[feature] Implement scrollable page list

src/main/java/net/vulkanmod/config/gui/AbstractScrollList.java

@@ -0,0 +1,297 @@
+package net.vulkanmod.config.gui;
+
+import com.mojang.blaze3d.opengl.GlStateManager;
+import it.unimi.dsi.fastutil.objects.ObjectArrayList;
+import net.minecraft.client.gui.components.events.GuiEventListener;
+import net.minecraft.client.input.MouseButtonEvent;
+import net.minecraft.util.Mth;
+import net.vulkanmod.config.gui.render.GuiRenderer;
+import net.vulkanmod.config.gui.widget.VAbstractWidget;
+import net.vulkanmod.vulkan.util.ColorUtil;
+import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NonNull;
+
+import java.util.List;
+
+public abstract class AbstractScrollList extends GuiElement {
+    protected final List<Entry> children = new ObjectArrayList<>();
+    protected boolean scrolling = false;
+    protected float scrollAmount = 0.0f;
+    protected int itemWidth;
+    protected int totalItemHeight;
+    protected int itemMargin;
+    protected int listLength = 0;
+    protected Entry focused;
+
+    protected AbstractScrollList() {
+    }
+
+    protected void addEntry(Entry entry) {
+        this.children.add(entry);
+        this.listLength += entry.getTotalHeight();
+    }
+
+    public void clearEntries() {
+        this.listLength = 0;
+        this.children.clear();
+    }
+
+    protected void updateScrollingState(double mouseX, int button) {
+        this.scrolling = button == 0 && mouseX >= (double) this.getScrollbarPosition() && mouseX < (double) (this.getScrollbarPosition() + 6);
+    }
+
+    protected float getScrollAmount() {
+        return scrollAmount;
+    }
+
+    public void setScrollAmount(double d) {
+        this.scrollAmount = (float) Mth.clamp(d, 0.0, this.getMaxScroll());
+    }
+
+    protected int getItemCount() {
+        return this.children.size();
+    }
+
+    protected GuiEventListener getFocused() {
+        return focused;
+    }
+
+    protected void setFocused(Entry focussed) {
+        this.focused = focussed;
+    }
+
+    @Override
+    public boolean mouseClicked(MouseButtonEvent event, boolean bl) {
+        this.updateScrollingState(event.x(), event.button());
+        if (this.isMouseOver(event.x(), event.y())) {
+            Entry entry = this.getEntryAtPos(event.x(), event.y());
+            if (entry != null && entry.mouseClicked(event, bl)) {
+                setFocused(entry);
+                entry.setFocused(true);
+                return true;
+            }
+
+            return event.button() == 0;
+        }
+
+        return false;
+    }
+
+    @Override
+    public boolean mouseReleased(MouseButtonEvent event) {
+        if (this.isValidClickButton(event.button())) {
+            Entry entry = this.getEntryAtPos(event.x(), event.y());
+            if (entry != null) {
+                if (entry.mouseReleased(event)) {
+                    entry.setFocused(false);
+                    setFocused(null);
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public boolean mouseDragged(MouseButtonEvent event, double deltaX, double deltaY) {
+        if (event.button() != 0) {
+            return false;
+        }
+
+        if (this.getFocused() != null) {
+            return this.getFocused().mouseDragged(event, deltaX, deltaY);
+        }
+
+        if (!this.scrolling) {
+            return false;
+        }
+
+        double maxScroll = this.getMaxScroll();
+        if (event.y() < this.y) {
+            this.setScrollAmount(0.0);
+        } else if (event.y() > this.getBottom()) {
+            this.setScrollAmount(maxScroll);
+        } else if (maxScroll > 0.0) {
+            double barHeight = (double) this.height * this.height / this.getTotalLength();
+            double scrollFactor = Math.max(1.0, maxScroll / (this.height - barHeight));
+            this.setScrollAmount(this.getScrollAmount() + deltaY * scrollFactor);
+        }
+
+        return true;
+    }
+
+    public boolean mouseScrolled(double mouseX, double mouseY, double xScroll, double yScroll) {
+        this.setScrollAmount(this.getScrollAmount() - yScroll * (double) this.totalItemHeight / 2.0);
+        return true;
+    }
+
+    public int getMaxScroll() {
+        return Math.max(0, this.getTotalLength() - (this.height));
+    }
+
+    protected int getTotalLength() {
+        return this.listLength;
+    }
+
+    public int getBottom() {
+        return this.y + this.height;
+    }
+
+    @Nullable
+    protected Entry getEntryAtPos(double x, double y) {
+        int x0 = this.x;
+
+        if (x > this.getScrollbarPosition() || x < (double) x0)
+            return null;
+
+        for (var entry : this.children) {
