Move API-agnostic image procs out of texture, to prepare to add threads.

* Procs `loadFileFromPointersLen`, `getDimensionsFormat` and related graphics
API-agnostic functions have been moved into their own module `texture_decode`.
* New directory `gpu_formats` added, where we will put all modules related to
decoding, optimizing and caching meshes and textures (independently of the
graphics API being used) in a separate thread or threads.

src/gpu_formats/texture_decode.nim

@@ -0,0 +1,200 @@
+# The contents of this file are subject to the Common Public Attribution License
+# Version 1.0 (the “License”); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+# https://myou.dev/licenses/LICENSE-CPAL. The License is based on the Mozilla
+# Public License Version 1.1 but Sections 14 and 15 have been added to cover use
+# of software over a computer network and provide for limited attribution for
+# the Original Developer. In addition, Exhibit A has been modified to be
+# consistent with Exhibit B.
+#
+# Software distributed under the License is distributed on an “AS IS” basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
+# the specific language governing rights and limitations under the License.
+#
+# The Original Code is Myou Engine.
+#
+# the Original Developer is the Initial Developer.
+#
+# The Initial Developer of the Original Code is the Myou Engine developers.
+# All portions of the code written by the Myou Engine developers are Copyright
+# (c) 2024. All Rights Reserved.
+#
+# Alternatively, the contents of this file may be used under the terms of the
+# GNU Affero General Public License version 3 (the [AGPL-3] License), in which
+# case the provisions of [AGPL-3] License are applicable instead of those above.
+#
+# If you wish to allow use of your version of this file only under the terms of
+# the [AGPL-3] License and not to allow others to use your version of this file
+# under the CPAL, indicate your decision by deleting the provisions above and
+# replace them with the notice and other provisions required by the [AGPL-3]
+# License. If you do not delete the provisions above, a recipient may use your
+# version of this file under either the CPAL or the [AGPL-3] License.
+
+import ../types
+
+# Forward declarations
+proc swap_lines(p: pointer, line_stride, line_count: int)
+# End forward declarations
+
+import std/strformat
+import vmath except Quat
+import arr_ref
+import float16
+
+when defined(myouUsePixie):
+    import pixie
+else:
+    import stb_image/read as stbi
+    const myouConvertHdrToFloat16 {.booldefine.} = true
+
+when not defined(nimdoc):
+    import tinyexr
+
+proc stride*(format: TextureFormat): int =
+    case format:
+    of SRGB_u8: 3
+    of SRGB_Alpha_u8: 4
+    of R_u8: 1
+    of RG_u8: 2
+    of RGB_u8: 3
+    of RGBA_u8: 4
+    of R_u16, R_f16: 2
+    of RG_u16, RG_f16: 4
+    of RGB_u16, RGB_f16: 6
+    of RGBA_u16, RGBA_f16: 8
+    of R_f32: 4
+    of RG_f32: 8
+    of RGB_f32: 12
+    of RGBA_f32: 16
+    of Depth_u16: 2
+    of Depth_u24: 3 # TODO: are you sure?
+    # of Depth_u24_s8: 4
+    of Depth_f32: 4
+
+proc channel_count*(format: TextureFormat): int =
+    case format:
+        of R_u8, R_u16, R_f16, R_f32, Depth_u16, Depth_u24, Depth_f32: 1
+        of RG_u8, RG_u16, RG_f16, RG_f32: 2
+        of SRGB_u8, RGB_u8, RGB_u16, RGB_f16, RGB_f32: 3
+        else: 4
+
+template toOpenArrayByte(p: pointer, a,b: untyped): untyped =
+    cast[ptr UncheckedArray[byte]](p).toOpenArray(a,b)
+
+# template toOpenArray[T](p: pointer, a,b: untyped): untyped =
+#     cast[ptr UncheckedArray[T]](p).toOpenArray(a,b)
+
+proc f32_to_f16(source: ptr UncheckedArray[float32], dest: ptr UncheckedArray[Float16], len: int) =
+    for i in 0 ..< len:
+        dest[i] = source[i].tofloat16(clamp=true)
+
+proc getDimensionsFormat*(p: pointer, len: int): (int, int, TextureFormat) =
+    when not defined(nimdoc):
+        if isEXR(p, len):
+            let dims = getEXRDimensions(p, len)
+            return (dims[0], dims[1], RGBA_f16)
+        when defined(myouUsePixie):
+            let dims = decodeImageDimensions(p, len)
+            return (dims.width, dims.height, RGBA_u8)
+        else:
+            var width, height, channels = 0
+            if not infoFromMemory(p.toOpenArrayByte(0, len-1), width, height, channels):
+                raise ValueError.newException "Could not read image"
+            let hdr = isHDRFromMemory(p.toOpenArrayByte(0, len-1))
+            let is16 = is16BitFromMemory(p.toOpenArrayByte(0, len-1))
+            # Calculate format with channels, and whether it's hdr or 16 bit
+            assert (RG_u8.int - R_u8.int) == 1 # (just in case someone changes the enum)
