrix.h            |  3 ++
 12 files changed, 183 insertions(+), 75 deletions(-)

diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 4647cbed..15ed65be 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -10,24 +10,21 @@
 #include <assimp/postprocess.h>
 #include "../headset/headset.h"
 
-typedef struct {
-  Shader* activeShader;
-  vec_mat4_t transforms;
-  mat4 lastTransform;
-  mat4 projection;
-  mat4 lastProjection;
-} GraphicsState;
-
-static GraphicsState graphicsState;
+static GraphicsState state;
 
 void lovrGraphicsInit() {
-  vec_init(&graphicsState.transforms);
-  vec_push(&graphicsState.transforms, mat4_init());
-  graphicsState.lastTransform = mat4_init();
-  memset(graphicsState.lastTransform, 0, 16);
-  graphicsState.projection = mat4_init();
-  graphicsState.lastProjection = mat4_init();
-  memset(graphicsState.lastProjection, 0, 16);
+  vec_init(&state.transforms);
+  vec_push(&state.transforms, mat4_init());
+
+  state.projection = mat4_init();
+  state.lastTransform = mat4_init();
+  state.lastProjection = mat4_init();
+
+  memset(state.lastTransform, 0, 16);
+  memset(state.lastProjection, 0, 16);
+
+  // TODO customize via lovr.conf
+  lovrGraphicsSetProjection(.1f, 100.f, 67 * M_PI / 180);
 }
 
 void lovrGraphicsClear(int color, int depth) {
@@ -55,8 +52,8 @@ void lovrGraphicsPrepare() {
     return;
   }
 
-  mat4 transform = vec_last(&graphicsState.transforms);
-  mat4 lastTransform = graphicsState.lastTransform;
+  mat4 transform = vec_last(&state.transforms);
+  mat4 lastTransform = state.lastTransform;
 
   if (memcmp(transform, lastTransform, 16 * sizeof(float))) {
     int uniformId = lovrShaderGetUniformId(shader, "lovrTransform");
@@ -64,8 +61,8 @@ void lovrGraphicsPrepare() {
     memcpy(lastTransform, transform, 16 * sizeof(float));
   }
 
-  mat4 projection = graphicsState.projection;
-  mat4 lastProjection = graphicsState.lastProjection;
+  mat4 projection = state.projection;
+  mat4 lastProjection = state.lastProjection;
 
   if (memcmp(projection, lastProjection, 16 * sizeof(float))) {
     int uniformId = lovrShaderGetUniformId(shader, "lovrProjection");
@@ -88,48 +85,55 @@ void lovrGraphicsSetClearColor(float r, float g, float b, float a) {
 }
 
 Shader* lovrGraphicsGetShader() {
-  return graphicsState.activeShader;
+  return state.activeShader;
 }
 
 // TODO default shader
 void lovrGraphicsSetShader(Shader* shader) {
-  graphicsState.activeShader = shader;
+  state.activeShader = shader;
   glUseProgram(shader->id);
 }
 
-void lovrGraphicsSetProjection(float near, float far, float fov, float aspect) {
-  mat4_setProjection(graphicsState.projection, near, far, fov, aspect);
+void lovrGraphicsGetProjection(float* near, float* far, float* fov) {
+  float aspect;
+  mat4_getProjection(state.projection, near, far, fov, &aspect);
+}
+
+void lovrGraphicsSetProjection(float near, float far, float fov) {
+  int width, height;
+  glfwGetWindowSize(window, &width, &height);
+  mat4_setProjection(state.projection, near, far, fov, (float) width / height);
 }
 
 int lovrGraphicsPush() {
-  vec_mat4_t* transforms = &graphicsState.transforms;
+  vec_mat4_t* transforms = &state.transforms;
   if (transforms->length >= 64) { return 1; }
   vec_push(transforms, mat4_copy(vec_last(transforms)));
   return 0;
 }
 
