texture

package.nix

@@ -35,8 +35,8 @@
   ];
   ghcPackages = p: [
     p.GLFW-b
+    p.GLUtil
     p.linear
-    p.linear-opengl
     p.OpenGL
     p.relude
   ];

src/Haskengl/IO.hs

@@ -6,11 +6,12 @@ module Haskengl.IO (openWindow, shutdownWindow, view) where
 -- IMPORTS --
 
 import qualified Graphics.Rendering.OpenGL as GL
-import           Graphics.Rendering.OpenGL (($=))
+import           Graphics.Rendering.OpenGL         (($=))
+import qualified Graphics.GLUtil           as GLU  (readTexture, texture2DWrap)
 import qualified Graphics.UI.GLFW          as GLFW
 import qualified Language.GLSL             as GLSL
 import qualified Linear                    as L
-import Linear.V4 (V4(..))
+import           Linear.V4                         (V4(..))
 
 import Control.Exception
 import Control.Monad
@@ -83,6 +84,14 @@ testArray =
   , GL.Vertex3 0.5 0.5 0
   ]
 
+verticesUVArray :: [GL.Vertex2 GL.GLfloat]
+verticesUVArray =
+  [ GL.Vertex2 0 0
+  , GL.Vertex2 1 0
+  , GL.Vertex2 0 1
+  , GL.Vertex2 1 1
+  ]
+
 generateRGBA :: Int -> [GL.Color4 GL.GLfloat]
 generateRGBA i =
   take i $ cycle rgba
@@ -123,6 +132,7 @@ createDisplayableObject array numComponents primitiveMode = do
   GL.bindVertexArrayObject $= Just vao
   vbo_0 <- createVBO array numComponents $ GL.AttribLocation 0
   vbo_1 <- createVBO (generateRGBA $ length array) 4 $ GL.AttribLocation 1
+  vbo_2 <- createVBO verticesUVArray 2 $ GL.AttribLocation 2
   return
     (DisplayableObject
       vao
@@ -132,6 +142,13 @@ createDisplayableObject array numComponents primitiveMode = do
       primitiveMode
     )
 
+loadTexture :: FilePath -> IO GL.TextureObject
+loadTexture f = do
+  Right t <- GLU.readTexture f
+  GL.textureFilter GL.Texture2D $= ((GL.Linear', Nothing), GL.Nearest)
+  GLU.texture2DWrap $= (GL.Repeated, GL.ClampToEdge)
+  return t
+
 initResources :: GLFW.Window -> IO DisplayableObjects
 initResources window = do
   -- init objects
@@ -142,6 +159,12 @@ initResources window = do
   putStrLn (unpack $ GLSL.generateGLSL vertShader)
   putStrLn (unpack $ GLSL.generateGLSL fragShader)
 
+  GL.activeTexture $= GL.TextureUnit 0
+  let tex = "assets/flag.png"
+  tx <- loadTexture tex
+  GL.texture GL.Texture2D $= GL.Enabled
+  GL.textureBinding GL.Texture2D $= Just tx
+
   -- load shaders
   program <- loadShaders
     [ ShaderInfo GL.VertexShader (StringSource $ unpack $ GLSL.generateGLSL vertShader)
@@ -156,7 +179,7 @@ initResources window = do
   (w, h) <- GLFW.getFramebufferSize window
 
   let
-    perspectiveMatrix = toGLMatrix $ L.perspective (78 * 3.141592653 / 180) ((fromIntegral w) / (fromIntegral h)) 0.1 100 L.!*! L.lookAt (L.V3 0 0 (-3)) (L.V3 0 0 0) (L.V3 0 1 0)
+    perspectiveMatrix = toGLMatrix $ L.perspective (78 * 3.141592653 / 180) ((fromIntegral w) / (fromIntegral h)) 0.1 100 L.!*! L.lookAt (L.V3 0 0 (-2)) (L.V3 0 0 0) (L.V3 0 1 0)
   putStrLn $ show perspectiveMatrix
 
   let
@@ -170,6 +193,9 @@ initResources window = do
   location0 <- GL.get $ GL.uniformLocation program "projection"
   GL.uniform location0 $= projection
 
+  location1 <- GL.get $ GL.uniformLocation program "tex"
+  GL.uniform location1 $= (GL.TextureUnit 0)
+
   putStrLn $ show projection
   putStrLn $ show location0
 

src/Haskengl/IO/Shaders/Shaders.hs

@@ -13,9 +13,11 @@ fragShader :: Program
 fragShader =
   [ VersionDeclaration 450 Core
   , VariableDeclaration Nothing In fragColorOut
+  , VariableDeclaration Nothing In uv
   , VariableDeclaration Nothing Out fragColor
+  , DangerousExpression "uniform sampler2D tex;"
   , MainStart
-  , VariableAssignment fragColor fragColorOut
+  , DangerousExpression "fragColor = texture(tex, uv);"
   ]
 
 vertShader :: Program
@@ -23,11 +25,14 @@ vertShader =
   [ VersionDeclaration 450 Core
   , VariableDeclaration (Just $ Location 0) In vertexPosition
   , VariableDeclaration (Just $ Location 1) In vertexColor
+  , VariableDeclaration (Just $ Location 2) In uvCoords
   , VariableDeclaration Nothing Out fragColorOut
+  , VariableDeclaration Nothing Out uv
   , VariableDeclaration Nothing Uniform projection
   , MainStart
   , DangerousExpression "gl_Position = projection * vec4(vertexPosition, 1.0);"
   , VariableAssignment fragColorOut vertexColor
+  , VariableAssignment uv uvCoords
   ]
 
 fragColor = Variable "fragColor" $ GLSLVec4 GLSLFloat
@@ -35,3 +40,5 @@ fragColorOut = Variable "fragColorOut" $ GLSLVec4 GLSLFloat
 vertexPosition = Variable "vertexPosition" $ GLSLVec3 GLSLFloat
 vertexColor = Variable "vertexColor" $ GLSLVec4 GLSLFloat
 projection = Variable "projection" $ GLSLMat4 GLSLFloat
+uvCoords = Variable "uvCoords" $ GLSLVec2 GLSLFloat
+uv = Variable "uv" $ GLSLVec2 GLSLFloat