+            const toHDR = when myouConvertHdrToFloat16: (R_f16.int-R_u8.int) else: (R_f32.int-R_u8.int)
+            let format = (R_u8.int - 1 + channels +
+                hdr.int * toHDR + is16.int * (R_u16.int-R_u8.int)).TextureFormat
+            return (width, height, format)
+
+proc loadFileFromPointersLen*(tex: Texture, pointers: seq[(pointer, int)],
+                        callback: proc(tex: Texture, p: pointer), flip = true) =
+
+    when not defined(nimdoc):
+        assert tex.tex_type != TexCube, "Loading a cube texture from file is not supported yet"
+        let layer_stride = tex.width * tex.height * tex.format.stride
+        var multilayer_buffer: ArrRef[byte]
+        assert tex.depth == pointers.len
+        if tex.depth > 1:
+            multilayer_buffer = newArrRef[byte](layer_stride * tex.depth)
+        var pos = 0
+        for (p, len) in pointers:
+            when defined(myouUsePixie):
+                var image: Image
+            else:
+                var image: imagePixelData[byte]
+                var image_16: imagePixelData[uint16]
+                var image_f: imagePixelData[float32]
+            var buffer: ArrRef[byte]
+            # a reference to this pointer is kept with one of the vars above
+            var pixels_ptr: pointer
+            var pixels_len: int
+            var flip = flip
+            if isEXR(p, len):
+                let (width, height, pixels) = decodeEXR(p, len)
+                assert width == tex.width and height == tex.height, "Image size mismatch"
+                buffer = pixels.to byte
+                pixels_ptr = buffer[0].addr
+                pixels_len = buffer.len
+            else:
+                when defined(myouUsePixie):
+                    image = decodeImage(p, len)
+                    assert image.width == tex.width and image.height == tex.height, "Image size mismatch"
+                    pixels_ptr = image.data[0].addr
+                    pixels_len = image.data.len * sizeof image.data[0]
+                else:
+                    setFlipVerticallyOnLoad(flip)
+                    flip = false
+                    var w,h,c = 0
+                    if isHDRFromMemory(p.toOpenArrayByte(0, len-1)):
+                        image_f = loadFFromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
+                        pixels_ptr = image_f.data
+                        pixels_len = image_f.byteLen
+                        when myouConvertHdrToFloat16:
+                            f32_to_f16(
+                                cast[ptr UncheckedArray[float32]](pixels_ptr),
+                                cast[ptr UncheckedArray[Float16]](pixels_ptr),
+                                image_f.len)
+                            pixels_len = pixels_len div 2
+                    elif is16BitFromMemory(p.toOpenArrayByte(0, len-1)):
+                        image_16 = load16FromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
+                        pixels_ptr = image_16.data
+                        pixels_len = image_16.byteLen
+                    else:
+                        image = loadFromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
+                        pixels_ptr = image.data
+                        pixels_len = image.len
+            assert layer_stride == pixels_len,
+                &"Image '{tex.name}' has a length of {pixels_len}, expected {layer_stride}"
+            if flip:
+                swap_lines(pixels_ptr, tex.width * tex.format.stride, tex.height)
+            if tex.depth == 1:
+                callback(tex, pixels_ptr)
+                return
+            copyMem(multilayer_buffer[pos].addr, pixels_ptr, layer_stride)
+            pos += layer_stride
+        callback(tex, multilayer_buffer[0].addr)
+
+
+proc swap_lines(p: pointer, line_stride, line_count: int) =
+    template `+`(p: pointer, i: Natural): pointer = cast[pointer](cast[int](p) +% cast[int](i))
+    template `-`(p: pointer, i: Natural): pointer = cast[pointer](cast[int](p) -% cast[int](i))
+    let int_stride = line_stride div sizeof(int)
+    let int_stride_bytes = int_stride * sizeof(int)
+    var p1 = p
+    var p2 = p + line_stride*(line_count-1)
+    var a1, a2: ptr UncheckedArray[int]
+    var b1, b2: ptr UncheckedArray[byte]
+    for i in 0 ..< line_count div 2:
+        a1 = cast[ptr UncheckedArray[int]](p1)
+        a2 = cast[ptr UncheckedArray[int]](p2)
+        b1 = cast[ptr UncheckedArray[byte]](p1)
+        b2 = cast[ptr UncheckedArray[byte]](p2)
+        for j in 0 ..< int_stride:
+            swap(a1[j], a2[j])
+        for j in int_stride_bytes ..< line_stride:
+            swap(b1[j], b2[j])
+        p1 = p1 + line_stride
+        p2 = p2 - line_stride

