gpu_tonemapper: Adjust sample points to maintain linearity

Adjust texture sample points to maintain linearity throughout the
sample range

CRs-Fixed: 1110654
Change-Id: I2c198c9f330a0b6001d2eda28c0355f2c9ecbde4
diff --git a/gpu_tonemapper/engine.h b/gpu_tonemapper/engine.h
index ca914b2..c07f13e 100644
--- a/gpu_tonemapper/engine.h
+++ b/gpu_tonemapper/engine.h
@@ -36,6 +36,7 @@
 void engine_set3DInputBuffer(int binding, unsigned int textureID);
 void engine_setExternalInputBuffer(int binding, unsigned int textureID);
 void engine_setDestination(int id, int x, int y, int w, int h);
+void engine_setData2f(int loc, float* data);
 
 int engine_blit(int);