LibGL+LibGPU+LibSoftGPU: Implement flexible pixel format conversion

A GPU (driver) is now responsible for reading and writing pixels from
and to user data. The client (LibGL) is responsible for specifying how
the user data must be interpreted or written to.

This allows us to centralize all pixel format conversion in one class,
`LibSoftGPU::PixelConverter`. For both the input and output image, it
takes a specification containing the image dimensions, the pixel type
and the selection (basically a clipping rect), and converts the pixels
from the input image to the output image.

Effectively this means we now support almost all OpenGL 1.5 formats,
and all custom logic has disappeared from:
  - `glDrawPixels`
  - `glReadPixels`
  - `glTexImage2D`
  - `glTexSubImage2D`

The new logic is still unoptimized, but on my machine I experienced no
noticeable slowdown. :^)

1 files changed, 223 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGL/Image.cpp b/Userland/Libraries/LibGL/Image.cpp
new file mode 100644
index 0000000000..aaff615eac
--- /dev/null
+++ b/Userland/Libraries/LibGL/Image.cpp
@@ -0,0 +1,223 @@
+/*
+ * Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibGL/Image.h>
+
+namespace GL {
+
+ErrorOr<GPU::PixelType> get_validated_pixel_type(GLenum target, GLenum internal_format, GLenum format, GLenum type)
+{
+    // We accept GL_NONE as target for non-texture related calls (such as `glDrawPixels`)
+    if (target != GL_NONE
+        && target != GL_TEXTURE_1D
+        && target != GL_TEXTURE_2D
+        && target != GL_TEXTURE_3D
+        && target != GL_TEXTURE_1D_ARRAY
+        && target != GL_TEXTURE_2D_ARRAY
+        && target != GL_TEXTURE_CUBE_MAP
+        && target != GL_PROXY_TEXTURE_1D
+        && target != GL_PROXY_TEXTURE_2D
+        && target != GL_PROXY_TEXTURE_3D)
+        return Error::from_errno(GL_INVALID_ENUM);
+
+    // Internal format can be a number between 1 and 4. Symbolic formats were only added with EXT_texture, promoted to core in OpenGL 1.1
+    if (internal_format == 1)
+        internal_format = GL_ALPHA;
+    else if (internal_format == 2)
+        internal_format = GL_LUMINANCE_ALPHA;
+    else if (internal_format == 3)
+        internal_format = GL_RGB;
+    else if (internal_format == 4)
+        internal_format = GL_RGBA;
+
+    if (internal_format != GL_NONE
+        && internal_format != GL_ALPHA
+        && internal_format != GL_ALPHA4
+        && internal_format != GL_ALPHA8
+        && internal_format != GL_ALPHA12
+        && internal_format != GL_ALPHA16
+        && internal_format != GL_COMPRESSED_ALPHA
+        && internal_format != GL_COMPRESSED_LUMINANCE
+        && internal_format != GL_COMPRESSED_LUMINANCE_ALPHA
+        && internal_format != GL_COMPRESSED_INTENSITY
+        && internal_format != GL_COMPRESSED_RGB
+        && internal_format != GL_COMPRESSED_RGBA
+        && internal_format != GL_DEPTH_COMPONENT
+        && internal_format != GL_DEPTH_COMPONENT16
+        && internal_format != GL_DEPTH_COMPONENT24
+        && internal_format != GL_DEPTH_COMPONENT32
+        && internal_format != GL_DEPTH_STENCIL
+        && internal_format != GL_LUMINANCE
+        && internal_format != GL_LUMINANCE4
+        && internal_format != GL_LUMINANCE8
+        && internal_format != GL_LUMINANCE12
+        && internal_format != GL_LUMINANCE16
+        && internal_format != GL_LUMINANCE_ALPHA
+        && internal_format != GL_LUMINANCE4_ALPHA4
+        && internal_format != GL_LUMINANCE6_ALPHA2
+        && internal_format != GL_LUMINANCE8_ALPHA8
+        && internal_format != GL_LUMINANCE12_ALPHA4
+        && internal_format != GL_LUMINANCE12_ALPHA12
+        && internal_format != GL_LUMINANCE16_ALPHA16
+        && internal_format != GL_INTENSITY
+        && internal_format != GL_INTENSITY4