+            VAbstractWidget widget = entry.widget;
+            if (widget != null && y >= widget.y && y <= widget.y + widget.height) {
+                return entry;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public void updateState(double mX, double mY) {
+        if (this.focused != null)
+            return;
+
+        super.updateState(mX, mY);
+    }
+
+    public void renderWidget(int mouseX, int mouseY) {
+        GuiRenderer.enableScissor(x, y, x + width, y + height);
+
+        this.renderList(mouseX, mouseY);
+        GuiRenderer.disableScissor();
+
+        // Scroll bar
+        int maxScroll = this.getMaxScroll();
+        if (maxScroll > 0) {
+            GlStateManager._enableBlend();
+
+            int height = this.getHeight();
+            int totalLength = this.getTotalLength();
+            int barHeight = (int) ((float) (height * height) / totalLength);
+            barHeight = Mth.clamp(barHeight, 32, height - 8);
+
+            int scrollAmount = (int) this.getScrollAmount();
+            int barY = scrollAmount * (height - barHeight) / maxScroll + this.getY();
+            barY = Math.max(barY, this.getY());
+
+            int scrollbarPosition = this.getScrollbarPosition();
+            int thickness = 3;
+
+            int backgroundColor = ColorUtil.ARGB.pack(0.8f, 0.8f, 0.8f, 0.2f);
+            GuiRenderer.fill(scrollbarPosition, this.getY(), scrollbarPosition + thickness, this.getY() + height, backgroundColor);
+
+            int barColor = ColorUtil.ARGB.pack(0.3f, 0.0f, 0.0f, 0.6f);
+            GuiRenderer.fill(scrollbarPosition, barY, scrollbarPosition + thickness, barY + barHeight, barColor);
+        }
+    }
+
+    protected int getScrollbarPosition() {
+        return this.x + this.width;
+    }
+
+    public VAbstractWidget getHoveredWidget(double mouseX, double mouseY) {
+        if (this.focused != null)
+            return focused.widget;
+
+        if (!this.isMouseOver(mouseX, mouseY))
+            return null;
+
+        for (Entry entry : this.children) {
+            var widget = entry.widget;
+
+            if (widget == null || !widget.isMouseOver(mouseX, mouseY))
+                continue;
+            return widget;
+        }
+        return null;
+    }
+
+    protected void renderList(int mouseX, int mouseY) {
+        int itemCount = this.getItemCount();
+
+        int rowTop = this.y - (int) this.getScrollAmount();
+        for (int j = 0; j < itemCount; ++j) {
+            Entry entry = this.getEntry(j);
+
+            if (rowTop + entry.getTotalHeight() >= this.y && rowTop <= (this.y + this.height)) {
+                boolean updateState = this.focused == null;
+                entry.render(rowTop, mouseX, mouseY, updateState, this.x);
+            }
+
+            rowTop += entry.getTotalHeight();
+        }
+    }
+
+    protected Entry getEntry(int j) {
+        return this.children.get(j);
+    }
+
+    protected boolean isValidClickButton(int i) {
+        return i == 0;
+    }
+
+    protected static class Entry implements GuiEventListener {
+        final VAbstractWidget widget;
+        final int margin;
+
+        protected Entry(VAbstractWidget widget, int margin) {
+            this.widget = widget;
+            this.margin = margin;
+        }
+
+        public void render(int y, int mouseX, int mouseY, boolean updateState, int listX) {
+            if (widget == null)
+                return;
+
+            widget.y = y;
+
+            if (updateState)
+                widget.updateState(mouseX, mouseY);
+
+            widget.render(mouseX, mouseY);
+        }
+
+        public int getTotalHeight() {
+            if (widget != null)
+                return widget.height + margin;
+            else
+                return margin;
+        }
+
+        @Override
+        public boolean mouseClicked(@NonNull MouseButtonEvent event, boolean bl) {
+            if (widget == null) return false;
+            return widget.mouseClicked(event, bl);
+        }
+
+        @Override
+        public boolean mouseReleased(@NonNull MouseButtonEvent event) {
+            if (widget == null) return false;
+            return widget.mouseReleased(event);
+        }
+
+        @Override
+        public boolean mouseDragged(@NonNull MouseButtonEvent event, double deltaX, double deltaY) {
+            if (widget == null) return false;
+            return widget.mouseDragged(event, deltaX, deltaY);
+        }
+
+        @Override
+        public boolean isFocused() {
+            return false;
+        }
+
+        @Override
+        public void setFocused(boolean bl) {
+            if (widget != null)
+                widget.setFocused(bl);
+        }
+    }
+}