 int lovrGraphicsPop() {
-  vec_mat4_t* transforms = &graphicsState.transforms;
+  vec_mat4_t* transforms = &state.transforms;
   if (transforms->length <= 1) { return 1; }
   mat4_deinit(vec_pop(transforms));
   return 0;
 }
 
 void lovrGraphicsOrigin() {
-  vec_mat4_t* transforms = &graphicsState.transforms;
+  vec_mat4_t* transforms = &state.transforms;
   mat4_setIdentity(vec_last(transforms));
 }
 
 void lovrGraphicsTranslate(float x, float y, float z) {
-  mat4_translate(vec_last(&graphicsState.transforms), x, y, z);
+  mat4_translate(vec_last(&state.transforms), x, y, z);
 }
 
 void lovrGraphicsRotate(float w, float x, float y, float z) {
-  mat4_rotate(vec_last(&graphicsState.transforms), w, x, y, z);
+  mat4_rotate(vec_last(&state.transforms), w, x, y, z);
 }
 
 void lovrGraphicsScale(float x, float y, float z) {
-  mat4_scale(vec_last(&graphicsState.transforms), x, y, z);
+  mat4_scale(vec_last(&state.transforms), x, y, z);
 }
 
 Buffer* lovrGraphicsNewBuffer(int size, BufferDrawMode drawMode, BufferUsage usage) {
diff --git a/src/graphics/graphics.h b/src/graphics/graphics.h
index baad5ca0..8c20d53d 100644
--- a/src/graphics/graphics.h
+++ b/src/graphics/graphics.h
@@ -6,6 +6,14 @@
 #ifndef LOVR_GRAPHICS_TYPES
 #define LOVR_GRAPHICS_TYPES
 typedef vec_t(mat4) vec_mat4_t;
+
+typedef struct {
+  Shader* activeShader;
+  vec_mat4_t transforms;
+  mat4 lastTransform;
+  mat4 projection;
+  mat4 lastProjection;
+} GraphicsState;
 #endif
 
 void lovrGraphicsInit();
@@ -16,7 +24,8 @@ void lovrGraphicsGetClearColor(float* r, float* g, float* b, float* a);
 void lovrGraphicsSetClearColor(float r, float g, float b, float a);
 Shader* lovrGraphicsGetShader();
 void lovrGraphicsSetShader(Shader* shader);
-void lovrGraphicsSetProjection(float near, float far, float fov, float aspect);
+void lovrGraphicsGetProjection(float* near, float* far, float* fov);
+void lovrGraphicsSetProjection(float near, float far, float fov);
 int lovrGraphicsPush();
 int lovrGraphicsPop();
 void lovrGraphicsOrigin();
diff --git a/src/headset/headset.c b/src/headset/headset.c
index 3a669e5c..a4760e42 100644
--- a/src/headset/headset.c
+++ b/src/headset/headset.c
@@ -7,20 +7,24 @@ void lovrHeadsetInit() {
   headset = viveInit();
 }
 
-void lovrHeadsetGetPosition(float* x, float* y, float* z) {
-  headset->interface->getPosition(headset, x, y, z);
+void lovrHeadsetGetAngularVelocity(float* x, float* y, float* z) {
+  headset->interface->getAngularVelocity(headset, x, y, z);
+}
+
+void lovrHeadsetGetClipDistance(float* near, float* far) {
+  headset->interface->getClipDistance(headset, near, far);
 }
 
 void lovrHeadsetGetOrientation(float* x, float* y, float* z, float* w) {
   headset->interface->getOrientation(headset, x, y, z, w);
 }
 
-void lovrHeadsetGetVelocity(float* x, float* y, float* z) {
-  headset->interface->getVelocity(headset, x, y, z);
+void lovrHeadsetGetPosition(float* x, float* y, float* z) {
+  headset->interface->getPosition(headset, x, y, z);
 }
 