src/graphics/texture.nim

@@ -35,11 +35,10 @@ import vmath except Quat
 import arr_ref
 # import tinyre
 import std/tables
+import ../gpu_formats/texture_decode
 import ../platform/gl
 
 # Forward declarations
-proc stride*(format: TextureFormat): int
-proc channel_count*(format: TextureFormat): int
 func mipmapHigh*(self: Texture): int
 proc needsMipmap*(self: Texture): bool
 proc setMaxTextures*(count: int32)
@@ -52,7 +51,6 @@ proc unbindAllTextures*()
 proc destroy*(texture: Texture)
 proc loadFromPixels*(self: Texture, pixels: pointer)
 proc loadCubeSideFromPixels*(self: Texture, pixels: pointer, side: int32 = 0)
-proc loadFileFromPointersLen*(self: Texture, pointers: seq[(pointer, int)], flip = true)
 proc setFilter*(self: Texture, filter: TextureFilter)
 proc newTexture*(engine: MyouEngine, name: string, width, height: int, depth: int = 1,
         format: TextureFormat,
@@ -60,7 +58,6 @@ proc newTexture*(engine: MyouEngine, name: string, width, height: int, depth: in
         filter: TextureFilter = Trilinear,
         pixels: ArrRef[float32] = nil): Texture
 proc generateMipmap*(self: Texture)
-proc getDimensionsFormat(p: pointer, len: int): (int, int, TextureFormat)
 func to_sRGB*(format: TextureFormat): TextureFormat
 proc newTexture*(engine: MyouEngine, name: string, p: pointer, len: int, is_sRGB: bool, filter: TextureFilter = Trilinear, depth=1, flip=true): Texture
 proc newTexture*(engine: MyouEngine, name: string, file_name: string, is_sRGB: bool,
@@ -69,7 +66,6 @@ proc newTexture*(engine: MyouEngine, name: string, file_name: string, is_sRGB: b
         flip = true,
     ): Texture
 proc setExtrapolation*(self: Texture, ext: TextureExtrapolation)
-proc swap_lines(p: pointer, line_stride, line_count: int)
 proc getTexturePixels*(self: Texture): TexturePixels
 proc setMipmapRange*(self: Texture, first = 0, last = 1000)
 func vec3size*(self: Texture, mip_level = -1): Vec3
@@ -78,18 +74,8 @@ func toInternalFormat*(format: TextureFormat): GLenum
 
 # import sugar
 
-when defined(myouUsePixie):
-    import pixie
-else:
-    import stb_image/read as stbi
-    const myouConvertHdrToFloat16 {.booldefine.} = true
-
-when not defined(nimdoc):
-    import tinyexr
-
 import std/bitops
 import std/strformat
-import float16
 import loadable
 import ddx_ktx
 
@@ -110,34 +96,6 @@ if defined(android):
     # even if it's not used, we should test it
     reserved = 1
 
