From ff53e8fe7121bc66a010ea92cccc4f46552b9d7f Mon Sep 17 00:00:00 2001
From: Alex Szpakowski <slime73@gmail.com>
Date: Mon, 24 Oct 2016 18:14:09 -0300
Subject: [PATCH] Fix non-integer coordinates passed to
 ImageData:mapPixel/setPixel/getPixel and SoundData:set/getSample.

LuaJIT does interesting things when you index into a FFI array using a non-integer value.
---
 src/modules/image/wrap_ImageData.lua | 12 ++++++++++++
 src/modules/sound/wrap_SoundData.lua |  5 +++++
 2 files changed, 17 insertions(+)

diff --git a/src/modules/image/wrap_ImageData.lua b/src/modules/image/wrap_ImageData.lua
index 22fbc451b..ddc0e7fd4 100644
--- a/src/modules/image/wrap_ImageData.lua
+++ b/src/modules/image/wrap_ImageData.lua
@@ -27,6 +27,7 @@ local ImageData = ImageData_mt.__index
 
 local tonumber, assert, error = tonumber, assert, error
 local type, pcall = type, pcall
+local floor = math.floor
 
 local function inside(x, y, w, h)
 	return x >= 0 and x < w and y >= 0 and y < h
@@ -126,6 +127,11 @@ function ImageData:_mapPixelUnsafe(func, ix, iy, iw, ih)
 	local p = objectcache[self]
 	local idw, idh = p.width, p.height
 
+	ix = floor(ix)
+	iy = floor(iy)
+	iw = floor(iw)
+	ih = floor(ih)
+
 	local pixels = p.pointer
 
 	for y=iy, iy+ih-1 do
@@ -144,6 +150,9 @@ function ImageData:getPixel(x, y)
 	if type(x) ~= "number" then error("bad argument #1 to ImageData:getPixel (expected number)", 2) end
 	if type(y) ~= "number" then error("bad argument #2 to ImageData:getPixel (expected number)", 2) end
 
+	x = floor(x)
+	y = floor(y)
+
 	local p = objectcache[self]
 	if not inside(x, y, p.width, p.height) then error("Attempt to get out-of-range pixel!", 2) end
 
@@ -161,6 +170,9 @@ function ImageData:setPixel(x, y, r, g, b, a)
 	if type(x) ~= "number" then error("bad argument #1 to ImageData:setPixel (expected number)", 2) end
 	if type(y) ~= "number" then error("bad argument #2 to ImageData:setPixel (expected number)", 2) end
 
+	x = floor(x)
+	y = floor(y)
+
 	if type(r) == "table" then
 		local t = r
 		r, g, b, a = t[1], t[2], t[3], t[4]
diff --git a/src/modules/sound/wrap_SoundData.lua b/src/modules/sound/wrap_SoundData.lua
index 803a9a2d1..e74482397 100644
--- a/src/modules/sound/wrap_SoundData.lua
+++ b/src/modules/sound/wrap_SoundData.lua
@@ -35,6 +35,7 @@ local status, ffi = pcall(require, "ffi")
 if not status then return end
 
 local tonumber, assert, error = tonumber, assert, error
+local floor = math.floor
 
 local float = ffi.typeof("float")
 local datatypes = {ffi.typeof("uint8_t *"), ffi.typeof("int16_t *")}
@@ -77,6 +78,8 @@ local objectcache = setmetatable({}, {
 function SoundData:getSample(i)
 	if type(i) ~= "number" then error("bad argument #1 to SoundData:getSample (expected number)", 2) end
 
+	i = floor(i)
+
 	local p = objectcache[self]
 
 	if not (i >= 0 and i < p.size/p.bytedepth) then
@@ -96,6 +99,8 @@ function SoundData:setSample(i, sample)
 	if type(i) ~= "number" then error("bad argument #1 to SoundData:setSample (expected number)", 2) end
 	if type(sample) ~= "number" then error("bad argument #2 to SoundData:setSample (expected number)", 2) end
 
+	i = floor(i)
+
 	local p = objectcache[self]
 
 	if not (i >= 0 and i < p.size/p.bytedepth) then