Simplify rotations;

src/graphics/graphics.c

@@ -294,8 +294,8 @@ void lovrGraphicsTranslate(float x, float y, float z) {
   mat4_translate(state.transforms[state.transform], x, y, z);
 }
 
-void lovrGraphicsRotate(float w, float x, float y, float z) {
-  mat4_rotate(state.transforms[state.transform], w, x, y, z);
+void lovrGraphicsRotate(float angle, float ax, float ay, float az) {
+  mat4_rotate(state.transforms[state.transform], angle, ax, ay, az);
 }
 
 void lovrGraphicsScale(float x, float y, float z) {
@@ -304,28 +304,11 @@ 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) {
 
-  // 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 qw = cos2;
-  float qx = sin2 * ax;
-  float qy = sin2 * ay;
-  float qz = sin2 * az;
-
   // M *= T * S * R
   float transform[16];
   mat4_setTranslation(transform, tx, ty, tz);
   mat4_scale(transform, sx, sy, sz);
-  mat4_rotate(transform, qw, qx, qy, qz);
+  mat4_rotate(transform, angle, ax, ay, az);
   lovrGraphicsMatrixTransform(transform);
 }
 
@@ -552,17 +535,10 @@ void lovrGraphicsSkybox(Skybox* skybox, float angle, float ax, float ay, float a
   lovrRetain(&lastShader->ref);
   lovrGraphicsSetShader(state.skyboxShader);
 
-  float cos2 = cos(angle / 2);
-  float sin2 = sin(angle / 2);
-  float rw = cos2;
-  float rx = sin2 * ax;
-  float ry = sin2 * ay;
-  float rz = sin2 * az;
-
   lovrGraphicsPrepare();
   lovrGraphicsPush();
   lovrGraphicsOrigin();
-  lovrGraphicsRotate(rw, rx, ry, rz);
+  lovrGraphicsRotate(angle, ax, ay, az);
 
   float cube[] = {
     // Front

src/graphics/graphics.h

@@ -108,7 +108,7 @@ int lovrGraphicsPush();
 int lovrGraphicsPop();
 void lovrGraphicsOrigin();
 void lovrGraphicsTranslate(float x, float y, float z);
-void lovrGraphicsRotate(float w, float x, float y, float z);
+void lovrGraphicsRotate(float angle, float ax, float ay, float az);
 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);
 void lovrGraphicsMatrixTransform(mat4 transform);

src/lovr/graphics.c

@@ -426,13 +426,7 @@ int l_lovrGraphicsRotate(lua_State* L) {
   float axisX = luaL_checknumber(L, 2);
   float axisY = luaL_checknumber(L, 3);
   float axisZ = luaL_checknumber(L, 4);
-  float cos2 = cos(angle / 2);
-  float sin2 = sin(angle / 2);
-  float w = cos2;
-  float x = sin2 * axisX;
-  float y = sin2 * axisY;
-  float z = sin2 * axisZ;
-  lovrGraphicsRotate(w, x, y, z);
+  lovrGraphicsRotate(angle, axisX, axisY, axisZ);
   return 0;
 }
 

src/matrix.c

@@ -80,7 +80,25 @@ mat4 mat4_setTranslation(mat4 matrix, float x, float y, float z) {
   return matrix;
 }
 
-mat4 mat4_setRotation(mat4 matrix, float w, float x, float y, float z) {
+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;
@@ -141,9 +159,9 @@ mat4 mat4_translate(mat4 matrix, float x, float y, float z) {
   return mat4_multiply(matrix, translation);
 }
 
-mat4 mat4_rotate(mat4 matrix, float w, float x, float y, float z) {
+mat4 mat4_rotate(mat4 matrix, float angle, float ax, float ay, float az) {
   float rotation[16];
-  mat4_setRotation(rotation, w, x, y, z);
+  mat4_setRotation(rotation, angle, ax, ay, az);
   return mat4_multiply(matrix, rotation);
 }
 

src/matrix.h

@@ -13,12 +13,12 @@ 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_setRotation(mat4 matrix, float angle, float ax, float ay, float az);
 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_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 w, 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);