-proc stride*(format: TextureFormat): int =
-    case format:
-    of SRGB_u8: 3
-    of SRGB_Alpha_u8: 4
-    of R_u8: 1
-    of RG_u8: 2
-    of RGB_u8: 3
-    of RGBA_u8: 4
-    of R_u16, R_f16: 2
-    of RG_u16, RG_f16: 4
-    of RGB_u16, RGB_f16: 6
-    of RGBA_u16, RGBA_f16: 8
-    of R_f32: 4
-    of RG_f32: 8
-    of RGB_f32: 12
-    of RGBA_f32: 16
-    of Depth_u16: 2
-    of Depth_u24: 3 # TODO: are you sure?
-    # of Depth_u24_s8: 4
-    of Depth_f32: 4
-
-proc channel_count*(format: TextureFormat): int =
-    case format:
-        of R_u8, R_u16, R_f16, R_f32, Depth_u16, Depth_u24, Depth_f32: 1
-        of RG_u8, RG_u16, RG_f16, RG_f32: 2
-        of SRGB_u8, RGB_u8, RGB_u16, RGB_f16, RGB_f32: 3
-        else: 4
-
 func samplerType*(tex_type: TextureType): string =
     case tex_type:
         of Tex2D: "sampler2D"
@@ -409,82 +367,6 @@ proc loadCompressedData*(self: Texture, info: KtxInfo, data: seq[KtxPart]) =
             info.internal_format.GLenum, self.width.GLsizei, self.height.GLsizei,
             0, part.len.GLsizei, part.data)
 
-template toOpenArrayByte(p: pointer, a,b: untyped): untyped =
-    cast[ptr UncheckedArray[byte]](p).toOpenArray(a,b)
-
-template toOpenArray[T](p: pointer, a,b: untyped): untyped =
-    cast[ptr UncheckedArray[T]](p).toOpenArray(a,b)
-
-proc f32_to_f16(source: ptr UncheckedArray[float32], dest: ptr UncheckedArray[Float16], len: int) =
-    for i in 0 ..< len:
-        dest[i] = source[i].tofloat16(clamp=true)
-
-proc loadFileFromPointersLen*(self: Texture, pointers: seq[(pointer, int)], flip = true) =
-    when not defined(nimdoc):
-        assert self.tex_type != TexCube, "Loading a cube texture from file is not supported yet"
-        let layer_stride = self.width * self.height * self.format.stride
-        var multilayer_buffer: ArrRef[byte]
-        assert self.depth == pointers.len
-        if self.depth > 1:
-            multilayer_buffer = newArrRef[byte](layer_stride * self.depth)
-        var pos = 0
-        for (p, len) in pointers:
-            when defined(myouUsePixie):
-                var image: Image
-            else:
-                var image: imagePixelData[byte]
-                var image_16: imagePixelData[uint16]
-                var image_f: imagePixelData[float32]
-            var buffer: ArrRef[byte]
-            # a reference to this pointer is kept with one of the vars above
-            var pixels_ptr: pointer
-            var pixels_len: int
-            var flip = flip
-            if isEXR(p, len):
-                let (width, height, pixels) = decodeEXR(p, len)
-                assert width == self.width and height == self.height, "Image size mismatch"
-                buffer = pixels.to byte
-                pixels_ptr = buffer[0].addr
-                pixels_len = buffer.len
-            else:
-                when defined(myouUsePixie):
-                    image = decodeImage(p, len)
-                    assert image.width == self.width and image.height == self.height, "Image size mismatch"
-                    pixels_ptr = image.data[0].addr
-                    pixels_len = image.data.len * sizeof image.data[0]
-                else:
-                    setFlipVerticallyOnLoad(flip)
-                    flip = false
-                    var w,h,c = 0
-                    if isHDRFromMemory(p.toOpenArrayByte(0, len-1)):
-                        image_f = loadFFromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
-                        pixels_ptr = image_f.data
-                        pixels_len = image_f.byteLen
-                        when myouConvertHdrToFloat16:
-                            f32_to_f16(
-                                cast[ptr UncheckedArray[float32]](pixels_ptr),
-                                cast[ptr UncheckedArray[Float16]](pixels_ptr),
-                                image_f.len)
-                            pixels_len = pixels_len div 2
-                    elif is16BitFromMemory(p.toOpenArrayByte(0, len-1)):
-                        image_16 = load16FromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
-                        pixels_ptr = image_16.data
-                        pixels_len = image_16.byteLen
-                    else:
-                        image = loadFromMemory(p.toOpenArrayByte(0, len-1), w,h,c,0)
-                        pixels_ptr = image.data
-                        pixels_len = image.len
-            assert layer_stride == pixels_len,
-                &"Image '{self.name}' has a length of {pixels_len}, expected {layer_stride}"
-            if flip:
-                swap_lines(pixels_ptr, self.width * self.format.stride, self.height)
-            if self.depth == 1:
-                self.loadFromPixels pixels_ptr
-                return
-            copyMem(multilayer_buffer[pos].addr, pixels_ptr, layer_stride)
-            pos += layer_stride
-        self.loadFromPixels multilayer_buffer[0].addr
-
 proc setFilter*(self: Texture, filter: TextureFilter) =
     self.filter = filter
     self.engine.renderer.enqueue proc()=
@@ -548,27 +430,6 @@ proc generateMipmap*(self: Texture) =
     self.bind_it(needs_active_texture=true)
     glGenerateMipmap(self.storage.target)
 
