consistently use float arithmetic in build_rotmatrix

By avoiding mixing doubles and floats, we avoid ever down-converting from a
float to a double and losing precision. Squashes some -Wfloat-conversion
warnings.

diff --git a/cmd/smyrna/trackball.c b/cmd/smyrna/trackball.c
index 294756ec4b7be4bcaeb7811879509ed7f693b4bb..bada247e4efbf867602790117262301060c7e7c9 100644 (file)
--- a/cmd/smyrna/trackball.c
+++ b/cmd/smyrna/trackball.c
@@ -286,23 +286,23 @@ static void normalize_quat(float q[4])
  */
 void build_rotmatrix(float m[4][4], float q[4])
 {
-    m[0][0] = 1.0 - 2.0 * (q[1] * q[1] + q[2] * q[2]);
-    m[0][1] = 2.0 * (q[0] * q[1] - q[2] * q[3]);
-    m[0][2] = 2.0 * (q[2] * q[0] + q[1] * q[3]);
-    m[0][3] = 0.0;
-
-    m[1][0] = 2.0 * (q[0] * q[1] + q[2] * q[3]);
-    m[1][1] = 1.0 - 2.0 * (q[2] * q[2] + q[0] * q[0]);
-    m[1][2] = 2.0 * (q[1] * q[2] - q[0] * q[3]);
-    m[1][3] = 0.0;
-
-    m[2][0] = 2.0 * (q[2] * q[0] - q[1] * q[3]);
-    m[2][1] = 2.0 * (q[1] * q[2] + q[0] * q[3]);
-    m[2][2] = 1.0 - 2.0 * (q[1] * q[1] + q[0] * q[0]);
-    m[2][3] = 0.0;
-
-    m[3][0] = 0.0;
-    m[3][1] = 0.0;
-    m[3][2] = 0.0;
-    m[3][3] = 1.0;
+    m[0][0] = 1.0f - 2.0f * (q[1] * q[1] + q[2] * q[2]);
+    m[0][1] = 2.0f * (q[0] * q[1] - q[2] * q[3]);
+    m[0][2] = 2.0f * (q[2] * q[0] + q[1] * q[3]);
+    m[0][3] = 0.0f;
+
+    m[1][0] = 2.0f * (q[0] * q[1] + q[2] * q[3]);
+    m[1][1] = 1.0f - 2.0f * (q[2] * q[2] + q[0] * q[0]);
+    m[1][2] = 2.0f * (q[1] * q[2] - q[0] * q[3]);
+    m[1][3] = 0.0f;
+
+    m[2][0] = 2.0f * (q[2] * q[0] - q[1] * q[3]);
+    m[2][1] = 2.0f * (q[1] * q[2] + q[0] * q[3]);
+    m[2][2] = 1.0f - 2.0f * (q[1] * q[1] + q[0] * q[0]);
+    m[2][3] = 0.0f;
+
+    m[3][0] = 0.0f;
+    m[3][1] = 0.0f;
+    m[3][2] = 0.0f;
+    m[3][3] = 1.0f;
 }