Tidy up image example (#96)

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Alexander Bondarenko 2021-09-12 14:56:43 +03:00 committed by GitHub
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commit 88326420b8
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3 changed files with 105 additions and 78 deletions

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@ -264,7 +264,7 @@ executable image
import: common
main-is: Image.hs
hs-source-dirs: examples/sdl
build-depends: sdl2, gl, dear-imgui, managed, vector, hmatrix
build-depends: sdl2, gl, dear-imgui, managed, vector
if (!flag(examples) || !flag(sdl) || !flag(opengl2))
buildable: False

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@ -2,11 +2,16 @@
{-# language LambdaCase #-}
{-# language OverloadedStrings #-}
{- | Drawing an DearImGui image using OpenGL textures.
https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples
-}
module Main ( main ) where
import Control.Exception
import Control.Monad.IO.Class
import Control.Monad.Managed
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.Managed (managed, managed_, runManaged)
import DearImGui
import qualified DearImGui.Raw as Raw
import DearImGui.OpenGL3
@ -17,117 +22,143 @@ import qualified SDL as SDL
-- For the texture creation
import Foreign
import Foreign.Ptr
import qualified Numeric.LinearAlgebra as M
import Foreign.Marshal.Alloc
import Data.IORef
import qualified Data.Vector.Storable as VS
data Texture = Texture {textureID :: GLuint, textureWidth :: GLsizei, textureHeight :: GLsizei}
data Texture = Texture
{ textureID :: GLuint
, textureWidth :: GLsizei
, textureHeight :: GLsizei
}
-- |Creates a texture in memory
--
-- Reserves space on the texture-memory for width*height
textureSize :: Texture -> ImVec2
textureSize texture =
ImVec2
(fromIntegral $ textureWidth texture)
(fromIntegral $ textureHeight texture)
-- | Create a texture pointer in GL memory.
create2DTexture :: Int -> Int -> IO Texture
create2DTexture width height = do
alloca $ \ptr -> do
create2DTexture width height =
alloca \ptr -> do
glGenTextures 1 ptr
tID <- peek ptr
return Texture {textureID = tID, textureWidth = fromIntegral width, textureHeight = fromIntegral height}
return Texture
{ textureID = tID
, textureWidth = fromIntegral width
, textureHeight = fromIntegral height
}
--createDummyTexture :: IORef Texture -> M.Matrix (Float) -> IO ()
--createDummyTexture texture matrix = do
createDummyTexture :: Texture -> IO ()
createDummyTexture texture = do
let width = textureWidth texture
let height = textureWidth texture
bindTexture :: Texture -> Ptr GLubyte -> IO ()
bindTexture texture dataPtr = do
glEnable GL_TEXTURE_2D
glBindTexture GL_TEXTURE_2D $ textureID texture
glBindTexture GL_TEXTURE_2D (textureID texture)
glTexParameteri GL_TEXTURE_2D GL_TEXTURE_MIN_FILTER GL_LINEAR
glTexParameteri GL_TEXTURE_2D GL_TEXTURE_MAG_FILTER GL_LINEAR
glTexParameteri GL_TEXTURE_2D GL_TEXTURE_WRAP_S GL_REPEAT
glTexParameteri GL_TEXTURE_2D GL_TEXTURE_WRAP_T GL_REPEAT
let dat = VS.generate (3*(fromIntegral width)*(fromIntegral height)) (\i -> fromIntegral $ 17 + (50 * (i `mod` 3)):: GLubyte) :: VS.Vector GLubyte -- some blueish
VS.unsafeWith dat $ \dataPtr -> do
glTexImage2D GL_TEXTURE_2D 0 GL_RGB width height 0 GL_RGB GL_UNSIGNED_BYTE (castPtr dataPtr)
return()
glBindTexture GL_TEXTURE_2D 0
return ()
gui :: IO ()
gui = do
glTexImage2D
GL_TEXTURE_2D
0
GL_RGB
(textureWidth texture)
(textureHeight texture)
0
GL_RGB
GL_UNSIGNED_BYTE
(castPtr dataPtr)
fill :: Integral size => size -> size -> VS.Vector GLubyte
fill width height =
VS.generate
(3 * fromIntegral width * fromIntegral height)
(\i ->
case i `mod` 3 of
0 -> 0x00
1 -> 0x7F
2 -> 0xFF
_ -> error "assert: 3-byte pitch"
)
main :: IO ()
main = do
-- Initialize SDL
SDL.initializeAll
runManaged do
-- Create a window using SDL. As we're using OpenGL, we need to enable OpenGL too.
w <- do
window <- do
let title = "Hello, Dear ImGui!"
let config = SDL.defaultWindow { SDL.windowGraphicsContext = SDL.OpenGLContext SDL.defaultOpenGL, SDL.windowResizable = True }
managed $ bracket (SDL.createWindow title config) SDL.destroyWindow
-- Create an OpenGL context
glContext <- managed $ bracket (SDL.glCreateContext w) SDL.glDeleteContext
glContext <- managed $ bracket (SDL.glCreateContext window) SDL.glDeleteContext
-- Create an ImGui context
_ <- managed $ bracket createContext destroyContext
_dearContext <- managed $ bracket createContext destroyContext
-- Initialize ImGui's SDL2 backend
_ <- managed_ $ bracket_ (sdl2InitForOpenGL w glContext) sdl2Shutdown
managed_ $ bracket_ (sdl2InitForOpenGL window glContext) sdl2Shutdown
-- Initialize ImGui's OpenGL backend
_ <- managed_ $ bracket_ openGL3Init (do
managed_ $ bracket_ openGL3Init do
putStrLn "ImguiOpenGL shut down"
openGL3Shutdown)
openGL3Shutdown
liftIO $ do
txt <- create2DTexture 500 500
createDummyTexture txt
liftIO do
let width = 320
height = 240
texture <- create2DTexture width height
VS.unsafeWith (fill width height) $
bindTexture texture
err <- glGetError
putStrLn $ "Error-code: " ++ show err
liftIO $ do
mainLoop w 1 -- 1 is actually the Ptr address
putStrLn $ "Error-code: " ++ show err
mainLoop window texture
mainLoop :: SDL.Window -> GLuint -> IO ()
mainLoop w c = do
-- Process the event loop
untilNothingM pollEventWithImGui
mainLoop :: SDL.Window -> Texture -> IO ()
mainLoop window texture = unlessQuit do
-- Tell ImGui we're starting a new frame
openGL3NewFrame
sdl2NewFrame
newFrame
-- Build the GUI
bracket_ (begin "GL") end $ do
-- image (intPtrToPtr $ fromIntegral c) (ImVec2 500 500)(ImVec2 0 0)(ImVec2 1 1)(ImVec4 1 1 1 1)(ImVec4 0 0 0 0)
Foreign.with (ImVec2 500 500) \sizePtr ->
Foreign.with (ImVec2 0 0) \uv0Ptr ->
Foreign.with (ImVec2 1 1) \uv1Ptr ->
Foreign.with (ImVec4 1 1 1 1) \tintColPtr ->
Foreign.with (ImVec4 0 0 0 0) \borderColPtr -> do
Raw.image (intPtrToPtr $ fromIntegral c) sizePtr uv0Ptr uv1Ptr tintColPtr borderColPtr
withWindowOpen "Image example" $ runManaged do
-- Drawing images require some backend-specific code.
-- Meanwhile, we have to deal with raw binding.
let openGLtextureID = intPtrToPtr $ fromIntegral $ textureID texture
sizePtr <- managed $ Foreign.with (textureSize texture)
uv0Ptr <- managed $ Foreign.with (ImVec2 0 0)
uv1Ptr <- managed $ Foreign.with (ImVec2 1 1)
tintColPtr <- managed $ Foreign.with (ImVec4 1 1 1 1)
borderColPtr <- managed $ Foreign.with (ImVec4 0 1 0 0)
Raw.image openGLtextureID sizePtr uv0Ptr uv1Ptr tintColPtr borderColPtr
-- Render
render
glClear GL_COLOR_BUFFER_BIT
openGL3RenderDrawData =<< getDrawData
DearImGui.render
DearImGui.getDrawData >>= openGL3RenderDrawData
SDL.glSwapWindow w
SDL.glSwapWindow window
mainLoop w c
mainLoop window texture
where
untilNothingM m = m >>= maybe (return ()) (\_ -> untilNothingM m)
unlessQuit action = do
shouldQuit <- checkEvents
if shouldQuit then pure () else action
main = do gui
checkEvents = do
pollEventWithImGui >>= \case
Nothing ->
return False
Just event ->
(isQuit event ||) <$> checkEvents
isQuit event =
SDL.eventPayload event == SDL.QuitEvent

