Try to add compute shaders

src/Render.hs

@@ -44,6 +44,7 @@ createLightMap cfig = case shadrendertype of
     InstancingShads -> instanceLightMap cfig
     NoShadows -> const . const . const renderLightingNoShadows
     NoLighting -> const . const . const . const . const . const renderFlatLighting
+    ComputeShader -> renderComputeShadows
     _ -> renderShadows shadrendertype
   where
     shadrendertype = cfig ^. graphics_shadow_rendering
@@ -103,6 +104,28 @@ renderLightingNoShadows positiontexture normaltexture lightPoints pdata = do
     glDisable GL_CULL_FACE
     glDisable GL_STENCIL_TEST
 
+renderComputeShadows ::
+    GLsizei ->
+    Int ->
+    Int ->
+    TO ->
+    TO ->
+    [(Point3, Float, Point3)] ->
+    RenderData ->
+    IO ()
+renderComputeShadows _ _ _ toPos tanormals lightPoints rd = do
+    withArray (lightsToArray lightPoints) $ \ptr ->
+        glNamedBufferSubData (rd ^. lightsUBO) 0 620 ptr
+    glBindTextureUnit 0 (toPos ^. unTO)
+    glBindTextureUnit 1 (tanormals ^. unTO)
+    glBindImageTexture 5 (rd ^. fboLighting . _2 . unTO) 0 GL_FALSE 0 GL_WRITE_ONLY GL_RGBA8
+    glUseProgram (rd ^. computeShadowShader)
+    glDispatchCompute 800 835 1
+    -- the following should be later, just before the texture is accessed
+    --glMemoryBarrier GL_SHADER_IMAGE_ACCESS_BARRIER_BIT
+    glMemoryBarrier GL_TEXTURE_FETCH_BARRIER_BIT
+    return ()
+
 renderFlatLighting :: RenderData -> IO ()
 renderFlatLighting pdata = do
     glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
@@ -145,12 +168,14 @@ renderShadows shadrendertype nWalls nSils nCaps positiontexture normaltexture li
             ptr
     -- for each of the lights:
     -- 1. stencil out the shadows from this light's point of view
-    -- 2. calculate lighting based on each fragment's position
-    -- to consider: adding normals/a "material" for each fragment
+    -- 2. calculate lighting based on each fragment's position and normal
     glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
     glEnable GL_STENCIL_TEST
     glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
     glStencilOpSeparate GL_BACK GL_KEEP GL_KEEP GL_DECR_WRAP
+    -- bind world position texture-- these will be used by the lighting shader
+    glBindTextureUnit 0 (positiontexture ^. unTO)
+    glBindTextureUnit 1 (normaltexture ^. unTO)
     flip VFSM.mapM_ (VFSM.fromList lightPoints) $ \(V3 x y z, rad, V3 r g b) -> do
         glDepthFunc GL_LESS
         -- setup stencil
@@ -200,10 +225,7 @@ renderShadows shadrendertype nWalls nSils nCaps positiontexture normaltexture li
             _ -> return ()
         --draw lightmap itself
         glDepthFunc GL_ALWAYS
-        -- bind world position texture
         glDisable GL_CULL_FACE
-        glBindTextureUnit 0 (positiontexture ^. unTO)
-        glBindTextureUnit 1 (normaltexture ^. unTO)
         glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
         glStencilFunc GL_EQUAL 0 255
         glUseProgram (ltextShad ^. shaderUINT) --Just (_shadProg ltextShad)