-void lovrHeadsetGetAngularVelocity(float* x, float* y, float* z) {
-  headset->interface->getAngularVelocity(headset, x, y, z);
+void lovrHeadsetGetVelocity(float* x, float* y, float* z) {
+  headset->interface->getVelocity(headset, x, y, z);
 }
 
 int lovrHeadsetIsPresent() {
@@ -30,3 +34,7 @@ int lovrHeadsetIsPresent() {
 void lovrHeadsetRenderTo(headsetRenderCallback callback, void* userdata) {
   headset->interface->renderTo(headset, callback, userdata);
 }
+
+void lovrHeadsetSetClipDistance(float near, float far) {
+  headset->interface->setClipDistance(headset, near, far);
+}
diff --git a/src/headset/headset.h b/src/headset/headset.h
index a94ef47b..f61ed4e8 100644
--- a/src/headset/headset.h
+++ b/src/headset/headset.h
@@ -4,12 +4,14 @@ typedef void (*headsetRenderCallback)(int eyeIndex, void* userdata);
 
 typedef struct {
   void (*getAngularVelocity)(void* headset, float* x, float* y, float* z);
+  void (*getClipDistance)(void* headset, float* near, float* far);
   void (*getOrientation)(void* headset, float* x, float* y, float* z, float* w);
   void (*getPosition)(void* headset, float* x, float* y, float* z);
   const char* (*getType)(void* headset);
   void (*getVelocity)(void* headset, float* x, float* y, float* z);
   int (*isPresent)(void* headset);
   void (*renderTo)(void* headset, headsetRenderCallback callback, void* userdata);
+  void (*setClipDistance)(void* headset, float near, float far);
 } HeadsetInterface;
 
 typedef struct {
@@ -20,9 +22,11 @@ typedef struct {
 
 void lovrHeadsetInit();
 void lovrHeadsetGetAngularVelocity(float* x, float* y, float* z);
+void lovrHeadsetGetClipDistance(float* near, float* far);
 void lovrHeadsetGetOrientation(float* x, float* y, float* z, float* w);
 void lovrHeadsetGetPosition(float* x, float* y, float* z);
 const char* lovrHeadsetGetType();
 void lovrHeadsetGetVelocity(float* x, float* y, float* z);
 int lovrHeadsetIsPresent();
 void lovrHeadsetRenderTo(headsetRenderCallback callback, void* userdata);
+void lovrHeadsetSetClipDistance(float near, float far);
diff --git a/src/headset/vive.c b/src/headset/vive.c
index 63e975f8..b2090c57 100644
--- a/src/headset/vive.c
+++ b/src/headset/vive.c
@@ -10,6 +10,9 @@ typedef struct {
 
   unsigned int deviceIndex;
 
+  float clipNear;
+  float clipFar;
+
   uint32_t renderWidth;
   uint32_t renderHeight;
 
@@ -44,7 +47,7 @@ Headset* viveInit() {
   }
 
   EVRInitError vrError;
-  uint32_t vrHandle = VR_InitInternal(&vrError, EVRApplicationType_VRApplication_Scene);
+  VR_InitInternal(&vrError, EVRApplicationType_VRApplication_Scene);
 
   if (vrError != EVRInitError_VRInitError_None) {
     error("Problem initializing OpenVR");
@@ -127,6 +130,13 @@ void viveGetAngularVelocity(void* headset, float* x, float* y, float* z) {
   *z = pose.vAngularVelocity.v[2];
 }
 
+void viveGetClipDistance(void* headset, float* near, float* far) {
+  Headset* this = (Headset*) headset;
+  ViveState* state = this->state;
+  *near = state->clipNear;
+  *far = state->clipFar;
+}
+
 // TODO convert matrix to quaternion!
 void viveGetOrientation(void* headset, float* x, float* y, float *z, float* w) {
   *x = *y = *z = *w = 0.f;
@@ -184,46 +194,32 @@ int viveIsPresent(void* headset) {
 void viveRenderTo(void* headset, headsetRenderCallback callback, void* userdata) {
   Headset* this = headset;
   ViveState* state = this->state;
-
+  float headMatrix[16], eyeMatrix[16], projectionMatrix[16];
+  float (*matrix)[4];
+  EGraphicsAPIConvention graphicsConvention = EGraphicsAPIConvention_API_OpenGL;
   TrackedDevicePose_t pose;
+
   state->vrCompositor->WaitGetPoses(&pose, 1, NULL, 0);
-
-  float (*m)[4];
-  m = pose.mDeviceToAbsoluteTracking.m;
-  float headMatrix[16] = {
-    m[0][0], m[1][0], m[2][0], 0.0,
-    m[0][1], m[1][1], m[2][1], 0.0,
-    m[0][2], m[1][2], m[2][2], 0.0,
-    m[0][3], m[1][3], m[2][3], 1.0
-  };
-
-  mat4_invert(headMatrix);
+  matrix = pose.mDeviceToAbsoluteTracking.m;
+  mat4_invert(mat4_fromMat34(headMatrix, matrix));
 