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@ -559,22 +559,18 @@ arrowButton strIdPtr dir = liftIO do
(0 /=) <$> [C.exp| bool { ArrowButton($(char* strIdPtr), $(ImGuiDir dir)) } |]
-- | Image Area to draw a texture
-- | Image Area to draw a texture.
--
-- Wraps @ImGui::Image()
-- For OpenGL: The @userTextureIDPtr@ points to the texture memory (eg. @0x0000000000000001@)
--
-- For OpenGL: The userTextureIDPtr points to the texture memory (eg. 0x0x0000000000000001), it is the number from glBindTexture.
-- Eg:
-- glBindTexture GL_TEXTURE_2D $ textureID texture
-- -- fill textureID
-- image (intPtrToPtr $ fromIntegral textureID) (ImVec2 500 500)(ImVec2 0 0)(ImVec2 1 1)(ImVec4 1 1 1 1)(ImVec4 0 0 0 0)
-- See @examples/sdl/Image.hs@ for the whole process.
--
-- See https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples#About-texture-coordinates and under examples/sdl/Image.hs
image :: (MonadIO m) => Ptr ()-> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec4 -> Ptr ImVec4 -> m()
-- Wraps @ImGui::Image()@.
image :: (MonadIO m) => Ptr () -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec4 -> Ptr ImVec4 -> m ()
image userTextureIDPtr sizePtr uv0Ptr uv1Ptr tintColPtr borderColPtr = liftIO do
[C.exp| void {
[C.exp| void {
Image(
$(void* userTextureIDPtr),
$(void* userTextureIDPtr),
*$(ImVec2* sizePtr),
*$(ImVec2* uv0Ptr),
*$(ImVec2* uv1Ptr),