Merge pull request #262 from evo-lua/encode-tga-function

Add EncodeTGA to the image processing API

Runtime/API/C_ImageProcessing.lua

@@ -121,4 +121,32 @@ function C_ImageProcessing.EncodeJPG(rgbaPixelArray, imageWidthInPixels, imageHe
 	return tostring(outputBuffer)
 end
 
+function C_ImageProcessing.EncodeTGA(rgbaPixelArray, imageWidthInPixels, imageHeightInPixels)
+	if type(rgbaPixelArray) == "userdata" then
+		rgbaPixelArray = tostring(rgbaPixelArray)
+	end
+
+	validateString(rgbaPixelArray, "rgbaPixelArray")
+	validateNumber(imageWidthInPixels, "imageWidthInPixels")
+	validateNumber(imageHeightInPixels, "imageHeightInPixels")
+
+	local rgbaPixelBuffer = buffer.new(#rgbaPixelArray):put(rgbaPixelArray)
+
+	local image = ffi_new("stbi_image_t")
+	image.width = imageWidthInPixels
+	image.height = imageHeightInPixels
+	image.data = rgbaPixelBuffer
+	image.channels = 4
+
+	local requiredBufferSize = stbi.bindings.stbi_get_required_tga_size(image)
+	local outputBuffer = buffer.new()
+	local startPointer, reservedBufferSize = outputBuffer:reserve(requiredBufferSize)
+
+	local numBytesWritten = stbi.bindings.stbi_encode_tga(image, startPointer, reservedBufferSize)
+	assert(numBytesWritten > 0, "Failed to encode TGA image (preallocated buffer too small?)")
+	outputBuffer:commit(numBytesWritten)
+
+	return tostring(outputBuffer)
+end
+
 return C_ImageProcessing

Tests/BDD/imageprocessing-namespace.spec.lua

@@ -3,9 +3,11 @@ local EXAMPLE_IMAGE_BUFFER = buffer.new():put(EXAMPLE_IMAGE_DATA)
 local EXAMPLE_BMP_BYTES = C_FileSystem.ReadFile(path.join("Tests", "Fixtures", "rgba-pixels.bmp"))
 local EXAMPLE_PNG_BYTES = C_FileSystem.ReadFile(path.join("Tests", "Fixtures", "rgba-pixels.png"))
 local EXAMPLE_JPG_BYTES = C_FileSystem.ReadFile(path.join("Tests", "Fixtures", "rgba-pixels.jpg"))
+local EXAMPLE_TGA_BYTES = C_FileSystem.ReadFile(path.join("Tests", "Fixtures", "rgba-pixels.tga"))
 local EXAMPLE_BMP_BUFFER = buffer.new():put(EXAMPLE_BMP_BYTES)
 local EXAMPLE_PNG_BUFFER = buffer.new():put(EXAMPLE_PNG_BYTES)
 local EXAMPLE_JPG_BUFFER = buffer.new():put(EXAMPLE_JPG_BYTES)
+local EXAMPLE_TGA_BUFFER = buffer.new():put(EXAMPLE_TGA_BYTES)
 
 describe("C_ImageProcessing", function()
 	describe("DecodeFileContents", function()
@@ -93,6 +95,22 @@ describe("C_ImageProcessing", function()
 			assertEquals(imageHeightInPixels, 2)
 		end)
 
+		it("should be able to decode TGA file contents from a string", function()
+			local rgbaPixelArray, imageWidthInPixels, imageHeightInPixels =
+				C_ImageProcessing.DecodeFileContents(EXAMPLE_TGA_BYTES)
+			assertEquals(rgbaPixelArray, EXAMPLE_IMAGE_DATA)
+			assertEquals(imageWidthInPixels, 2)
+			assertEquals(imageHeightInPixels, 2)
+		end)
+
+		it("should be able to decode TGA file contents from a string buffer", function()
+			local rgbaPixelArray, imageWidthInPixels, imageHeightInPixels =
+				C_ImageProcessing.DecodeFileContents(EXAMPLE_TGA_BUFFER)
+			assertEquals(rgbaPixelArray, EXAMPLE_IMAGE_DATA)
+			assertEquals(imageWidthInPixels, 2)
+			assertEquals(imageHeightInPixels, 2)
+		end)
+
 		it("should throw if garbage bytes are passed as the file contents", function()
 			local function attemptToDecodeInvalidFile()
 				C_ImageProcessing.DecodeFileContents("Not a valid image file")
@@ -227,4 +245,43 @@ describe("C_ImageProcessing", function()
 			assertThrows(attemptToEncodeInvalidFile, expectedErrorMessage)
 		end)
 	end)
+
+	describe("EncodeTGA", function()
+		it("should be able to encode pixel data given as a string", function()
+			local bmpFileContents = C_ImageProcessing.EncodeTGA(EXAMPLE_IMAGE_DATA, 2, 2)
+			assertEquals(bmpFileContents, EXAMPLE_TGA_BYTES)
+		end)
+
+		it("should be able to encode pixel data given as a string buffer", function()
+			local bmpFileContents = C_ImageProcessing.EncodeTGA(EXAMPLE_IMAGE_BUFFER, 2, 2)
+			assertEquals(bmpFileContents, EXAMPLE_TGA_BYTES)
+		end)
+
+		it("should throw if a non-string type was passed as the pixel buffer", function()
+			local function attemptToEncodeInvalidFile()
+				C_ImageProcessing.EncodeTGA(123, 2, 2)
+			end
+			local expectedErrorMessage =
+				"Expected argument rgbaPixelArray to be a string value, but received a number value instead"
+			assertThrows(attemptToEncodeInvalidFile, expectedErrorMessage)
+		end)
+
+		it("should throw if a non-number type was passed as the image width", function()
+			local function attemptToEncodeInvalidFile()
+				C_ImageProcessing.EncodeTGA(EXAMPLE_IMAGE_DATA, "2", 2)
+			end
+			local expectedErrorMessage =
+				"Expected argument imageWidthInPixels to be a number value, but received a string value instead"
+			assertThrows(attemptToEncodeInvalidFile, expectedErrorMessage)
+		end)
+
+		it("should throw if a non-number type was passed as the image height", function()
+			local function attemptToEncodeInvalidFile()
+				C_ImageProcessing.EncodeTGA(EXAMPLE_IMAGE_DATA, 2, "2")
+			end
+			local expectedErrorMessage =
+				"Expected argument imageHeightInPixels to be a number value, but received a string value instead"
+			assertThrows(attemptToEncodeInvalidFile, expectedErrorMessage)
+		end)
+	end)
 end)