LibGL: Introduce Texture base class for all texture types

Userland/Libraries/LibGL/Tex/Texture2D.cpp

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Format.h>
+#include <LibGL/GL/gl.h>
+#include <LibGL/Tex/Texture2D.h>
+#include <string.h>
+
+namespace GL {
+
+void Texture2D::upload_texture_data(GLenum, GLint lod, GLint internal_format, GLsizei width, GLsizei height, GLint, GLenum format, GLenum, const GLvoid* pixels)
+{
+    // NOTE: Some target, format, and internal formats are currently unsupported.
+    // Considering we control this library, and `gl.h` itself, we don't need to add any
+    // checks here to see if we support them; the program will simply fail to compile..
+
+    // Somebody passed us in nullptr...
+    // Apparently this allocates memory on the GPU (according to Khronos docs..)?
+    if (pixels == nullptr) {
+        dbgln("LibGL: pixels == nullptr when uploading texture data.");
+        VERIFY_NOT_REACHED();
+    }
+
+    m_internal_format = internal_format;
+
+    // Get reference to the mip
+    auto& mip = m_mipmaps[lod];
+    const u8* pixel_byte_array = reinterpret_cast<const u8*>(pixels);
+
+    // Copy pixel data to storage
+
+    // Pixels are already 32-bits wide
+    if (format == GL_RGBA || format == GL_BGRA) {
+        mip.pixel_data().resize(width * height * sizeof(u32));
+        memcpy(mip.pixel_data().data(), pixels, width * height * sizeof(u32));
+    } else {
+        mip.pixel_data().resize(width * height * 3);
+        // Copy RGB or BGR pixel data
+        for (auto i = 0; i < width * height * 3; i += 3) {
+            u32 b0 = pixel_byte_array[i];     // B or R
+            u32 b1 = pixel_byte_array[i + 1]; // G
+            u32 b2 = pixel_byte_array[i + 2]; // R or B
+
+            u32 pixel = ((0xffu << 24) | (b0 << 16) | (b1 << 8) | b2);
+            mip.pixel_data().append(pixel);
+        }
+    }
+
+    // Now we need to swizzle the texture data from `format` to `internal_format`
+    switch (format) {
+    case GL_BGR: {
+        if (internal_format == GL_RGB) {
+            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
+                u8 r = pixel & 0xff;
+                u8 g = (pixel >> 8) & 0xff;
+                u8 b = (pixel >> 16) & 0xff;
+
+                return (0xff << 24) | (r << 16) | (g << 8) | b;
+            });
+        } else if (internal_format == GL_RGBA) {
+            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
+                u8 r = pixel & 0xff;
+                u8 g = (pixel >> 8) & 0xff;
+                u8 b = (pixel >> 16) & 0xff;
+
+                return (r << 24) | (g << 16) | (b << 8) | 0xff;
+            });
+        }
+    } break;
+    case GL_BGRA: {
+        if (internal_format == GL_RGB) {
+            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
+                u8 r = (pixel >> 8) & 0xff;
+                u8 g = (pixel >> 16) & 0xff;
+                u8 b = (pixel >> 24) & 0xff;
+
+                return (0xff << 24) | (r << 16) | (g << 8) | b;
+            });
+        } else if (internal_format == GL_RGBA) {
+            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
+                u8 a = pixel & 0xff;
+                u8 r = (pixel >> 8) & 0xff;
+                u8 g = (pixel >> 16) & 0xff;
+                u8 b = (pixel >> 24) & 0xff;
+
+                return (r << 24) | (g << 16) | (b << 8) | a;
+            });
+        }
+    } break;
+    case GL_RGB: {
+        if (internal_format == GL_RGBA) {
+            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
+                u8 r = pixel & 0xff;
+                u8 g = (pixel >> 8) & 0xff;
+                u8 b = (pixel >> 16) & 0xff;
+
+                return (r << 24) | (g << 16) | (b << 8) | 0xff;
+            });
+        }
+    } break;
+    case GL_RGBA:
+        break;
+    default:
+        // Let's crash for now so we can implement format by format
+        VERIFY_NOT_REACHED();
+    }
+
+    mip.set_width(width);
+    mip.set_height(height);
+}
+
+FloatVector4 Texture2D::sample_texel(const FloatVector2& uv) const
+{
+    auto& mip = m_mipmaps.at(0);
+
+    // FIXME: Remove this to prevent a crash when we have proper texture binding
+    if (mip.width() == 0 || mip.height() == 0)
+        return { 1.0f, 1.0f, 1.0f, 1.0f };
+
+    u32 u = static_cast<u32>(uv.x() * mip.width());
+    u32 v = static_cast<u32>(uv.y() * mip.height());
+
+    u32 pixel = mip.pixel_data().at(v * mip.width() + u);
+
+    float b0 = ((pixel)&0xff) / 255.0f;
+    float b1 = ((pixel >> 8) & 0xff) / 255.0f;
+    float b2 = ((pixel >> 16) & 0xff) / 255.0f;
+
+    return { b0, b1, b2, 1.0f };
+}
+
+}