   for (int i = 0; i < 2; i++) {
     EVREye eye = (i == 0) ? EVREye_Eye_Left : EVREye_Eye_Right;
 
-    m = state->vrSystem->GetEyeToHeadTransform(eye).m;
-    float eyeMatrix[16] = {
-      m[0][0], m[1][0], m[2][0], 0.0,
-      m[0][1], m[1][1], m[2][1], 0.0,
-      m[0][2], m[1][2], m[2][2], 0.0,
-      m[0][3], m[1][3], m[2][3], 1.0
-    };
+    matrix = state->vrSystem->GetEyeToHeadTransform(eye).m;
+    mat4_invert(mat4_fromMat34(eyeMatrix, matrix));
 
-    m = state->vrSystem->GetProjectionMatrix(eye, 0.1f, 30.0f, EGraphicsAPIConvention_API_OpenGL).m;
-    float projectionMatrix[16] = {
-      m[0][0], m[1][0], m[2][0], m[3][0],
-      m[0][1], m[1][1], m[2][1], m[3][1],
-      m[0][2], m[1][2], m[2][2], m[3][2],
-      m[0][3], m[1][3], m[2][3], m[3][3]
-    };
+    float near = state->clipNear;
+    float far = state->clipFar;
+    matrix = state->vrSystem->GetProjectionMatrix(eye, near, far, graphicsConvention).m;
+    mat4_fromMat44(projectionMatrix, matrix);
 
     Shader* shader = lovrGraphicsGetShader();
     if (shader) {
       int lovrTransformId = lovrShaderGetUniformId(shader, "lovrTransform");
       int lovrProjectionId = lovrShaderGetUniformId(shader, "lovrProjection");
-      mat4 m = mat4_multiply(mat4_multiply(projectionMatrix, mat4_invert(eyeMatrix)), headMatrix);
-      lovrShaderSendFloatMat4(shader, lovrTransformId, m);
+      mat4 transformMatrix = mat4_multiply(eyeMatrix, headMatrix);
+      lovrShaderSendFloatMat4(shader, lovrTransformId, transformMatrix);
       lovrShaderSendFloatMat4(shader, lovrProjectionId, projectionMatrix);
     }
 
@@ -243,8 +239,16 @@ void viveRenderTo(void* headset, headsetRenderCallback callback, void* userdata)
     glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
     glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 
-    Texture_t eyeTexture = { (void*) state->resolveTexture, EGraphicsAPIConvention_API_OpenGL, EColorSpace_ColorSpace_Gamma };
+    Texture_t eyeTexture = { (void*) state->resolveTexture, graphicsConvention, EColorSpace_ColorSpace_Gamma };
     EVRSubmitFlags flags = EVRSubmitFlags_Submit_Default;
     state->vrCompositor->Submit(eye, &eyeTexture, NULL, flags);
   }
 }
+
+void viveSetClipDistance(void* headset, float near, float far) {
+  Headset* this = (Headset*) headset;
+  ViveState* state = this->state;
+  state->clipNear = near;
+  state->clipFar = far;
+  // TODO recompute matrix (only if we're rendering?)
+}
diff --git a/src/headset/vive.h b/src/headset/vive.h
index 555c5b17..0ec29b3a 100644
--- a/src/headset/vive.h
+++ b/src/headset/vive.h
@@ -4,9 +4,11 @@ typedef char bool;
 
