From ade45b5b9930b52b6a1d399306539073e8e2196d Mon Sep 17 00:00:00 2001
From: wwylele <wwylele@gmail.com>
Date: Mon, 17 Apr 2017 10:01:45 +0300
Subject: pica/swrasterizer: implement procedural texture

---
 src/common/vector_math.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'src/common/vector_math.h')

diff --git a/src/common/vector_math.h b/src/common/vector_math.h
index 7ca8e15f5..c7a461a1e 100644
--- a/src/common/vector_math.h
+++ b/src/common/vector_math.h
@@ -652,6 +652,16 @@ static inline decltype((X{} * int{} + X{} * int{}) / base) LerpInt(const X& begi
     return (begin * (base - t) + end * t) / base;
 }
 
+// bilinear interpolation. s is for interpolating x00-x01 and x10-x11, and t is for the second
+// interpolation.
+template <typename X>
+inline auto BilinearInterp(const X& x00, const X& x01, const X& x10, const X& x11, const float s,
+                           const float t) {
+    auto y0 = Lerp(x00, x01, s);
+    auto y1 = Lerp(x10, x11, s);
+    return Lerp(y0, y1, t);
+}
+
 // Utility vector factories
 template <typename T>
 static inline Vec2<T> MakeVec(const T& x, const T& y) {
-- 
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