libkwineffects: add a lookup table class

src/CMakeLists.txt

@@ -109,6 +109,7 @@ target_sources(kwin PRIVATE
     libkwineffects/colorspace.cpp
     libkwineffects/effecttogglablestate.cpp
     libkwineffects/glframebuffer.cpp
+    libkwineffects/gllut.cpp
     libkwineffects/glplatform.cpp
     libkwineffects/glshader.cpp
     libkwineffects/glshadermanager.cpp
@@ -122,11 +123,8 @@ target_sources(kwin PRIVATE
     libkwineffects/kwinoffscreenquickview.cpp
     libkwineffects/kwinquickeffect.cpp
     libkwineffects/logging.cpp
-    libkwineffects/logging.cpp
     libkwineffects/openglcontext.cpp
     libkwineffects/rendertarget.cpp
-    libkwineffects/rendertarget.cpp
-    libkwineffects/renderviewport.cpp
     libkwineffects/renderviewport.cpp
     libkwineffects/version.cpp
     lidswitchtracker.cpp
@@ -433,6 +431,7 @@ install(FILES
 install(FILES
     libkwineffects/colorspace.h
     libkwineffects/glframebuffer.h
+    libkwineffects/gllut.h
     libkwineffects/glplatform.h
     libkwineffects/glshader.h
     libkwineffects/glshadermanager.h

src/libkwineffects/gllut.cpp

@@ -0,0 +1,70 @@
+/*
+    KWin - the KDE window manager
+    This file is part of the KDE project.
+
+    SPDX-FileCopyrightText: 2023 Xaver Hugl <xaver.hugl@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#include "gllut.h"
+
+#include <vector>
+
+namespace KWin
+{
+
+GlLookUpTable::GlLookUpTable(GLuint handle, size_t size)
+    : m_handle(handle)
+    , m_size(size)
+{
+}
+
+GlLookUpTable::~GlLookUpTable()
+{
+    glDeleteTextures(1, &m_handle);
+}
+
+GLuint GlLookUpTable::handle() const
+{
+    return m_handle;
+}
+
+size_t GlLookUpTable::size() const
+{
+    return m_size;
+}
+
+void GlLookUpTable::bind()
+{
+    glBindTexture(GL_TEXTURE_1D, m_handle);
+}
+
+std::unique_ptr<GlLookUpTable> GlLookUpTable::create(const std::function<QVector3D(size_t value)> &func, size_t size)
+{
+    GLuint handle = 0;
+    glGenTextures(1, &handle);
+    if (!handle) {
+        return nullptr;
+    }
+    glBindTexture(GL_TEXTURE_1D, handle);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAX_LEVEL, 0);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_LOD, 0);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAX_LOD, 0);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    std::vector<float> data;
+    data.reserve(4 * size);
+    for (size_t i = 0; i < size; i++) {
+        const auto color = func(i);
+        data.push_back(color.x());
+        data.push_back(color.y());
+        data.push_back(color.z());
+        data.push_back(1);
+    }
+    glTexImage1D(GL_TEXTURE_1D, 0, GL_RGBA16F, size, 0, GL_RGBA, GL_FLOAT, data.data());
+    glBindTexture(GL_TEXTURE_1D, 0);
+    return std::make_unique<GlLookUpTable>(handle, size);
+}
+
+}

src/libkwineffects/gllut.h

@@ -0,0 +1,40 @@
+/*
+    KWin - the KDE window manager
+    This file is part of the KDE project.
+
+    SPDX-FileCopyrightText: 2023 Xaver Hugl <xaver.hugl@gmail.com>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#pragma once
+
+#include "kwin_export.h"
+
+#include <QVector3D>
+#include <QVector>
+#include <epoxy/gl.h>
+#include <functional>
+#include <memory>
+
+namespace KWin
+{
+
+class KWIN_EXPORT GlLookUpTable
+{
+public:
+    explicit GlLookUpTable(GLuint handle, size_t size);
+    ~GlLookUpTable();
+
+    GLuint handle() const;
+    size_t size() const;
+
+    void bind();
+
+    static std::unique_ptr<GlLookUpTable> create(const std::function<QVector3D(size_t value)> &func, size_t size);
+
+private:
+    const GLuint m_handle;
+    const size_t m_size;
+};
+
+}