 Headset* viveInit();
 void viveGetAngularVelocity(void* headset, float* x, float* y, float* z);
+void viveGetClipDistance(void* headset, float* near, float* far);
 void viveGetOrientation(void* headset, float* x, float* y, float* z, float* w);
 void viveGetPosition(void* headset, float* x, float* y, float* z);
 const char* viveGetType(void* headset);
 void viveGetVelocity(void* headset, float* x, float* y, float* z);
 int viveIsPresent(void* headset);
 void viveRenderTo(void* headset, headsetRenderCallback callback, void* userdata);
+void viveSetClipDistance(void* headset, float near, float far);
diff --git a/src/lovr/graphics.c b/src/lovr/graphics.c
index ccf8aa25..55f37090 100644
--- a/src/lovr/graphics.c
+++ b/src/lovr/graphics.c
@@ -11,6 +11,7 @@ const luaL_Reg lovrGraphics[] = {
   { "getClearColor", l_lovrGraphicsGetClearColor },
   { "setClearColor", l_lovrGraphicsSetClearColor },
   { "setShader", l_lovrGraphicsSetShader },
+  { "getProjection", l_lovrGraphicsGetProjection },
   { "setProjection", l_lovrGraphicsSetProjection },
   { "push", l_lovrGraphicsPush },
   { "pop", l_lovrGraphicsPop },
@@ -91,12 +92,20 @@ int l_lovrGraphicsSetShader(lua_State* L) {
   return 0;
 }
 
+int l_lovrGraphicsGetProjection(lua_State* L) {
+  float near, far, fov;
+  lovrGraphicsGetProjection(&near, &far, &fov);
+  lua_pushnumber(L, near);
+  lua_pushnumber(L, far);
+  lua_pushnumber(L, fov);
+  return 3;
+}
+
 int l_lovrGraphicsSetProjection(lua_State* L) {
   float near = luaL_checknumber(L, 1);
   float far = luaL_checknumber(L, 2);
   float fov = luaL_checknumber(L, 3);
-  float aspect = luaL_checknumber(L, 4);
-  lovrGraphicsSetProjection(near, far, fov, aspect);
+  lovrGraphicsSetProjection(near, far, fov);
   return 0;
 }
 
diff --git a/src/lovr/graphics.h b/src/lovr/graphics.h
index 730cbd60..d5576ea0 100644
--- a/src/lovr/graphics.h
+++ b/src/lovr/graphics.h
@@ -14,6 +14,7 @@ int l_lovrGraphicsGetClearColor(lua_State* L);
 int l_lovrGraphicsSetClearColor(lua_State* L);
 int l_lovrGraphicsGetShader(lua_State* L);
 int l_lovrGraphicsSetShader(lua_State* L);
+int l_lovrGraphicsGetProjection(lua_State* L);
 int l_lovrGraphicsSetProjection(lua_State* L);
 int l_lovrGraphicsPush(lua_State* L);
 int l_lovrGraphicsPop(lua_State* L);
diff --git a/src/lovr/headset.c b/src/lovr/headset.c
index 9b1441b1..69827e2a 100644
--- a/src/lovr/headset.c
+++ b/src/lovr/headset.c
@@ -10,12 +10,14 @@ void renderHelper(int eyeIndex, void* userdata) {
 }
 
 const luaL_Reg lovrHeadset[] = {
-  { "getPosition", l_lovrHeadsetGetPosition },
-  { "getOrientation", l_lovrHeadsetGetPosition },
-  { "getVelocity", l_lovrHeadsetGetVelocity },
   { "getAngularVelocity", l_lovrHeadsetGetAngularVelocity },
+  { "getClipDistance", l_lovrHeadsetGetClipDistance },
+  { "getOrientation", l_lovrHeadsetGetPosition },
+  { "getPosition", l_lovrHeadsetGetPosition },
+  { "getVelocity", l_lovrHeadsetGetVelocity },
   { "isPresent", l_lovrHeadsetIsPresent },
   { "renderTo", l_lovrHeadsetRenderTo },
+  { "setClipDistance", l_lovrHeadsetSetClipDistance },
   { NULL, NULL }
 };
 