-proc getDimensionsFormat(p: pointer, len: int): (int, int, TextureFormat) =
-    when not defined(nimdoc):
-        if isEXR(p, len):
-            let dims = getEXRDimensions(p, len)
-            return (dims[0], dims[1], RGBA_f16)
-        when defined(myouUsePixie):
-            let dims = decodeImageDimensions(p, len)
-            return (dims.width, dims.height, RGBA_u8)
-        else:
-            var width, height, channels = 0
-            if not infoFromMemory(p.toOpenArrayByte(0, len-1), width, height, channels):
-                raise ValueError.newException "Could not read image"
-            let hdr = isHDRFromMemory(p.toOpenArrayByte(0, len-1))
-            let is16 = is16BitFromMemory(p.toOpenArrayByte(0, len-1))
-            # Calculate format with channels, and whether it's hdr or 16 bit
-            assert (RG_u8.int - R_u8.int) == 1 # (just in case someone changes the enum)
-            const toHDR = when myouConvertHdrToFloat16: (R_f16.int-R_u8.int) else: (R_f32.int-R_u8.int)
-            let format = (R_u8.int - 1 + channels +
-                hdr.int * toHDR + is16.int * (R_u16.int-R_u8.int)).TextureFormat
-            return (width, height, format)
-
 func to_sRGB*(format: TextureFormat): TextureFormat =
     return case format:
         of RGBA_u8: SRGB_Alpha_u8
@@ -582,7 +443,7 @@ proc newTexture*(engine: MyouEngine, name: string, p: pointer, len: int, is_sRGB
         format = format.to_sRGB
     let self = engine.newTexture(name, width, height, depth, format, filter=filter)
     engine.renderer.enqueue proc() =
-        self.loadFileFromPointersLen(@[(p, len)], flip=flip)
+        self.loadFileFromPointersLen(@[(p, len)], loadFromPixels, flip=flip)
         self.loaded = true
     return self
 
@@ -633,7 +494,7 @@ proc newTexture*(engine: MyouEngine, name: string, file_name: string, is_sRGB: b
             engine.renderer.enqueue proc()=
                 try:
                     self.ensure_storage()
-                    self.loadFileFromPointersLen(@[(p, len)])
+                    self.loadFileFromPointersLen(@[(p, len)], loadFromPixels)
                     self.loaded = true
                 except:
                     # TODO: use logging
@@ -657,27 +518,6 @@ proc setExtrapolation*(self: Texture, ext: TextureExtrapolation) =
         glTexParameteri(self.storage.target, GL_TEXTURE_WRAP_T, e.GLint)
         glTexParameteri(self.storage.target, GL_TEXTURE_WRAP_R, e.GLint)
 
-proc swap_lines(p: pointer, line_stride, line_count: int) =
-    template `+`(p: pointer, i: Natural): pointer = cast[pointer](cast[int](p) +% cast[int](i))
-    template `-`(p: pointer, i: Natural): pointer = cast[pointer](cast[int](p) -% cast[int](i))
-    let int_stride = line_stride div sizeof(int)
-    let int_stride_bytes = int_stride * sizeof(int)
-    var p1 = p
-    var p2 = p + line_stride*(line_count-1)
-    var a1, a2: ptr UncheckedArray[int]
-    var b1, b2: ptr UncheckedArray[byte]
-    for i in 0 ..< line_count div 2:
-        a1 = cast[ptr UncheckedArray[int]](p1)
-        a2 = cast[ptr UncheckedArray[int]](p2)
-        b1 = cast[ptr UncheckedArray[byte]](p1)
-        b2 = cast[ptr UncheckedArray[byte]](p2)
-        for j in 0 ..< int_stride:
-            swap(a1[j], a2[j])
-        for j in int_stride_bytes ..< line_stride:
-            swap(b1[j], b2[j])
-        p1 = p1 + line_stride
-        p2 = p2 - line_stride
-
 proc getTexturePixels*(self: Texture): TexturePixels =
     when false:
         var len_bytes, cube_stride = self.width * self.height * self.format.stride