+        && internal_format != GL_INTENSITY8
+        && internal_format != GL_INTENSITY12
+        && internal_format != GL_INTENSITY16
+        && internal_format != GL_R3_G3_B2
+        && internal_format != GL_RED
+        && internal_format != GL_RG
+        && internal_format != GL_RGB
+        && internal_format != GL_RGB4
+        && internal_format != GL_RGB5
+        && internal_format != GL_RGB8
+        && internal_format != GL_RGB10
+        && internal_format != GL_RGB12
+        && internal_format != GL_RGB16
+        && internal_format != GL_RGBA
+        && internal_format != GL_RGBA2
+        && internal_format != GL_RGBA4
+        && internal_format != GL_RGB5_A1
+        && internal_format != GL_RGBA8
+        && internal_format != GL_RGB10_A2
+        && internal_format != GL_RGBA12
+        && internal_format != GL_RGBA16
+        && internal_format != GL_SLUMINANCE
+        && internal_format != GL_SLUMINANCE8
+        && internal_format != GL_SLUMINANCE_ALPHA
+        && internal_format != GL_SLUMINANCE8_ALPHA8
+        && internal_format != GL_SRGB
+        && internal_format != GL_SRGB8
+        && internal_format != GL_SRGB_ALPHA
+        && internal_format != GL_SRGB8_ALPHA8)
+        return Error::from_errno(GL_INVALID_ENUM);
+
+    if ((format < GL_COLOR_INDEX || format > GL_LUMINANCE_ALPHA) && format != GL_BGR && format != GL_BGRA)
+        return Error::from_errno(GL_INVALID_ENUM);
+
+    if (type != GL_BITMAP
+        && (type < GL_BYTE || type > GL_FLOAT)
+        && type != GL_HALF_FLOAT
+        && (type < GL_UNSIGNED_BYTE_3_3_2 || type > GL_UNSIGNED_INT_10_10_10_2)
+        && (type < GL_UNSIGNED_BYTE_2_3_3_REV || type > GL_UNSIGNED_INT_2_10_10_10_REV))
+        return Error::from_errno(GL_INVALID_ENUM);
+
+    if (type == GL_BITMAP && format != GL_COLOR_INDEX && format != GL_STENCIL_INDEX)
+        return Error::from_errno(GL_INVALID_ENUM);
+
+    if (format != GL_RGB && (type == GL_UNSIGNED_BYTE_3_3_2 || type == GL_UNSIGNED_BYTE_2_3_3_REV || type == GL_UNSIGNED_SHORT_5_6_5 || type == GL_UNSIGNED_SHORT_5_6_5_REV))
+        return Error::from_errno(GL_INVALID_OPERATION);
+
+    if ((type == GL_UNSIGNED_SHORT_4_4_4_4
+            || type == GL_UNSIGNED_SHORT_4_4_4_4_REV
+            || type == GL_UNSIGNED_SHORT_5_5_5_1
+            || type == GL_UNSIGNED_SHORT_1_5_5_5_REV
+            || type == GL_UNSIGNED_INT_8_8_8_8
+            || type == GL_UNSIGNED_INT_8_8_8_8_REV
+            || type == GL_UNSIGNED_INT_10_10_10_2
+            || type == GL_UNSIGNED_INT_2_10_10_10_REV)
+        && format != GL_RGBA
+        && format != GL_BGRA)
+        return Error::from_errno(GL_INVALID_OPERATION);
+
+    if (internal_format != GL_NONE) {
+        auto const internal_format_is_depth = internal_format == GL_DEPTH_COMPONENT
+            || internal_format == GL_DEPTH_COMPONENT16
+            || internal_format == GL_DEPTH_COMPONENT24
+            || internal_format == GL_DEPTH_COMPONENT32;
+
+        if ((target != GL_TEXTURE_2D && target != GL_PROXY_TEXTURE_2D && internal_format_is_depth)
+            || (format == GL_DEPTH_COMPONENT && !internal_format_is_depth)
+            || (format != GL_DEPTH_COMPONENT && internal_format_is_depth))
+            return Error::from_errno(GL_INVALID_OPERATION);
+    }
+
+    return get_format_specification(format, type);
+}
+
+GPU::PixelType get_format_specification(GLenum format, GLenum type)
+{
+    auto get_format = [](GLenum format) -> GPU::PixelFormat {
+        switch (format) {
+        case GL_ALPHA:
+            return GPU::PixelFormat::Alpha;
+        case GL_BGR:
+            return GPU::PixelFormat::BGR;
+        case GL_BGRA:
+            return GPU::PixelFormat::BGRA;
+        case GL_BLUE:
+            return GPU::PixelFormat::Blue;
+        case GL_COLOR_INDEX:
+            return GPU::PixelFormat::ColorIndex;
+        case GL_DEPTH_COMPONENT:
+            return GPU::PixelFormat::DepthComponent;
+        case GL_GREEN:
+            return GPU::PixelFormat::Green;
+        case GL_LUMINANCE:
+            return GPU::PixelFormat::Luminance;
+        case GL_LUMINANCE_ALPHA:
+            return GPU::PixelFormat::LuminanceAlpha;
+        case GL_RED:
+            return GPU::PixelFormat::Red;
+        case GL_RGB:
+            return GPU::PixelFormat::RGB;
+        case GL_RGBA:
+            return GPU::PixelFormat::RGBA;
+        case GL_STENCIL_INDEX:
+            return GPU::PixelFormat::StencilIndex;
+        }
+        VERIFY_NOT_REACHED();
+    };
+    auto pixel_format = get_format(format);
+
+    switch (type) {
+    case GL_BITMAP:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::Bitmap, GPU::ComponentsOrder::Normal };
+    case GL_BYTE:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::Byte, GPU::ComponentsOrder::Normal };
+    case GL_FLOAT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::Float, GPU::ComponentsOrder::Normal };
+    case GL_HALF_FLOAT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::HalfFloat, GPU::ComponentsOrder::Normal };
+    case GL_INT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::Int, GPU::ComponentsOrder::Normal };
+    case GL_SHORT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::Short, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_BYTE:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::UnsignedByte, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_BYTE_2_3_3_REV:
+        return { pixel_format, GPU::PixelComponentBits::B2_3_3, GPU::PixelDataType::UnsignedByte, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_BYTE_3_3_2:
+        return { pixel_format, GPU::PixelComponentBits::B3_3_2, GPU::PixelDataType::UnsignedByte, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_INT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::UnsignedInt, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_INT_2_10_10_10_REV:
+        return { pixel_format, GPU::PixelComponentBits::B2_10_10_10, GPU::PixelDataType::UnsignedInt, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_INT_8_8_8_8:
+        return { pixel_format, GPU::PixelComponentBits::B8_8_8_8, GPU::PixelDataType::UnsignedInt, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_INT_8_8_8_8_REV:
+        return { pixel_format, GPU::PixelComponentBits::B8_8_8_8, GPU::PixelDataType::UnsignedInt, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_INT_10_10_10_2:
+        return { pixel_format, GPU::PixelComponentBits::B10_10_10_2, GPU::PixelDataType::UnsignedInt, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_SHORT:
+        return { pixel_format, GPU::PixelComponentBits::AllBits, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_SHORT_1_5_5_5_REV:
+        return { pixel_format, GPU::PixelComponentBits::B1_5_5_5, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_SHORT_4_4_4_4:
+        return { pixel_format, GPU::PixelComponentBits::B4_4_4_4, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_SHORT_4_4_4_4_REV:
+        return { pixel_format, GPU::PixelComponentBits::B4_4_4_4, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_SHORT_5_6_5:
+        return { pixel_format, GPU::PixelComponentBits::B5_6_5, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Normal };
+    case GL_UNSIGNED_SHORT_5_6_5_REV:
+        return { pixel_format, GPU::PixelComponentBits::B5_6_5, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Reversed };
+    case GL_UNSIGNED_SHORT_5_5_5_1:
+        return { pixel_format, GPU::PixelComponentBits::B5_5_5_1, GPU::PixelDataType::UnsignedShort, GPU::ComponentsOrder::Normal };
+    }
+    VERIFY_NOT_REACHED();
+}
+
+}