@@ -35,6 +37,14 @@ int l_lovrHeadsetGetAngularVelocity(lua_State* L) {
   return 3;
 }
 
+int l_lovrHeadsetGetClipDistance(lua_State* L) {
+  float near, far;
+  lovrHeadsetGetClipDistance(&near, &far);
+  lua_pushnumber(L, near);
+  lua_pushnumber(L, far);
+  return 2;
+}
+
 int l_lovrHeadsetGetOrientation(lua_State* L) {
   float x, y, z, w;
   lovrHeadsetGetOrientation(&x, &y, &z, &w);
@@ -73,3 +83,11 @@ int l_lovrHeadsetRenderTo(lua_State* L) {
   lovrHeadsetRenderTo(renderHelper, L);
   return 0;
 }
+
+int l_lovrHeadsetSetClipDistance(lua_State* L) {
+  float near = luaL_checknumber(L, 1);
+  float far = luaL_checknumber(L, 2);
+  lovrHeadsetSetClipDistance(near, far);
+  return 0;
+}
+
diff --git a/src/lovr/headset.h b/src/lovr/headset.h
index a911d2da..12f28174 100644
--- a/src/lovr/headset.h
+++ b/src/lovr/headset.h
@@ -4,9 +4,11 @@
 
 extern const luaL_Reg lovrHeadset[];
 int l_lovrHeadsetInit(lua_State* L);
-int l_lovrHeadsetGetPosition(lua_State* L);
-int l_lovrHeadsetGetOrientation(lua_State* L);
-int l_lovrHeadsetGetVelocity(lua_State* L);
 int l_lovrHeadsetGetAngularVelocity(lua_State* L);
+int l_lovrHeadsetGetClipDistance(lua_State* L);
+int l_lovrHeadsetGetOrientation(lua_State* L);
+int l_lovrHeadsetGetPosition(lua_State* L);
+int l_lovrHeadsetGetVelocity(lua_State* L);
 int l_lovrHeadsetIsPresent(lua_State* L);
 int l_lovrHeadsetRenderTo(lua_State* L);
+int l_lovrHeadsetSetClipDistance(lua_State* L);
diff --git a/src/matrix.c b/src/matrix.c
index 2296d0ca..ae2e3b4e 100644
--- a/src/matrix.c
+++ b/src/matrix.c
@@ -21,6 +21,46 @@ mat4 mat4_copy(mat4 source) {
   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;
+}
+
 void mat4_deinit(mat4 matrix) {
   free(matrix);
 }
@@ -77,6 +117,10 @@ mat4 mat4_setProjection(mat4 matrix, float near, float far, float fov, float asp
   return matrix;
 }
 
+void mat4_getProjection(mat4 matrix, float* near, float* far, float* fov, float* aspect) {
+  *near = *far = *fov = *aspect = 0.f;
+}
+
 mat4 mat4_translate(mat4 matrix, float x, float y, float z) {
   float translation[16];
   mat4_setTranslation(translation, x, y, z);
diff --git a/src/matrix.h b/src/matrix.h
index 99ee611c..fd3723a3 100644
--- a/src/matrix.h
+++ b/src/matrix.h
@@ -3,11 +3,14 @@ typedef float* mat4;
 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 w, float x, float y, float z);
 mat4 mat4_setScale(mat4 matrix, float x, float y, float z);
 mat4 mat4_setProjection(mat4 matrix, float near, float far, float fov, float aspect);
+void mat4_getProjection(mat4 matrix, float* near, float* far, float* fov, float* aspect);
 mat4 mat4_translate(mat4 matrix, float x, float y, float z);
 mat4 mat4_rotate(mat4 matrix, float w, float x, float y, float z);
 mat4 mat4_scale(mat4 matrix, float x, float y, float z);